LT1 turbo project
08-02-2009, 11:42 AM
#1
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Join Date: Aug 2009
Posts: 5
LT1 turbo project
I have done alot of searching, but some questions still remain. I want to install a single turbo on my LT1, stock for now. I will build a second 355 later with lower compression and forged internals. Here's the questions i have:
1) I have read the T70/.96 AR should be a good match for my car. I want to run 5-6 psi now, then turn it up to 10-12psi once the motor is built. Is this turbo going to do the job now then later as boost is increased? Or is it going to hold me back later?
2) Build the crossover pipe. Will 2.25" be sufficient from each header to the merge at the T4 flange be enough? Or should it be 2.50"?
3) Wastegate. Will a 38mm work if it is tapped in right at the collector before entering the turbo or should it be a larger wastegate?
4) I have read that the standard SBC header flange will work on the D-port head. Is this true? i'm planning on running 1 5/8" primaries into the header collector.
I'm very capable of fabricating this system, but my knowledge of v-8 turbos isn't that great. I'm moving over from the turbo 4 world, so this a bit new to me.
1) I have read the T70/.96 AR should be a good match for my car. I want to run 5-6 psi now, then turn it up to 10-12psi once the motor is built. Is this turbo going to do the job now then later as boost is increased? Or is it going to hold me back later?
2) Build the crossover pipe. Will 2.25" be sufficient from each header to the merge at the T4 flange be enough? Or should it be 2.50"?
3) Wastegate. Will a 38mm work if it is tapped in right at the collector before entering the turbo or should it be a larger wastegate?
4) I have read that the standard SBC header flange will work on the D-port head. Is this true? i'm planning on running 1 5/8" primaries into the header collector.
I'm very capable of fabricating this system, but my knowledge of v-8 turbos isn't that great. I'm moving over from the turbo 4 world, so this a bit new to me.
08-03-2009, 10:24 AM
#4
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Join Date: Feb 2002
Location: Bridgewater, MA
Posts: 5,645
[QUOTE=Quick Impala;6059846]I have done alot of searching, but some questions still remain. I want to install a single turbo on my LT1, stock for now. I will build a second 355 later with lower compression and forged internals. Here's the questions i have:
1) I have read the T70/.96 AR should be a good match for my car. I want to run 5-6 psi now, then turn it up to 10-12psi once the motor is built. Is this turbo going to do the job now then later as boost is increased? Or is it going to hold me back later?
2) Build the crossover pipe. Will 2.25" be sufficient from each header to the merge at the T4 flange be enough? Or should it be 2.50"?
3) Wastegate. Will a 38mm work if it is tapped in right at the collector before entering the turbo or should it be a larger wastegate?
4) I have read that the standard SBC header flange will work on the D-port head. Is this true? i'm planning on running 1 5/8" primaries into the header collector.
QUOTE]
1. 70mm is fine
2. 2.5" minimum IMO
3. Go with a 40mm+ gate if you want 5-6psi without boost creep (be sure to pick a gate that offers that low of a spring)
4. SBC flange is fine on a D-port head as long as the flange doesn't hang over the port opening.
1) I have read the T70/.96 AR should be a good match for my car. I want to run 5-6 psi now, then turn it up to 10-12psi once the motor is built. Is this turbo going to do the job now then later as boost is increased? Or is it going to hold me back later?
2) Build the crossover pipe. Will 2.25" be sufficient from each header to the merge at the T4 flange be enough? Or should it be 2.50"?
3) Wastegate. Will a 38mm work if it is tapped in right at the collector before entering the turbo or should it be a larger wastegate?
4) I have read that the standard SBC header flange will work on the D-port head. Is this true? i'm planning on running 1 5/8" primaries into the header collector.
QUOTE]
1. 70mm is fine
2. 2.5" minimum IMO
3. Go with a 40mm+ gate if you want 5-6psi without boost creep (be sure to pick a gate that offers that low of a spring)
4. SBC flange is fine on a D-port head as long as the flange doesn't hang over the port opening.
08-03-2009, 11:37 AM
#5
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Join Date: Feb 2004
Location: Moore OK
Posts: 2,182
1. It will, but what are your power goals? 10psi on a low compression motor from a t70 will not make the same power as a different turbo at 10psi. I run my t70 in the upper teens psi wise.
2. 2.5" - Its going to be restrictive anyways
3. Toughie - For low boos you need one thats big enough for to vent all the extra. For high boost your waste gate can be too big. Mine is like a 70-72mm and when it finally opens it drops too much.
4. Will work, but I had bad luck with getting them to seal. LT1 D ports on ebay for cheap.
2. 2.5" - Its going to be restrictive anyways
3. Toughie - For low boos you need one thats big enough for to vent all the extra. For high boost your waste gate can be too big. Mine is like a 70-72mm and when it finally opens it drops too much.
4. Will work, but I had bad luck with getting them to seal. LT1 D ports on ebay for cheap.
08-03-2009, 12:16 PM
#6
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Join Date: Aug 2009
Posts: 5
Thanks alot for the helpful replies. I was thinking the 38mm wastegate may be a bit small since i plan on a low boost setting to start. Looks as though my original thoughts seem to be more or less correct. Now to start fabbing...
08-06-2009, 07:33 AM
#7
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Join Date: Dec 1999
Location: Upstate New York,USA
Posts: 1,791
What criteria are you specifying on Ebay to find those flanges? I tried everything I could think of but couldn't find any. I tried "LT1 D Flange", "LT1 Flange", "LT1 Engine", "LT1 Turbo", etc and never found them.
08-06-2009, 01:23 PM
#8
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Join Date: Feb 2002
Location: Bridgewater, MA
Posts: 5,645
08-06-2009, 02:03 PM
#9
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Join Date: Feb 2004
Location: Moore OK
Posts: 2,182
Email someone at www.clearimageautomotive.com as they are the ones that i bought my EBay D port flanges off of.
08-20-2009, 04:55 AM
#10
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Join Date: Aug 2009
Posts: 5
Does anyone know if there are dimensions on Master Power turbos available? I was wanting to compare physical sizes between the MPT70 and MPT76. Are they pysically the the same size as Turbonetics T-series turbos?
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