347 stroker turbo size?

Brozum

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I have a sn95 347 stroker 10:1 compression 5 speed car. Motor makes 500 HP N/A. TF twisted wedge heads ported polished 180cc. TF track heat R upper lower ported and polished everything port matched. 93 80mm throttle body. I'm installing a 76/65 turbo kit and am having a hard time picking the correct housing AR size. Motor tunes 6200rpm. 700-800 whp would be nice. It's a street driven 5 speed and I'm looking for fast spool speed that will pull to 6200rpm. Seems like housing size I can get is.68 or. 96. Can anyone help me? Or does anyone thing a 78/75 turbo would be better for this application? What AR size would be good with my motor for fast spool that pulls to 6200
 
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a91what

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agreed, if its an auto you need timing timing timing.... lean the AFR to create heat and timing to get it up on the converter/ create cylinder pressure... If a stick then no worries about the converter, you can easily retard the timing to 0-5* or even less [negative numbers], then when you get up on the 2 step dump extra fuel.
generic advice but works for most.
 

Brozum

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I'm trying to pick the right size turbo for the size and power my motor makes N/A. 347ci 500hp N/A 10:1 compression. The car is 5 speed and I want the turbo to spool quick and pull to 6200rpm. Will the 76/65 CBB turbo work or will I over spin it? And what size AR will work for me.. 68 or. 96.i know the. 68 will spool faster but will it be to small for my motor and I'll have too much back pressure? It's a street driven 5 speed car and I don't want a ton of lag to get good HP
 

FastDriver

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T4 or T6, and split or single housing?

I would start at .96, possibly go bigger depending on the above answers, if bigger is available. .68 is going to have back pressure issues.

I should say, you're going to have a lot of back pressure regardless. I have this turbo under its old name "76 GTS" on the blue car. Spool is awesome. Car made 954 rwhp on E85 at one point before it ran out of fuel. Turbo might have had a little more, but was mostly done.
 
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Brozum

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Jun 20, 2019
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T4 or T6, and split or single housing?

I would start at .96, possibly go bigger depending on the above answers. .68 is going to have back pressure issues.
T4 76/67 is what I've been looking at through On3. The largest AR they have is. 96. I wasnt sure if I would have a ton of lag with that housing. They have it with ceramic bearings but No billet wheel.
 

FastDriver

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You're going to have 0 lag. You have a big motor for a turbine that small. You will have a ton of backpressure with such a small turbine. How much power are you trying to make? Try to go with the 76/75 if you can. I have the same compressor with a 102mm turbine wheel and a 1.15 A/R (because precision failed to send me the 1.28 I ordered) and it still has 3:1 back pressure
 

Brozum

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Jun 20, 2019
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T4 or T6, and split or single housing?

I would start at .96, possibly go bigger depending on the above answers, if bigger is available. .68 is going to have back pressure issues.

I should say, you're going to have a lot of back pressure regardless. I have this turbo under its old name "76 GTS" on the blue car. Spool is awesome. Car made 954 rwhp on E85 at one point before it ran out of fuel. Turbo might have had a little more, but was mostly done.
I'm hoping I can get 700-800whp out of this. But honestly drivability and less lad with a 5 speed
You're going to have 0 lag. You have a big motor for a turbine that small. You will have a ton of backpressure with such a small turbine. How much power are you trying to make? Try to go with the 76/75 if you can. I have the same compressor with a 102mm turbine wheel and a 1.15 A/R (because precision failed to send me the 1.28 I ordered) and it still has 3:1 back pressure
I.
 

Brozum

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I'm hoping I can get 700-800whp out of this. But honestly drivability and less lad with a 5 speed

I.
I'm hoping for 700-800 whp. I'm gunna run a low boost 93 tune and I higher boost e85 tune. Yeah I can go with the 76/75. I have to chech if the offer CBB and billet wheel. Housing wise with the larger turbine wheel should I use. 96 housing. It's a street car 5 speed with almost no drag time. I've drag raced for so many years and got yo expensive after kids
 

Brozum

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I'm hoping I can get 700-800whp out of this. But honestly drivability and less lad with a 5 speed

I.
I just looked the 76/75 has billet wheel but not ceramic bearings. They also have a 78/75 with billet wheel but no ceramic bearings. The one that you can get ceramic bearings is the 76/65 but can't get it with a billet wheel
 

FastDriver

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A billet wheel is offered on the 76/75. If you're buying the kit, most places will sell you the kit without turbo.

Don't expect too much from the CBB. You'll get a couple/few hundred RPM quicker spool. You be the judge if that's worth the money to you. I think I'm at full spool with the 363 with journal bearings by around 3500 rpm. The car never sees less than that from launch to any speed when I'm getting after it.
 

Brozum

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A billet wheel is offered on the 76/75. If you're buying the kit, most places will sell you the kit without turbo.

Don't expect too much from the CBB. You'll get a couple/few hundred RPM quicker spool. You be the judge if that's worth the money to you. I think I'm at full spool with the 363 with journal bearings by around 3500 rpm. The car never sees less than that from launch to any speed when I'm getting after it.
Awesome. What are your thoughts on the 78/75? Is a. 96 housing going to work for me
 

Brozum

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What's your thoughts on reverse split duration lift cams. I hear they help spool faster with no decrease in top end. My cam will not work for turbo.
 

FastDriver

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Ok, I was assuming that based on the power you were talking, but wanted to make sure. I think 10:1 compression is a pretty rough starting point for a street car with a turbo, and it made me start wondering about your whole setup.

Isn't the 7875 a turbonetics? No personal experience here on that one. Maybe it's worth more power, but is it even a precision turbo? Might not be worth the quality difference. I'll leave that to your research. If you're really shooting for 700-800, then you won't be using up the 7675 precision turbo.