alittle different turbo question
06-22-2009, 08:32 PM
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alittle different turbo question most people ask what turbo for an engine. but i have a tc78 and would like to know what size engine would be the max one would recommend to put it on. max being keeping it efficient and make around 700-800hp. its a tc78 with the largest turbine wheel you can get 68mm IIRC and a .96A/R housing. its currently on a 5.3l but i'm going to have to build it at some point and would like to know what to build it to.
also what would be the minimum CI to spool two of these? that's something else i have thought of.
also what would be the minimum CI to spool two of these? that's something else i have thought of.
06-22-2009, 08:52 PM
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really? i thought alot of people say not to do 402 with a tc78. if it will work i'd do it. if i have to i would upgrade the a/r of the turbine housing.
06-22-2009, 10:34 PM
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What you have is ideal on a 346, a 370 would prob be pretty good as well, I have one on a 383 and think i need to step up to a bigger AR housing, spools up stupid fast though 
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06-23-2009, 07:23 PM
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not really unless you had a $1000 doorknob and was building a $3000 house. the turbo is install on the truck now. works great but if the motor goes i'll need to rebuild it. not everybody has the money to buy new **** all the time so i would prefer to not have to buy another turbo. so if i can build a good motor that fits the turbo that's what i would rather do. also if i go stock ls1 displacement i can use my stock 5.3l block and not have to buy a new block.
06-23-2009, 07:37 PM
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not really unless you had a $1000 doorknob and was building a $3000 house. the turbo is install on the truck now. works great but if the motor goes i'll need to rebuild it. not everybody has the money to buy new **** all the time so i would prefer to not have to buy another turbo. so if i can build a good motor that fits the turbo that's what i would rather do. also if i go stock ls1 displacement i can use my stock 5.3l block and not have to buy a new block.
If you're running a single, you could do it with 14-15 psi.
Twin turbo's will give you alot more flow... but remember, you're also cutting the exhaust supply in half by feeding two turbo's. A single turbo will get you more boost down low. (good for daily driver)
By the way... trucks with boost > cars with boost
06-23-2009, 07:58 PM
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If you have Twins of that turbo, a 408 would do just nicely for 800hp. You'll need about 12~ psi to get there with that setup.
If you're running a single, you could do it with 14-15 psi.
Twin turbo's will give you alot more flow... but remember, you're also cutting the exhaust supply in half by feeding two turbo's. A single turbo will get you more boost down low. (good for daily driver)
By the way... trucks with boost > cars with boost
If you're running a single, you could do it with 14-15 psi.
Twin turbo's will give you alot more flow... but remember, you're also cutting the exhaust supply in half by feeding two turbo's. A single turbo will get you more boost down low. (good for daily driver)
By the way... trucks with boost > cars with boost
i agree the down low boost is great for DD. especially in a truck. i need to go look at what a/r housings they make for the tc78. twins sound cool, they really do but then there is that $$$$$ thing again. buuuut if a tc78 will feed a 408 until i gather money for twins that would work!
i agree with the truck thing at the bottom, only my heavy *** truck broke the trans and i'm waiting on mine to get here. oh, how i can't wait.
06-24-2009, 07:20 AM
#11
there is some really bad advise in this thread.............
with that turbo and being a t4 frame, plus i'm thinking you dont want to rev it out to far, i would say the best option would be a 346 cubed and rev it to about 6800-7000
if you want to make a little more power (probably not a whole lot but a little more) and rev it out, build the 5.3 and rev it to 7500 or so.
with that turbo and being a t4 frame, plus i'm thinking you dont want to rev it out to far, i would say the best option would be a 346 cubed and rev it to about 6800-7000
if you want to make a little more power (probably not a whole lot but a little more) and rev it out, build the 5.3 and rev it to 7500 or so.
06-24-2009, 07:49 AM
#12
No kidding really bad advice for sure.
From experience with the TC units......370 is the absolute max I would go. Exhaust back pressure even with a 1.15 a/r turbine housing is really high at the 800rwhp mark. They work great on 5.3l's!
To run two of them on a 402 you would want to go with a .81 turbine housing at the 1000hp level and they will not light up any time soon. I would expect full boost at about 5000-5500.
From experience with the TC units......370 is the absolute max I would go. Exhaust back pressure even with a 1.15 a/r turbine housing is really high at the 800rwhp mark. They work great on 5.3l's!
To run two of them on a 402 you would want to go with a .81 turbine housing at the 1000hp level and they will not light up any time soon. I would expect full boost at about 5000-5500.
06-24-2009, 11:44 AM
#13
No kidding really bad advice for sure.
From experience with the TC units......370 is the absolute max I would go. Exhaust back pressure even with a 1.15 a/r turbine housing is really high at the 800rwhp mark. They work great on 5.3l's!
To run two of them on a 402 you would want to go with a .81 turbine housing at the 1000hp level and they will not light up any time soon. I would expect full boost at about 5000-5500.
From experience with the TC units......370 is the absolute max I would go. Exhaust back pressure even with a 1.15 a/r turbine housing is really high at the 800rwhp mark. They work great on 5.3l's!
To run two of them on a 402 you would want to go with a .81 turbine housing at the 1000hp level and they will not light up any time soon. I would expect full boost at about 5000-5500.
however i also had the t76's
06-24-2009, 04:36 PM
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No kidding really bad advice for sure.
From experience with the TC units......370 is the absolute max I would go. Exhaust back pressure even with a 1.15 a/r turbine housing is really high at the 800rwhp mark. They work great on 5.3l's!
To run two of them on a 402 you would want to go with a .81 turbine housing at the 1000hp level and they will not light up any time soon. I would expect full boost at about 5000-5500.
From experience with the TC units......370 is the absolute max I would go. Exhaust back pressure even with a 1.15 a/r turbine housing is really high at the 800rwhp mark. They work great on 5.3l's!
To run two of them on a 402 you would want to go with a .81 turbine housing at the 1000hp level and they will not light up any time soon. I would expect full boost at about 5000-5500.
06-25-2009, 07:15 AM
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So you're saying a 5.3 will be a better choice over a 6.0 when using a tc series turbo? That would make my day because those are everywhere here. If anybody can use 650hp on the street, then I personally think they're getting away from a "street car" set up.
06-25-2009, 12:38 PM
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Wow... i think alot of people here are talking about what they have read, not experience.
Remember this... the STS kit with a .60 trim turbo makes 600hp on a 347 @10-11 lbs of boost. Stock engine.
Your 5.3L as it is now, keep your single tc78... they're matched up well.
When you get twins, going to a 5.7L, you'll not be boosting till mid RPMS, not down low at all. It will feel squishy haha.
With the 408, and twins, you'll be able to push 800hp on low boost easily. And you'll get the power down low, and WILL NOT die off. meaning, you will not choke out both of those turbos.
My recomendation... keep the 5.3 and tc78, you'll be golden... Later on, Bore to a 408 and buy another tc78.
Remember... twin .98 a/r turbine housings is a pretty substantial size... and you'll only be spinning it with HALF your engine! You could go to a 1.xx a/r for more power down the road, but i wouldn't worry about it.
Remember this... the STS kit with a .60 trim turbo makes 600hp on a 347 @10-11 lbs of boost. Stock engine.
Your 5.3L as it is now, keep your single tc78... they're matched up well.
When you get twins, going to a 5.7L, you'll not be boosting till mid RPMS, not down low at all. It will feel squishy haha.
With the 408, and twins, you'll be able to push 800hp on low boost easily. And you'll get the power down low, and WILL NOT die off. meaning, you will not choke out both of those turbos.
My recomendation... keep the 5.3 and tc78, you'll be golden... Later on, Bore to a 408 and buy another tc78.
Remember... twin .98 a/r turbine housings is a pretty substantial size... and you'll only be spinning it with HALF your engine! You could go to a 1.xx a/r for more power down the road, but i wouldn't worry about it.
