The Aftermarket for the GM 3.8l is is abundant... It has been around since 1962, and was even used in 60's Jeep's.

It does not, however, share a single thing in common with the 3.8l Chrysler V6 desgined in the early 90's... Since this motor was most prominently featured in Mini vans and LH series car's, that no one raced, ever, part's are hardly abundant. There are no aftermarket cam's, intakes, head's, rod's, cranks. There are pistons, and that's it.

If you are claiming compatibility with the Gm 3.8... Then i need to see that to beleive it. If not, my apologies.

As to the question of cat's, they can be removed, and the computer easily fooled. However, the amount of air flowed by the stock motor (CAI's don't count, stock internally), isn't enough for the cat's to impede flow at all. Basically your just being a hillbilly and not helping things at all if you hack them off.

As for the engine needing "backpressure", it doesn't, that is a misnomer. What the engine needs is effective scavenging from the exhaust. Which aparently, it doesn't have. That is a exhaust manifold problem, which makes me think header's will be a very effective upgrade, if they are properly sized and merged...

 

And the reason for so many is this... The front two are placed as near to the manifold as possible, in order to remain hot and burn any left over fuel coming out of the exhaust port's, the rear two are actually pretty ineffectual, since they don't get hot enough to ignite fuel, but they are there to catch anything that get's past the first two.

 

there was a guy a while back that got banks headers forlike 600 bucks....they only suppossedly gave him like 4-5 hp...that sucks, and is not worth it, so why do you think headers are the answer...??

 

I don't think they are THE answer. However, I do think properly designed header's would help and allow the rest of the exhaust to be opened up. Like I said, the reason these engines are being so sensitive to a loss in "backpressure" is because the manifolds are not effectively scavenging the exhaust from the cylinder's. A properly designed header would do that, and allow the rest of the exhaust to be opened up without penalty.

However, it's all conjecture on my part. I haven't documented any gains or losses due to exhaust, nor do I intend to. It's a mini van motor, all i want it to do is run exactly the way it does, reliably and economically. Hence the reason for me personally purchasing a JK, rather than a CJ or YJ and building it.

I think some of the JK community would have been better served with an H3 or other SUV.

 

WOW.... Ok...

 

That's a nonsensical statement, at best.

By that logic, let's have a look at arguably the greatest motor of all time - the all-purpose Chevy 350. That motor probably powered half the planet's vehicles at one point or another - OK, maybe that's an exaggeration, but not by much.

So is the Chevy 350 a boat motor because it powers so many sport motorboats? Is that a Hummer motor because it powers Hummers? Maybe it's a motor for retiree's cars, because it powers so many Buicks. Then again, maybe it's a sportscar engine, because it was in so many Corvettes. You see where I am going with this.

A motor isn't anything, inherently, except a mechanical lung. How you gear it, flow it, time it, crank it - that's what specifies what it can do. The 3.8l is not a minivan motor. It is a motor that was put in a minivan. The motor's potential is what you make of it. You want pistons, cams, valving, boring and stroking? There are thousands of engine builders and fabricators around the country who will work with you to do anything you might ever want to do. Cheaper than you think, too.

The only reason some motors have all this type of thing available as prepackaged mods is that someone took the time to see what works, and worked with builders and fabricators to make the stuff. In short, the "minivan" tag is a cop-out - as a community, we should really start developing the hand we are dealt.

FWIW, the displacement of the motor is the biggest challenge I see with it - who knows yet how far we can bore and stroke. But there's plenty of untapped power in there that can be had - we just need to find it instead of bemoaning the fact that we don't have an ezmode 5-second solution.

 

You are choosing to look past the point. The point being that it is not a performance motor. It has no performance attributes, nothing about the design is good from a performance standpoint. To fix it's shortcoming's would take more money and effort than it would be worth. Yes you can stroke it, easily. You can port the head's, you can have a cam ground for it, you can strap a centri blower easily to it, with some fab work a root's. How much would all this cost, and what would the low speed characteristics of a 300 whp be like?

You can build 500 hp 4 cylinder's, but it's so much easier and cost effective to build a V8.

The JK has plenty of power for what I want to do with it, medium duty trails, and crawling, with some randome mud and sand thrown in. Those wanting to smoke the tires and race people purchased the wrong vehicle, period. Jeeps and fast have never been synonomous (unless you are talking about SRT models, and I won't comment on those).

 

i just figure, when the time comes, i will just throw a supercharger on it that would most likely be in 6 years or more, and im sure by then they will have other things out for it.

 

Nah, I dont think I am looking past the point, per se - I mean, you are right, this engine in stock form isn't tweaked from the factory like a Viper engine, sure. No "100 WHP per liter" going on here - haha. I guess I've just seen alot of motors over the years, even so-called performance motors, to be quite lacking from the factory - there wouldn't be an aftermarket if that weren't the case. And they have all needed some work to get the most power, in the right areas of the powerband. Whether I am coaxing 20 WHP out of a custom camshaft, or more torque low down, or whatever, it costs about the same, really. In fact, from this standpoint, I really LOVE inefficient engines, because the subsequent gains per dollar spent are larger and that greatly increase the fun factor But pistons are pistons, and all else being equal cost the same, whatever size you have them built - etc. etc. Nothing about this motor is really going to change that.

And that's my point - I don't think there are challenges unique to this motor that preclude us from doing what has been done to every other motor that has ever been. Be glad it's inefficient in stock form - it'll be that much better when it's built, and it won't really cost more than doing that type of thing to any other motor.

Of course, if you are referring to those who want big, factory HP (and want to pay big factory engine $$$'s), then yes, this vehicle was probably a pretty poor choice. Still, I'm willing to bet that 80+ WHP are readily available in this motor for under a couple of grand in fab costs, which isnt bad at all - more reliable and usable than a supercharger, too. I don't think that's more money than it's worth. Jeep didn't give us a demon of an engine, no, but we didn't pay that kind of money, either, so that's OK. There's plenty of people who own these that wouldnt own anything else anyway, so - I see this as a need to make the best out of what we have to work with. It can be done, and it will be done, of that I am sure - hell, maybe it'll even be me...depending on how the money fights with the wife turn out, of course

 

I'd really be interested to see a dyno number comparison regarding stock versus stock with no cats at all and then A/M muffler with no cats at all with a CAI.