Are gen3 intakes much better then gen2?

[JH]

I have a 91 3.1L mpfi and so i quess that would be a gen2 i am wondering if the gen 3 intake is much better then the gen2. If so does anyone know how much better they are.

[geoffinbc]

Oh hell yes they are much better. Better runners bigger ports and a larger throttle body.

[JH]

So it should increase HP by a bit?

[geoffinbc]

Yes by quite a bit. Works best with a cam uprade though

[JH]

So which intake would be better the 3100 or the 3400?

[bszopi]

Depends on the year of the 3100... 00+ 3100s are the same as 3400s, which are better than the 93-99 3100s.

[JH]

So if i were to take the intake off a 95 3100 it should bolt right up to my 91 3.1L engine?. And are there any sensors that i would need to change?

[dbtk2]

Well, the intake itself wouldn't bolt right up...you have to get the heads too. Then it would bolt right up. You would have to custom modify some things, and extend a few sensors so they reach to the new location, but its pretty much a simple swap. There is a guide on this site that tells you everything you need.

Shawn

[JH]

Damn i was hoping that i wouldn't have to change the heads.

[XLR8ING]

I tried to do the intake swap years ago without doing the heads. I almost made it too, but what eventually stumped me was the different thicknesses between the gen 2 and gen 3 intake gaskets.

[Slowpoke]

What if you have a 98 gen 3, would the intake of a 3400 bolt right on without any headache?

[dbtk2]

Damn i was hoping that i wouldn't have to change the heads.

Why's that? Its only 8 bolts per head, then the exhaust manifolds have to come off and be changed to 3100 manifolds. Although, the head bolts and head gaskets do cost a lot. However, the heads flow like 30% better than the 3.1 heads, so it would give you a much larger power increase than just the intakes (if it were possible to just swap intakes). Not only that but you could do some port work on them too. And, it allows you to slightly raise compression if you wish too, because you can run the iron head gasket to gain about a half a point compression. (bringing you from your 8.9:1 to 9.4:1) But seriously, if you do a mild cam (like on of the 260 cams for instance) and 3100 topend you will gain like 30+hp. So its a lot of work, but its worth it in the end, because it REALLY wakes up your 3.1. Yeah, I'm running boost, but before the swap I was trapping 94.5mph, now I trapping about 5mph more (although I haven't verified this at the track, just with the g-tech), and I gained about 7 tenths. I can imagine you would see similar gains though since my boost level didn't go up.

Shawn

[Jon89LE]

I tried to do the intake swap years ago without doing the heads. I almost made it too, but what eventually stumped me was the different thicknesses between the gen 2 and gen 3 intake gaskets.

Was that the only problem? Did everything else line up? Let me know because I already have fully ported heads with valve job on them. I have gen2 heads.

[XLR8ING]

The thickness is the main problem, but the ports are shaped differently. Gen 3 are short and fat ports, where Gen 2 are tall and skinny ports. If you got some aluminum tig welded on the Gen 3 intake manifold ports and blended it together, it might be able to work.