FAST 90/90 over LS6
"You dont call 15-20whp through out the curve after about 4.5k rpms and another 15 peak THAT MUCH ? Damn..I must be crazy then"
in this thread https://ls1tech.com/forums/dynamometer-results-comparisons/480398-ha-ha-ha.html
Sir, maybe you gained 20whp and 15 peak hp, but I sure as hell did not. I do not believe a FAST 90/90 makes a SIGNIFICANT difference over an LS6/ported TB combo on a cam-only car. MAYBE 10whp at the most. Heads/cam, sure, you'll start to see a change. I trapped 119-120 before, and 120 after the 90/90 install. Cant argue with results.
Discuss.
Edit: lets say a mid sized cam-only car. Im sure some of the bigger cams Trex, MS3, G5x4 cams will see slightly more of course.
Last edited by RaNsOm; Apr 2, 2006 at 05:20 PM.
I'm at 439rwhp/385rwtq with AFR 205's, TSP 233/239 cam, LS6 intake/ported TB, March pulley and 1 7/8" long tube headers (average collector design on them). Just ordered a FAST 90 intake and Holley 90mm TB. Hoping for 470rwhp/405rwtq with a speed density tune. Hoping for 130+mph in the 1/4 n/a on 91 octane in daily driver tune with 346ci.
Last edited by gnx7; Apr 2, 2006 at 05:29 PM.
I'm at 439rwhp/385rwtq with AFR 205's, TSP 233/239 cam, LS6 intake/ported TB, March pulley and 1 7/8" long tube headers (average collector design on them). Just ordered a FAST 90 intake and Holley 90mm TB. Hoping for 470rwhp/405rwtq with a speed density tune.
I'm at 439rwhp/385rwtq with AFR 205's, TSP 233/239 cam, LS6 intake/ported TB, March pulley and 1 7/8" long tube headers (average collector design on them). Just ordered a FAST 90 intake and Holley 90mm TB. Hoping for 470rwhp/405rwtq with a speed density tune.
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Well-ported heads on the other hand flow more like 300 cfm and the LS6 intake will knock down the flow into the 260 range. A FAST 90/90 will only knock it down to the 280 range. The better the heads, the more the FAST intake works. It's not really cam related. If you'd like to see where I gained 28 rwhp with the addition of a FAST 90/90, click on my signature and look for the dyno sheets.

2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
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2023 Corvette 3LT Z51 soon to be modified.
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To reiterate and clarify once again....A FAST 90 install over an LS6 /stock TB combo is worth between 10 and 15 RWHP, most of the gains seen in the higher portion of the power curve. Down low (under 3500) I have seen between a slight loss (5 ft/lbs) in TQ and HP to just about the same.....meaning the lower portion of the curve is close to a "over-lay" when comparing the same combination with the LS6/stock TB set-up. Even right out of the box the FAST is simply a better designed piece (than an LS1-6) and the benefit of its design should be realized on every engine it's bolted on top of. It has better shaped runners, a better "approach" to those runners, and a larger plenum....all of which aid in it allowing more air to pass thru it....especially at higher RPM's when there is so little time to do so (much quicker valve events that happen in tiny fractions of a second).
I have personally seen these results backed up close to a dozen times and they all fall in line with what I mentioned above. Half of those times I was the guy installing and testing the intake on a particular combination. Others were tests performed by friends in the industry who's input I rely on without hesitation.
Another myth I would like to dispel (again...LOL) is the FAST is a "waste of money" unless you have a heads and cam or a more aggressive 346....Total BS
On a bonestock 346 (with an LS1 cam) I saw a clean 10-11 HP gain at the top end of the curve. Is that worth the price of admission?....It depends on how much you value those additional ten ponies.
Regarding the work I do, it is usually worth an additional 6-8 peak RWHP (in addition to the gains you would get out of the box), but you will see a much improved area under the curve with a solid 10 RWTQ gain as early as 2500 RPM's (versus a slight loss to "flat" curve with a stock out of the box unit). In fact, the area under the curve is as good a reason (if not better) to rework the manifold if you are one of those guys that want to fully optimize their combo and don't want to leave any power untapped. You can check out Patricks gragh in the link a few posts up and see the immediate gains in low speed TQ and HP on his gragh comparing the before and after FAST install. Some of his peak RWHP gains I attribute to the larger MAF install (2-4 HP) which is a nice complimenting mod to a ported FAST, both of which are essentially removing restrictions seen in "front" of the heads which reduce their effectiveness.
BTW....all of these gains assume you have tuned the car to take advantage of the newfound airflow the FAST provides. Personally, I think the guys not seeing the gains are really just needing to tune the car to take advantage of it. Some tunes might be able to get away with just dropping it on and put down the number....others might need a little tweaking.
Hope this info helps...
Tony M.
A ported stock TB will knock the net gains down 2-4 HP depending on who did the porting.....meaning the delta from the FAST install will be a little less.
Last edited by Tony Mamo @ AFR; Apr 3, 2006 at 12:39 PM.
If not that is going to be $100/hp at this point. yikes
I hope with cleaning up any mold flashings in the FAST 90, Speed Density Tune (MAF sensor removal), 4" intake piping, to achieve 25rwhp+/15rwtq+.







