IRONFIST

I've searched this site, as well as Google and Yahoo and there's lots of comparisons of Fast intakes to LS6 intakes, dyno runs, everything.
Except.. every comparison I see is a LS6 intake with a 78mm TB VS a Fast with a 90mm TB.
Now I do know that you can get LS6 manifolds modified to 90mm's and Fast does make a 78 mm intake. But has anyone ever compared Fast vs LS6 on an "apples to apples" basis?
Do any of you have results or know of results of one of the following:
Fast 78 VS LS6 intake manifold
OR
LS6 with 90mm TB VS Fast 90/92?

thunderstruck507

iTrader: (18)

Older articles and posts from experts such as Tony Mamo I remember seeing stated that the 78mm would get the majority of the gains as a 90mm over the ls6 (within a couple HP).

Don't know if you've ever handled a Fast intake in person but they are considerably larger for more volume and have the same runner designs regardless of intake opening size. Also consider a lot of the tests you will see might have a 90mm intake/tb but a stock MAF which will most likely be the bigger restriction on either TB setup.


If I were in a bet, my money would be on the Fast 78mm over a 85-90mm ls6 intake. Even more so on a cammed or heads/cam car.

Just my $.02, search the site using google and you should be able to find those old threads about the 78mm.

xX-Z28-Xx

iTrader: (4)

^^^this.

thunderstruck507

iTrader: (18)

https://ls1tech.com/forums/dynamomet...s6-intake.html

https://ls1tech.com/forums/generatio...ake-worth.html

https://ls1tech.com/forums/generatio...s6-intake.html


Also keep in mind the 78mm can be properly disassembled and ported for more gains, where the ls6 porting results I've seen on here have been fairly minimal.

IRONFIST

Awesome! Thanks..
Clearly I suck at searching, however, I figured it was a good thread to post.

thunderstruck507

iTrader: (18)

The search on here blows, but if you google it then click on "more results from ls1tech.com" you can get some great info.

And as you can see there are naysayers too, but I would trust the word of someone like Tony and people that actually tried them over the "ls6 or fast 90/92/101 there are no other intakes worth a damn. Oh and heat soak!" crowd.

SweetS10V8

iTrader: (4)

The throttle body size has a small influence on power, the design of the runners (length, taper, etc) are what make the most difference.

I tested a 102mm FAST with 102mm throttle body, then swapped a 75mm throttle body on the exact same intake. FAST makes an adaptor, and I saw a 5-7fwhp drop accross the board. So you might not even see the difference on a chassis dyno.

IRONFIST

I got a fast 78, and an 85mm Maf. I will post dyno results once it's all together. I was going to go with the 85tb. But it doesn't look like I'll need to.

Blk98Vert

iTrader: (2)

I would still go with the 85mm TB. The FAST 78 and 90 are the same intake, they just have different top shells. And the 90 gains over the 78. As far as your question about the LS6 goes the 90 mm tb will show gains on it, but by the time you spend the money to do it you could have had a FAST

IRONFIST

I'm just afraid of well it will seal up with an 85mm TB, particularly if I boost the car down the road.
Also, that means a new TB, and a new Lid... so the price of getting a 78 isn't economical anymore.