I have been reading a lot about this intake lately. Most of the threads say to just buy a FAST 90 but those are more rare than a unicorn now a days. I already have a LS6 intake and a LS2 TB can be had for a hundred bucks so we are talking 450 for the TPIS and throttle body. There is no way you can get a FAST 90 and then a throttle body for anywhere near that these days. So I was wondering if it was was worth it to have them do the 90mm snout to be able to accept the LS2 throttle body? It is an otherwise stock LS1 with headers. A 228R cam and 243 heads are on the shelf awaiting the funds and time to install as well. I was also told that I would get more bang for the buck to just have the LS6 ported and stick with the ported stock TB I already have. Money is almost identical for each service so I was hoping for the voice of experience as to either do the 90mm conversion, the LS6 porting, or just leave the LS6 stock cause the other two are snake oil.

 

There are definitely gains to be had with the 90mm snout and larger tb on an ls6 intake.

 

IMHO, since you are at stock 346ci and you will be driving this car on the street, stick with the LS6 and have it ported.
I know there is a better thread or article I have seen somewhere with dyno graphs of the intakes and throttle bodies, but here is one I found with a quick search:
http://www.gearchatter.com/viewtopic10974.php
I am no expert, but it would seem to me that unless you have enough displacement and/or RPM's, the larger throttle body is not going to help. Same goes for the intake manifold. I imagine it has to do with the velocity of the air. ie, bigger is not always better in this case.
Search around and I think you will find that this is an oft-discussed topic. Whatever you choose to do, best of luck with it.

 

I did search around. In 90% of all the threads it was "Buy a FAST" The rest were exactly what we have already seen here. One opinion was that it was a good idea. Another that it wasnt.

 

I have a PP 78mm TPiS tb and LS6 intake

TPiS also makes a PP 90mm tb and mates to a LS6 intake. Check that one out.

something about the LS2 90 tb that may not be a good option.

 

I'd say the ported LS6 is a unicorn, I have never seen one

your near Cocoa Beach/Orlando, have you talked to Geoff over at Next Level Performance in Altamonte, His number is 407-869-7223

 

I havent heard of next level performance. There are so many shops down here it is hard to keep track of all of them. I will definitely give them a look. I know that cccajundude (bareessentialracing) here ports them for 200.

 

I have to agree ---IF you have larger than stock cubes--- or----IF you "consistantly" run above 6200 RPM's you may benefit from larger T-bodies MAF's and intake manifolds--
Taking into consideraton the parts you have on the shelf--Your engine will be very similar to mine--mild cam ---Stock cleaned up 243 heads
I do have a 78mm Fast but the only reason is that I got it for $350--otherise I ran an LS6 intake before---( could NOT tell any difference) just looks "cool"--
Old sch knowlegde says larger TB's & intakes may make some minimal HP
gains down low but the TQ suffers--You may get some better HP gains--but only above 6200 RPM--A D/Dcat occasional drag racer would benefit more from better TQ than top end HP---So it's a trade off--But to me the clincher is the high cost of a Fast or TPIS or any ported manifold--$$ is best spend somewhere else--
I had Shaner do myT-Body--very happy with it--
I would--keeep your LS6 intake--clean up or port match it yourself---have Shaner do your STOCK T-Body---No need for anything larger-
Instead---get a set of LT headers--X-pipe--Underdrive pulley-- and of course a TUNE--
IF your car is an automatic---The best mod you can get period is a stall converter--something in the 2800-3200 range for your cam-Can make your car 3-5 tenths quicker in the 1/4 mi without even touching your engine--read my profile and see what my car does--amazing
what can be achieved with a stock cubed , A4, -- the ability to outrun or keep up with most new 505HP Z's

 

And now you have! Here is a unicorn, sitting on top of my engine...

 

That doesn't look like an LS6 manifold...(but I could be wrong)..

 

FWIW: The TPIS modded LS6 manifold with the 90mm TB will perform every close to the FAST 90 - and the LS2 TB works great with both the TPIS and the FAST intake.

 

Good advice, Bare Essential racing has already ported my throttle body so sending them my LS6 intake may not be a bad idea. MN6 tranny, already has a stage 2 monster clutch in preparation for the new heads and cam. Already has TSP long tubes, X, and TI exhaust. With my cam I have a new powerbond UDP ready to go on as well. Once I get back from the desert I;ll have the time to do the install work but 228 cam, 243 heads and UDP are going on. I was figuring that since the intake is coming off anyway, If I can squeeze out a few more horses relatively cheaply it might be worth it. I have read 10 or so more can be gained by porting the LS6 so for 200 dollars that seems worth it. Of course a good dyno tune is in order as well. Way too many tuning shops to begin thinking about that now. I have antivenom, efialchemy, hp sales, and I am sure a lot more within a few hours.