FAST on ls4
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From: K.C.
FAST on ls4 seeing as the ls4's share the same heads as the z06 {243 number}
would this lead one to believe that a fast would work? or is there more that is different then i know about.
i know someone with a fast forsale, hence why im asking
would this lead one to believe that a fast would work? or is there more that is different then i know about.
i know someone with a fast forsale, hence why im asking
Staging Lane
Joined: Dec 2004
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It should physically bolt to the heads, but I'm not sure what accessories/accessory mounts may or may not be in the way. If I remember correctly, the LSX heads are symmetric so you should be able to spin it to face the correct way. Our throttlebody is 89mm so I wonder what kind of adapting (if any) would need to occur to get it to bolt up.
Sorry, not much help.
Chip
Sorry, not much help.
Chip
Launching!
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From: Brandon, MS
Like Chip says it will bolt up. However other things may get in the way... such as the DOD VLOM assembly on top of the lifter area (under the intake manifold)... it sticks up a little bit higher than the plate that other LSx motors have.
I pulled off the throttle body a few weeks ago and measured it. It is an oddball actually. A 4 bolt 76mm... not a 90mm. All aftermarket intake manifolds are for the 76mm 3 bolt or 90mm 4 bolt.
Honestly I think the Fast would have way to much volume for our 5.3L. They are more suited for larger displacement motors. After reading dozens of threads on this site it seems the LS6 manifold is better suited for the smaller displacement motors. Though you would have to rig up some sort of adaptor to put the throttle body on it.
I pulled off the throttle body a few weeks ago and measured it. It is an oddball actually. A 4 bolt 76mm... not a 90mm. All aftermarket intake manifolds are for the 76mm 3 bolt or 90mm 4 bolt.
Honestly I think the Fast would have way to much volume for our 5.3L. They are more suited for larger displacement motors. After reading dozens of threads on this site it seems the LS6 manifold is better suited for the smaller displacement motors. Though you would have to rig up some sort of adaptor to put the throttle body on it.
Staging Lane
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Mike, good info on the throttlebody. I thought I had read somewhere that it was 89mm, so I stand corrected. Maybe we could use a 90mm LS2 TB. It appears to be a four bolt also. This would retain the drive-by-wire, but would be more expense.
Chip
Chip
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From: K.C.
here is what im thinking
ls6 cam {405 car}
mild head work
ls6 or stock fast manifold
ls2 tb
this should be good for more then 300 to the tire with the right tuning done to it. all of the above i can get for less then 1500 bucks. which really isn't too bad. beats filling a bottle every two weeks. but it also gives the power all the time.
dunno. this is the least of my worries right now. i still have to finish my other car before i go motor deeper in the gxp
ls6 cam {405 car}
mild head work
ls6 or stock fast manifold
ls2 tb
this should be good for more then 300 to the tire with the right tuning done to it. all of the above i can get for less then 1500 bucks. which really isn't too bad. beats filling a bottle every two weeks. but it also gives the power all the time.
dunno. this is the least of my worries right now. i still have to finish my other car before i go motor deeper in the gxp
Originally Posted by BigMikeGXP
When I get enough money im probably going to go with a LS2 90mm throttle body, LS2 MAF, and one of these intakes. It will cost alot but its the only good option I can come up with.
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Originally Posted by Stang's Bane
If you put that manifold on your car you lose power. The bigger manifold will not help unless you make a cam change. honestly right now the cam in these cars is holding you back more than anything. Sure you will be able to take i more air, but there will be no where for it to go. Hope this helps.
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From: Brandon, MS
Originally Posted by Stang's Bane
If you put that manifold on your car you lose power. The bigger manifold will not help unless you make a cam change. honestly right now the cam in these cars is holding you back more than anything. Sure you will be able to take i more air, but there will be no where for it to go. Hope this helps.
I'm with Stang Bane. The FAST is a bit too much for the displacment. The LS6 would be a good upgrade from the stock manifold. The curve seems to nose over fast after peak TQ. It's made to be a lower RPM breathing piece. The LS6 would be a nice gain on the top end without sacraficing too much on the low end. It's a great piece of engineer from GM actually.
Now. The cam would probably be where you'd see nice gains. Just like the rest of the Gen III/IV line. The cams are not that agressive comming from GM.
But then you would need to address the exhaust 1st for either upgrade on top of a better flowing induction to the manifold.
Now. The cam would probably be where you'd see nice gains. Just like the rest of the Gen III/IV line. The cams are not that agressive comming from GM.
But then you would need to address the exhaust 1st for either upgrade on top of a better flowing induction to the manifold.
Launching!
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From: Brandon, MS
Im ordering a LS6 intake within the next week or so... going to see what kinda of fitament (sp) issues it has. Im sure different injectors and fuel rails would probably have to be used. Hopefully I can find someone that will machine some sort of adaptor to use with our throttle body.
Money money money
Money money money
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From: Ohio
I'm no sure if this is being accounted for, and it may be a stupid statement, but what about the mass air flow sensor/housing. I've looked at other lsx vehicles and the ls4 maf seems very small (constrictive) compared to the trucks and vetts. In fact the maf housing seems to be the same as a 3.5 or 3.9 litre motor. Is there a fix or replacement for this? It seems like the benefits of replaceing the intake and/or the throtle body would be hindered by the small maf housing.
Launching!
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From: Brandon, MS
Originally Posted by SILVER LS4
I'm no sure if this is being accounted for, and it may be a stupid statement, but what about the mass air flow sensor/housing. I've looked at other lsx vehicles and the ls4 maf seems very small (constrictive) compared to the trucks and vetts. In fact the maf housing seems to be the same as a 3.5 or 3.9 litre motor. Is there a fix or replacement for this? It seems like the benefits of replaceing the intake and/or the throtle body would be hindered by the small maf housing.
It is the same one the V6 models use.However im thinking the LS2/Z06 type maf will plug right in, however it would require tuning and some different intake piping.
