^^^ like I said 78 can keep up with 92 in some cases... Never said 78 was better than 92... Like I said "it can keep up"... And about the TPIS we wer talking about port. Not the 90mm snout mod. And the 92 has better runner design. The snout isn't the big part. 92 is better than the 90 and it isn't because of 2mm difference. And you can open up the snout of a FAST78 to 90mm. I've seen it done. Or swap top shells.

 

"Keep up" is very subjective, the LS1 intake can keep up lol....


Bottom line is the FAST 78 is no better than the LS6 to justify buying one for the price tag. Like I said, if the FAST 92 is only good for 10-15hp over the LS6, the FAST 78 isnt going to yield much gain if anything over the LS6.

 

Again yes it is. Spend 30 minutes on a 78 with a dremel and you have a Fast 85. So you get the performance of a 90 for less money

 

I'm going to suck up to the wife and by a 92mm !!

 

Tony Mamo has posted results which contradict your thought process. IIRC his testing on the 78mm versus the 90mm was within 5hp.

The reason being the same as the reasoning of a 92 versus a 102...the gains are in improved runner design and overall intake volume more than the size of the TB opening.

Also, how much a car picks up with the intake depends on the other mods. 10-15rwhp is a good estimate for a bolt on car...a cam or head/cam car often sees more.

Another member here (Nitroused383) picked up 33rwhp with a ported 78mm (ported to 85mm) and an underdrive pulley . https://ls1tech.com/forums/ls1-domes...t-1275072.html

 

^^^ I glad sum ppl with knowledge jumped in. Thanks blk98vert, thunderstruck507... You guys actually KNOW what ur talkn about...

 

No problem. Its just a matter of researching and getting to know the right people

 

^^^ well I've done my research... That's why I wouldn't let this thread go lol... I talked to Mamo about this a while ago when I got my FAST78.

 

I have a VERY hard time believing that post...444RWHP?? From a 224 cam and just milled 243 heads?? ON AN LS1!! That so contradicts so many dyno post I have seen here.

I have seem post of cars here with full bolt ons, AI heads and a decent cam, AND FAST and they are at that level

It even contradicts your own post. A gain of 33 hp from a FAST 85, with unported heads...So I guess a set of ported heads....raise the flag

 

A F.A.S.T 90 would make more than 5 whp of a 78mm c'mon man. I know Tony, he's an awesome guy and knows his ****, but that was one test. However, the topic pf this thread is a 92mm F.A.S.T and is completely superior to the 90mm, lets not discuss the 78mm.

 

The numbers do not matter except before/after. Dynos are tools. I agree the numbers are high but that's not the point. The point was the gain.


How does it contradict my post? I said "often" not always. It is all about the combo. A cam like my old 230/224 reverse split that peaked at 6000rpm would see less gain than the same setup with a MS4 that gets revved to 7000rpm.

Also you missed the part where a portion of that gain was an underdrive pulley and surely some retuning.



You guys are way too focused on the size of the TB instead of the runner design which is where the real gains are. If it was just the 92mm snout, FAST would have real competition in the market...but they don't.

Think about it...if the TB size was the primary source of all these gains everyone would gain double digit power from a bigger MAF too. Someone can correct me if I'm wrong but I find it hard to believe an 85mm throttle body is a bigger intake restriction than a stock screened MAF.

Even with a 90mm intake/tb setup, ported heads, mid size cam, full 3" exhaust my car gained so little from the bigger MAF it wouldn't show at the track.

For reference, here is a picture which shows how much space the screen and airfoil take up in the flow path (picture is a 85mm maf but same principle applies):





The reason the 78mm is being discussed is because someone felt the need to post completely false information that the 78mm is "no better" than the ls6 and is a waste of money. This is a tech site and false information should be corrected. The 92mm is an all around better piece but that doesn't make the 78mm and 90mm "junk" either.

 

^^^ exactly what Thunder said!

 

^^^^ I'm glad somebody finally chimed in with some decent and correct info.
The majority of the gains most of us see from FAST intakes are from their runner design, not from the size of the TB.
In fact, being that you can get a Fast 78 for almost the same price as an LS6 and you need zero other modifications to make it work, it just might be the best bang for the buck intake out there.

 

^^^ why thanks you. Another with knowledge. I'd pick a 78 over LS6 anyday... Like I did... Port snout to 85-90 and BOOM! FAST90 for less. Same runners as 90. So same gains... Can't port out LS6 to 90. Even if you could runners are WAY smaller...