Boost Won’t go Any Higher…???
Thread Starter
Launching!
Joined: Jun 2008
Posts: 218
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Boost Won’t go Any Higher…??? Car is a 2000 t/a, on3 kit and 78/75. Manual boost controller.
Tried to turn the boost up a little bit from 12lbs.
Turned the **** on the boost controller in and was not seeing any gain.
The boost controller is completely closed, not letting any air to the wastegate…yet boost still peaks below 13 psi.
So how is the wastegate still opening..back pressure? Or something else is going on?
Tried to turn the boost up a little bit from 12lbs.
Turned the **** on the boost controller in and was not seeing any gain.
The boost controller is completely closed, not letting any air to the wastegate…yet boost still peaks below 13 psi.
So how is the wastegate still opening..back pressure? Or something else is going on?
Put an EBC in it.
I used the Cortex in my last car and with it tied into the engine RPM and speed sensor in the transmission I could do boost by gear and boost by speed, worked really well.
I used the Cortex in my last car and with it tied into the engine RPM and speed sensor in the transmission I could do boost by gear and boost by speed, worked really well.
Car is a 2000 t/a, on3 kit and 78/75. Manual boost controller.
Tried to turn the boost up a little bit from 12lbs.
Turned the **** on the boost controller in and was not seeing any gain.
The boost controller is completely closed, not letting any air to the wastegate…yet boost still peaks below 13 psi.
So how is the wastegate still opening..back pressure? Or something else is going on?
Tried to turn the boost up a little bit from 12lbs.
Turned the **** on the boost controller in and was not seeing any gain.
The boost controller is completely closed, not letting any air to the wastegate…yet boost still peaks below 13 psi.
So how is the wastegate still opening..back pressure? Or something else is going on?
I tried using a 3-4 lb. spring but the BP would push the gate open, had to step up to a 7 lb. spring to get control back.
Even with the cutout open I still couldn't run that light of a spring.
This was on gate only as well, I never tried going back to the lighter spring when the EBC went in.
Try disconnecting the bottom port to the wastegate (plug that line). You should see more than 12psi. Boost applied to under the diaphragm will help open the gate... even if you remove the top line its still assisting. remove the bottom line and keep an eye on the boost gate it will def go up. Likely its BP pushing the gate open... its worse the bigger the gate is and the pre turb BP. I have 21psi worth of springs in a 60mm summit WG (piston style) to get 7psi of boost out of a 5.3 with a 2.5" crossover and a VS billet 70/70 turbo with a 3" down pipe. I know its 21psi bc I bench test the cracking pressure and open pressure. On my other car with a 60mm HKS knock off WG with basically the same combo I saw 2.5-3:1 on the BP pre turbo so at 7psi of boost that was 18-21psi pre turbo pushing on the gate piston. Also its not a 1:1 ratio as the bigger the WG piston the more air the pressure has to push on it which means bigger WG will open easier than smaller gates as they have more surface area. If your getting 12psi on spring with a MBC or EBC you should be able to effectively double that pressure as it cancels out the pressure being applied to the underside of the diaphragm (bottom port).
Also you didn't say if your referencing to turbo compressor housing, intake pipe, intake manifold? You need to measure the pressure drop if your using anything after the intercooler. Basically if your compressor housing sourced you could have 12psi at the housing and only 10psi in the intake... so the gate is reacting to the 12psi source not the 10psi your seeing.
Also you didn't say if your referencing to turbo compressor housing, intake pipe, intake manifold? You need to measure the pressure drop if your using anything after the intercooler. Basically if your compressor housing sourced you could have 12psi at the housing and only 10psi in the intake... so the gate is reacting to the 12psi source not the 10psi your seeing.
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Joined: Dec 2022
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Definitely backpressure blowing the gate.
I had a 3584rs turbo on my setup last year and with 14 psi worth of spring it made only 8 with the ebc off. And I could hardly get over 15psi with the controller on due to the backpressure that was over 3 to 1
Swapped the turbo over the winter for a g42 and with the same spring setup I can make much more boost. Haven't measured backpressure on this setup yet
I had a 3584rs turbo on my setup last year and with 14 psi worth of spring it made only 8 with the ebc off. And I could hardly get over 15psi with the controller on due to the backpressure that was over 3 to 1
Swapped the turbo over the winter for a g42 and with the same spring setup I can make much more boost. Haven't measured backpressure on this setup yet
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This thread is exactly what I needed to read. I swapped a turbo on my car this winter and was surprised that with the 8psi springs in my car, I was only seeing 5psi, but when I went to the 16 psi springs (hoping to see 10psi) I was only seeing about 8psi. I'm running a 7875 billet wheel with .96 A/R with 2.5" crossover and Summit 50mm BOV. Full 3" exhaust to a pretty restrictive quiet walker muffler. I was thinking it was something else causing this, but it sounds like it's "normal" based on the higher BP. Currently not running an EBC and running only on the springs, but I'm working on installing a Dial-a-Boost and updating my tune.
I don't mean to piggyback on the OP's thread, but this nearly the same question I was about to ask. What is the preference for referencing the wastegate? Right now I have pulling off of my lower intake manifold since I was hoping to have the wastegate see the true boost my engine is seeing. Is that wrong?
I don't mean to piggyback on the OP's thread, but this nearly the same question I was about to ask. What is the preference for referencing the wastegate? Right now I have pulling off of my lower intake manifold since I was hoping to have the wastegate see the true boost my engine is seeing. Is that wrong?
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Verdad Gallardo This thread is exactly what I needed to read. I swapped a turbo on my car this winter and was surprised that with the 8psi springs in my car, I was only seeing 5psi, but when I went to the 16 psi springs (hoping to see 10psi) I was only seeing about 8psi. I'm running a 7875 billet wheel with .96 A/R with 2.5" crossover and Summit 50mm BOV. Full 3" exhaust to a pretty restrictive quiet walker muffler. I was thinking it was something else causing this, but it sounds like it's "normal" based on the higher BP. Currently not running an EBC and running only on the springs, but I'm working on installing a Dial-a-Boost and updating my tune.
I don't mean to piggyback on the OP's thread, but this nearly the same question I was about to ask. What is the preference for referencing the wastegate? Right now I have pulling off of my lower intake manifold since I was hoping to have the wastegate see the true boost my engine is seeing. Is that wrong?
I don't mean to piggyback on the OP's thread, but this nearly the same question I was about to ask. What is the preference for referencing the wastegate? Right now I have pulling off of my lower intake manifold since I was hoping to have the wastegate see the true boost my engine is seeing. Is that wrong?
I'm only running 3 lb springs (2 wgs), I can't find the box with the other ones. Without wg reference my car will make 14 psi at 7100. With C02 my car will make as much as I commanded, which is 18 psi so far.
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Joined: Dec 2022
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By no reference you mean nothing to the bottom side of the gate? That will definitely makes loads of boost haha
one thing to take into consideration when referencing the wastegate to the manifold is that the gate will also see vacuum vs referencing the compressor housing.
Some gates will not like that. I had a gate that whistled at idle from the vacuum on it so I put a one way valve in until I moved it to the compressor
one thing to take into consideration when referencing the wastegate to the manifold is that the gate will also see vacuum vs referencing the compressor housing.
Some gates will not like that. I had a gate that whistled at idle from the vacuum on it so I put a one way valve in until I moved it to the compressor
This thread is exactly what I needed to read. I swapped a turbo on my car this winter and was surprised that with the 8psi springs in my car, I was only seeing 5psi, but when I went to the 16 psi springs (hoping to see 10psi) I was only seeing about 8psi. I'm running a 7875 billet wheel with .96 A/R with 2.5" crossover and Summit 50mm BOV. Full 3" exhaust to a pretty restrictive quiet walker muffler. I was thinking it was something else causing this, but it sounds like it's "normal" based on the higher BP. Currently not running an EBC and running only on the springs, but I'm working on installing a Dial-a-Boost and updating my tune.
I don't mean to piggyback on the OP's thread, but this nearly the same question I was about to ask. What is the preference for referencing the wastegate? Right now I have pulling off of my lower intake manifold since I was hoping to have the wastegate see the true boost my engine is seeing. Is that wrong?
I don't mean to piggyback on the OP's thread, but this nearly the same question I was about to ask. What is the preference for referencing the wastegate? Right now I have pulling off of my lower intake manifold since I was hoping to have the wastegate see the true boost my engine is seeing. Is that wrong?
All good ideas, I appreciate them. Maybe I'll try tapping into the compressor housing for the wastegate and see if that changes anything. The compressor is a good idea with the cutoffs. Any suggestions for a brand for the cutout? Lots of overseas parts out there to weed through.
All good ideas, I appreciate them. Maybe I'll try tapping into the compressor housing for the wastegate and see if that changes anything. The compressor is a good idea with the cutoffs. Any suggestions for a brand for the cutout? Lots of overseas parts out there to weed through.
I firmly believe the closer they are to the turbo, the shorter the lifespan.
Yours would be perfect under the floorboard where the exhaust makes the turn under the firewall, I think.
Someone could tag Zack and he could tell you what boost cutout he's using, he also had his on a toggle switch so he could open it manually.
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Joined: Oct 2022
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From: Louisiana
Vs racing 78/75 next gen 2.5 1.25 ar, dual mac valves, dome pressure sensor, and viair tank controlled by holley. My exhaust is full 3" to the back of the truck but coming off my turbo it has a 4" v band with a y pipe, one side is 3" and goes under the truck to the exhaust, the other side is 4" which goes out the fender with has an electric cutout. My cut out is controlled by a switch but i also have it controlled by a output which is rpm activated, I have it set at 3400rpm and my brake is set at 3800. So when I launch it right before it starts hitting hard on the transbrake the exhaust opens. My dome vs boost is exactly 1v1. I have set on 18 psi and have gone up to 22 with no issues.
Thread Starter
Launching!
Joined: Jun 2008
Posts: 218
Likes: 13
Thanks for all the input and replies
The Wastegate was supposed to have 10-11 psi springs in it.
With only the manifold reference to the bottom port it made like 8psi.
with boost controller installed and completely closed and going to bottom port (so essentially bottom port open) it made 12psi like stated in first post.
i added an 8 lb spring to the wastegate and then it made 12-13 with just manifold reference and no boost controller.
then ran hose to the top port with boost controller inline and was able to make 15psi.
And blew the charge pipe off at the throttle body lol.
Seems it was indeed back pressure opening the gate early.
Now the 80lb injectors are maxed out at 100% duty cycle.
The Wastegate was supposed to have 10-11 psi springs in it.
With only the manifold reference to the bottom port it made like 8psi.
with boost controller installed and completely closed and going to bottom port (so essentially bottom port open) it made 12psi like stated in first post.
i added an 8 lb spring to the wastegate and then it made 12-13 with just manifold reference and no boost controller.
then ran hose to the top port with boost controller inline and was able to make 15psi.
And blew the charge pipe off at the throttle body lol.
Seems it was indeed back pressure opening the gate early.
Now the 80lb injectors are maxed out at 100% duty cycle.
Thanks for all the input and replies
The Wastegate was supposed to have 10-11 psi springs in it.
With only the manifold reference to the bottom port it made like 8psi.
with boost controller installed and completely closed and going to bottom port (so essentially bottom port open) it made 12psi like stated in first post.
i added an 8 lb spring to the wastegate and then it made 12-13 with just manifold reference and no boost controller.
then ran hose to the top port with boost controller inline and was able to make 15psi.
And blew the charge pipe off at the throttle body lol.
Seems it was indeed back pressure opening the gate early.
Now the 80lb injectors are maxed out at 100% duty cycle.
The Wastegate was supposed to have 10-11 psi springs in it.
With only the manifold reference to the bottom port it made like 8psi.
with boost controller installed and completely closed and going to bottom port (so essentially bottom port open) it made 12psi like stated in first post.
i added an 8 lb spring to the wastegate and then it made 12-13 with just manifold reference and no boost controller.
then ran hose to the top port with boost controller inline and was able to make 15psi.
And blew the charge pipe off at the throttle body lol.
Seems it was indeed back pressure opening the gate early.
Now the 80lb injectors are maxed out at 100% duty cycle.
Now get more injector and an EBC, the boost will hit much harder and be more consistent with an EBC as well.
What are you running fuel wise?
If you're on pump gas at 15lbs. you need to be careful, if you have E around go that route for sure.