engine swap

[bigredTJ]

I am planning on doing a 4.3 swap into my 97 TJ. I put a call into Painless to see about a harness to make things simpler but as it is the holidays their answering service said they wouldn't be back till the 3rd. I was wondering since this is a popular swap if anyone knows if they offer a kit for this or if I'll have to have something custom made? Also what difficulties am I looking at in this swap other than the wiring. I have the 2.5w/air now. I also have a set of D44 out of a 72 MJ that I am thinking about swapping over. As this is my first major build up I am not sure of all the smaller things that have to be done.


thanks for any help
Mike

[razorbackME]

I'd say you're wasting your time with the 4.3. Either swap in a 350, which would be basically the same amount of work, or get a 4.0L out of another jeep, since it would more or less be a direct swap.

[mango_g_a]

If your looking for just more power than a 2.5.... go 4.0L........ 4.3 doesn't have any more power than the 4.0L.......

[MBood82]

Stock for stock a 4.3 has a little more power. Aftermarket is probably about the same for the two motors though it seems the parts are cheaper for the 4.3.

One of the guys on here I thought was tossing a 4.3 into a YJ, you should look him up if you can.

[razorbackME]

Stock for stock a 4.3 has a little more power. Aftermarket is probably about the same for the two motors though it seems the parts are cheaper for the 4.3.

One of the guys on here I thought was tossing a 4.3 into a YJ, you should look him up if you can.

There's probably CONSIDERABLY more aftermarket for the 4.3, since it's basically a small block chevy.

My point in NOT using the 4.3 is that engine swaps are a ton of work to get right and get all of the bugs worked out. The 4.0L is basically a drop in deal. If you're going to swap in a 4.3, there's not much more effort in swapping in a 350 V8...you'll have to address most of the same issues on a 4.3 that you'd have to worry about with a 350. The dressed 350 is also probably about the same length as the dressed 4.0L.

[MBood82]

There's probably CONSIDERABLY more aftermarket for the 4.3, since it's basically a small block chevy.

My point in NOT using the 4.3 is that engine swaps are a ton of work to get right and get all of the bugs worked out. The 4.0L is basically a drop in deal. If you're going to swap in a 4.3, there's not much more effort in swapping in a 350 V8...you'll have to address most of the same issues on a 4.3 that you'd have to worry about with a 350. The dressed 350 is also probably about the same length as the dressed 4.0L.

Yeah, I wasn't arguing with that, just pointing out to the other guy that the 4.3 makes more power, unlike his statement. Then added a few other items.

[bigredTJ]

thanks for you help...the reason I was planning on going with the 4.3 is that I have run across a blazer that runs and drives with a 4.3/5spd for 300. I have yet to hear from Painless to see how much it is going to cost me for a wiring harness.

Another question...If I can get the adapter to mount my transmission (4cyl/5spd) to the 4.3 will it hold up to the aditional power or would it be better to just go ahead and do a trannsmission swap too?

thanks for your help
Michael

[MBood82]

do the tranny swap, pretty sure the four banger has the weaker tranny, the AX5.

[razorbackME]

thanks for you help...the reason I was planning on going with the 4.3 is that I have run across a blazer that runs and drives with a 4.3/5spd for 300. I have yet to hear from Painless to see how much it is going to cost me for a wiring harness.

Another question...If I can get the adapter to mount my transmission (4cyl/5spd) to the 4.3 will it hold up to the aditional power or would it be better to just go ahead and do a trannsmission swap too?

thanks for your help
Michael

I wouldn't worry about the painless harness. The factory harnesses on those vehicles really aren't that bad. It just looks that way because they run a shiitload of wires in the loom with the stuff that goes between the computer and the engine. But, it's just run in the same loom, not connected.

The wiring will be one of the easier parts of a swap like this.

[bigredTJ]

Ok thanks for all your help...


Michael

[HotSEXJ]

Yeah, I'd worry more about motor mounts and transmissions than wiring -

you could just yank the computer out of the blazer, and leave most of the wires hooked up to the engine, that'd simplify at least a few hours' work.

[mango_g_a]

Stock for stock a 4.3 has a little more power. Aftermarket is probably about the same for the two motors though it seems the parts are cheaper for the 4.3.

One of the guys on here I thought was tossing a 4.3 into a YJ, you should look him up if you can.

A little more power, as in 5HP....... if you can tell that difference by the seat of your pants..... You must have a dyno in there...... The 4.0L produces torque at a lower RPM, where the 4.3 produces everything @ a higher RPM. You pick which is better for wheeling...... As for Aftermarket for them..... IMO its about the same for the two.

[bigredTJ]

Well, I have a 4.0 out of a 95 cherokee with the aw4 but I really don't want to go with a auto transmission. That is one reason I wanted to go with the 4.3 plus the 4.0 doesn't have any of the wiring with it. I'll have to get a harness from painless to put this motor into my jeep since I don't have any of the wiring with this motor.

[nblehm]

There's probably CONSIDERABLY more aftermarket for the 4.3, since it's basically a small block chevy.

My point in NOT using the 4.3 is that engine swaps are a ton of work to get right and get all of the bugs worked out. The 4.0L is basically a drop in deal. If you're going to swap in a 4.3, there's not much more effort in swapping in a 350 V8...you'll have to address most of the same issues on a 4.3 that you'd have to worry about with a 350. The dressed 350 is also probably about the same length as the dressed 4.0L.


how is a 4.0l a direct swap? new motor mounts, maybe the same wiring, but then you need new computer. I wouldnt call it a drop in deal

[MBood82]

A little more power, as in 5HP....... if you can tell that difference by the seat of your pants..... You must have a dyno in there...... The 4.0L produces torque at a lower RPM, where the 4.3 produces everything @ a higher RPM. You pick which is better for wheeling...... As for Aftermarket for them..... IMO its about the same for the two.

The 25 ft-lb of torque also makes a difference too.

As for rpm range, the inline 6 has pretty decent torque down low but so did my Blazer.

[razorbackME]

how is a 4.0l a direct swap? new motor mounts, maybe the same wiring, but then you need new computer. I wouldnt call it a drop in deal

But at least there's no fab involved. You can pick up junkyard or factory parts and just bolt everything together. With the 4.3, you'll have to fab or source custom motor mounts, figure out what to do with the exhaust, get an adapter for the trans (or use a chevy trans and probably have to get driveshafts lengthened or shortened).....and that's just the big stuff. The little details (like fan shroud) will drive you NUTS.

The 4.0L is easy because TJs came with them.

[mango_g_a]

The 25 ft-lb of torque also makes a difference too.

As for rpm range, the inline 6 has pretty decent torque down low but so did my Blazer.

From all the 4.3L I have drove........ and thats about 7 that have went thru my family (Older bro had 2 Blazers, Younger bro had a 4.3L 5SP 4WD S-10 and now a ZR2, Dad has had 2 Astro Vans, and I have a Blazer), your not gaining anything from going to the 4.3L with all the work thats coming with getting it to mount up...... My $.02 :driving:

[mango_g_a]

The dressed 350 is also probably about the same length as the dressed 4.0L.

I think the 350 is prolly a little shorter......... I might have to go measure.......

[MBood82]

From all the 4.3L I have drove........ and thats about 7 that have went thru my family (Older bro had 2 Blazers, Younger bro had a 4.3L 5SP 4WD S-10 and now a ZR2, Dad has had 2 Astro Vans, and I have a Blazer), your not gaining anything from going to the 4.3L with all the work thats coming with getting it to mount up...... My $.02 :driving:

It really wouldn't be my first choice but since he's already got the access to the 4.3 and all that for pretty cheap, whereas the 4.0 would cost him more initially at least, it's certainly worth looking into.

[nblehm]

But at least there's no fab involved. You can pick up junkyard or factory parts and just bolt everything together. With the 4.3, you'll have to fab or source custom motor mounts, figure out what to do with the exhaust, get an adapter for the trans (or use a chevy trans and probably have to get driveshafts lengthened or shortened).....and that's just the big stuff. The little details (like fan shroud) will drive you NUTS.

The 4.0L is easy because TJs came with them.


yeah the 4.3 is more involved but the 4.0 still takes some work... still gotta weld mm on, put a new trans in...sure everything is cut and dry of what you need but it still takes some doin

[razorbackME]

From all the 4.3L I have drove........ and thats about 7 that have went thru my family (Older bro had 2 Blazers, Younger bro had a 4.3L 5SP 4WD S-10 and now a ZR2, Dad has had 2 Astro Vans, and I have a Blazer), your not gaining anything from going to the 4.3L with all the work thats coming with getting it to mount up...... My $.02 :driving:

well yeah, but a 4WD S-10 is actually pretty heavy. I know that a 4WD, 4 door s-10 blazer weighs in at like 4200 or 4300 pounds, and that's a few hundred pounds heavier than a grand cherokee, and considerably heavier than a TJ.

[razorbackME]

yeah the 4.3 is more involved but the 4.0 still takes some work... still gotta weld mm on, put a new trans in...sure everything is cut and dry of what you need but it still takes some doin

well, true, it'll take some work. But if you've never done an engine swap before, you have NO idea about how much work it takes to get an engine that was never factory installed into a vehicle and working properly.

The 4.3 will be 10 times the work the 4.0L.

[wrath]

A TBI 4.3L out of a 87-91 S10 makes more power than the 4.0L I6 EVER made. If you want to compare it to a MPFI 4.3L... haha, poor little 4.0L.

If it's a TBI 4.3L then don't worry about wiring. It's only a chore if it has MPFI.

If you're going to swap motor/transmission/transfer case then I'd go with the 4.3L. The weakest transmission they put behind a 4.3L is better than anything they put behind an affordable 4.0L (NV3500/3550 isn't included in "affordable"). The NP231 is also considerably stronger.

If you're not going to go with all Chevy then I'd consider the 4.0L. The 4.3L has a lot more potential than a 4.0L does, especially dollar for dollar. Two grand to get 300hp from a 4.0L or 400hp from a 4.3L.

[razorbackME]

A TBI 4.3L out of a 87-91 S10 makes more power than the 4.0L I6 EVER made. If you want to compare it to a MPFI 4.3L... haha, poor little 4.0L.

Really?

Current 4.0L: 190 hp, 235 ft-lbs

TBI 4.3: 150 hp, 230 ft-lbs

SFI 4.3: 190 hp, 250 ft-lbs

[wrath]

Really?

Current 4.0L: 190 hp, 235 ft-lbs

TBI 4.3: 150 hp, 230 ft-lbs

SFI 4.3: 190 hp, 250 ft-lbs

The TBI 4.3L was virtually the same in all vehicles... the HP ranged from 130hp to 200hp. Most of them ran the same computer with the same programming as the TBI 5.0L. They also ran the same injectors, always. The highest hp TBI 4.3L was 200hp/245ftlbs and I believe they were either in a car or minivan. I forget. I think it was an AWD Astro or something. Pretty much the limit of the 40lb/hr injectors.

The TBI 4.3L's with the balance shafts were oddballs. I don't know much about them. The CPI motors had these.

The CPI 4.3L was GM's most junk 4.3L ever made and even it made 200hp... and was gutless compared to the earlier TBI 4.3L.

The MPFI 4.3L V6 has made 195hp@4600 and 260ftlbs@2800 since it got multiport as far as I know. GM usually says it has 195hp@5200 though since that's where their automatic transmissions shift.

[razorbackME]

The TBI 4.3L was virtually the same in all vehicles... the HP ranged from 130hp to 200hp. Most of them ran the same computer with the same programming as the TBI 5.0L. They also ran the same injectors, always. The highest hp TBI 4.3L was 200hp/245ftlbs and I believe they were either in a car or minivan. I forget. I think it was an AWD Astro or something. Pretty much the limit of the 40lb/hr injectors.

The TBI 4.3L's with the balance shafts were oddballs. I don't know much about them. The CPI motors had these.

The CPI 4.3L was GM's most junk 4.3L ever made and even it made 200hp... and was gutless compared to the earlier TBI 4.3L.

The MPFI 4.3L V6 has made 195hp@4600 and 260ftlbs@2800 since it got multiport as far as I know. GM usually says it has 195hp@5200 though since that's where their automatic transmissions shift.

Well, that COMPLETELY contradicts the statement you made earlier.....it doesn't make significantly more power than the 4.0L.

The TBI is MUCH worse than the 4.0L, and differences of 5 or 10 hp/ft-lbs aren't really a huge deal between the 4.0L and MPFI 4.3s.

[wrath]

GM doesn't/didn't play the horsepower wars with the 4.3L... the fact that they rated it as 195hp at 4600 and 5200 should tell you that. They did the same thing with the TBI motor. I don't think the 4.0L makes much, if any, more power than rated.

I know my friend made 145hp@4000 210ftlbs@2800 on his 91 S10 before he put a blower on it. Yeah, he put a blower on a 4.3L V6. :bangtard:

I'll take the 4.3L just for the simple fact that half of it won't be lying on the ground before it gets to 6,000rpm.

I know the MPFI 4.3L is underrated because my friend thought it'd be funny to put on the dyno. It made 170some horsepower in a ragged out 200,000 mile 2001 C1500.

[mango_g_a]

The 4.3L is not underrated...... Its a kick@$$ motor....... My blazer has 166,000 miles on it and runs like a friggin top..... My dad's one in his old Astro van had almost 300,000 miles and it would still power brake (Dad had it when me, my older bro, and younger bro all turned 16, it went thru some major beatings). Dad towed farm wagons with it all the time. No one ever said that it was a bad motor. As trying to get it in a jeep, mounted and running, I'll stick with the 4.0L. Its got the same power, (and don't tell me it doesn't, I can keep adding to the list of 4.3L's I've driven & worked on) and its gonna be alot bigger pain to fab up mounts and this and that to get it up and running compared to the 4.0L. Now if your were to go for the coolness factor...... Mount the 4.3L :chug: :driving: :pimp: :rock: :)

Edit: But I'll always stick with the 4.0L..... for the Inline factor.........

[swish]

I like the 4.3 better from personal experience. Having 200hp and 260lbft was good for a V6 and I could power through a lot of deep **** for being barely lifted. (3" and 32's). I'll dig this up from the S10 site for how to make power out of it.

http://www.s10extremist.org/tech_articles/more_power.htm

[mango_g_a]

My bro has full Flowmaster exhaust, with a high flow cat, & a K&N FIPK....... and my Jeep produces the same power with a FIPK 62mm TB & TB spacer..............

[bigredTJ]

Thanks for the help guys...I am going to stick with a the 4.0L I believe. I have found another deal on a 97 TJ that was hit by a train that a guy is trying to get rid of around here. All the goodies are still good on the jeep, though. If I can turn some of the "goodies'' and make a little of my money back on the wrecked jeep I am just going to buy it and do the swap. I am looking to do a little work to the 4.0L before I install it in my Jeep. As I have never worked on a 6cyl jeep motor, what (realitivly cheap) mods can I do to stur up some of that hidden potential of the motor? Kind of want to stick with the stock short block unless it is just really cheap to do other wise...:D.


Thanks
Michael

[MBood82]

99+ intake manifold is good for a few ponies and changes the torque curve around. bigger throttle body is always a bonus. banks header if you have the cash.

[razorbackME]

I'll take the 4.3L just for the simple fact that half of it won't be lying on the ground before it gets to 6,000rpm.

If you're making power where you need it, then spinning to 6000 rpm isn't necessary. I don't understand people's fascination with rpm. Spinning to a high rpm figure is NOT a sign of a powerful engine.

I know the MPFI 4.3L is underrated because my friend thought it'd be funny to put on the dyno. It made 170some horsepower in a ragged out 200,000 mile 2001 C1500.

1. Don't bother comparing chassis dyno results with brake horsepower numbers. Those two numbers are measured in completely different ways, and there are many variables involved which can affect the outcome of a chassis dyno run.

2. Measuring one engine that makes more power than what the factory rated doesn't mean anything. There are variances. The factory is FORCED by SAE to dyno multiple engines and take an average. Ford got in trouble for this back in the early 90s about the hp figures on the 5.0L used in the Mustang.

[wrath]

If you're making power where you need it, then spinning to 6000 rpm isn't necessary. I don't understand people's fascination with rpm. Spinning to a high rpm figure is NOT a sign of a powerful engine.

It's called usable RPM range. A 4.0L has a pathetic usable RPM range no matter what you do to it. Stroke it and baby jesus cries. 4.2L is so bad that it reminds me of a 16hp Kohler one lunger. If you can make the same power at 6,000rpm as 4,000rpm with one motor and the other motor goes aenemic at 4,500rpm and falls apart at 5,500rpm... the foremost is the better motor. At say, 70:1 crawl, that extra 2,000rpm means you don't have to shift. I know with my abomination having a motor that didn't spin would've been useless. And the aenemic 7 cylinder 305 didn't like to spin.

If that motor doesn't make any power below 2500rpm then I'd agree it doesn't have a lot of value... but when it does, a 4500rpm window is better than a 2500rpm window (most motors don't make worthwhile power until 1500rpm).



1. Don't bother comparing chassis dyno results with brake horsepower numbers. Those two numbers are measured in completely different ways, and there are many variables involved which can affect the outcome of a chassis dyno run.

It's pretty reasonable to assume that a 2wd vehicle will lose 12% through the driveline with an automatic transmission. Around 9% with a manual transmission. This is assuming testing in direct drive... which some automatic transmissions don't have anymore. This has been tried and proven true over the last decade.


2. Measuring one engine that makes more power than what the factory rated doesn't mean anything. There are variances. The factory is FORCED by SAE to dyno multiple engines and take an average. Ford got in trouble for this back in the early 90s about the hp figures on the 5.0L used in the Mustang.

The factory is forced to publish a number not more than what has been tested using SAE's guidelines. GM regularly underrates their motors. The Z71 package in the 88-98 pickups added 20hp to the truck (which is why among GM folk people jokingly say that the Z71 sticker adds 20hp) yet had all the same parts... all the way down to the programming.

[mango_g_a]

It's called usable RPM range. A 4.0L has a pathetic usable RPM range no matter what you do to it. Stroke it and baby jesus cries. 4.2L is so bad that it reminds me of a 16hp Kohler one lunger. If you can make the same power at 6,000rpm as 4,000rpm with one motor and the other motor goes aenemic at 4,500rpm and falls apart at 5,500rpm... the foremost is the better motor. At say, 70:1 crawl, that extra 2,000rpm means you don't have to shift. I know with my abomination having a motor that didn't spin would've been useless. And the aenemic 7 cylinder 305 didn't like to spin.

If that motor doesn't make any power below 2500rpm then I'd agree it doesn't have a lot of value... but when it does, a 4500rpm window is better than a 2500rpm window (most motors don't make worthwhile power until 1500rpm).

Where are you getting you RPM # from????? Last time I looked...... 4.0L redlined @ 5,250 RPM's acording to the tach ( and the computer won't let it go any higher) & the 4.3L was redlining @ 5,500 RPM's......

And for useable power....... Check the dyno.......

2004 Jeep Wrangler X 4.0L on 33's with 5 Speed Manual (http://www.hypertech-inc.com/get_dynochart.php?cid=13&vid=1363441&tp=jpeg)

2003 Chevy Blazer 4.3L 4 Speed Auto Stock Gears and Tires (http://www.hypertech-inc.com/get_dynochart.php?cid=72&vid=1430986&tp=jpeg)

Looks like the 4.0L has a better power curve on both HP & Torque lines...... :dunno: maybe thats my 20/20 vision acting up?????

[wrath]

Where are you getting you RPM # from????? Last time I looked...... 4.0L redlined @ 5,250 RPM's acording to the tach ( and the computer won't let it go any higher) & the 4.3L was redlining @ 5,500 RPM's......

And for useable power....... Check the dyno.......

2004 Jeep Wrangler X 4.0L on 33's with 5 Speed Manual (http://www.hypertech-inc.com/get_dynochart.php?cid=13&vid=1363441&tp=jpeg)

2003 Chevy Blazer 4.3L 4 Speed Auto Stock Gears and Tires (http://www.hypertech-inc.com/get_dynochart.php?cid=72&vid=1430986&tp=jpeg)

Looks like the 4.0L has a better power curve on both HP & Torque lines...... :dunno: maybe thats my 20/20 vision acting up?????

I'll give you that the torque curve is better... but the horsepower curve isn't. Which has more parasitic losses? The slushbox or the 3550?

Unless I'm mistaken, that was the "best 4.0L ever made" not the one you're going to find in a 1996 Cherokee junkyard gem.

To be honest, the redline doesn't mean crap to me. All my SBCs redlined at 4500 but spun to 6k if stock or 6500 with new valvesprings.

[razorbackME]

It's pretty reasonable to assume that a 2wd vehicle will lose 12% through the driveline with an automatic transmission. Around 9% with a manual transmission. This is assuming testing in direct drive... which some automatic transmissions don't have anymore. This has been tried and proven true over the last decade.

That's a "fudge factor" used to make some valid comparison between engine dynos and chassis dynos. If you look at how much "loss" the chassis dyno shows, and realize that ALL of that loss has to be turned into heat, it's easy to see that there's really not that much loss in the system. Since chassis dynos are intertial and don't actually measure the torque output of the engine, there's a big discrepancy here. It's not an apples to apples comparison.


The factory is forced to publish a number not more than what has been tested using SAE's guidelines. GM regularly underrates their motors. The Z71 package in the 88-98 pickups added 20hp to the truck (which is why among GM folk people jokingly say that the Z71 sticker adds 20hp) yet had all the same parts... all the way down to the programming.

You're full of shiit. The factory has NO reason to underrate an engine. Lots of power is a selling point. The whole reason that the SAE net standard was instituted in the first place was because manufacturers were grossly OVERRATING their engines. The reason that hp figures dropped 20%overnight in 1972 wasn't due to any changes; it was due to the engines actually being rated for real world use.

And yes, the factory is forced to report no more than the power numbers they get from the SAE test method, but what else do you propose? There will be production tolerances. Most engines will be within a few percent of the SAE number, and some will be dogs, while others will be factory hot rods.

And the same engine, installed in a different vehicle, may very well be rated at a different power level than another installation, since the SAE test method requires that the engine be dressed with the production intake and exhaust systems as installed in the vehicle the engine is being tested for.

[razorbackME]

I'll give you that the torque curve is better... but the horsepower curve isn't. Which has more parasitic losses? The slushbox or the 3550?

There's really no such thing as a horsepower curve. HP is simply the torque as a function of rpm. A dyno does not measure horsepower, it measures torque (and a chassis dyno doesn't even do that). You give me any torque curve, and I can tell you what the HP curve looks like. I can calculate that just like a computer can.

To be honest, the redline doesn't mean crap to me. All my SBCs redlined at 4500 but spun to 6k if stock or 6500 with new valvesprings.

Who cares? It's not going to be making significant power at that point, so it's useless to turn the engine in that range.

[wrath]

That's a "fudge factor" used to make some valid comparison between engine dynos and chassis dynos. If you look at how much "loss" the chassis dyno shows, and realize that ALL of that loss has to be turned into heat, it's easy to see that there's really not that much loss in the system. Since chassis dynos are intertial and don't actually measure the torque output of the engine, there's a big discrepancy here. It's not an apples to apples comparison.

So... you're saying there are no losses in a transmission, transfer cases, and rear ends? Does windage loss not exist?

Have you ever actually seen an automatic transmission fluid cooler?

A horsepower is only 750 watts. 750 watts is nothing in the form of heat.

I know measuring a rolling load is different than with a brake load. But, there is a comparison. You just have a lot more losses... all the way down to squishing the sidewalls on the tire.




You're full of shiit. The factory has NO reason to underrate an engine. Lots of power is a selling point. The whole reason that the SAE net standard was instituted in the first place was because manufacturers were grossly OVERRATING their engines. The reason that hp figures dropped 20%overnight in 1972 wasn't due to any changes; it was due to the engines actually being rated for real world use.

There is no reason to underrate an engine... unless you want to say that every year you make more power but you don't. GM's crate LS1 made 330hp its entire life (prior to the f-body leaving, now it is rated at 350hp but has different parts in it) while the F-body was rated at 295-315hp. Same motor, same programming. If your cars make more and more power every year, why wouldn't that be a better selling point?

They did the same thing with the Vortec 350.

I know Chrysler did this up until the 90s.

The reason engines lost horsepower in 1972 when they switched from gross to net was because they standardized how it was to be measured. It was to be measured with all accessories on the motor with factory air cleaner and exhaust. No more zoomies, running the motor off the battery with no alternator/power steering pump, air horn, et cetera.


And yes, the factory is forced to report no more than the power numbers they get from the SAE test method, but what else do you propose? There will be production tolerances. Most engines will be within a few percent of the SAE number, and some will be dogs, while others will be factory hot rods.

Yes, production tolerances, why wouldn't a manufacturer play it safe?


And the same engine, installed in a different vehicle, may very well be rated at a different power level than another installation, since the SAE test method requires that the engine be dressed with the production intake and exhaust systems as installed in the vehicle the engine is being tested for.

I didn't know it had to be sitting in the vehicle.

[JayDee]

Razorback is correct, get used to it.

[wrath]

There's really no such thing as a horsepower curve. HP is simply the torque as a function of rpm. A dyno does not measure horsepower, it measures torque (and a chassis dyno doesn't even do that). You give me any torque curve, and I can tell you what the HP curve looks like. I can calculate that just like a computer can.



Who cares? It's not going to be making significant power at that point, so it's useless to turn the engine in that range.

Well, there is a "curve" but you can calculate it like the dyno does with the magic 5250. If you compare a "curve" from a Yamaha engine out of a Taurus and a small block chevy they look different. It's a lot easier to measure torque via an inertial load or brake than it is to convert actual work output (say, horsepower) into measurable heat or current. In the olden days they used to use giant synchronous motors.

But you're right, the nicer the torque curve the nicer the horsepower "curve".




Apparently you've never wheeled in a situation where you run out of motor at 4500rpm but if you shift you run out of power at 2800rpm (next gear). The wheelspeed gained by going another 1500rpm on the motor can be just enough whereas grabbing another gear might either spin the tires too fast or you don't have enough power at that lower engine speed to spin the tires.

If you've ever ridden a Yamaha Banshee you'd know they're pretty peaky whereas a Raptor is pretty flat. The Banshee is faster if you know how to ride it but the broad powerband of the Raptor keeps the average rider going faster than on a Banshee.

[razorbackME]

So... you're saying there are no losses in a transmission, transfer cases, and rear ends? Does windage loss not exist?

Have you ever actually seen an automatic transmission fluid cooler?

A horsepower is only 750 watts. 750 watts is nothing in the form of heat.

Yes, there are losses. But to say you're going to lose 10% of 500 hp is absurd. one hp may only be 746 watts, but when you have no active cooling on a manual transmission or a diff, having to get rid of 20 or 25 hp worth of heat is a HUGE deal. 20 hp is roughly 50,000 BTUs or 15kW. That's the size of the furnace in my house....my kerosene shop heater is 55,000 BTUs. An electric water heater is only 4.5kW. Can you imagine putting a 15kW heating element in a bucket full of a few quarts of gear oil? The stuff would be cooked in minutes. That's a TON of heat, and that's basically what you're saying is rejected in the manual transmission of a NASCAR stocker. Not gonna happen.



There is no reason to underrate an engine... unless you want to say that every year you make more power but you don't. GM's crate LS1 made 330hp its entire life (prior to the f-body leaving, now it is rated at 350hp but has different parts in it) while the F-body was rated at 295-315hp. Same motor, same programming. If your cars make more and more power every year, why wouldn't that be a better selling point?

The LS1 had minor cam changes throughout its run, and some of those numbers come from the SLP cars (Firehawk/SS) with an optional exhaust, and that accounts for the difference. Also keep in mind that since the engines have to be tested fully dressed, minor changes in the intake or exhaust systems, even if the engine is unchanged, have an effect.



The reason engines lost horsepower in 1972 when they switched from gross to net was because they standardized how it was to be measured. It was to be measured with all accessories on the motor with factory air cleaner and exhaust. No more zoomies, running the motor off the battery with no alternator/power steering pump, air horn, et cetera.



The engine doesn't have to be sitting in the vehicle (in fact it can't, since we're talking about an engine dyno here), but ALL of the accessories, intake, and exhaust systems have to be attached to the engine, just like it will be when it is installed in that vehicle.

[razorbackME]

Well, there is a "curve" but you can calculate it like the dyno does with the magic 5250. If you compare a "curve" from a Yamaha engine out of a Taurus and a small block chevy they look different. It's a lot easier to measure torque via an inertial load or brake than it is to convert actual work output (say, horsepower) into measurable heat or current. In the olden days they used to use giant synchronous motors.

But you're right, the nicer the torque curve the nicer the horsepower "curve".

Basically, you can't measure horsepower. It's a derived quantity, and really it's not worth all that much. Torque is all that matters.


Apparently you've never wheeled in a situation where you run out of motor at 4500rpm but if you shift you run out of power at 2800rpm (next gear). The wheelspeed gained by going another 1500rpm on the motor can be just enough whereas grabbing another gear might either spin the tires too fast or you don't have enough power at that lower engine speed to spin the tires.

I try to use more finesse when I wheel...not just romp the skinny pedal to get over an obstacle. Besides, if your engine doesn't make power at 4500 rpm OR 2800 rpm, you have bigger problems anyway.

[wrath]

Yes, there are losses. But to say you're going to lose 10% of 500 hp is absurd. one hp may only be 746 watts, but when you have no active cooling on a manual transmission or a diff, having to get rid of 20 or 25 hp worth of heat is a HUGE deal. 20 hp is roughly 50,000 BTUs or 15kW. That's the size of the furnace in my house....my kerosene shop heater is 55,000 BTUs. An electric water heater is only 4.5kW. Can you imagine putting a 15kW heating element in a bucket full of a few quarts of gear oil? The stuff would be cooked in minutes. That's a TON of heat, and that's basically what you're saying is rejected in the manual transmission of a NASCAR stocker. Not gonna happen.

A TH400 can easily steal 40hp from a 500hp motor. The losses in the non-lockup torque converter are astronomical. It's not like it's stealing this power all the time and turning it to heat. The more power something transmits the more it consumes. Direct drive is by far the most efficient in any transmission, especially a manual since the least amount of stuff is spinning.

NASCAR transmissions don't last very long. What is their top gear ratio?

Have you ever touched a rear differential after a few dyno pulls?





The LS1 had minor cam changes throughout its run, and some of those numbers come from the SLP cars (Firehawk/SS) with an optional exhaust, and that accounts for the difference. Also keep in mind that since the engines have to be tested fully dressed, minor changes in the intake or exhaust systems, even if the engine is unchanged, have an effect.

Yeah, the cam changed a few times throughout the run, especially if you include the Corvette which I tend to forget about. The WS6 TransAm made the highest numbers. The SLP cars (such as the WU6 you mentioned) don't really count though, it'd be like including a Roush Mustang, I think the 2002 Firehawk made 345hp or something.







The engine doesn't have to be sitting in the vehicle (in fact it can't, since we're talking about an engine dyno here), but ALL of the accessories, intake, and exhaust systems have to be attached to the engine, just like it will be when it is installed in that vehicle.

I thought you said it had to be sitting in the vehicle? And I already stated was SAE net was.

[wrath]

I try to use more finesse when I wheel...not just romp the skinny pedal to get over an obstacle. Besides, if your engine doesn't make power at 4500 rpm OR 2800 rpm, you have bigger problems anyway.

Well, someday when you exceed 31s on an XJ you'll find how nice it is to have a wide RPM range. Or maybe with a manual transmission.

Have you never watched any of Travis' videos? Do you think he always just romps the skinny pedal to get over stuff?

[razorbackME]

A TH400 can easily steal 40hp from a 500hp motor. The losses in the non-lockup torque converter are astronomical. It's not like it's stealing this power all the time and turning it to heat. The more power something transmits the more it consumes. Direct drive is by far the most efficient in any transmission, especially a manual since the least amount of stuff is spinning.

Until you put an engine + a TH400 on a brake, we'll never know, now will we? And I wouldn't say the losses are astronomical on a nonlocking TC.

Have you ever touched a rear differential after a few dyno pulls?

Don't get me wrong, there's heat there, and the hypoid gearset is less efficient than the helical gears found in a trans, but you're NOT rejecting 30,000 BTUs or something like that, which is what the numbers suggest.

The SLP cars (such as the WU6 you mentioned) don't really count though, it'd be like including a Roush Mustang, I think the 2002 Firehawk made 345hp or something.

SLP is different than Roush....SLP was basically just tacking on some body parts, and that was it. The exhaust was about the only thing that was really different than the regular trans am and Z28, and that was an option. Otherwise, SLP was just changing wheels and making a few other cosmetic changes. Roush will actually mod the engines. None of that going on at SLP.


I thought you said it had to be sitting in the vehicle? And I already stated was SAE net was.

No, not sitting in the vehicle, but the engine has to be configured just as if it were, to get an accurate number that actually is available at the crank.

[razorbackME]

Well, someday when you exceed 31s on an XJ you'll find how nice it is to have a wide RPM range. Or maybe with a manual transmission.

Have you never watched any of Travis' videos? Do you think he always just romps the skinny pedal to get over stuff?

:rolleyes:

I think my 5.2 has plenty of power and rpm for wheeling.

Here's an idea: if you have to bounce the thing of the rev limiter every time you wheel, then perhaps you need taller gears.

[mango_g_a]

Unless I'm mistaken, that was the "best 4.0L ever made" not the one you're going to find in a 1996 Cherokee junkyard gem.


Yea, and the 4.3L/5 Speed he found for $300..... I'm sure it is just golden.........

[NickDCJ7]

hey Wrath, aren't you the one that told me I'm wasting my time upgrading from a 4.2 to a 454? You sir, are an idiot, and you have no place even opening your mouth if you can't even comprehend that HPx2 and TQx2 over the same rpm band is indeed an upgrade. And if you really need that extra 1500rpm to get over an obstacle, maybe you're doing something wrong, or maybe you need to re-gear or get an engine that runs on all 8. :o oh, and STFU already, you're just wrong. :p

[JayDee]

Well, this isn't the first time Wrath's mouth has emminated erroneous caca.

[wrath]

:rolleyes:

I think my 5.2 has plenty of power and rpm for wheeling.

Here's an idea: if you have to bounce the thing of the rev limiter every time you wheel, then perhaps you need taller gears.


220 earth shattering hp? That's like 10hp more than a TBI350 from 1987. Then again, if you're driving a unibody pile of crap with minivan tires and open differentials you can probably get them spinning in third gear high range.

The only thing I have that has a rev limiter outside of the valves is the 99.

If you look at the speed vs RPM range for 60:1 with 40" tires a 4.0L would die a horrible death at like 7mph. Granted, 1500rpm doesn't get you much but it probably gets you enough.

Yea, and the 4.3L/5 Speed he found for $300..... I'm sure it is just golden.........

You can usually buy a whole S10 for that. As long as the motor runs and has oil pressure chances are it's in good shape, it's fuel injected remember.

hey Wrath, aren't you the one that told me I'm wasting my time upgrading from a 4.2 to a 454? You sir, are an idiot, and you have no place even opening your mouth if you can't even comprehend that HPx2 and TQx2 over the same rpm band is indeed an upgrade. And if you really need that extra 1500rpm to get over an obstacle, maybe you're doing something wrong, or maybe you need to re-gear or get an engine that runs on all 8. :o oh, and STFU already, you're just wrong. :p

4.2L => TBI 7.4L = adding a couple hundred pounds to the wrong end of a light vehicle not intended to have twice the torque applied to the motormounts... with 35" tires... yeah, you're cool.

"1500rpm over an obstacle"... I think this is the 13th time I've read that, got anything original? since-u-so-h4rdc0r3, why don't you ask some people that actually wheel how often they use 6k?

My 305 has long since been retired, why don't you retire "runs on all 8"? I wouldn't be knocking someone else's junk when you spent 30 grand on a polished turd.

[JayDee]

Give it up. You can't dig yourself out now.

[wrath]

Give it up. You can't dig yourself out now.

Don't you have some penis to go chew on?

This newsgroup is my entertainment. Quit trying to ruin it.

[mango_g_a]

You can usually buy a whole S10 for that. As long as the motor runs and has oil pressure chances are it's in good shape, it's fuel injected remember.

A whole S-10...... Like my '88 I got for $400....... Yea, its a good little truck.... but I would rather have a '96 XJ "gem", I would cut the top off and make it into a truck...... And If I'm not mistaken, a '96 XJ would be FI????? :screwy:

[wrath]

A whole S-10...... Like my '88 I got for $400....... Yea, its a good little truck.... but I would rather have a '96 XJ "gem", I would cut the top off and make it into a truck...... And If I'm not mistaken, a '96 XJ would be FI????? :screwy:

I have gotten S10s that run for free. It's a good source for a roller 4.3L... if only I knew then what I know now... I never would've junked so many of them.

A 96XJ would have multitudes more problems for $400 than the S10. And nobody that plans on running big tires wheels an XJ. Nobody. Lots of people run big tires on a S10.

You completely missed my comment about fuel injection. A fuel injected motor tends to fair better for wear than a carbureted motor. No cylinder washing... if there is something wrong with it the computer puts up the nifty light... has some protections from stupidity... they tend to endure life a wee bit better. A carbureted era vehicle that is still alive today has probably been severely molested... most fuel injection vehicles are just somebody's appliance to get them from point A to point B. Get it?

[Krazy]

Why don't you leave? Nobody likes you.

[mango_g_a]

I have gotten S10s that run for free. It's a good source for a roller 4.3L... if only I knew then what I know now... I never would've junked so many of them.

A 96XJ would have multitudes more problems for $400 than the S10. And nobody that plans on running big tires wheels an XJ. Nobody. Lots of people run big tires on a S10.

You completely missed my comment about fuel injection. A fuel injected motor tends to fair better for wear than a carbureted motor. No cylinder washing... if there is something wrong with it the computer puts up the nifty light... has some protections from stupidity... they tend to endure life a wee bit better. A carbureted era vehicle that is still alive today has probably been severely molested... most fuel injection vehicles are just somebody's appliance to get them from point A to point B. Get it?

How did I miss you point on FI????? I just pointed out the fact that the XJ would be FI also..... Don't get me wrong, like I said in a post earlier..... the 4.3L is a great motor..... But at least the 4.0L wasn't built differently at 2 different plants (as far as I know)...... you wanna know about the 4.3L..... Here Ya Go (http://www.s10forum.com/forum/showthread.php?t=131868)

You've never seen a XJ with big tire that wheels???? Well may I say.....
Welcome to :jeepin:

[mudpuppy]

Ahh....just find an entire GMC Typhoon drivetrain and put some gears in it...fastest production SUV ever until the BMW X5 I think.

[mango_g_a]

Ahh....just find an entire GMC Typhoon drivetrain and put some gears in it...fastest production SUV ever until the BMW X5 I think.

Yea, but you would be paying big money to get one of those......

[razorbackME]

Ahh....just find an entire GMC Typhoon drivetrain and put some gears in it...fastest production SUV ever until the BMW X5 I think.

And that would be a piss poor drivetrain for a jeep. We can start with the transfer case that lacks a low range, and then move on to the fact that the drivetrain would probably cost more than his TJ is worth.

[mudpuppy]

yeah well...it'd still be sweet...

[mango_g_a]

yeah well...it'd still be sweet...

no one said it wouldn't be sweet (if set up right), just not very logical......