FAST 90 or 102 on a 408?
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Joined: Feb 2002
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From: Silver Spring, Md.
FAST 90 or 102 on a 408? I've done a search but can't seem to find much info...surprisingly. Has anyone any first-hand knowledge about what gains there are to be seen when switching from a non-ported FAST 90 to a FAST 102 on a larger than stock ci engine? My motor is seeing 96 kpa at wot with the 90mm intake/throttle body. The intake seems to be a restriction. How much am I losing?
About 10 RWHP difference stock vs stock. You could get close to that by porting your intake. Going to a 102 will require new fuel rails so you will have to figure that into the price for the swap. Is all of that money worth the 10 hp? That's the big question.
Are you sure the restriction is the intake/tb and not the tubing/MAF? Not an apples/oranges comparison but I was seeing a 2-3 kpa change on my 408 by removing the filter on the dyno with my Vic jr., FAST 90 and 4" cai in sd trim.
Thread Starter
11 Second Club
Joined: Feb 2002
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From: Silver Spring, Md.
The cost of the 102 over the 90 isn't worth it for only a few hp.
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I too pulled 96 at WOT, right at 4300rpm.
Took the stock MAF out and replaced it with (2) 4" couplers and a 4" tube. SLP Lid is a 4" OD, and picked up 9/5 respectively. Closed Loop SD tune.
WOT stayed at 100 after that. This was with an unported Fast 92 and NW 92 TB. Perfect seamless transition from lid to TB.
Just the MAF being in the intake tract cost me 9hp and 5ftlbs.
Took the stock MAF out and replaced it with (2) 4" couplers and a 4" tube. SLP Lid is a 4" OD, and picked up 9/5 respectively. Closed Loop SD tune.
WOT stayed at 100 after that. This was with an unported Fast 92 and NW 92 TB. Perfect seamless transition from lid to TB.
Just the MAF being in the intake tract cost me 9hp and 5ftlbs.
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Thread Starter
11 Second Club
Joined: Feb 2002
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From: Silver Spring, Md.
Well I guess I'm bringing this thread back from the dead. I installed the FAST 102 intake but I'm still running the non-ported 90mm throttle body. The car picked up no power and ran no faster at the track. While having it dynoed last week, I decided to remove everything from the MAF forward. The car picked up 23 rwhp!!! I'm only sorry that I didn't just remove everything from the the throttle body forward. My question is...what options do I have as far as improving the breathing ability of this motor? The car is obviously starving for air if it picked up that much. Is it possible that MAF is still a restriction? I'm running an SLP lid along with the original ribbed hose in between that and the MAF. The car does have SD tune.
Air can only flow as much as the tightest restriction will allow. Your 102 intake has more volume and a larger throat, but it can only flow what the MAF and throttle will allow.
Your restriction points in order of priority with suggested part:
1. SLP lid, the exit throat chokes down to factory size coupler. Look into a 102 or 104mm lid with matching 4" couplers and hoses. Be sure to use couplers and hose that won't collapse under full load.
2. 90mm throttle body. Look into one of the many 102 or 104mm throttle bodies, don't bother porting.
3. MAF. If you are running SD tune, yank this thing completely. If you are using MAF tune, look into a matching 102-104 high flow MAF.
Questions that can change variables, what is your redline? What size headers do you run? Do you spray? Feel free to PM me if you don't want to post publicly, I got a pissed off 408 too (Greg Good heads on HKE motor).
Your restriction points in order of priority with suggested part:
1. SLP lid, the exit throat chokes down to factory size coupler. Look into a 102 or 104mm lid with matching 4" couplers and hoses. Be sure to use couplers and hose that won't collapse under full load.
2. 90mm throttle body. Look into one of the many 102 or 104mm throttle bodies, don't bother porting.
3. MAF. If you are running SD tune, yank this thing completely. If you are using MAF tune, look into a matching 102-104 high flow MAF.
Questions that can change variables, what is your redline? What size headers do you run? Do you spray? Feel free to PM me if you don't want to post publicly, I got a pissed off 408 too (Greg Good heads on HKE motor).
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From: Coast of San Mateo County Between Pacifica & HMB
Check out the Martin/Tick Ram/Cold Air Funnel in the Grill set-up.
Not everyone's cup of tea aesthetically but worth .2-.3 & 2-3 MPH
in the 1/4, and some think it looks BAD....
Not everyone's cup of tea aesthetically but worth .2-.3 & 2-3 MPH
in the 1/4, and some think it looks BAD....
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From: Mississippi
Thread Starter
11 Second Club
Joined: Feb 2002
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From: Silver Spring, Md.
Thanks a bunch for the replies and ideas. I should've also mentioned that I do have the FTRA. Because I do still have all my ac stuff on the car, I don't know if I can go with a different ram air setup. Would it be worthwhile to check out other options for improving the amount of air coming into the lid or will the FTRA be sufficient? If anyone has any ideas on how I can improve the airflow, I'm all ears.
Ultimately, my goal is to run 130 mph in the quarter with everything intact. I think 129 may be possible just on the intake side alone. I'm hoping with the addition of dual cutouts, or maybe a better flowing exhaust after the 4" Y pipe, I may have a few more ponies to pick up there.
Ultimately, my goal is to run 130 mph in the quarter with everything intact. I think 129 may be possible just on the intake side alone. I'm hoping with the addition of dual cutouts, or maybe a better flowing exhaust after the 4" Y pipe, I may have a few more ponies to pick up there.
Last edited by big dave; Jan 8, 2015 at 04:44 PM.
Thread Starter
11 Second Club
Joined: Feb 2002
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From: Silver Spring, Md.
I thought the FTRA was the same as the SSRA. Mine sucks from the bottom just like the others...what are the differences? I was concerned about the size of the opening under the filter.
I was told by a very reliable source that going from a ported 90 to a ported 102 would only produce maybe 8rhwp in the upper rpm.
I would replace your 90mm with a larger unit and a Ram Air would help. Also you may look into the new FAST runners whenever they come out? Not sure how they will perform.
I have a ported FAST 90 on mine and it pulls 98+kpa at wot w/no maf - SD Tune.
I would replace your 90mm with a larger unit and a Ram Air would help. Also you may look into the new FAST runners whenever they come out? Not sure how they will perform.
I have a ported FAST 90 on mine and it pulls 98+kpa at wot w/no maf - SD Tune.
We have a couple prototype lids you could try if you want to swap to 85mm maf or the TSP 100mm maf sensor housing. 
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Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com