Just installed alta boost gauge the other day and recorded highest boost at 29-30 psi with all mods on my sig.my car is a factory JCW european version 211hp from factory as opposed to US 208 hp. Not sure if this make any difference at all.


Let me know your numbers as i think i have too much boost. My car runs very string though with a very aggressive tune from Evolve.

 

Do you have the Dyno graphs to show your numbers?

 

With Alta AP stage 3 tune I'm seeing 21psi. Anything over 23 on a JCW would have me double checking things.

 

You shouldnt have 30 psi. I hit 22 with the AP, and I was shocked at that. Just wondering: Did you follow the instructions alta gave you? Im thinking about the gauge but the install looks complicated with ripping out the center console as suggested. Also would like to know what tools were needed. Thanks

 

I would just like to know how he made the numbers and to see the Dyno sheet.

 

Boost sounds high. hp/tq numbers seem about right if they are bhp and not whp.

 

I had a mechanic help me with install which was pretty straight forwarded per ALTA instructions. It sounds high, normally is hitting 25 at high boost but twice I saw going up to 29-30 psi

 

I didn't even think the stock Turbo could hit 30psi. I can't see your mods as I'm on my phone, but 25 is alright with the proper mods and a good tune. And when do the spikes occur? Like 2k revs, or near red line?

 

Hitting 30 psi would have me very concerned.

 

Correct, NOT WHP. I wish...

 

third gear seems to be where I get most boost. Today I tried a vid but I hit 22-25 max. It seems like over that is when tires get loose, lost traction.

 

So how do you have exact HP/TQ numbers? Do you have a dyno sheet?

 

I like to see this too.

 

I'm thinking your gauge is off considerably.

 

dyno graph

 

dyno

 

with a stage one AP 21lbs tops

 

Does that dyno graph not worry you?

Was the car strapped down properly and looks like they ended the run early...

 

Any chance for a bigger better copy so we can see more details?

 

You might want to check that the turbo wastegate is functioning properly. Try connecting a vacuum pump to the diaphragm on the turbo --- engine off, and look for movement of the wastegate actuator. Not real easy to get to, but this is one cause of over boosting. You might just have a bad vacuum hose / connection --- best case. Worst case would be a broken wastegate.

A little background --- when I converted to a Garrett, I took it to Jan for a tune. Had to limp over the Sierra's because of terrible noises when boosting. Jan told me the wastegate is probably not functioning, then proceeded to explain how / why wastegates work. Turns out I had the wastegate connected wrong --- Garrett wastegate works on positive pressure, not a vacuum. Point here is my boost went ape, and with a GT28RS, that's way to much boost.

Hope your problem is as simple as a bad hose ---

 

If you hit 30 psi flooring it around 2k revs, then I can see why you are getting 30 psi. I get around 16 normally, but can hit 22psi while manually selecting gears and flooring it at low revs. Maybe try getting over boost removed on tune, or just downshift when you accelerate. Not really sure what else to say. Does the tune get rid of the boost limiter?

 

Quick question concerning your tune. Was it a dyno tune or E-tune?