TT rear mount question
07-19-2008, 02:46 AM
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TT rear mount question A buddy and I are discussing building a TT rear mount system for my lt1 formula.
right now the debate is on what turbos.
we are trying to figure out if a pair of 16g or 14b mitsubishi turbos would work efficently for what I am trying to do. (stock motor, low boost, intercooled hoping for 450rwhp (sitting at 256 rwhp now))
on junkyardturbo.com they talk about how to find the effiency of a turbo for your engine utilizing flow maps (cfm and pressure ratio @ 6000rpm) for a single turbo system.
http://www.junkyardturbos.com/101_1.html
how do you look at the compressor maps when you are using two turbos?
do I cut the cfm in half and see if the turbo is efficient at that point on the map????
right now the debate is on what turbos.
we are trying to figure out if a pair of 16g or 14b mitsubishi turbos would work efficently for what I am trying to do. (stock motor, low boost, intercooled hoping for 450rwhp (sitting at 256 rwhp now))
on junkyardturbo.com they talk about how to find the effiency of a turbo for your engine utilizing flow maps (cfm and pressure ratio @ 6000rpm) for a single turbo system.
http://www.junkyardturbos.com/101_1.html
how do you look at the compressor maps when you are using two turbos?
do I cut the cfm in half and see if the turbo is efficient at that point on the map????
Last edited by jester1614; 07-19-2008 at 02:56 AM.
07-19-2008, 08:12 PM
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Isn't the APS system using 2 mitsu 20gs or something close? I'd just go with a bigger single rear mount. A single 70-72 should get you the numbers you're looking for pretty easily
07-19-2008, 08:45 PM
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Here take a look:
Flow Rates @ 15psi:
TDO4-9B-6CM2 265 CFM
TDO5-12A-8CM2 320 CFM
TDO4-13G-5CM2 360 CFM
TEO4-13C-6CM2 360 CFM
TDO4L-13G-6CM2 360 CFM
TDO4L-15C-8.5CM2 390 CFM
TDO5H-14B-6CM2 405 CFM
TDO5H-14G-8CM2 465 CFM
TDO5H-16G-7CM2 505 CFM
TDO5H-16G-10CM2 505 CFM
TDO6-17C-8CM2 550 CFM
TDO6H-20G-14CM2 650 CFM
TDO7S-25G-17CM2 850 CFM
TFO8L-30V-18CM2 1200 CFM
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07-19-2008, 09:37 PM
#9
I would get two Hy35w turbos off of the dodge ram cummins trucks. They have the regular T3 flange and a pretty damn cheap. You can find them for cheap, because the diesel guys are always upgrading those turbos.
Those should be perfect, and are meant to handle 25psi stock lol.
Look those up.
Those should be perfect, and are meant to handle 25psi stock lol.
Look those up.
07-20-2008, 01:13 AM
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ok now that we have all the bs out of the way about someones negative opinions on mitsubishi turbos, can any one answer the second half of the question
thanks for the turbo suggestions as well and i will look into those.
and also just so you know I want to do a twin rear mount to be different and be able to run physically smaller turbos (easier packaging).
thanks for the turbo suggestions as well and i will look into those.
and also just so you know I want to do a twin rear mount to be different and be able to run physically smaller turbos (easier packaging).
on junkyardturbo.com they talk about how to find the effiency of a turbo for your engine utilizing flow maps (cfm and pressure ratio @ 6000rpm) for a single turbo system.
http://www.junkyardturbos.com/101_1.html
how do you look at the compressor maps when you are using two turbos?
do I cut the cfm in half and see if the turbo is efficient at that point on the map????
http://www.junkyardturbos.com/101_1.html
how do you look at the compressor maps when you are using two turbos?
do I cut the cfm in half and see if the turbo is efficient at that point on the map????
07-20-2008, 10:21 AM
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You'd need to look at the compressor maps of the turbos to really be able to tell if they will work for you.
Alright... there you go. At 6000 rpm you are going to need 70 lb/min of air at 15 psi (PR=2). That converts to about 1013 cfm. Divide that in half to 500 cfm which is on the map but at about 62%, hardly ideal. Although at 4300 ish rpm you will be much closer to the center of the compressor map.
At 10 psi (PR=1.68)... What it will probably take you to make your power goal. You're going to need 58 lbs/min or 840 cfm. That in half is 420cfm
which is on the 65% efficiency line again.
So... not horrible but not ideal... I believe they put twin 16gs on the 3000gt/stealth which had a 3L i believe.
(I may be completely off on my calculations here, can anyone back me up on this)
But for packaging...
Quite a few of us have TC-76 or bigger turbos back there (ST-80s) without much issue. I think twins would be a bigger pain, because now you have two turbos to oil, two flanges, you need to merge the two cold sides. Yes they are small but when it comes to clearance issues back there the piping is really the concern not the turbo itself.
Alright... there you go. At 6000 rpm you are going to need 70 lb/min of air at 15 psi (PR=2). That converts to about 1013 cfm. Divide that in half to 500 cfm which is on the map but at about 62%, hardly ideal. Although at 4300 ish rpm you will be much closer to the center of the compressor map.
At 10 psi (PR=1.68)... What it will probably take you to make your power goal. You're going to need 58 lbs/min or 840 cfm. That in half is 420cfm
which is on the 65% efficiency line again.So... not horrible but not ideal... I believe they put twin 16gs on the 3000gt/stealth which had a 3L i believe.
(I may be completely off on my calculations here, can anyone back me up on this)
But for packaging...
Quite a few of us have TC-76 or bigger turbos back there (ST-80s) without much issue. I think twins would be a bigger pain, because now you have two turbos to oil, two flanges, you need to merge the two cold sides. Yes they are small but when it comes to clearance issues back there the piping is really the concern not the turbo itself.
07-20-2008, 09:52 PM
#14
ok now that we have all the bs out of the way about someones negative opinions on mitsubishi turbos, can any one answer the second half of the question
thanks for the turbo suggestions as well and i will look into those.
and also just so you know I want to do a twin rear mount to be different and be able to run physically smaller turbos (easier packaging).
thanks for the turbo suggestions as well and i will look into those.
and also just so you know I want to do a twin rear mount to be different and be able to run physically smaller turbos (easier packaging).
I have a custom rearmount so I know the little odds and ends on the subject. FYI there was a twin rearmount done on a ta long time ago using twin 60-1 or 67 I cant rember and the owner said it was a bit of a chore. Im not bashin those mitsu turbos but it will be a fair amount of trial and error. On that note I will 
