alittle different turbo question
also what would be the minimum CI to spool two of these? that's something else i have thought of.
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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.
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.
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
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.
so you will have a better chance of making 800 with the 5.3 then a 5.7
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.



