3400 intake on 3100

[96PontGaGT]

I have been looking at old posts someone had done the 00 mali 3100 on a 98 3100. I would like to know is what would be better, the 3400 or the 3100 intake, or if the 3400 would fit. I have a 97 gt with the 3100 it has cai and custom exhaust. also looking into the milzy pcm. Just after alittle more go.

[nice96gt]

It would be the same deal as this. This guys doesn't have his GA anymore but he did the 00+ 3100 top end swap on his '98 with minor complications...
http://www.gaownersclub.com/forum/showthread.php?s=&threadid=39366

It would look better than a 3400 plenum

[MantaGreen97]

Originally posted by 96PontGaGT
I have been looking at old posts someone had done the 00 mali 3100 on a 98 3100. I would like to know is what would be better, the 3400 or the 3100 intake, or if the 3400 would fit. I have a 97 gt with the 3100 it has cai and custom exhaust. also looking into the milzy pcm. Just after alittle more go.

The 3100 LG8 (2000+ 3100 engine) and the 3400 LA1 engines both have the same upper and lower intake as well as throttle body, IIRC. They are both higher flowing than the 3100 L82 intakes and the TB is slightly larger.

So if you're doing the the UIM/LIM/TB swap you can use either and it will be the same. However note that the LG8 UIM will obviously say "3100 SFI" on it whereas the LA1 UIM will say "3400 SFI" on top. Therefore, since your engine will still be a 3100 you might want to use the LG8 stuff but it's just cosmetics.

Note that one thing you won't get is the higher flow injectors and FPR of the LG8 and LA1. Well you might get them with those parts (or separately) but note you can't use the injectors/rail and FPR from those engines without having the PCM programmed for them specifically. (The tables in the PCM don't have enough range to accomodate the injectors and still run the engine properly.) But you can just re-use your L82 injectors/rail and FPR and the engine will run fine.

Also note that if you did reprogram your PCM for the LG8/LA1 injectors and FPR, you'd still probably have to upgrade the fuel pump as well because those cars also had to have a higher output fuel pump for the higher fuel pressure.

[96PontGaGT]

Thanx for your help i have that post saved. now its just getting the parts. Is there any noticeable gains? hope there is.

[wokeupscreamin]

I have an upper and lower 3400 intake manifold out of the pontiac van which is the pre 00 style that bolts right onto the 96-98 3100 with little or no problems. It doesn't have the 3400 logo on top, its smoothed and polished. Email me at pysher@gmail.com with an offer if interested.


I was going to do this swap until I came to my sences and realised the grand am is just a family car with no expectations of going "fast".