Wastegate Too Small?
10-04-2009, 11:37 PM
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Wastegate Too Small? Ok so we started tuning my STOCK LS1 Long Block (other than springs/pushrods) Single T70 front mount car this weekend, and I have a MP T70 with a TiAL 38MM Wastegate and a 50mm Blow-Off Valve.... The spring in the Wastegate is a small red spring (should be 5.8psi)... It seems we were seeing closer to 8psi even by 5,000rpms, so Im wondering if there is anything I can do to pull it back a little bit....
I have the reference in the cold pipe after the intercooler....so I was wondering if I placed the reference pre-intercooler if I could cheat a little less psi by catching the reference charge before the pressure drop of the IC....and get the gate to open on that charge.
Also, the car has an open 3" Downpipe that dumps AT the K-Member....I plan to run some pipe and a muffler dumping a bit father back...will that reel me back down any as far as losing any boost?
Im not overly concerned as long as the car doesnt end up 10+psi by 6000... but I would really like to see a lower PSI off the Gate, and then dial it up with my MBC... Thoughts?
I have the reference in the cold pipe after the intercooler....so I was wondering if I placed the reference pre-intercooler if I could cheat a little less psi by catching the reference charge before the pressure drop of the IC....and get the gate to open on that charge.
Also, the car has an open 3" Downpipe that dumps AT the K-Member....I plan to run some pipe and a muffler dumping a bit father back...will that reel me back down any as far as losing any boost?
Im not overly concerned as long as the car doesnt end up 10+psi by 6000... but I would really like to see a lower PSI off the Gate, and then dial it up with my MBC... Thoughts?
10-05-2009, 12:41 AM
#2
Having more of an exhaust maybe help alittle bit and referencing the gate before the intercooler may also help alittle bit. I have not had much luck with 38mm gates on ls1 motor's, I only use 44mm+.
I try to shoot for one boost level for pump gas and use a controller for the rest. To me it always seems like gate spring only controls boost best when the gate is properly sized and installed.
I try to shoot for one boost level for pump gas and use a controller for the rest. To me it always seems like gate spring only controls boost best when the gate is properly sized and installed.
10-05-2009, 01:00 AM
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I guess I'll see what the exhaust does, and possibly move the reference... I got a good deal on the 38mm and knew it miiight be pushing it but I was hoping on a dead stock LS1 it would be sufficient...
Not a big deal as long as the creep doesnt go too far on me....
Not a big deal as long as the creep doesnt go too far on me....
10-05-2009, 09:48 AM
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Same issue you are having, I am having.
We figured out it was my wastegate pipe routing that causes the boost creep.
If I remember correctly, you have the wastegate plumbed into only 1 side of the merge right? If so, Bingo.
Remember, the pipe needs to be angled with flow direction of the crossover and in the middle of the merge.
BTW, you probably won't see more than 10psi even with boost creep and 5.8 spring. Your reference location is ok.
We figured out it was my wastegate pipe routing that causes the boost creep.
If I remember correctly, you have the wastegate plumbed into only 1 side of the merge right? If so, Bingo.
Remember, the pipe needs to be angled with flow direction of the crossover and in the middle of the merge.
BTW, you probably won't see more than 10psi even with boost creep and 5.8 spring. Your reference location is ok.
10-05-2009, 11:14 AM
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This is probably the problem...
As for my WG location, it LOOKS like its on one pipe, but its reading both...Its just on the side vs the front or back, but its up high enough that its after the two pipes merge....and its almost a 90* turn so I know its not 100% optimal, but it is not going back against flow...
Again, as long as it doesnt get out of hand, Im not changing it probably
As for my WG location, it LOOKS like its on one pipe, but its reading both...Its just on the side vs the front or back, but its up high enough that its after the two pipes merge....and its almost a 90* turn so I know its not 100% optimal, but it is not going back against flow...
Again, as long as it doesnt get out of hand, Im not changing it probably
