I was just curious as to whether or not the Fast LSX Intake Manifold, or any intake manifold for that matter will be worth installing on my 1999 LS1 for reasonable gains. I have a stock LS1 except for SLP Lid and Loudmouth II (and Hyper"junk" if that counts). I see that these manifolds are going for 400for the top shell (if that is even usable with a stock lower manifold), and up to 1000 for the complete 90mm throttle body inlet versions. I also understand that with this manifold I will need to run a bigger TB, but the question is dollar per hp, is this project worth it? I want my LS1 to be a little quicker without tearing into the valvetrain/heads/lower end for now. Any advice is welcome.


~Mike

 

may have been teke, but someone posted a link that showed results of the fast 78mm, 90mm and ls6 intakes on a ls1, lightly modded. the 90/90 setup actually lost power and the ls6 did the best. like mentioned above, 90/90 is for serious power but with the right combo, i.e more cubes or f.i.
some f.i and n20 cars run great with just the ls6, so right now 90/90 is probably a waste of money for you. if you plan on a stroker kit, get it then along with better flowing heads.

 

Okay so in this case, would an LS6 intake be good for my application? Also, what are the differences between the LS1 and LS6 intake, and hp per $$ should I even worry about it?

 

The FAST setup usually is most optimal for guys running more displacement. If you're going to stick with the stock cubes, I'd say the LS6 will be good enough.

 

These guys are both right AND wrong. The LS6 is great for smaller cubes and less aggressive applications, but it's not the best. The 90/90 <b>IS</b> too much for anything less than a radical H/C setup. The perfect balance is having a 78mm F.A.S.T. It's what I went with and have absolutely no regrets. I was able to keep the stock TB size (although I had mine ported by MTI) so that was nice too. The only thing I recommend is trying to find a used one. There's lots of guys that went to the 78 but decided to upgrade to the 90/90 when they're plans got bigger. So yeah, if you can find a good deal, go with the 78. I don't have the link, but there was a comparison between the LS1, LS6, and 78mm LSX on the dyno. The LS6 made something like 12hp over the LS1, and the LSX made an ADDITIONAL 12hp over the LS6 on the same vehicle.

 

As it's been said before unless you're going with a H/C setup I wouldn't bother.
I had a ported TB and an LS6 intake on mine before the Fast90/90. Here's a before and after of what I put down.
Before:
http://www.seth-sons.com/gallery/dis...?album=9&pos=1
After:
http://www.seth-sons.com/gallery/dis...?album=9&pos=0

Here's a current mod list on the car:
http://projects.seth-sons.com/meangreenmods.htm

The only things that aren't on the list or incorrect is in place of the FAST TB I put in a Nick Williams TB. And I'm running a custom cam from Arizona Power & Sound with AFR 205's.

So with that being said unless you're going with a H/C setup I wouldn't worry about it. The LS6 with a ported TB will be just fine..

Tails

 

you myspace too much

 

for your application and your budget...the LS6 intake is all you'll need.

it's been dyno proven over and over to yield about 10rwhp on bolt-on cars, and more on cammed cars. you can find them usedd for $200-350, or buy one brand new with emissions or without for $400 or so.

you can use your stock TB with not problems what so ever.

it's a worthwhile mod...just shop around for the best deal. watch here and on ebay.

 

LS6 and call it a day.

 

I'd go with the FAST 90/90 only if you are getting a cam. Otherwise, get the LS6.

Mike

 

alright i get what everybody is saying. I could get the LS6 intake manifold and drop it on, but then go with a 90/90 if i get a cam. if i put a cam in it (nothing too aggressive that would drastically affect drivability, but something to be a little more powerful) would that be a major job that would require replacement of lifters/injectors/computer remapping..etc?

 

When people say the 90/90 combo is to much do you mean that there is no power gain from this?Or do you mean for the money your better to run with the Ls6 for about same gain?Or is there other problems with 90mmtb e.g.need changes to computer etc.

 

Bingo, you take a bolt-on car and spend the $1200 for a 90/90 or spend $400 for an LS6 and get the same hp numbers. Why waste $800.
Now "if" your plans were to go big in the future then why not get the 90/90 now and skip the LS6? See?

 

So the 90/90 makes the same as the ls6?

 

putting a mild cam in won't require new lifters or injectors. but you'll need a new set of springs, pushrods and a timing chain is advisable. as is a computer tune. you can run on stock tuning, but it won't run the smoothest nor will you be getting all the power the cam has to offer.

if all you plan to do is a mild cam and no head work, the LS6 intake would still be the better choice. you could probalby gain a few hp form the FAST intake, but not much more than the LS6 would gain you. if you were going full heads, and cam...the gain would be more worthwhile.

it really depends on your budget and intended goals.

for the $800 or so higher price to get the FAST, you can buy a cam with slightly more aggressive duration or lift and make the same if not more hp than what you would have gained by adding the FAST. and with todays tuning capabilities...even a mid 33x cam is streetable.

i know i drive my TSP torquer 233 cam daily....only thing that makes it touchy in heavy traffic is the SPEC 4 clutch and lightweight aluminum flywheel. had i gone with the SPEC 3 and steel or stock flywheel it would be a pussycat in traffic.