Lexus 4.0 engine swap ??

[JohnX]

The lexus/toyota 1UZ-FE engine spec's are 250hp @ 5600rpm & 260 ft/tq @ 4400 rpms.

The 4.0 jeep engine spec's are 177hp @ 4200rpm & 190ft/tq @ 4000rpm

Both of these engine spec's are for the 1990 year models.

...and as far as the engine being peaky...pffft...when you are talkin' about an extra 60 lb-ft at peak, you aren't gonna miss anything at off-roading rpms. i'm sure the numbers at least match the jeep at low revs...

I'd have to agree here. Even IF the 4.0 has a flatter curve, the V8's larger numbers would indicate that it has similar torque at lower rpms.

Heres a mock up with totally made up figures, but as you can see I gave the I6 a VERY flat curve and the V8 is "peaky".
RPM V8 I6
1000 140 140
2000 190 170
3000 225 180
4000 250 190
5000 250 170
6000 200 --

Even if I'm not accurate with the numbers, you can see that the V8 will always have more tq. than the I6. I see no way you would lose ground with the V8

BTW...Lets see some pics of the rig its going in.

I think the swap would be fun and "original" DO IT!

 

[dizzymac]

Is there something wrong with yours? My 90' 4.0 cruises up hills and very seldom downshifts. Mine is pretty much stock 4.0, AW-4, 242TC w/ 177k on the odom.

 

[PapaPump]

it DOES have 200k! it feels like it runs fine...i think the biggest problem was the 3.07s...i have 3.55s now, it's better but not great. maybe the hills are bigger here! it mostly feels fast actually, has a lot of pickup between 3000-4500. my year did have a torque peak at 3950...that's pretty high up there for a cam-in-block engine

 

[LilRedRover]

uh is it just me, isn't the aw4 an automatic ???

 

[Handlebars]

Looking at the 1990 LS400 new`car features, the torque curve for the 1UZ-FE is as follows:

1000rpm: 210
2000rpm: 230
3000rpm: 230
4000 rpm: 240
5000rpm: 255

Torque peak of 260 at 4400rpm. Call it peaky if you like but it still has more torque at 1000 rpm than the 4.0 I6 has at peak!

 

[1badxlxj]

Thanks Handlebars that is great info.
I fired up the lexus today and it is very snappy. Runs great. There's even a factory lexus cell phone in the center console. That might find it way in the ol XJ.
If i could post picks I would, There are some early pic's on the XJDB.com site. It is the only yellow xj on 44 TSL's

Hey 5-90 what type of spec's do you need? It is a twin over head cam. I have alldata pro to provide engine spec's

 

[1badxlxj]

This is what, the 1UZ-FE? I always liked the 3UZ-FE myself

4.3 L (4292 cc) version. Bore is 91 mm and stroke is 82.5 mm. Output is 290 to 300 hp at 5600 rpm with 325 ft·lbs of torque at 3400 rpm. It has an aluminum engine block and aluminum DOHC cylinder heads. It uses SEFI fuel injection, has 4 valves per cylinder with VVT-i.

Darn skippy that is a better engine and would love to have one. But the one i have was at the right price and i have the whole car to run over when the lexus engine is in the XJ.

 

[Chero-King]

This one?

 

[1badxlxj]

Okay here you go. This link will take you to a pic of my rig. http://www.extreme4wheelin.com/images/outlaw_2005/img_9024.htm

 

[1badxlxj]

This one?

WOW that was it's maiden voyage about 5 years ago. Grand lake Oklahoma

 

[JohnX]

Sweeet. Definitely go for the Lexus motor. If you decide it needs more oomph, you can always supercharge it later

 

[1badxlxj]

So if car engines (that have higher HP & TQ rpm's) are a bad idea than why do pro buggies run alot of these type engine's? alot of them are even supercharged. I think this swap will be great and can't wait to get it in.

The only problem with the electronic's so far that i have found is that the tranny ECM for the Lexus is incorporated into the engine ECM.
The jeep is a seperate computer. and can be wired as a stand alone system.

 

[JohnX]

So if car engines (that have higher HP & TQ rpm's) are a bad idea than why do pro buggies run alot of these type engine's? alot of them are even supercharged. I think this swap will be great and can't wait to get it in.

The only problem with the electronic's so far that i have found is that the tranny ECM for the Lexus is incorporated into the engine ECM.
The jeep is a seperate computer. and can be wired as a stand alone system.

Not sure if this was directed to me or not? But I am totally serious when I say you should do it. The supercharger idea wasn't a joke either.

 

[motorcityxj]

So if car engines (that have higher HP & TQ rpm's) are a bad idea than why do pro buggies run alot of these type engine's? alot of them are even supercharged. I think this swap will be great and can't wait to get it in.

The only problem with the electronic's so far that i have found is that the tranny ECM for the Lexus is incorporated into the engine ECM.
The jeep is a seperate computer. and can be wired as a stand alone system.

why not run the toyota/lexus version of the aw4 just to make it easier ?

I think they are professionally worked over once you get into pro levels of racing. They are bored stroked, racing cams, NOT street legal etc. Apples to oranges. They put tractor derived motors in either MG or triumphs doesnt mean it was a good idea :laugh3: or the best motor, sure it worked not that great though i would imagine it was a total dog. I think for a jeep or wheeler not daily driver a toyota I-6 from the lancruisers fj 80 series i think ... would be much superior to the v8 for most wheeling situations. Power should be fine though. Guys wheel with 2.5 4 bangers so you got plenty to spare.

 

[Root Moose]

The only problem with the electronic's so far that i have found is that the tranny ECM for the Lexus is incorporated into the engine ECM.
The jeep is a seperate computer. and can be wired as a stand alone system.

Was this engine ever used in a car with a manual transmission? Use that ECU.

 

[twisted_ed]

Can I ask, what is the deciding factor for this swap idea? if it because you want to, because you need more power? Why?

 

[lawsoncl]

1badxlxj[/b]]The only problem with the electronic's so far that i have found is that the tranny ECM for the Lexus is incorporated into the engine ECM.
The jeep is a seperate computer. and can be wired as a stand alone system.

The AW4 is almost completely standalone with it's own sensors on the tranny, but you will need to provide it a TPS signal. I say go for it!

 

[Kittrell]

Was this engine ever used in a car with a manual transmission? Use that ECU.

I doubt it, I know for sure the SC 400s never did, and I highly doubt the LS/GS 400 ever did. As far as I know, they all had 4 or 5 speed Autos.

 

[gradon]

I dunno if handlebars is referring to crank peak or rear wheel peak but Imma gonna call B.S. to the 1UZ-FE making more torque@1K than the 4.0 peak (maybe '90 stock) cause I know my '94 makes more than 260 ft/lbs @peak@crank on my '94 with exhaust mods, chip, '99.5 intake mani, FIPK, and 62mm TB. Yeah it'd be cool to get an aluminum v8 in there, but I'd rather stroke her out right and $#!+ on that v8 with my i6.

 

[1badxlxj]

Not sure if this was directed to me or not? But I am totally serious when I say you should do it. The supercharger idea wasn't a joke either.

Oh I am totally going to do this indeed. The supercharge idea is not a bad idea either. Since this is a toyota engine there are plenty of computer & other performance mods i look forward to messing with.

I want the HP and im doing it just because no one else has YET.
5 years ago when i built this rig with 44" TSL's and one ton axles everyone said it would never work or hold together because it's a unibody.
I did it anyway and it out flexes some of my freind tube buggies

So next week i will be pulling the engine out and getting it under way. Got to have it ready for next spring and summer