Originally Posted by THEMEMPHISFORCE

Well dude. My gauge does read vacuum at IDLE, you assume to much. It reads -20 on the vacuum side at idle. And plus I never said it was holding 27 psi at redline. It is a defi boost gauge it isn't some 50 dollar auto meter gauge. And obvisely the ecu is not cuting it because it is reading 27 psi on the gauge. Prior to changing the UIP it only would peak at around 24 - 25 psi plus I had a tuner here locally take a look at everything and he couldn't see anything wrong with anything.

So will an ap with an off the shelf map fix this for me, since everyone seems to think my gauge is broke even when it appears to be working fine to me?

Originally Posted by TTP Engineering

We had the opportunity this week to tune another few 2008 Evo X's in house on the Mustang Dyno AWD-500.



This particular car came in already equipped with the AEM intake system.

The first pull on the dyno we aborted due to excessive boost (in our opinion) on a stock BCS (boost control solenoid) vehicle. (or so we thought)

The boost spike we aborted upon rolling into the throttle was 25.8psi before we let out which we assumed was a result of a problem with the Evo X's boost control system.

We soon learned that along with the AEM intake system's cone filter and airbox, enlarged intake pipe, there was also something very interesting.

We found that the boost control line from the stock BCS which is SUPPOSED to tee both of the outputs from the dual solenoids into a single line back into the intake snorkel was in fact modified by the AEM intake kit.

AEM uses TWO BCS inputs into their intake pipe in conjunction with large hoses designed to increase vacuum onto the smaller BCS lines. The stock BCS lines have the tee removed and not only are they connected individually, they also are connected to AEM's MUCH LARGER intake lines to "suck" the boost control signal to the wastegate away from the dual BCS's, decreasing the signal to the wastegate and increasing boost tremendously.

As previously stated, we aborted the pull due to the boost spike so it could have very well kept climbing.

AEM claims +17whp and +17wtq according to their ad, with the addition of 6psi of boost from their BCS vacuum hosing alone sold with their intake, this is concerning.



____________________

OK, so being that we had deemed 25.8psi and climbing to be excessive, we proceeded to cap one of the two lines to the AEM intake-BCS solenoid lines so that only ONE BCS solenoid was being forced to allow additional boost through.

Here is the result;



As you can see, there is still a peak of 23.8psi which is a few psi more than stock, but not so much as to max out any 25psi boost gauge on the market.

The AFR still appeared well into the rich side of things at 10.3 AFR or so, however the ignition timing appeared to be a bit on the high side with the AEM intake.

Originally Posted by THEMEMPHISFORCE

^^^^So now since you just explained everything which would have been great in your first response, that would have cleared up alot. So my car is fine is what you are telling me, just the gauge is reading like 5 psi high even if it is at 0 psi with the ign on and the car off??? TIA

Originally Posted by dani6785

Its the AEM Intake, that Intake acts like a boost controller and molest your boost.



http://www.zchip.net/newreply.php?do=newreply&p=328

Originally Posted by Hiboost

It's possible that your factory WGA was preloaded more so than most other cars, and after the mods that increased flow your boost is a bit higher. Watch your boost gauge needle next time you get on the highway. If it is hitting 27 psi for 1-2 seconds and then settling to 24-26 psi range it SHOULD be safe to continue to run it like that due to the 10.0:1 or richer tune. Your gauge may also be reading high, I know mine is about 1-1.5 psi high and on higher pressure days it even starts at 1.5 psi when the car is off.

I know the original flash from the factory was allowing more boost from the 3000-4000 rpm range and then after I got the rev 2 reflash it was a bit lower. Try getting the latest reflash and it will lean things out a bit and lower the boost slightly at lower RPM's. No matter what you do the boost will start tapering on the stock turbo at 5500 RPM's from 25 psi down to 19 psi at 7500 best case scenario so the higher boost is really only increasing the low to mid range.

Originally Posted by THEMEMPHISFORCE

I took that evo out for a drive today and this is exactly what it is doing, it will only spike to 27 psi for less than a second and fall very quickly to 18-19 and hold there all the way to redline in every gear except 5th. I did about a dozen pulls on the highway, all where the same, and once in 5th it will hold 23-24 psi up to about 115 mph after that I don't know cuz well I was doing 115 mph. It does this 27 psi boost spike right at 4000 rpm is the best I could tell while watching the road and the boost gauge. So I think my boost gauge is working correctly, but I will have it dyno'd in the months to come to confirm. My best guess at this point from all the comments between two forums is that I don't have anything to worry about and my car is fine at this point. Tune soon to come. Thanks all

Originally Posted by THEMEMPHISFORCE

First off, NO tune, it even says no tune in the title. Secondly, it is just a 27 psi spike, if my gauge is not off, which it could be. And lastly no pill mod, the AEM intake does that for me. Just to bring this to rest since I continue to get different responses from everyone, and some probably have NO idea what they are talking about, I am just going to call a few shops on monday and get it all figured out.

Originally Posted by Project_Evo

No Tune boosting at 27psi's your gauge may be off, because you can not boost 27 psi's with the stock lines, and without the pill mod. I'd be careful being you have no tune, and your boosting anything near 27psi's.
Off topic, but where did you buy your uicp? Real nice.