What Size MP Turbo 346cid?
03-01-2009, 10:28 PM
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What Size MP Turbo 346cid? **I ask all this knowing full well that a built 6.0 will be in the cars for me down the road...and I also realize all the drive train upgrades that should accompany a turbo car...for this moment Im just looking to get my feet wet in the Turbo world, and WANT to see what I can get out of the stock long block**
So I am contemplating fabricating a turbo set-up on my 98 SS. As of right now the car has only a Borla Cat-Back and a Walbro255 and HotWire Kit (will go dual 255s if I need to). To keep costs down I would be seeing what I can push out of a stock long block (other than injectors, valve springs and push rods maybe)...I would be using truck manifolds and would go with a MP Turbo since they seem to be the "best budget" turbo I can find without going with a knockoff. What size turbo do you think would work well with stock displacement with stock heads, and what should I limit my boost to on 93 octane?... I may throw some 6.0 heads on down the road so I would like to leave enough room with the Turbo to turn up the wick later but not be way oversized at first either...advice?
So I am contemplating fabricating a turbo set-up on my 98 SS. As of right now the car has only a Borla Cat-Back and a Walbro255 and HotWire Kit (will go dual 255s if I need to). To keep costs down I would be seeing what I can push out of a stock long block (other than injectors, valve springs and push rods maybe)...I would be using truck manifolds and would go with a MP Turbo since they seem to be the "best budget" turbo I can find without going with a knockoff. What size turbo do you think would work well with stock displacement with stock heads, and what should I limit my boost to on 93 octane?... I may throw some 6.0 heads on down the road so I would like to leave enough room with the Turbo to turn up the wick later but not be way oversized at first either...advice?
03-02-2009, 09:41 AM
#5
My motor is a Ls1 with 6l heads forged pistons and rods and I started with a MP T70 with .68 A/R and it made good power and fast spool up. I swapped out to a .96 A/r on the T70 and spool came a tad later but felt a little better on the top end, but not much. Then I put the T76 with .96 A/R on it. A little more lag, but that helped with traction a little 
but dropped intake temps a bit and seemed to pick up a bit more on the top end. The numbers in my sig are of my 5200# truck at this high elevation and with the T70 and a .68 A/R at 14.5 psi of boost. Weekend before last, I went down to SAR in TX (700' elv.) and with the T76 went the same time and speed with only 10psi. Turned it up to 13 psi and broke the output shaft on the tranny on the 1-2 shift 
but dropped intake temps a bit and seemed to pick up a bit more on the top end. The numbers in my sig are of my 5200# truck at this high elevation and with the T70 and a .68 A/R at 14.5 psi of boost. Weekend before last, I went down to SAR in TX (700' elv.) and with the T76 went the same time and speed with only 10psi. Turned it up to 13 psi and broke the output shaft on the tranny on the 1-2 shift 
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03-03-2009, 01:04 AM
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Oh, well I can live with any size lock-up converter. I used to have a 4000. I just didn't know what converter will generally put a Turbo for my application in its sweet spot....
03-03-2009, 01:09 AM
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Ive got a single 60 trim turbo on my 350, its a nice size turbo and start to hit boost pretty low in the rpm range. My suggestion for a street/track, around 3500 stall would be best. Thats just the way im setup and I like it.
03-19-2009, 12:25 PM
#11
My motor is a Ls1 with 6l heads forged pistons and rods and I started with a MP T70 with .68 A/R and it made good power and fast spool up. I swapped out to a .96 A/r on the T70 and spool came a tad later but felt a little better on the top end, but not much. Then I put the T76 with .96 A/R on it. A little more lag, but that helped with traction a little but dropped intake temps a bit and seemed to pick up a bit more on the top end. The numbers in my sig are of my 5200# truck at this high elevation and with the T70 and a .68 A/R at 14.5 psi of boost. Weekend before last, I went down to SAR in TX (700' elv.) and with the T76 went the same time and speed with only 10psi. Turned it up to 13 psi and broke the output shaft on the tranny on the 1-2 shift
but dropped intake temps a bit and seemed to pick up a bit more on the top end. The numbers in my sig are of my 5200# truck at this high elevation and with the T70 and a .68 A/R at 14.5 psi of boost. Weekend before last, I went down to SAR in TX (700' elv.) and with the T76 went the same time and speed with only 10psi. Turned it up to 13 psi and broke the output shaft on the tranny on the 1-2 shift for someone just looking for a DD application is that t70 with the .68 a good choice. im looking for around 500 whp on my gto. ls1 a4. ill be stalling it eventually. just want to give her some more go power for these pesky little light ricers. LOL
