badpewter-z

iTrader: (4)

keep what you have or get a 90/90 setup no point in spending the money and still starve the motor. when you do go with heads you wont regret getting the 90/90 setup

trukk

iTrader: (1)

Somewhat related, also don't frequent here much so sorry if this has been hashed a million times:

I have LS6 + Ported stock TB. Been thinking about TPIS's moded LS6 intake moded for use with a stock 90mm TB (this is a stock LS2, not the oval one TPIS also offers). Cost is approx $500 (after core exchange) + cost of a 90mm TB.

Anyone doe this?

-Chris

vettenuts

iTrader: (4)

Haven't seen much on the TPIS setup, but for $500 and still needing a new throttle body, it would seem more prudent to just spend the extra and go with the FAST. Also, Brian Tooley just posted some test data that included several combinations of heads, etc. and the FAST 90/90 out of the box appears to be a very good upgrade over the LS6.

Pro Mouse

iTrader: (15)

Yeppers! Thats Right!I went to the Fast 90/90 set up with My MTI H/C package on a stock LS1 bottom end,Right out of the Box I Picked up 21 Peak rwhp and 17 rwtq Over the LS6 Intake ,But what I had really Gained was 25 hp under the curve and was the Best Bolt on mod I have done.

01Z0H6

iTrader: (63)

Man... this makes me feel great!! i purchased my 90/90 last week, it is being ported to match my heads & painted black...

I am currently putting out 400rwhp & 375tq...

i'll have that intak/TB on next week!!! I can't wait!!

allngn_c5

iTrader: (3)

78 mm for good performance and nice gas mileage, 90 mm for all performance, and no consideration for gas mileage. JMO

xaon

iTrader: (12)

what are you basing gas mileage differences between a FAST 78mm and 90mm setups on?

The motor will only take in the air that it needs, whether you have a 78mm opening or a 200mm opening, it's still only going to pull in X amount of air.

badpewter-z

iTrader: (4)

driver has a tendency to get into more often

01Z0H6

iTrader: (63)

"Just your opinion".. that you are definately entitled to..

Don't know exactly what you are basing it on...? Pretty broad statement..
It's all in how you drive... JMO..

allngn_c5

iTrader: (3)

I was basing it on two of my friends. It seems that when we all go out with full tanks the 90/90 guy is always needing to stop for fuel. We all have Head/Cam full bolt on cars. I just assumed that a H/C car with raised compression could flow more air then what my 78 mm Fast was letting in. Due to my friend with the 90/90 setup on a 99 FRC seems to be about 4 mpg less then me. He has a comprable cam, same heads, and the 90 setup vs my 78. More air flow, more fuel. Please correct me if I am assuming incorrectly. I appreciate the help.

HotWhipT/A

iTrader: (31)

Whats in front of the 90/90 set ups? I mean the MAF and lid/filter? I can assume its a K&N filter with a normal aftermarket lid. Smooth bellows? I have heard of a larger than normal lid like 85-90mm though. What are people doing with the MAF? Is it stock, ported, !sceen, or aftermarket?

Pro Mouse

iTrader: (15)

I have an MTI stock sized lid ,Composite MAF Ends that Flow 1000 CFM,if this Helps?Good Luck!

Tony Mamo @ AFR

iTrader: (13)

A 90 mm will make slightly more peak power than a 78 (about 5 ponies) all else being equal....the low end TQ and fuel economy will be unchanged, and the larger TB will usually provide more snap in the throttle which I happen to like.

The TB is an air valve....that is all. We are not mixing and atomizing fuel so concerns that a smaller TB might be more fuel efficient or provide better low speed/part throttle TQ (due to better signal and fuel atomization) is obviously not the case. Only when we are talking carb's is the previous statement applicable. A fuel injected motor's TB is just a door to meter airflow and a smaller door (TB blade) will simply have to open a little more to provide the same power as a larger TB with a bigger opening (the same volume of air is actually passing thru both in that hypothetical scenario).

Upstairs, the additional airflow the larger opening provides will show small gains as I mentioned earlier, but there are no penalties to running a 90 mm versus a 78 except for the cost of admission (more $$ on manifold and having to purchase a 90 mm TB).

Hope this clears things up....

Tony M.

01tam6

iTrader: (1)

Was wondering sort of the same thing. Is it recommended to get a 85mm lid and also what about the bellow leading to the tb? I am thinking of getting one too, hopefully to finally get some decent numbers out of my car.

00transamnh

iTrader: (1)

it seems to me that if you go 90/90 then you either need to dump your maf sensor or find a 90mm one (if such a thing exists)... whats the point of doing a 90/90 setup if you have a 75mm bottleneck?

verbs

78 is ******* worthless. Get the 90. I went through the same thing, got the 78 first, then upgraded to the 90 and it cost me an extra $300 or so to do it.

Don't listen to anyone who says 78.

Tony Mamo @ AFR

iTrader: (13)

Upgrading the MAF to an 85 mm when you step up to a 90 mm FAST is obviously a good complimentary move and smart from the standpoint of tuning the new combo with both the better intake in place as well as the less restrictive MAF. A little more money yielding of course a little better results....typical scenario that will play over and over again as you continue to mod the car in search of better performance.

Tony M.

PS....I wouldnt say the 78 set-up is useless because I initially ran that exact set-up not wanting to deal with C5 throttle by wire dirvability issues that were a concern with the early 90 mm TB's (NW was the first to come out with a more tuner friendly shape to the TB). It was worth just under 20 HP over a an LS6 intake (my FAST was ported of course), but I did find about 5-6 more later with an NW 90 mm TB and another 4 ponies stepping into the larger 85 mm MAF at the same time.

Considering the F-Body's dont have any tuning issues with the 90 mm and that costs have come down significantly (and new better design throttle by wire TB's are around that are less finicky for the Vette crowd), stepping into the 90 right away does make the most sense as undoubtedly you will be looking for more (power) down the road. Its a fact of life once the "mod bug" has bitten you.

Patrick G

iTrader: (14)

For the most part, the only people advocating running 78mm FAST intakes are the ones trying to sell them. Keep that in mind.

NOS USER

If you wanna get a 78mm fast so dont waste your money just stick with your LS6 intake or buy a used one & port your TB ....ported 90 mm fast from Tony Mamo i think its the best one ..

Thanks.

Mr.Nitrous

iTrader: (51)

Well, just to add some more input I just did a back to back dyno session with the following mods on a 04' c5 vette a4 car : Crane 224 228 cam,dyna tech headers no cats,corsa cb,vara ram, tune, yank 3200, all other stuff stock.
Tested both intakes turning the motor to 6400rpm, and saw no differnce between the 2 intakes for power or tq. No diff. through the curve or peak.It had a tpis 90 and a ported fast intake done by Champion racing head service.