JPH

iTrader: (2)

i have noticed with my experience with the fast 78/90 vs ls1,ls6 intake are there is improvements all the way across the rpm range as well as peak. But the one big thing that i have noticed between the 78 vs 90, is that the 78 stuff is alot more responsive down low than the 90's.

Benjamin Russick

iTrader: (1)

Man. So much conflicting info... I tried doing a "search" and it was more of the same. I have a 383 and need more air, dammit!

Tony Mamo @ AFR

iTrader: (13)

If the confusion is regarding which set-up to get (a 78 or a 90 mm unit), dont lose any sleep there because the right decision is easy....a 90 just flat out works better. Or should I say a properly shaped 90 mm TB (NOT a stock LS2 for the Vette crowd) such as a unit from Nick Williams for an F-Body, will experience zero loss of power or responsiveness when compared to a 78 and make more power in the upper RPM range. If you want it all just step into the FAST 90/90 set-up and be done with it....Yes a FAST 78 is a good piece but a 90 mm version of the same is worth 5 or so more upstairs (and usually gives better throttle response with the right TB....a stock LS2 is the worst and needs major work to improve its response AND peak power numbers so if you think a 90 isn't responsive you may have had some dealings with that particular TB.

Tony M.

Benjamin Russick

iTrader: (1)

How does the rest of the curve look? Does the 78mm stay with the 90mm up until stratopheric revs? I'm mainly looking at 5900-6400rpms where my LS6 intake just can't keep up. A good ported 90/90 set-up is well over $1K and that is just crazy to me. Hopefully, more alternatives will materielize as this price is crazy. If I get 20-25rwhp over the LS6, it might be justified, but 12-15rwhp?

Tony Mamo @ AFR

iTrader: (13)

A 90 mm curve is essentially a "lay-over" of a 78 curve till 5000 or so then starts to show its stuff upstairs as you would expect.

A ported 90/90 set-up is usually worth about 25 over an LS6/stock TB....big money but sizable gains IMO. Its all a personal decision of how much you value that extra power. At roughly $75 per pony its actually not that bad all things considered....the porting while increasing the initial cost actually drops the $$ per HP figure...essentially makes it more of a cost effective mod if your willing to invest a little bit more.

Either way, ported or unported, the bottom line is most of the high power cars you see on this site and others run a FAST 90....its not a coincidence and its also not cheap....that's for sure.

Tony M.

SSippi

iTrader: (2)

I know I have come to the end of the road and I have asked my self certain questions do I want to buy this piece or that piece of Horse Power gains and either made the choice or not. So I think we have the information now that the 78 is better than the LS6 and the fast 90 is even better than the fast 78 and so the question is....do you want to take the red pill and follow the rabbit or not!

yobabiesdaddy2001

iTrader: (20)

definatly the 78 over the ls6 and 90 over the 78, Duhh!

BlueSix

What about a ported FAST 78? Would that show additional gains? Are the 78 and 90 similar in that they both need porting to show their full potential?

Benjamin Russick

iTrader: (1)

Who does FAST porting and do the heads need to be present for port matching? How much is usually charged for this service? If I got 25rwhp, the 90/90 wouldn't be so bad, but is that increase the exception or the rule. Thanks for everybody's help.

Patrick G

iTrader: (14)

Not all intake porters know what they're doing. Some will actually make the manifold worse than it was. The only two people that I've seen that put out work that consistently makes more power in ported form are Tony Mamo and Jeremy Formato. My Mamo ported FAST 90 gained me 28 rwhp over my LS6 intake with epoxy ported TB.

383ss

iTrader: (14)

years ago on my 383 I picked up 10rwhp going from an LS6 to fast 78 and then about another 5 going to the 90/90.

Tony Mamo @ AFR

iTrader: (13)

Those gains back up exactly what I wrote in my first post on this thread....pretty much to the letter and they represent what I have personally witnessed time and time again on the dyno.

Tony M.

OhIt'sBeenBraughten

Tony, how much do charge to port the Fast 90?

Tony Mamo @ AFR

iTrader: (13)

About $500....its a very thorough (time consuming) job. Much like ported cylinder heads, ported manifolds are not all alike (nor do they perform the same).

PM me for more information if you like...

Tony

Benjamin Russick

iTrader: (1)

If this is the norm, I will probably forgo the 90/90 with its extra $500 price tag. I'm probably going to buy a FAST 78 and clean it up a little. I'll be sure to post results...good or bad. I can't justify the extra money for a few more ponies all the way up in the rev range.

Justin00SS

iTrader: (5)

I'm a little late to the scene on this one but here goes.

How would a FAST 78 do on an otherwise stock cam/stock head f-car w/LS6? Ported 78? Money is not an issue. I'm curious as to the ported 78 over stock is.

I'm trying to maximize my bolt-ons potential because I can't afford the down time (not the price) of a cam at the time.

Also I plan stoker motor in the future (next summer hopefully) and it would be just another part I can reuse then. Besides all you need is the top shell of a 90 to upgrade to 90 later on right?

52172

iTrader: (2)

You won't gain nothin unless you through a cam in there. There would not be a reason to port the 78 or for that matter run one unless you through a cam in there. If you run a nice cam such as one of the vengenance street cams or a custon edc cam and you are running full exhaust like QTP headers or AMR or Kooks headers with offroad x pipe or high flow cats you might see a 10 rwhp gain with the ported fast 78 over the ls6.

Justin00SS

iTrader: (5)

Thats what I was thinking. The LS6 intake provides plenty of air for the tiny stock cam.