Convertor and Boost?
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Joined: Oct 2011
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Convertor and Boost? Just finished up my 3 month project. We went from a 498 Big Block Chevy to an 5.3 twin turbo. We just started tuning it on the dyno and noticed immediately that it would go to 15lbs of boost footbraking. Can I assume that the convertor is probably NOT going to work then? It is an ATI 9" I was only hoping to run 15lbs total to reach my goal and definitely no more than 19lbs.
How much will it affect it on the dyno also? We are using a rear wheel dyno and surely it will affect the numbers it puts down if it is blowing through the convertor.
How much will it affect it on the dyno also? We are using a rear wheel dyno and surely it will affect the numbers it puts down if it is blowing through the convertor.
i guess i dont understand your problem... the converter really doesnt matter as far as boost.. wastegate controls boost. now if the power your making is blowing through the converter thats another problem.
His new motor is making more power obviously than his old one. Higher tq. output will push the stall speed higher than it is rated for at the power output it was designed to stall for. It's obviously way loose and it's not big enough in diameter to hold the sudden increase in power the way boost comes in unlike a linear curve of a N/A motor.
Where did the tq. peak on the old motor and what was it rated to stall at? What rpm are you seeing when it makes the 15psi and as it gets to 15psi how fast does it rise? Does it make target boost and not go over it or have you seen if it holds the boost your targeting? Manual or Electronic boost controller?
Thread Starter
TECH Fanatic
Joined: Oct 2011
Posts: 1,425
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Read up a little more on how torque output affects stall speed.
His new motor is making more power obviously than his old one. Higher tq. output will push the stall speed higher than it is rated for at the power output it was designed to stall for. It's obviously way loose and it's not big enough in diameter to hold the sudden increase in power the way boost comes in unlike a linear curve of a N/A motor.
Where did the tq. peak on the old motor and what was it rated to stall at? What rpm are you seeing when it makes the 15psi and as it gets to 15psi how fast does it rise? Does it make target boost and not go over it or have you seen if it holds the boost your targeting? Manual or Electronic boost controller?
His new motor is making more power obviously than his old one. Higher tq. output will push the stall speed higher than it is rated for at the power output it was designed to stall for. It's obviously way loose and it's not big enough in diameter to hold the sudden increase in power the way boost comes in unlike a linear curve of a N/A motor.
Where did the tq. peak on the old motor and what was it rated to stall at? What rpm are you seeing when it makes the 15psi and as it gets to 15psi how fast does it rise? Does it make target boost and not go over it or have you seen if it holds the boost your targeting? Manual or Electronic boost controller?
Thanks again.
Thanks for the input. I am not sure but will find out. I do know I have a manual boost controller and it is all the way off. The wastegates came with one set of springs and never took it apart so I am not sure. I will find out the other info. The tuner just said it footbraked to 15lbs of boost and it surprised him. Said nothing else. That was why I was posting. He thought the convertor might be way loose and with how quickly the power comes in the convertor would slip. Not sure I am repeating this correctly. Still trying to learn.
Thanks again.
Thanks again.
So if you have light springs in it, only made 5 or so lbs on wot pulls and your controller is off how did he make 15lbs footbraking it? Was he footbraking it all out on the dyno with the dyno brake on? Something sounds fishy here.
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