Question about blow through turbo design
09-20-2010, 02:43 PM
#1
Staging Lane
Thread Starter
Question about blow through turbo design So I picked up a magazine a couple days ago and it had an article on an ebay twin turbo build.
http://www.carcraft.com/techarticles...ine/index.html
My question isnt about the turbos, ive read plenty on those POS's. My questions are about the blow through setup. They did some stuff to the carb to make it work with the turbo. Their carb is just an old holley 850 double pumper. The first thing they did was drill out the power valve channel restrictors with a 3/32 drill bit. The next thing they did was replace the brass floats with nitrophyl so they werent crushed by boost pressure??
My questions: Why did they drill it and what does it do? How much boost will crush stock floats? What power level can i get to with my holley HP 750 before i need more carb? Is it worth it to hack up my new carb or should i start with a bigger one? How are blow through setups when it comes to tuning, are they manageable?
I have a built/forged ls6 w/243's that has 10.65 comp. It made 500FWHP at 6000rpm on 90 octane. I want to put a single turbo infront of it but i dont know how far i need to bring down the compression. My engine builder said I could run about 5lbs of boost now, before i need race gas or lower comp. How much more power will 5lbs get me? How will my motor act with a small turbo and low boost? Is it even worth it or should I get some different heads and go with more boost?
Thanks, any advice is greatly appreciated (and needed!)
http://www.carcraft.com/techarticles...ine/index.html
My question isnt about the turbos, ive read plenty on those POS's. My questions are about the blow through setup. They did some stuff to the carb to make it work with the turbo. Their carb is just an old holley 850 double pumper. The first thing they did was drill out the power valve channel restrictors with a 3/32 drill bit. The next thing they did was replace the brass floats with nitrophyl so they werent crushed by boost pressure??
My questions: Why did they drill it and what does it do? How much boost will crush stock floats? What power level can i get to with my holley HP 750 before i need more carb? Is it worth it to hack up my new carb or should i start with a bigger one? How are blow through setups when it comes to tuning, are they manageable?
I have a built/forged ls6 w/243's that has 10.65 comp. It made 500FWHP at 6000rpm on 90 octane. I want to put a single turbo infront of it but i dont know how far i need to bring down the compression. My engine builder said I could run about 5lbs of boost now, before i need race gas or lower comp. How much more power will 5lbs get me? How will my motor act with a small turbo and low boost? Is it even worth it or should I get some different heads and go with more boost?
Thanks, any advice is greatly appreciated (and needed!)
09-20-2010, 06:18 PM
#4
i have a blow thru set up. i use to run a D1SC 9psi cam only lq9. made 626rwtq and 510rwhp reving to 5800rpms. best run i had was 9.8@139.xx still had some left in it was on the limiter about 200ft before the stripe and 60ft needed some help. i just switched to a tc78 turbo and now the tuning has started all over again. with the procharger that was the first carb i have ever touched. and with a blower it is easier to tune then a turbo.
if you want good info you have to go to theturboforums ALOT of blow thru on there.
if you want good info you have to go to theturboforums ALOT of blow thru on there.
09-21-2010, 03:30 AM
#5
Staging Lane
Thread Starter
thanks. I will check it out. It seems to me that it can be done with out too much trouble. My power goals arent very high, (whatever my tko600 will take)
about 600tq. I am going to think about it for awhile, I can always sell my intake/carb setup and go with fuel injection. It looks like the general opinion is injection is easier to tune.
about 600tq. I am going to think about it for awhile, I can always sell my intake/carb setup and go with fuel injection. It looks like the general opinion is injection is easier to tune.
