Which intake is better for performanceon 1st Gen 4.oL:plastic or aluminum?

[rocklaurence]

I know that the plastic (composit) is lighter and cooler but does it flow better? Does anyone have experience with both?:redexp:

 

[jimbo74]

there are no comercially made intakes for our vehicles.... i do know that rick is trying to work something out with Kurtz Kustoms (makers of the KKM) to get us one made out of heat resistant plastic

 

[HH1]

Custom Fabricated 3in stainless pics comming soon. I think it looks good. It sounds incredibly angry at WOT. He may fab a few more for the right $$.

 

[prozachappy]

ifab.net makes a custom crome 3" intake for the 91-94 X. price $133.99 complete with blue silicone couplings and hoses

 

[yob_yeknom]

For performance, heat resistant plastic would be much better. It would have to be really smooth on the inside too.

Flow wise, so long as they were both the same size, they'd be the same. If the plastic could help keep the engine heat from warming the air passing through the tube, it would be better because of that.

 

[rocklaurence]

No, No , Wait!
I'm talking about the intake manifold on top of the engine...The later 4.0's got a composite intake and manifold. Is the composit better than the metal? I dont think that the rated HP was any different (160) when they went to the new heads and plastic intake.?:redexp:

 

[Alec]

The plastic intake manifold stays cooler due to less heat transfer. However, they are less sturdy than the metal ones and can crack. Both manifolds can also have sealing issues and cause air leaks.

IMO just use whatever you find. The plastic one may yield a bit better power but nothing noticable, and the metal one is a bit stronger. Use whatever you find cheaper

 

[yob_yeknom]

OH!

The plastic intake manifold was used for 2 reasons. First, I'm sure it's much cheaper to manufacture. Second, it is a lot lighter. Again, flow wise it won't matter, but the weight loss will help slightly.

The problem with plastic manifolds though is that they are prone to cracking, or at least they used to be. Maybe they are made of better materials now though, because I never had any problems with either of mine and don't remember reading about any problems here.

 

[rocklaurence]

Thanks guys, I'm reconsidering the rebuild of an old motor and may purchase one from a wreck with low miles and put the camm in before installing it in the truck. The reason I asked about the manifold was because I may try to purchase a 98 or later--they seem to have less problems with PINGING with the updated heads and pistons than the 1st Gens..Right?:redexp:

 

[rocklaurence]

Alec, are you running a new camm? I'm having trouble tracking down everything I need from a source that knows the 4.0L.:redexp:

 

[Jason_25]

rock, you're better off getting a 95-97. The flywheel bolt pattern is different on the 98+ and the lean burn heads don't play nicely with the pre-98 computers.

 

[Alec]

I'm still running the stock cam and probably still will after the top end rebuild. An aftermarket cam would probably give me too much power (yes, there is such a thing), at least while it's still a DD and has the stock tranny.

Now when it isn't a DD anymore and I can put in a C4.......