Throttle body size question

[Alwhite00]

I have a LQ4 in my 67 Chevelle. LS6 cam, LS2 intake, ported 853 heads, short headers and full magnaflow exhaust. I'm running the stock truck 3 bolt throttle body using a 3 to 4 bolt adapter on the LS2 intake. (I realize this isn't the greatest intake) car runs great, good power and great mpg.

. Is there ANY benefit to going with a 90 or 92mm 4 bolt throttle body? It seems like there would be but not sure so I figured I'd ask.

[68Formula]

Short answer.... absolutely.

[Alwhite00]

Short answer.... absolutely.

Ok. Is it worth the money to do the swap? They aren't that much $$ I guess I'm looking for a cheap upgrade.

[68Formula]

The LS2 was not a great manifold, but it had one thing going for it... the larger throttle body. It's really the only reason it outperforms the LS6 on the top end (literally an LS6 with modified inlet flange to fit a 90mm by TPIS outperforms the LS2... the throttle body size is limit). Add in the additional cubes and ported heads, it should be noticeable. It's not going to be huge, but bang for buck I''m sure is there.

[Alwhite00]

It's on the way. I'll try to report back with my findings.

[68Formula]

Come to think of it, the 320hp 5.3L in my truck came stock with a 87mm throttle body.

[protour_chevelle]

The LS2 was not a great manifold, but it had one thing going for it... the larger throttle body. It's really the only reason it outperforms the LS6 on the top end (literally an LS6 with modified inlet flange to fit a 90mm by TPIS outperforms the LS2... the throttle body size is limit). Add in the additional cubes and ported heads, it should be noticeable. It's not going to be huge, but bang for buck I''m sure is there.

The ls2 intake was not a great manifold? For what? An all motor build, max effort build maybe.

2 recent combos we did with them... 5.3, 88mm single turbo. 8800rpm. car made well over 1300rwhp. 6.0 single 76mm, 8000rpm, 750rwhp(turbo limited). You get fantastic packaging, great NA manners, revs to whatever you want it to and makes great power up top. To paint a broad picture of an intake is silly. Theres a reason why the ls2 intake value has gone up.

Back to the question, a 90/92mm will gain some. Its dependent on the rest of the combo, cam, long tube headers, air intake tube, compression, etc. Just dont buy a cheap throttle body or its gonna have god awful hissing noise from the garbage IAC port.

[68Formula]

The ls2 intake was not a great manifold? For what? An all motor build, max effort build maybe.


What I meant by that was in comparison to the LS6 intake. The runners were fairly similar, and the LS2 had a slight increase in plenum volume. However in manufacturing they switched from their lost-core mold process to a multi-piece sonic-welded process. The welding process had a propensity to allow a small amount of internal leaking that affected overall flow in a NA application like the OPs. Having positive pressure at the inlet (boost) would probably mitigate the effects.