So I was driving my car with a friend the other day and when I got on it in fourth gear he said my boost went up to 30psi. My car should be tuned to 22psi... So I did a first gear pull and got 22. Second I got 23. Third I got 25.

Guy before me who had the tune done said he tested after the tune and got 22 1st-3rd.

Anyone know why it is doing this? I dont think it is a big deal seeing I do not get on it in fourth often. Just curious as to what could be the reasoning.

 

im guessing its because of the higher load on the engine in that gear. happens to me sometimes too. If I do a pull 1,2,3 the boost stays where it should but im im cruising in 3rd or 4th and then just WOT it will spike higher.

 

He's right, the engine is pushing more exhaust gas through there in 4th for a longer period of time, so it's easier for the engine to pump up to 30psi. It probably can't sustain it in high RPM's, but I'd be a hair concerned if I was overboosting by 7psi. There are a couple security measures in place to prevent overboost, the first is the boost control solenoid's duty cycle, which you can fine tune in tephra modded ROM's per gear. The second is a fuel cut at X amount of load, which stock is like...245 or something.

So...the thing that you should be concerned about is "the guy before me" tune. If he did anything like, remove the fuel limit, remove the boost error correction, or something else like that, it could cause problems. Do you have EcuFlash and a Tactrix cable? Is that how the tune was done, or do you have something like an Access Port or similar?

 

ECU Flash and Tantrix cable was how it was done. I know the engine can take the boost with the right modifications... but I dont think mine is quite at a point where it would be healthy. When I did the fourth gear pull it wasnt from a strong 1-3 so I can see why it may build more from the long pull as you guys said.

 

30psi on pump gas is not something you want to do on the regular. How are you controlling boost? Ive never had this problem unless i was in really high load gears like 5th or 6th

 

GrimmSpeed Boost Controller

 

if you have a cable then pull your rom and check it out. Boost cut delay is probably maxed or Boost cut load is at some crazy high number that your car cant reach. Either way you will have to tweak the WGDC to prevent the spikes, no one wants to mash the gas and have fuel cut kick in all the time lol

 

Could also be spiking due to the colder weather. Either way, get a new tune.

 

I'll look at the rom and see if anything seems out of the ordinary. Yeah I am hoping that it wont come to getting a new tune. I should've learned by now that something small always leads to something that costs me hundreds of dollars when it comes to this car haha

Didn't consider the weather either. Seeing as my gauge is below the center counsel I do not look at my gauge unless I am on the highway trying to keep it out of boost... So I did not notice the problem in the warmer months.

 

These cars will def boost more in the colder weather. I've had to adjust my mbc during the winter in the past.

 

But did your boost change gear to gear like mine does? Or was it a consistent change through the gears? Either way spiking all the way to 30 seems a tad drastic... But quite honestly I would not know if its normal seeing as it is this cars first true winter and I bought it this spring.

 

This is your problem, the colder air will give you more boost pressure. Just turn the wic down a little until you hold 22psi on a 3rd gear pull. You might get a 23/24psi spike but that is normal and it should level out and then start to taper downward. Then try a 4th gear pull and see where it is, it shouldn't be to much higher the 22/23 hold. I hope this helps you out man

 

Ill give it a shot and post if it worked or not. Thanks for the help/heads up! Learn something new every day about this car...

 

He's right, I always get a couple psi more in the winter. More importantly just watch your a/f and knock count, if your a/f stays bellow about 11.5 under full throttle and no knock ur in the clear.

 

The previous owner is more than likely telling you the truth about a 22psi tune, that is very common for a flash tune on pump gas. If I were you though I would have it tweaked by a reputable shop or an email flash for peice of mind. Good luck with the car.