Tim King

iTrader: (7)

I have a g8 gt with twin 67mm turbos with 44mm wastegates. With 8lbs springs I was getting 6lbs of boost, 10lbs springs moved me to 7.5, 13lbs springs gave me 10psi, 14.5 springs has me at 12psi I had a eboost2 controller and couldn't get it to raise my boost so I got rid of it and put on a manual which would raise my boost. I just put a eboost street on it and still won't raise my boost consistantly, I had my setting to 40 and it gave me 14.5 psi but then an hour later had me at 12??? In my scan it hits 17psi but quckly bleeds down to 12psi I have no idea what to do next, I see you can add a 2nd solenoid, what is the purpose of this?

98Camarod

iTrader: (43)

The second solenoid is for faster response. How do you have it plumbed? Have you checked for hot/cold side leaks?

Shoaf85

iTrader: (9)

Try to do a smoke test to check for leaks. If no leaks are found use your boost source to the waste gates/boost controller from intake manifold instead of compressor housings, if not already like this.

stevieturbo

Draw exactly how you have it plumbed.

And when you say "you see you can add a 2nd solenoid"

There are quite a few ways you can make use of two or more solenoids. So again clarify what you have seen and are referring to

Which setting do you have at 40, and what are the other settings ?

Given you've basically had the same problem with both units, it has to be either a plumbing or settings problem.

Tim King

iTrader: (7)

I can't draw for crap but here is how I have it. Also will post a pic of how close the wastegates are, could that cause any issues?

ws6turbo

Only few hundred miles on my setup, no known leaks and I only boost 8psi on a 9psi spring, few people I talked to say they boost 1-3 psi under the springs psi. . I've also had the car inspected and couple loos ends tied up since the car has been done at H&D motorsports( who builds race cars) and they said nothing was wrong so I'm just fine with mine. I don't know why this happens but it does

stevieturbo

Plumbing looks ok. Ideally try and keep all hose runs as short as possible, and it's nice if they can be kept even.

ie run the line from solenoid to tee piece, then equal lengths from the tee to each wastegate.

But....am I seeing the turbo setup correctly in that the exhaust gases almost have to turn 180 degrees in order to escape out the wastegate ?

If so, that is terrible gate placement. Are they both like that ?

From a point of view of keeping lines as short as possible and a well balanced system, using Turbosmarts "Single port, twin solenoid, twin turbo connection Method" might be better.

What is control like when all settings are at zero, but controller turned on ?

ie GP1 and SN1 at zero and only working with SP1 to raise boost pressure.

Tim King

iTrader: (7)

I've never tried all settings @ 0 Right now I have GP1=11 SP1= 40 SN1= 30 overboost=17.5

stevieturbo

Turn them all to zero.

Your gate pressure is far too high for low boost, and so is the sensitivity.

GP will help improve spool a little once you have SP set to achieve your desired boost. Going too high will just cause overboosts, oscillations, all sorts of silly things. GP1 must be a 4-5 psi below your boost target. But always start with zero.

Likewise sensitivity if too high can cause all sorts of problems. Start at zero. Unless boost falls off at higher rpm's leave it alone.
Or you can increase it slowly to try and help it maintain boost higher in the rpms.

Tim King

iTrader: (7)

What should I set overboost to if I'm trying for 15psi

stevieturbo

set it to higher than 15psi, say 18-19. That way it'll allow for a small overboost still close the solenoid to reduce boost if it goes too high.

Again setting it too low will cause it to try and abruptly cut boost

Johnv

I've seen excessive back pressure from a restrictive exhaust and chambered mufflers cause the same problem,guy built a bigger exhaust with straight through muffler and had the opposite problem, was overboosting.

Try a run with dump pipes only and see what happens.

redss82

What steve said but I like to plumb my eboost street to put pressure to the top of the wastegate i run a can run 7psi at sp1 set at 0 and have had it hold 22 psi getting close too 80

Tim King

iTrader: (7)

So I ran new lines of equal length to the wastegates with 6mm silicone hose and ran a line from manifold vacuum and got rid of the compressor line. Turned all the setting on the controller to 0 except overboost set at 18psi. I drove the car and had
12psi@0 turned it duty cycle to 20 and got
13psi@20
14.2@35
14.5@40 but tappered down to 14psi

stevieturbo

Once you have the setpoint to achieve the boost you want, you can try raising the gate pressure to say 3-4psi below your target boost.

Going too high can cause an overboost, so just try and see what works.
This may also stabilise the slight drop off too. Although 0.5psi is nothing really.

If there is a larger drop off at the top end, then you can try raising the sensitivity to try and keep it steady.