Still losing boost at WOT.

[tbonitz301]

Ok, so i had a thread in here the other day, and have corrected a few things and i still have the same problem. I ran my boost source to the intake mani for now it was tee'd into the bov line. inspected my turboxs MBC it's a bleeder type so all i could really do was check the hoses and clean inside it, also i have zero boost leaks,.
The problem is when i accelerate the boost comes on and slowly rises to 15 psi which is what the MBC is set at, then it will fall off within a sec. to 11psi. If i let up on the gas a little the boost will rise to 15 again and settle back at 11. I just dont get it. Suggestions?

 

[mndsm1]

im not sure about dsm's since ive only owned 1 for about a month...but i kno that my srt4 would hit 15 on the stock actuator but wouldnt hold that til redline..not sure if thats exactly what your talking about though

 

[tbonitz301]

I think you may be talking about your motor sucking more air than the turbo could push with the stock turbo. I have upgraded and am on a brand new big 16g. Thanks for the thought though

 

[FP3065TSI]

I think you may be talking about your motor sucking more air than the turbo could push with the stock turbo. I have upgraded and am on a brand new big 16g. Thanks for the thought though

Whats does your fuel system consist of?!?

 

[tbonitz301]

Whats does your fuel system consist of?!?

I dont really believe this is fuel related.

 

[FP3065TSI]

I dont really believe this is fuel related.

What do you think might be going on with your car thats not allowing 15 psi? And yeah your right i dont think its fuel related as well i read your first post wrong. I thought you wanted to add 15 more psi on top of the 11.

 

[tbonitz301]

Honestly im not sure if its my mbc or what. If i disconnect the wastegate it will boost to the moon if i let it. So its not the turbo. I just dont really no enough to really zero in on the problem. I was hoping that someone would just pop in and say hey this is whats wrong, but no luck yet

 

[FP3065TSI]

well like you stated you don't have any boost leaks and all lines connected properly. The only thing would be the MBC since you disconnected the wastegate and since your boosting full force with the wastegate is no connected... im not a full guru when it comes to these turbo problems but i like to try to zero in on the problems...

 

[tbonitz301]

I hear ya there. I 'm ready to just buy an mbc, and try that, but if i get another one it will be a good one, and i dont want to drop 200 bucks on something i dont need.Know what i mean vern

 

[FP3065TSI]

yeah i know what you mean. Do you have any buddies with a turbo-ed car. they can try it to see if it holds the proper amount of psi.

 

[tbonitz301]

nope.not really. Theres a few guys but most of them are a pretty good drive. I live in the sticksnot to get off topic or anything,but the yuengling is going down great 2nite

 

[FP3065TSI]

the beer your talking about?!!?!?

 

[bluetlr2001]

If your wanting to get a good mbc i would reccomend the joeP mbc they are fairly reasonable also. But as for your problem it sounds like the mbc to me also. As if it aint holding the boost were you set it at. At what rpm is your car loosing boost. And are you sure that you arent just experiencing boost spike when you just punch the throttle and it leveling off to 11psi

 

[tbonitz301]

yes, beer is good.

 

[ekanddsm]

Have you tried hooking up the factory boost control solenoid, or is it long gone.

Your problem is with boost control, not building boost.

If you eliminate the mbc and just run the j-pipe to the actuator do you get like 7-8 psi?

Take the mbc off and try driving it.

Is your turbo a autherntic big 16g or some ebay knockoff?

How big of exhaust are you running? Size? Turbo back or catback

You just very well may need a ebc to control the boost, Because it sounds like your getting boost spikes.

Try that and let us know

 

[tbonitz301]

If your wanting to get a good mbc i would reccomend the joeP mbc they are fairly reasonable also. But as for your problem it sounds like the mbc to me also. As if it aint holding the boost were you set it at. At what rpm is your car loosing boost. And are you sure that you arent just experiencing boost spike when you just punch the throttle and it leveling off to 11psi

I should have been more clear, but it happens anytime i give it enough gas to reach full boost. I dont have to punch it to make it happen. I can pull out at 1/3 throttle and when i reach full boost it does it. it immediately drops off. Thanks for the input

 

[tbonitz301]

Have you tried hooking up the factory boost control solenoid, or is it long gone.

Your problem is with boost control, not building boost.

If you eliminate the mbc and just run the j-pipe to the actuator do you get like 7-8 psi?

Take the mbc off and try driving it.

Is your turbo a autherntic big 16g or some ebay knockoff?

How big of exhaust are you running? Size? Turbo back or catback

You just very well may need a ebc to control the boost, Because it sounds like your getting boost spikes.

Try that and let us know

Ok starting to get some good suggestions nowIf i run wastegate only its like 10-11psi.authentic 16g, although i did run a ebay 16g for a while when i was saving for my mhi, and it worked flawlessly for 2000mi.it still sits in the shed for backupBack on topic,im running 3" turboback with no creep,still got the cat. Explain exactly what a boost spike is please. The boost is set at 15psi then dropping to 11. if it was a spike wouldnt it jump to like 20 if it was set at 15 then drop back to 15?Keep em comin

 

[ekanddsm]

Someone said it perfectly in the last thread,

It sounds like your set at 11 and spiking to 15.

Your only spiking a little bit because your not running the boost other people run on here.

Some set the boost at 18 and run a near stock exhaust, but when they put on a 3in they have some issues.

That issue being creeping and/or spiking.
Your spiking because the turbo spools faster than it can slow down, 3in breaths good but by the time your mbc bleeds it to 11 psi your already past that point.

I would set the boost lower or buy a ebc that helps to prevent this, There are ebc's that can learn how quickly it builds boost and bleed off differently than a mbc which always bleeds.

Try a lower boost and see what happens?

 

[tbonitz301]

Like i was saying it runs 11psi on wastegate alone. Then i started to adjust my mbc upto 15, and then it started doing this. You'd just have to see what it does when drivin. I really dont think im spiking.

 

[ekanddsm]

Then try turning it up to 20 and see if it holds boost steady?

 

[tbonitz301]

Will do i'll post back

 

[tbonitz301]

I'm the worst your the best, my car is slow yours is fast,what do you want me to say you were right. I'M now SPIKING to 19 and settling at 15psi. Thank you. So you think i need an ebc?I also have a punishment racing o2 dump if that will help