lvNVevo

iTrader: (12)

here is what is happening. I installed a hallman pro rx mbc and i was having an issue with tapering about 6psi in 3rd gear from 21psi to about 14 by top of third. Everyone said it must be the BOV....well the stock plastic valve took a **** on me so i put a HKS SSQ in today and hoped that it would help with tapering. Well it didn't, I am still tapering the same amount from 5k to 7k i loose 6psi. I have looked at every line i have it the car to see if it leaks and have re-zip tied everything. Why am i Tapering still?????????????? Even with the HKS turned all the way to hard i still taper. HELP!!!!!


I set the HKS to the lightest possible setting and i am getting Flutter Is there any way to adjust it further to stop this???? The screw is all the way out to the softest setting.....

Warrtalon

iTrader: (6)

You have the wrong mods on the car, so it's bound to have issues. You got the WRONG BOV, that's for sure, and your intake is no good without a tune. It's hard to diagnose something like boost taper when you have multiple negative factors all at one time.

Can you tell me how your stock BOV broke? I'd like to hear the details. If it's really broken, then you can't return to stock in order to do some troubleshooting which is something that needs to be done. You also need to go back to the stock airbox, then test the boost. One other factor is the boost gauge. Your Defi should be good, but are you sure it's accurate? If you can borrow someone else's, hook that up and check. There is always going to be taper, but it shouldn't be 6psi unless you are trying to run 25psi or more...

lvNVevo

iTrader: (12)

swaped the gauge already it is fine. As for acurate the other gauge i tested it with read the same as the defi. It also feels like i loose a ton of HP when the tapering happens. The HKS cant be the problem of the leaking because of the type of valve it is. as for the stock air box it tapered the same with it in. The only reason i am running an intake now is because i am getting a tune in about a week (intake shouldnt cuase it to taper either).

The Stock valve blew apart at about 15 psi. the car fell on its face and i have to plug the hole to get it home. My car is an 05 with only 1800 miles on it- this shouldnt of happend.

As for having a BOV i put it on because it was only $100 and it had the evo flange already on it. I also need my car to get to work so i needed a valve by today. The stock went at about 5 on friday.

Could the ecu casue tappering???? Should i try a reset?

Warrtalon

iTrader: (6)

Wow, that shouldn't have happened to the stock BOV. You should have gotten a free replacement under warranty. When I referred to the SSQV being the wrong BOV, I wasn't referring to it leaking. I was referring to the fact that it's VTA, which does not work with a MAF-equipped car. It causes other problems that will exacerbate the pre-existing problem unless you have the recirculation kit on it. Even so, you're already encountering flutter problems.

No, the ECU can't cause taper if you have an MBC, because the BCS is no longer connected.

Since you said you checked all connections related to boost, then the logical deduction would be the MBC itself.

lvNVevo

iTrader: (12)

I know the VTA things is stupid but right now i needed smoething and no one in vegas caries the jdm mr valve, the one i want. I will be selling the hks soon so if your interested I've had a wrx and the same rules applied with it when it came to VTA and thats why i didnt do it then .

I could have gotten a free one and still can but even if i did i would still be pulling it out soon.

Anything you suggest i try with the hallman mbc to test that it is working properly? I just went out and made sure i can still adjust boost and that works. I am thinking i might pull out the heavy spring and try the softer one to see if for some odd reason that works.

Warrtalon

iTrader: (6)

No, I can't think of anything else other than a pressure test, which will show where your leaks are for sure...and will show how well the MBC is working.

Be sure to get that JDM MR DV as soon as you can. $110 from NoLimitMotorsports (username NoLimitMotors, I think).

Sam - PURE Tuning

It is possible that the halman you got had a weaker spring in it, I had the same problem with boost drop....I switched out the spring in the halman....problem solved.

lvNVevo

iTrader: (12)

no when i got it the heavy spring was still in the un opened bag. i opened it and installed it. the guy that had it before me was using the light spring with no problems. i am going to give it a shot

the4thpower3

iTrader: (1)

My forge MBC did the same thing with the stiffer spring in it. I sawpped it back to the softer spring and viola, more more crazy taper and no crazy spikes.

lvNVevo

iTrader: (12)

I just put the soft spring in. I will re-set it and let you know what happens

lvNVevo

iTrader: (12)

the soft spring does the same as the heavy. 5k hits and let the tapering begin. Its weird, every gear once 5k comes around i start loosing boost. tonight i am going to re-check every line to make sure they are not leaking (again).

What would happen if i pluged the little air port on the hallman mbc? could this cause the boost taper????

I also heard you can tighen the waste gate but i'll just search for that info.

thanks!!

titaniumkingpin

iTrader: (10)

make a pressure tester and search for a boost leak.

Warrtalon

iTrader: (6)

Don't plug the port on the MBC; that is crucial to proper operation. At this point, like kingpin said, you just need to do a pressure test to find this leak. For it to drop that drastically, you would have to have a sizeable leak...

lvNVevo

iTrader: (12)

off to home depot today. i will let you know what i find

lvNVevo

iTrader: (12)

Hooked up my pressure tester last night and found a few vaccum lines with leaks so i fixed those. I could only get it up to 14psi with my hand pump so i will be taking it to a friends house this weekend to hook it up to his compressor. Car is till tapering even with the vacume lines i managed to fix.

I do have a question about my hallman. At 11 psi it started venting air throught the small port on the wastegate side. Should this happen so early in boost??? I had to plug it to get the car to hold 14 psi.

Also the system was always leaking slowly i am assuming this is because it is leaking by the throttel body valve.......