125mm Throttle body on ls7 (was ls3)
08-28-2018, 12:33 PM
#1
125mm Throttle body on ls7 (was ls3) Hi everyone this is my first post.
Just finishing up a radical 7.0L LS3 stroker G8 build with my cousin. We have it all ready to go except its going to be a few months until we can bolt on the proper throttle body and intake. For now its a simple 90mm TB and stock ls3 intake manifold. The rest of the engine is built for RPM (Jesel rockers, 370cfm heads, 14:1 compression, scat bottom half, diamond pistons, 250/270 0.650/0.650 116 cam, short hyd lifters, kooks 1-7/8, etc.)
Anyone know how I can use a huge 125mm TB and high flow intake with this setup? I need drive by wire - the biggest I can find for that is 102mm. The simulation shows a huge improvement in high rpm power and a shifted torque peak of close to 1000 rpm. also shows a huge drop off below 4500 rpm but I don't care about that.
Thoughts appreciated
Just finishing up a radical 7.0L LS3 stroker G8 build with my cousin. We have it all ready to go except its going to be a few months until we can bolt on the proper throttle body and intake. For now its a simple 90mm TB and stock ls3 intake manifold. The rest of the engine is built for RPM (Jesel rockers, 370cfm heads, 14:1 compression, scat bottom half, diamond pistons, 250/270 0.650/0.650 116 cam, short hyd lifters, kooks 1-7/8, etc.)
Anyone know how I can use a huge 125mm TB and high flow intake with this setup? I need drive by wire - the biggest I can find for that is 102mm. The simulation shows a huge improvement in high rpm power and a shifted torque peak of close to 1000 rpm. also shows a huge drop off below 4500 rpm but I don't care about that.
Thoughts appreciated
Last edited by twistedneck; 09-14-2018 at 07:50 AM. Reason: Turns out this strange engine is actually ls7 based in every way)
08-28-2018, 02:56 PM
#2
ModSquad
iTrader: (6)
I’ve seen guys using a 108 TB on a high ram intake, but the intake opening has to be massively ported to make the larger TB effective, and even then, there only seeing a few more ponies than a 102. You’ll likely have to have the intake custom built.
Id love to know what heads your using, and I can assure you that your giving up power with those headers. 2” to 21/8” minimum in my opinion. Cool build! Show us some pics!
Id love to know what heads your using, and I can assure you that your giving up power with those headers. 2” to 21/8” minimum in my opinion. Cool build! Show us some pics!
08-31-2018, 11:05 AM
#4
102mm throttle body is as big as can be done with a factory stock intake with quick turn around.....Google: Peak Performance intake porting.
But I've seen a 105mm Holley on a factory Ls7 intake done by Lingenfelter. You run out of room for the O-ring, also would be into the bolt holes once you go bigger........
Holley High ram can use the 105......MSD/Fast with a 105 would be easiest and simplest!
To use a 125mm TB Easy and cheap would be to use a Carb style intake which would F up your hood. A custom intake is $3k +.... Your only flowing 370 cfm I'd just have the stock intake ported and move on. You can't use a 125mm TB and keep your hood without spending some major coin.
But I've seen a 105mm Holley on a factory Ls7 intake done by Lingenfelter. You run out of room for the O-ring, also would be into the bolt holes once you go bigger........
Holley High ram can use the 105......MSD/Fast with a 105 would be easiest and simplest!
To use a 125mm TB Easy and cheap would be to use a Carb style intake which would F up your hood. A custom intake is $3k +.... Your only flowing 370 cfm I'd just have the stock intake ported and move on. You can't use a 125mm TB and keep your hood without spending some major coin.
Last edited by Patron; 08-31-2018 at 11:15 AM.
09-04-2018, 07:43 AM
#7
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Or you could go 8 x 65mm throttle bodies...
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09-14-2018, 07:04 AM
#9
I’ve seen guys using a 108 TB on a high ram intake, but the intake opening has to be massively ported to make the larger TB effective, and even then, there only seeing a few more ponies than a 102. You’ll likely have to have the intake custom built.
Id love to know what heads your using, and I can assure you that your giving up power with those headers. 2” to 21/8” minimum in my opinion. Cool build! Show us some pics!
Id love to know what heads your using, and I can assure you that your giving up power with those headers. 2” to 21/8” minimum in my opinion. Cool build! Show us some pics!
Red and cyan represent a change to huge 125mm tb and tu nel ram type intake. Red is HP, cyan tq. Green and blue are exact same engi e w stock 90mm tb and stock intake. Its cleay a massive restriction w this race engjne. Fyi. Bigger than 1 7/8 exhaust reduced power, and making the collector longer did help a lot. Sure if i increased head flow to a massive 400cfm and put a 272 cam w 850 lift then yes, 2.3" were needed.. but not here. I ran a bunch of iterations w header tube length and collectoe variation and its not the limitstion on this simulation.
102mm throttle body is as big as can be done with a factory stock intake with quick turn around.....Google: Peak Performance intake porting.
But I've seen a 105mm Holley on a factory Ls7 intake done by Lingenfelter. You run out of room for the O-ring, also would be into the bolt holes once you go bigger........
Holley High ram can use the 105......MSD/Fast with a 105 would be easiest and simplest!
To use a 125mm TB Easy and cheap would be to use a Carb style intake which would F up your hood. A custom intake is $3k +.... Your only flowing 370 cfm I'd just have the stock intake ported and move on. You can't use a 125mm TB and keep your hood without spending some major coin.
But I've seen a 105mm Holley on a factory Ls7 intake done by Lingenfelter. You run out of room for the O-ring, also would be into the bolt holes once you go bigger........
Holley High ram can use the 105......MSD/Fast with a 105 would be easiest and simplest!
To use a 125mm TB Easy and cheap would be to use a Carb style intake which would F up your hood. A custom intake is $3k +.... Your only flowing 370 cfm I'd just have the stock intake ported and move on. You can't use a 125mm TB and keep your hood without spending some major coin.
sounds perfect and outrageous and $$$..
i want to use two cheap 90mm factory throttle bodies wired in parallel to act as a single unit. Just need a cheap intake.
Last edited by twistedneck; 09-14-2018 at 07:13 AM.
09-16-2018, 02:55 PM
#10
ModSquad
iTrader: (6)
Are you using a GM head casting? What simulation software is being used here?
09-16-2018, 03:22 PM
#11
software is pretty cool its the Engine analyser pro you get a ten day demo.
at work we use fluent and cfx along w the usual mechanical and ncode etc Im getting a demo of forte since it looks like a lot of fun. However i dont have access to a personal 3d scanner so no way to get the ls based models i need. Not to mention that has to be done after work and its not exactly easy to run a 3hr solve taking up 36 cores every night for my home projects. Enter engine analyser pro!
So long story is can i find a cheap way to make a twin throttle body setup?
09-26-2018, 02:09 AM
#17
https://www.summitracing.com/parts/h...oaAsPHEALw_wcB
10-04-2018, 08:51 AM
#20