Losing Boost at Higher rpm's?

[97fstclps]

I have a 1997 Mitsubishi Eclipse Gst, i have looked all over for information for this and can not find anything, i am hoping one of the proven members or one of the wisemen can help me a bit.

When i am on the highway and i get on the gas to accelerate as soon as the turbo starts to build boost, the car actually feels like it has shut down for a brief second and jerks the blow off maks the pssh noise and then the car immideatley starts to boost and pull again. I never get any check engine lights or anything.

One other problem i am having, i have read another post, i just wanted to make sure my 2g was the same as the 1g, my car is went through fazes of staling at lights with the clutch in, then all the sudden now it is idiling around 1500-2000 rpm's, at first i thought the man who tuned my car with the neo computer tuned the rpm's too low thats why it was stalling, then it started reving at 1500rpm's+ is my 2g the same as the 1g, most likely this is problem is being cause by my tb being dirty?

Thank you,
Brian

 

[DJYoshaBYD]

are you venting your BOV to the atmosphere?? If you are, it would do all of that.... it shouldn't go "PSSSHHHH" unless you have a blow-through setup or speed density....

 

[trboholc]

Yeah with the stalling at lights and the varying idle speed it sure sounds like you are venting your blowoff valve, whlie some people can vent and get away with it, most who do it improperly end up with the same problems you are having right now.

 

[97fstclps]

are you venting your BOV to the atmosphere??


Im not exactly sure what you mean by that, i am new to the turbo dsm world my uncle has built this car for me and i am just learning i can do easy stuff to it but he did all the crazy stuuf, hard piping, turbo, and inercooler, right now, the bov is setup along the harpiping kit right along the top of the engine almost where stock one was.

I can send a picture if this helps.

 

[DJYoshaBYD]

is there a tube connecting the opening of the BOV to the intake? Does it make the "PSSSSHHHH" sound when you let off the gas? If it does then you are venting to atmosphere... run a tube from the opening on your BOV and run in to your intake.... it will make that sound go away.... but you will be blown away by how much it affects the car

 

[97fstclps]

OK i am defiantley venting to the atompsphere, there is a rubber hose going to the intake manifold, also it does only make the pssh sound when i am getting off the gas swtiching gears or slowing down, i have just went outside and taken some pictures maybe this can help a little bit.

Thank you,
Brian

 

[DJYoshaBYD]

I dont mean the intake manifold... that is the line that makes the BOV work.... the air that is blowing out of it needs to be fed back in to the intake, before the turbo.... have whoever did the car fix it if you dont feel comfortable doing that yourself...

good luck trying to put a hose on that and running it to the intake.... you could always get a stock 1G BOV and put it in a vice and crush it about 2 mm.... it will make it hold more boost.... also, it will be easier to run a hose from there to the intake... but if you can figure out a way to

 

[HustlerTalon]

Please don't tell me that is an $15 Ebay HKS Style BOV...grrrr

 

[1stGenRocks]

it also looks like your mbc is connected to your bov line. this can make the bov leak boost which will only make your situation worse

 

[97fstclps]

Hello Guys,

Funny story about the 15.00 hks look alike, my uncle(who built the car) smashed the greddy one with a hammer after about 8 hours of trying to get it to go into the flange hense we were left with the backup, now that i remember the car did the same exact thing when it had the aftermarket intercooler installed but still had the stock 2g bov, as far as mbc, im hoping you mean manual boost controler, again i am very new this is my first dsm turbo, i have had this car since jan 2006 and have only been able to drive it for 1 month, i have it now, but the clutch slips after 4000 rpm's i have the boost controler set to 10lbs of of boost and the boost gauge still says the car still is boosting at around 16, im frustrated.

Thanks any help would be greatly apreciated.

Thank you,
Brian

 

[PieEyedPiper]

Please don't tell me that is an $15 Ebay HKS Style BOV...grrrr

Why do you ask?
1. they're more than $15
2. they work flawlessly, even better than the knock off type-s which works pretty darn good for the price.

 

[kenamond]

The vac line that is "T"ed into your BOV line shoul instead go to your compressor outlet nipple (if you have one - if you don't, add a nipple - search the forums for that to find out more). I'm ever-skeptical about getting the MBC signal from the intake manifold which is what you get when you T into the BOV vaccuum line. And yes, MBC=manual boost controller.

You can get a 1g BOV cheap on eBay (got mine for $25). It has the outlet for recirculating which you seem to need. I'm not sure how you'll get the 1g BOV to mount to your UICP, as it has a 1g flange, and you have something else. Maybe there's an adapter out there. If you're running less than 20psi boost, you shouldn't need to crush the 1g BOV, though you can buy them crushed already. Also, your intake pipe needs to have a large (~1.25" diameter) tube on it to accept the recirculation hose. If you have a blow-thru style intake pipe (no recirculation dump tube), you may need to get a new one.

Did your uncle do a boost leak test after all of these mods? If you're leaking boost in the intake, you could be hitting fuel cut causing the power loss and BOV wooosh at higher RPM.

I'm not sure why you're boosting to 16psi. You say you have it set at 10psi, but it boosts to 16psi. Maybe you have it set to 16psi. What makes you think you have it set to 10psi? You can run a vaccuum line straight from the compressor outlet nipple (if you have one) to the WGA (the can bolted to the turbo with an arm sticking out of it going to a lever on your turbine housing). I'm not sure what the actuation pressure for the WGA is, but many are around 10psi. That should limit your boost to the WGA actuation pressure.

Sounds like you have a few things to do. Reroute your MBC input hose, maybe add a nipple to your compressor outlet or LICP, do a boost leak test, and get a recirculating BOV and maybe an adapter to be able to bolt it to your UICP and maybe a new intake pipe if yours lacks a dump tube.

Good luck! Keep us posted.

 

[kmoore]

Have you done a boost leak test yet?

 

[97fstclps]

What i meant by 10 lbs of boost is, when we put the car on the dyno afte the last round of mods, the clutch was slipping horribliy over 4000-4500 rpm's the mbc was turned out 2 turns and the boost gauge was reading 16 lbs of so what we did was turn the dial back 1 full turn which was i thought would ave been 8 lbs 1\2 of 16 apparently this is not how this works becuase when i am driving the car and step on the accelerate the tubo gauge goes up to about 17 lbs and then stops, No i have not done a boost leak test yet, anyone live in or around philadelphia pa? i was looking for a place to take my car to get it tuned. my car put out 294 hp and 253 lb tq and it is running rough. i would love to get it tuned and see what it will run.


Thanks again for everyones help..
Brian