Carbed EFI manifold or F.A.S.T. 90/90
10-11-2007, 08:01 PM
#1
Carbed EFI manifold or F.A.S.T. 90/90 exactly what it says I want to know if on a 383 procharged motor with some hand ported MTI ls6 heads wich would flow better? I also am throwing in the weilend lingenfelter alum. intake. I am looking more towards the EFI converted carb manfold because it can be port matched, and I can run a holley 2000 cfm throttle body. But, at the same time I can do that to the lingenfelter as well and that would save some hood clearance. But on the other hand in an article that popular hot rodding or gm high tech performance did, I cant fully remeber. But I do remember that the FAST 90/90 made more torque from 3200 rpms and up, which was like 19 ft.lbs. more and it put it there 1600 rpm's less too. Plus its polymer so it wont be as much of a heat sink either. I really am at a crossroads with this decision because none of them are cheap, therefor I want to make the right decision the first time.
10-11-2007, 08:45 PM
#3
they tested it on a 408 with a t98 turbo it mad 1100fwhp. Which is why Im sceptical on the whole thing because it was a turbo motor, and more cubes. However on a supercharged app. I wonder if the gmpp manifold with an elbow or the 2000 cfm T.B. (which I havent seen done before) would be a better combo for a procharger. I've already made the decision on which procharger Im going with. It'll be the F1a. I already have the heads, and rotating assy. I just am researching as much as I can before I buy the procharger and intake system.
10-11-2007, 11:02 PM
#5
You probably wont get a definitive answer on this subject,it seems there are many different opinons on intake setups and no real compairitive tests.In general after long discussions,most agree it dosen't matter nearly as much with forced induction.There are some pretty good discussions on the subject if you do a search for"carb intakes,forced induction" but no real answers.Fast 90 is usually not used in high boost applications because of the two piece plastic design and the potential for leaks.Most,but not all,of the hardcore cars have gone to carb intakes.Both work well though.
10-11-2007, 11:22 PM
#6
I personally saw NO noticeable gain going from an ls6 to a fast intake on a turbo setup that sees less than 6700 rpm (peak is at 6400). My main reason was to use the ls6 intake on another motor, so I didn't care. With a positive displacement blower or a turbo, this would be a more difficult question. However, with a centrifugal, go with the carb style intake. My reasoning is as follows-- Centrifugal makes more boost at high rpm's, and the single plane carb intakes work better at high rpm. Also, high boost will be tolerated better by an aluminum manifold. This reasoning assumes a max HP effort as opposed to a DD car. The combo of high rpm cam, blower, and intake will make great power, but may be a dog at normal street rpm's.
10-11-2007, 11:30 PM
#7
well Im the type of person that drives it like im on the track no matter where im going so that is what I was thinking not to mention the head unit im using is an F1A. So I was thinking that would be the best choice, I just wanted some reassurence. I got all I need so my decision is made. thanks.
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10-12-2007, 12:03 AM
#9
I've decided to go with the gmpp manifold, it has shorter runners than the edl. vic jr. which will save 3/4 of an inch under the hood, matched up to a fabed up elbow I should be able to fit it under my cowl. Not to mention the gmpp manifold has wider plenums with more material so I can take more out of it to get the ports to match up that much more accurately.
10-12-2007, 12:08 AM
#10
I understand that manifold flow is not that inportant howerver if I am running 15-20lbs. of boost I want all 15-20 to make it to the valves. After taking into acount what I'm losing through the intercooler and piping, I want all the remainder I can get. Thats why Im fabing up my own piping and intercooler as well, no offense to ATI but I jst dont like the whole splitting into two intercoolers and coming back together. Ive seen 2-3lbs. of boost get lost through those setups.
10-12-2007, 12:28 AM
#11
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I've decided to go with the gmpp manifold, it has shorter runners than the edl. vic jr. which will save 3/4 of an inch under the hood, matched up to a fabed up elbow I should be able to fit it under my cowl. Not to mention the gmpp manifold has wider plenums with more material so I can take more out of it to get the ports to match up that much more accurately.
also-can someone on this site please educated me on why a good intake is not that important on a fi project-
i keep hearing that it is not that important-i was under the impression that a good intake will always be better on anything compareed to a average one wether in n/a or n20 or fi use-
Thanks in advance-
10-12-2007, 12:45 AM
#12
well the reason they say that the intake flow is not as important is because on F/I the air is being forced into the plenum and through the head. where as in a N/A application you are having to invite the air in with a very unrestrictive path to the combustion chamber. However, I am very boost loss concious. Therefor I feel that the unrestrictive path and a good flowing induction system (I/E: manifold, heads, and valves) plays a big part in getting 15lbs. of boost from the supercharger to the combustion chamber.
10-12-2007, 05:38 AM
#14
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10-12-2007, 10:05 AM
#16
He means it was a 90degree elbow and a 90mm throttle body, on a edel. carb manifold. And yes I have considered the fast 90 but I plan on running 20 plus lbs. of boost and I've heard horror stories about the 2 piece design leaking boost above 15lbs. Therefor I believe that I am firm on the gmpp manifold.
10-12-2007, 11:19 AM
#17
The only bad thing about the gmpp as compared to victor jr is you have to set it up for fuel rails costing you about $300 more,you can buy the victor jr ready to go for about $400.Of course its a little taller.You can mill the top a little but you'll have to spend a little to do that too.Not a big thing but you can save about $300 overall with almost the same set up.
