gnx7

iTrader: (28)

Who has tested if an LS2 intake and 90mm TB will make more power over an LS6 intake and ported stock 78mm TB with a turbo or supercharger?

What were the diffferences?

I want to spin my motor to 7K-7300 RPM with a CompTurbo CT81 1150hp rated T4 unit/1.15 A/R turbine housing triple BB. Engine is a 364ci with TFS 220cc heads with minor bowl work. I don't care if I make 1000rwhp... but want to know which makes more power under the curve and at peak.

I would appreciate any and all input. I have the LS6 intake/ported TB and wondering if it is worth the extra cost to go LS2/90mm setup. This will be finalizing my buildup of the motor.

Thanks!

trans2000am

iTrader: (49)

i heard the ls2 isnt that great for boost ls6 was lil better. 7300 is high hope everything i top notch on motor

gnx7

iTrader: (28)

I PM'd Kurt aka 427 and he said hands down the LS6 intake/ported stock TB setup. Bob @BruteSpeed confirmed. Bob did mention a FAST 90/92 setup would make more power.... but the thin plastic would be prone to popping/bursting.

Looks like I'm sticking with my LS6 setup.

99Z28LS1

iTrader: (4)

I skipped both and went vic jr with elbow... but if you already had the LS6, then there would have been no point in spendin the extra $$$ for a few horses. I on the other hand had the LS1 manifold. I too will be running the a ported 78mm with my set up. GL!

Big_Bird_WS6

iTrader: (7)

maybe bob and Kurt can step in hear and say how a 78 mm tb and LS6 can make more than a 90mm tb and LS2.

i have a LS2 ported. and a 92mm TB. so just want to know why that isnt better than a ls6?

C5kid

iTrader: (12)

LS2 is a three piece design and has all kinds of air gaps.

if you wash them out even alittle water pressure shows you all the gaps. The LS6 is a single casting and has no gaps.

I would think the turbulance from those gaps is more harmful than the smaller TB opening.

Big_Bird_WS6

iTrader: (7)

gaps? you mean it leaks? lol. expalin gaps.

TurboAv

iTrader: (6)

I didn't want to trust my Fast 90 with boost, so I went with a ported Super Victor. I hope it works out for me, lol. It makes sense if there is turbulance in the LS2 intake that it wouldn't make as much power. How much can you port the 78mm throttle body?

TurboS10

iTrader: (12)

Thanks,
You guys saved me some money on a Fast 90 or 102.
I'm more concerned with reliability on my 99% street build.
I've got an LS6 on my DD I'll swap for a truck intake I got for $100.
It's geared tall and needs the longer runner anyway.

C5kid

iTrader: (12)

no if you look inside the port of a LS2 intake you take notice of ridges and gaps. The intake is a three piece design and does not fit together well. There are places where you can see a 1/16'' in of space between the lower shell and the upper shell. They inert-lock some, but it still does not seal it up. Like I said, I have hosed out LS2 intakes and water comes pouring out in places you would not even expect on the inside.

Its sealed over all so there are no vacuum leaks, but the interals are another story.

ls1290

iTrader: (20)

I think C5Kid has something there. When I switched from a LS2 to a Vic Jr, it was a night and day difference.

Big_Bird_WS6

iTrader: (7)

Well ****. i bought it used and ported. do you think they might of fixed it. lol.

so has anyone tryed the Fibertuned intake that came out a few years back? i wonder how that would do.

https://ls1tech.com/forums/nitrous-o...manifolds.html

^^^ this thing

Quik

iTrader: (7)

the ls6 is a restriction in NA as rpms rise i can only imagine the restriction in boost. ive ran a ls2 with 90mm and had no issues, ran it as high as 20 psi and daily at 16. made good power with such a little motor. the ls2 intake with the cam i had, had no issues pulling 7500 rpms

i dont see a ls6 intake pulling that high

C5kid

iTrader: (12)

There is no way of fixing it. Unless you epoxy the SH*T out the inside and then sand it back down. I doubt that would even fix it.

So far the only intake that have seen that would be awesome for FI other than a LS6 is the LS3 & LS7. They both are back to the single casting design and are very smooth on the inside.

Big_Bird_WS6

iTrader: (7)

well ****. time for a willson. lol

gnx7

iTrader: (28)

I'm glad this topic was finally addressed. Saved many people lots of headaches.

427

iTrader: (3)

In the NA engines you may see something with the larger tb installed because as rpm increases the manifold will start to pull vac causing a reduction in flow. When you go from pulling the air in with na to forcing the air in with a power adder the tb is no longer a restriction as the air flows under boost fine with a stock tb. I only tested the truck manifold on the dyno with my engine for my Silverado with stock unported tb. That engine at 900hp had the exact same boost before the tb and in the manifold, showing that the tb was sized big enough or possibly to big (but not hurting anything). Making parts bigger that are not a flow restriction in the overall system will not gain power, although it won't make less either. The one thing that can hurt you is using the LS2 intake as the design does not seal as stated and that hurts port tuning from cross talk in the ports.

Kurt

Big_Bird_WS6

iTrader: (7)

****. well thanks for your in put Kurt.

so what is the next step? is a willson to big for a 377ci ( hoping for 1000 wheel horse power)?

TRMIN8R

iTrader: (42)

When I was at 815rwhp I broke an LS6 manifold where the map sensor plugs in to the back. That was on 22psi with a pt88. I just got the super vic with an elbow and 90mm tb, we'll see what happens with it.

98Z28CobraKiller

iTrader: (17)

Do a search for Fibertuned threads started by me. I did a very thorough review of that fibertuned. But the short answer is, no good for boost.


100% correct. At the last PRI show in Orlando, there was a guy with all the different stock plastic GM manifolds cut open. The problems are glaringly obvious when you see it this way.