can't decide between fast 78 or 90 intake
06-18-2006, 07:18 PM
#1
TECH Resident
Thread Starter
iTrader: (40)
Join Date: Jul 2004
Location: marion nc 28752
Posts: 911
Likes: 0
Received 0 Likes
on
0 Posts
can't decide between fast 78 or 90 intake just a cam now but will add heads later with intake but i want to know which would be better or if i even need a 90 mm intake for a stock cubed motor , is it just going to be a couple of horses difference and wasted money or will it be worth it
and should i port both of them
and should i port both of them
Trending Topics
06-19-2006, 01:01 AM
#9
TECH Fanatic
iTrader: (18)
Join Date: Oct 2004
Location: Bay area, ca.
Posts: 1,205
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by NOS USER
Guys use the search & you will find some compare between many intake manifolds ...my suggest use ported 90 mm 
Thanks.
Thanks.
You can always sell the top shell and TB later and pick up the 90 stuff later if you're unhappy.
Now if you plan on going FI or something, maybe it's a different story. I'm going off what you posted up in the beginning of the thread.
06-19-2006, 05:18 AM
#10
I have been looking at the 78 as well, Tony will tell you they are under rated and for no reason. He always sees a gain with them over the LS6. I have a ported throttle body that I can keep with the 78, but not with the 90 which is another consideration. The 90 "may" soften your lower RPM response as well. For the cost of the upper shell, you can always upgrade later with a new throttle body if you want to.
06-19-2006, 12:18 PM
#11
FAST 78 out of the box with a bone stock 78 mm TB worth approx. 6-8 RWHP
A well shaped epoxied stock TB worth another 3-4 RWHP on that same intake.
An unported FAST 90 set-up worth an additional 3-4 over the PORTED 78 set-up.
Tack on another 5-10 RWHP for ported (correctly) 90 mm package for the ultimate results and of course the most greenbacks spent....no surprise there. What's interesting is the gains are very similar whether you are talking about a combination that puts down 375 RWHP or 475 RWHP, but as you start stepping up from there the ported FAST 90 set-up could show you even more....airflow is at a premium once your approaching 600 flywheel HP (over 500 to the tires) and the manifold starts to become a larger and larger restriction.
Tony M.
PS....To better more directly answer your original question, a 90 mm set-up will be worth an additional 3-4 ponies over the same set-up with a ported 78 mm TB. Considering the 90 mm aftermarket TB's have come down a little in price, I would tell you just to step up and go with the 90....if you already have a Shaner or another well executed 78 mm TB, you may deem the extra 3-4 HP a 90 mm set-up could provide not worth it from a HP per dollar scenario....although while $125 per pony isn't cheap, its not a ludicrous amount to spend once you have hit all the other details (much like an EWP.....$500 gets you 5 extra ponies). Not to mention you could sell your ported 78 TB which now cuts the HP per dollar in half and IMO now makes the decision to step into a 90 a no-brainer. To summarize...buy the 90
A well shaped epoxied stock TB worth another 3-4 RWHP on that same intake.
An unported FAST 90 set-up worth an additional 3-4 over the PORTED 78 set-up.
Tack on another 5-10 RWHP for ported (correctly) 90 mm package for the ultimate results and of course the most greenbacks spent....no surprise there. What's interesting is the gains are very similar whether you are talking about a combination that puts down 375 RWHP or 475 RWHP, but as you start stepping up from there the ported FAST 90 set-up could show you even more....airflow is at a premium once your approaching 600 flywheel HP (over 500 to the tires) and the manifold starts to become a larger and larger restriction.
Tony M.
PS....To better more directly answer your original question, a 90 mm set-up will be worth an additional 3-4 ponies over the same set-up with a ported 78 mm TB. Considering the 90 mm aftermarket TB's have come down a little in price, I would tell you just to step up and go with the 90....if you already have a Shaner or another well executed 78 mm TB, you may deem the extra 3-4 HP a 90 mm set-up could provide not worth it from a HP per dollar scenario....although while $125 per pony isn't cheap, its not a ludicrous amount to spend once you have hit all the other details (much like an EWP.....$500 gets you 5 extra ponies). Not to mention you could sell your ported 78 TB which now cuts the HP per dollar in half and IMO now makes the decision to step into a 90 a no-brainer. To summarize...buy the 90
Last edited by Tony Mamo @ AFR; 06-19-2006 at 12:31 PM.
06-20-2006, 07:19 AM
#16
Go with the 90/90, in case you decide to do heads/cam later. The minimal results you get now will be greatly enhanced with other airflow mods. Just don't buy the fast throttle body- they are a total piece of ****. The Williams tb I put on to replace the fast hasn't given any problems.
06-20-2006, 08:25 PM
#19
I got my Mamo ported FAST 90 today and it looks sweet. Looking up the runners is so smoothed that it looks like it is a one piece unit and the seams can only be distinguished by the different shades of plastics. Nice work Tony! I will start working on getting it on (along with the new cam and the NW 90TB) tomorrow afternoon.
