Jeep and BMW

I have noticed a lot of you in here own jeeps, some of your names I even recognize from eyars of mostly lurking in the jeep groups. So I have a question. I have a '91 YJ four banger that is really tired... was thinking of doing the often discouraged conversion to the six cyl... and then I thought why not use a BMW I6? other than the obvious headache of marrying the two electrical systems and drive lines, it seems like the engine would fit the application well. Nice smooth, torquy straight six that would actually perform decent on the highway as well as off road at high RPM if needed...

now I know that there are gunna' be those that cry herresy... but what do you think about the application? Has anyone tried it... seems like I can't be the first to ponder it. Was thinking about a 3.5 (M60?). Thanks

Matt '91 318Is '91 YJ

Reply to
Matthew Warren
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Get yourself a Jeep 6 forget the BMW I6!!

Joe '89 YJ '02 325CI

Reply to
Joe C

Do this ;)

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-Branden

I also own a 99' BMW 528i and a 99' I6 Wrangler

Reply to
Branden Nelsen

Buy a 96-99 Land Rover Discovery, most of the parts are BMW branded and you will be amazed what it can do in comparison to the Jeep... Oh yeah, and its a V8

Reply to
Corey Shuman

I would tend to agree. Ought to be lots more of them around for an installed price that will pale in comparison to the misery you'll endure making this unholy alliance work. FWIW, the 4.0 in my Grand Cherokee puts out more power than the 3.5 in my 535is ...

-- C.R. Krieger '01 JGC '88 535is

Reply to
E28 Guy©

While I am quite fond of the Discovery, you will find next to no BMW parts in it. The 2003- Range Rover on the other hand............

Huw

Reply to
Huw

Thanks to all... I kind of figurd that is where I should come out, but thought I would seek a broader opinion. Thanks again.

Matt

Reply to
Matthew Warren

The BMW motor won't work well in your Jeep, ESPECIALLY if you are into offroading. The BMW motor makes its power and and torque well above idle, but the Jeep really needs its power to come on just off of idle. There isn't enough torque in the BMW motor to make offroading very rewarding. Now, if you wanted a Jeep that could do 130 mph, and kicked the power on at 3000+ RPM, then the BMW motor is just the thing.

I suggest you look at a V8 instead of a 6 anyway. The 8 and the 4 are the same length, the 6 is much longer. This means that stuff has to move fore or aft with the 6 that might remain where it is with the 4 to 8 conversion. And, the 8 makes torque at idle, if you get the right one.

Reply to
Jeff Strickland

I agree. The Jeep I6 is a tractor motor, making tons of torque at low rpm. That is what that type of vehicle demands. A BMW I6 *requires* revving. You would not be happy with that combination, even if you could even figure a way to marry the BMW engine to the Jeep drive train.

Reply to
Fred W

Nah. There is tons of room in the engine compartment of a Wrangler for an inline 6 and the 4.0 liter straight 6 makes plenty of power way down low. That, and you can buy a complete drive train (engine, transmission and transfer case) that was factory equipment and will drop right in.

Reply to
Fred W

Buick 455? anyway, the most favorable in my eyes is a diesel... but right now just exploring options. Thanks to all for the input.

Matt

Reply to
Matthew Warren

I think you should look again, heads are bmw remans, gauges, stepper motors, Airflow meter, stereo, amps, seat controls, seat motors, clock, locks, window regulators, the list goes on and on... pull the parts, take a look, there is a bmw stamp on each of them. also alot of the parts interchange, lots of E38 4.0 motor parts are the exact same. Keep in mind that BMW funded rover for a good part of the 90s before they gave it to ford. and while the 03-5 RaRo has the bmw motor, isnt that as far as it goes? suspension etc.. is still LR, right... at least until ford has them for a while longer... ;)

Reply to
Corey Shuman

Of course there's plenty of room. but, if one is converting from 4 to 6, why not convert to 8? The cost is essentially the same, but the reward is much higher. I've got a Jeep with the L6 motor, and I wouldn't change it for the world, but if I had a 4, I wouldn't hesitate to drop in an 8 instead of a 6.

Reply to
Jeff Strickland

A couple of reasons.

Most importantly, weight. While the cast iron 6 cyl is no featherweight, dropping a big V8 lump in there will certainly bias the weight even further towards the front and probably require some custom respringing.

Vibration. An I6 is smoother, especially at low rpm than any V8.

Ease of conversion. You just find a junker Jeep with the drivetrain you want and transfer the goods. Jeep does not fit V8's in and modern (fuel injected) models.

Gas mileage. Except the 4.0 Jeep I6 is a freekin gas hog already, so forget about that one.

In reality, while I owned an I6 Jeep Wrangler before, the 4 cylinder is actually the best engine, for a host of reasons. Yes, the vibration is a bit higher but, hey... we're talking Jeeps right? It weighs much less, has nearly the same power and torque and the fuel mileage is almost normal.

Reply to
Fred W

I can't agree that the 4 is the best... it has no where near the power of the 6, the fuel economy is about the same and they don't hold up. The six lasts for 200k pretty easily, where both of the 4 abngers I've had are getting noticibly tired at about 100k.

Matt

Reply to
Matthew Warren

I agree that the 4 is perhaps the best engine in a Jeep. The ONLY downside to the 4 is that it is a gutless wonder on the freeway, but it shines in nearly every kind of offroading environment, especially where brute strength takes a backseat to finesse and proper line.

Having said that, I still like the 8 over the 6 IF these are transplant options away from the 4. The weight of the 8 isn't significantly greater than the 6, and since it's shorter the weight is biased towards the center of the vehicle anyway.

Reply to
Jeff Strickland

Well, no. I was thinking more along the lines of a small block V8. The most popular candidate seems to be the Chevy 350, or the Ford 302. There is a guy in California that drops in 5.0L Mustang motors into Jeeps. He is a bit pricey, but if he can do it and you can do the swap of another engine, you can drop in the Mustang motor too.

One thing to keep in mind is that you will have to keep the smog system of whichever is the NEWER, the motor or the chassis. That is, if you find an old Z28 motor from a '69 Camaro, you will have to make it work with the smog equipment that you have on the Jeep -- which is probably the next best thing to impossible -- but if you get a motor from a late model Mustang, then you have to bring it's engine management computer along too.

I'm not very excited about the prospect of diesel fumes on the trail, but the low end torque is cool.

Reply to
Jeff Strickland

Personally I've always wanted to put a Chevy 4.3 v6 in a Wrangler (use an S-10 Trany and t-case (Chevy and Jeep use the same basic transfer cases). I think my 4.3 S-10 has better low end and off idle power than the 4.0 Jeeps I've had. But it doesn't have as much top end power as the 4.0 i6 and is definitely not a smooth or pleasant engine in any way.

Reply to
Todd Zuercher

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