Stock LS1 manifold to FAST LSXR 90 or 102???
11-15-2018, 12:31 AM
#1
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Stock LS1 manifold to FAST LSXR 90 or 102??? Im hearing some conflicting advice when it comes to whether I should go to 102 or 90 with the fast lsxr.
I have headers, catback, ORY, cutout, cam, intake annndddd I think that’s it performance wise...
Vehicle is a 2000 trans am ws6 with a stock LS1 manifold.
My local shop is telling me to go with the 90mm bc my engine isn’t that big and therefore not producing enough air to warrant the 102 and could lose performance.
Last dyno was 406rwhp.
Conversely, a bunch of discussions on the inter webs suggest the 102mm would be perfect for the LS1 regardless of its size.
I oersonally feel im pushing a damn good amount of power with about 465 to the flywheel from 325 stock. And coming from an LS1 (not even an LS6) manifold I’m going to see a pretty sizable hp increase anyway? So maybe that’s why my shop guy doesn’t GAF and says go 92mm? But obviously I the owner want that most performance possible.
Help me out here please. I’m new to this and have been trying to educate myself via many late night reading-a-thons 😅...... but to no avail i guess as I am here at your mercy....
thanks
I have headers, catback, ORY, cutout, cam, intake annndddd I think that’s it performance wise...
Vehicle is a 2000 trans am ws6 with a stock LS1 manifold.
My local shop is telling me to go with the 90mm bc my engine isn’t that big and therefore not producing enough air to warrant the 102 and could lose performance.
Last dyno was 406rwhp.
Conversely, a bunch of discussions on the inter webs suggest the 102mm would be perfect for the LS1 regardless of its size.
I oersonally feel im pushing a damn good amount of power with about 465 to the flywheel from 325 stock. And coming from an LS1 (not even an LS6) manifold I’m going to see a pretty sizable hp increase anyway? So maybe that’s why my shop guy doesn’t GAF and says go 92mm? But obviously I the owner want that most performance possible.
Help me out here please. I’m new to this and have been trying to educate myself via many late night reading-a-thons 😅...... but to no avail i guess as I am here at your mercy....
thanks
11-15-2018, 08:27 AM
#2
Any plans for future mods? I'd probably go with the 102 regardless. I have a ported Fast 90 on a bolt on car and it was a good upgrade all the way around, you're making more power than I am so I really cant see a downside of the 102.
11-15-2018, 08:39 AM
#4
Under most circumstances the 102 TB will make a few more hp on an LS1 than the 92 TB.
Two questions:
Do you have someone available to do the tuning who is outstandingly good at dialing in drive ability?
Does drive ability matter?
102 TB's are typically harder to dial in for good drive ability than a 92 TB. Some tuners struggle getting a 102 set up sorted out to drive decently on a stock displacement LS1. If your tuner has a proven record of getting LS1's to drive well without stalling and surging using a 102 TB on a stock cube LS1, it's worth considering. If drive ability doesn't matter all that much then the 102 is choice regardless of tuner skill. If the tuner doesn't have a track record of good driving 102 TB LS1's and drive ability matters the 92 TB is a safer choice.
Two questions:
Do you have someone available to do the tuning who is outstandingly good at dialing in drive ability?
Does drive ability matter?
102 TB's are typically harder to dial in for good drive ability than a 92 TB. Some tuners struggle getting a 102 set up sorted out to drive decently on a stock displacement LS1. If your tuner has a proven record of getting LS1's to drive well without stalling and surging using a 102 TB on a stock cube LS1, it's worth considering. If drive ability doesn't matter all that much then the 102 is choice regardless of tuner skill. If the tuner doesn't have a track record of good driving 102 TB LS1's and drive ability matters the 92 TB is a safer choice.
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11-15-2018, 02:47 PM
#8
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The FAST 102 is a better manifold than the 92 but does have more potential fitment issues.
The 102 TB will provide NO extra HP VS the 90/92 TB until you exceed 650 flywheel HP,
and as has been mentioned is much harder to tune.
My .02 if you are willing to deal with potential manifold fitment issues for the last HP, use a
90/92 TB with a V-MAX Velocity spacer ring to get the best drivability (eliminates the step/gap when using 90/92 TB with the FAST 102's Plenum entrance). Or for simplicities sake Ported 92/92.
The 102 TB will provide NO extra HP VS the 90/92 TB until you exceed 650 flywheel HP,
and as has been mentioned is much harder to tune.
My .02 if you are willing to deal with potential manifold fitment issues for the last HP, use a
90/92 TB with a V-MAX Velocity spacer ring to get the best drivability (eliminates the step/gap when using 90/92 TB with the FAST 102's Plenum entrance). Or for simplicities sake Ported 92/92.
11-15-2018, 02:59 PM
#9
The FAST 102 is a better manifold than the 92 but does have more potential fitment issues.
The 102 TB will provide NO extra HP VS the 90/92 TB until you exceed 650 flywheel HP,
and as has been mentioned is much harder to tune.
My .02 if you are willing to deal with potential manifold fitment issues for the last HP, use a
90/92 TB with a V-MAX Velocity spacer ring to get the best drivability (eliminates the step/gap when using 90/92 TB with the FAST 102's Plenum entrance). Or for simplicities sake Ported 92/92.
The 102 TB will provide NO extra HP VS the 90/92 TB until you exceed 650 flywheel HP,
and as has been mentioned is much harder to tune.
My .02 if you are willing to deal with potential manifold fitment issues for the last HP, use a
90/92 TB with a V-MAX Velocity spacer ring to get the best drivability (eliminates the step/gap when using 90/92 TB with the FAST 102's Plenum entrance). Or for simplicities sake Ported 92/92.
My ls1 did NOT come close to 650 FW
11-15-2018, 09:22 PM
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Thanks for all the info guys. My engine guy is great a tuning so I don’t think that will be an issue. In the future I may put a supercharger so I think the 102 will be the best bet. Especially when people on here are saying they’re getting an extra 18 rwhp from 92-102. Imagine from my stock 72 to 102 forget about it.
What kind of throttle body should I get? Trying not to break the bank over here. What do you think?
What kind of throttle body should I get? Trying not to break the bank over here. What do you think?
11-15-2018, 09:47 PM
#12
WARR Performance makes a nice budget throttle body, both 92's & 102's. The idle air circuit may need a little clean up. You will need to use the sensors from your current TB. They are slightly harder to tune drive ability wise than a Nick Williams. They also cost lessons than half of what the NW costs. I had a WARR 92 TB and it was very nice for the price.
There are a lot of junk-*** TB's that are dirt cheap so buyer beware.
There are a lot of junk-*** TB's that are dirt cheap so buyer beware.
11-15-2018, 10:08 PM
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Dude, my tuner keeps telling me that I may lose hp if u put the 102 on bc it’s too much air for my engine. He keeps comparing his Chevy SS to my car saying that when he put a 102 on his he LOST 20hp. I just don’t believe it. I mean I believe what he’s telling me about his car, but everything he’s told me to date has been underestimated and I’m not trying to pay all this money for something that’s an 8/10 when I can get a 10/10 for the same price.
Naturally aspirated, will I lose performance with the 102mm on my 350ci 5.7 LS1????
Naturally aspirated, will I lose performance with the 102mm on my 350ci 5.7 LS1????
11-15-2018, 10:10 PM
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WARR Performance makes a nice budget throttle body, both 92's & 102's. The idle air circuit may need a little clean up. You will need to use the sensors from your current TB. They are slightly harder to tune drive ability wise than a Nick Williams. They also cost lessons than half of what the NW costs. I had a WARR 92 TB and it was very nice for the price.
There are a lot of junk-*** TB's that are dirt cheap so buyer beware.
There are a lot of junk-*** TB's that are dirt cheap so buyer beware.
11-15-2018, 11:07 PM
#15
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No such thing as "too much air for the engine" It will take only what it needs, and if the TB is too big, airflow thru it will just slow down to what the engine will take. NO WAY will an engine lose 20HP because of the TB being too big. Besides, on the early LS1, the manifold is the limiting factor, not the TB.
BTW, LS1's are 346 cubic inches, not 350.
BTW, LS1's are 346 cubic inches, not 350.
11-15-2018, 11:21 PM
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No such thing as "too much air for the engine" It will take only what it needs, and if the TB is too big, airflow thru it will just slow down to what the engine will take. NO WAY will an engine lose 20HP because of the TB being too big. Besides, on the early LS1, the manifold is the limiting factor, not the TB.
BTW, LS1's are 346 cubic inches, not 350.
BTW, LS1's are 346 cubic inches, not 350.
11-16-2018, 12:11 AM
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Under most circumstances the 102 TB will make a few more hp on an LS1 than the 92 TB.
Two questions:
Do you have someone available to do the tuning who is outstandingly good at dialing in drive ability?
Does drive ability matter?
102 TB's are typically harder to dial in for good drive ability than a 92 TB. Some tuners struggle getting a 102 set up sorted out to drive decently on a stock displacement LS1. If your tuner has a proven record of getting LS1's to drive well without stalling and surging using a 102 TB on a stock cube LS1, it's worth considering. If drive ability doesn't matter all that much then the 102 is choice regardless of tuner skill. If the tuner doesn't have a track record of good driving 102 TB LS1's and drive ability matters the 92 TB is a safer choice.
Two questions:
Do you have someone available to do the tuning who is outstandingly good at dialing in drive ability?
Does drive ability matter?
102 TB's are typically harder to dial in for good drive ability than a 92 TB. Some tuners struggle getting a 102 set up sorted out to drive decently on a stock displacement LS1. If your tuner has a proven record of getting LS1's to drive well without stalling and surging using a 102 TB on a stock cube LS1, it's worth considering. If drive ability doesn't matter all that much then the 102 is choice regardless of tuner skill. If the tuner doesn't have a track record of good driving 102 TB LS1's and drive ability matters the 92 TB is a safer choice.
With all that said, I think it’s the 102 for me. Bc even if my tuner is average, and drive ability suffers, I’d rather have the gainzzzzzzzz
11-16-2018, 12:41 AM
#20
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Dumb statement. What good is a lot of power if it's an absolute BITCH to drive? Good performance includes reasonably good driveability.