I also over boosted w cut out open
May 24, 2013 | 01:27 PM
#22
Any one w a daily and no muffler is whacked. It's just to loud drone or no drone.
W my current setup, the spring chart is exactly what I see. I like that a lot.
Again my current thinking is install another wg w a higher spring for RACING where I want more power and the cut out open. When towing, daily or letting someone borrow my
Truck I don't want them hauling ***
W my current setup, the spring chart is exactly what I see. I like that a lot.
Again my current thinking is install another wg w a higher spring for RACING where I want more power and the cut out open. When towing, daily or letting someone borrow my
Truck I don't want them hauling ***
May 24, 2013 | 01:49 PM
#23
Or do a regulator and a solenoid for a home made boost controller. I had one with my old STS kit and it worked good.
Its on my buddys truck right now. 8psi off and 16psi on.
Its on my buddys truck right now. 8psi off and 16psi on.
May 24, 2013 | 02:20 PM
#25
Joined: Jan 2006
Posts: 16,282
Likes: 438
From: Huntsville, AL
Similar situation on my truck...with a 6lb spring, it will still make 18psi, just be more laggy. When I put my controller on it, it will stay closed longer, but once its opened, its still at 18psi.
The solution to overboosting is to either decrease the turbo efficiency with a smaller downpipe or lower AR turbine housing...neither of which you want to do because they hurt performance, or increase the wastegate effectiveness. You can do that by moving the gate to a better spot, venting it to atmosphere, or installing a second or third gate. Tuning multiple wastegate setups can get pretty tricky though.
May 24, 2013 | 02:23 PM
#26
Turbos dont like anything after the turbine. Their ideal world is a a straight dump to atmosphere after a few inches. I have a 4" full exhaust and a straight through muffler, and with a cutout it makes a large difference even with that. Thats why I went to a 5" dp and 5" cutout. After the cutout, it goes back to 4".
Turbines work off something called expansion ratio. Basically the turbine works better if you can get a very large pressure/heat drop before and after it. So this will be your backpressure from the engine compared to the pressure between the turbo and tailpipe exit. The bigger this ratio the happier the turbo is, meaning it will respond faster to a change in conditions (ie, more throttle), and allow a higher maximum speed (boost). There is a diminishing return here though, thats why backpressure ratio is so important, which is the drive pressure of the turbine divided by the boost pressure from the compressor. Most factory turbo setups are around 2-3, which a good aftermarket kit is between 1.5-2.5, and a pure race setup will be very close to 1. The higher the bp ratio, the more responsive the turbo, but the more choked it is in the upper rpms. The lower the ratio is exactly the opposite, very laggy but extremely efficient at upper rpm.
Now when you free up the turbo with an open exhaust your wastegate will probably have a harder time controlling the turbo because the turbo is much more efficient. Wastegate size and placement have a lot to do with how effective it is.
Case in point, with my setup with a 50mm gate, the least amount of boost I can run with my cutout open is about 18psi, even if the gate is wide open the whole time. This is due to the wastegate location and routing.
Turbines work off something called expansion ratio. Basically the turbine works better if you can get a very large pressure/heat drop before and after it. So this will be your backpressure from the engine compared to the pressure between the turbo and tailpipe exit. The bigger this ratio the happier the turbo is, meaning it will respond faster to a change in conditions (ie, more throttle), and allow a higher maximum speed (boost). There is a diminishing return here though, thats why backpressure ratio is so important, which is the drive pressure of the turbine divided by the boost pressure from the compressor. Most factory turbo setups are around 2-3, which a good aftermarket kit is between 1.5-2.5, and a pure race setup will be very close to 1. The higher the bp ratio, the more responsive the turbo, but the more choked it is in the upper rpms. The lower the ratio is exactly the opposite, very laggy but extremely efficient at upper rpm.
Now when you free up the turbo with an open exhaust your wastegate will probably have a harder time controlling the turbo because the turbo is much more efficient. Wastegate size and placement have a lot to do with how effective it is.
Case in point, with my setup with a 50mm gate, the least amount of boost I can run with my cutout open is about 18psi, even if the gate is wide open the whole time. This is due to the wastegate location and routing.
That's what I said.
. --
How much louder is it with the cut out open?
May 24, 2013 | 05:39 PM
#29
On The Tree
Joined: May 2013
Posts: 121
Likes: 0
From: Jennings LA
No, a boost controller really just controls the behavior of the wastegate within the limits of the gates. A good controller can control cracking pressure, opening rate, and gate position. It cannot under any circumstance alter how much the gate can physically flow when all the way open.
Similar situation on my truck...with a 6lb spring, it will still make 18psi, just be more laggy. When I put my controller on it, it will stay closed longer, but once its opened, its still at 18psi.
The solution to overboosting is to either decrease the turbo efficiency with a smaller downpipe or lower AR turbine housing...neither of which you want to do because they hurt performance, or increase the wastegate effectiveness. You can do that by moving the gate to a better spot, venting it to atmosphere, or installing a second or third gate. Tuning multiple wastegate setups can get pretty tricky though.
Similar situation on my truck...with a 6lb spring, it will still make 18psi, just be more laggy. When I put my controller on it, it will stay closed longer, but once its opened, its still at 18psi.
The solution to overboosting is to either decrease the turbo efficiency with a smaller downpipe or lower AR turbine housing...neither of which you want to do because they hurt performance, or increase the wastegate effectiveness. You can do that by moving the gate to a better spot, venting it to atmosphere, or installing a second or third gate. Tuning multiple wastegate setups can get pretty tricky though.
When I read the initial post he stated this was a kit he purchased and I assumed it was from a reputable vendor that would include the proper supporting components such as the wastegate... Is that the case? This is a kit purchased from a vendor that comes with a wastegate not matched to the turbo???
May 24, 2013 | 05:50 PM
#30
On The Tree
Joined: May 2013
Posts: 121
Likes: 0
From: Jennings LA
On the subject of wastegate springs.. I know at times we are all under budget constraints but I feel an electronic boost controller is a vital component of a turbo build. There is allot at stake to this part of the the system operating correctly.
When using springs lots of things can effect your actual boost allowing it vary widely. Even in low boost systems you can run into serious issues as Nonneiselman's case. Hitting 25 psi can bring on serious damage in a matter of seconds. I know Im new to this forum, Please don't take me as trolling. Jus voicing my opinion.
When using springs lots of things can effect your actual boost allowing it vary widely. Even in low boost systems you can run into serious issues as Nonneiselman's case. Hitting 25 psi can bring on serious damage in a matter of seconds. I know Im new to this forum, Please don't take me as trolling. Jus voicing my opinion.