VTC_CiViC

So I've finally gotten my wife's Integra rolling, the only issue I'm having though is maintaining boost. I've swapped out the wastgate spring so a "2.9psi" small yellow, it's giving me a consistent 6psi untill about 7500-8000 when the gauge suddenly pegs 20+psi untill you let off. I've tried running the gate straight from the manifold and through the Profec, same result. Tried a 10psi spring (which hold about 15psi) and the same thing happend near 8000 rpm. One suggestion I was told, my downpipe is VERY short, maybe 8" long give or take. Has anybody esle dealt with a very short downpipe and the subsequent inability for the wastegate to bleed off sufficient pressure to maintain boost? This is from a T3/60-1 on a Fullrace ramhorn and a TiAL 44mm V-band WG.

met

That doesn't sound right, I haven't dealt with a short dp. It almost sounds like something isn't hooked up correctly. The pressure from boost in the intake manifold pushes on the bottom of the wastegate via hose hooked up to the bottom fitting. The only way for it to slam shut some sort of malfunction in the boost controller directing air to the top port. You can always try leaving the top port open to the air and have only the one line on the bottom back to the manifold. Then you will only build spring pressure, unless something else is going on. In this cast no matter how much pressure there is in the down pipe your max should be the spring and with more press ie longer or smaller downpipe boost will drop, because the valve will have exhuast gases pushing on the wastegate's valve.
http://www.tialmedia.com/documents/w..._wginstall.pdf
Check that link out that will will net somewhere around double spring pressure, in your case a bit more but not 20psi on a 3lb spring.

93supercoupe

i had a similar problem when the set screws in the wastegate backed out.

Check the 4 little set screws that hold the diaphram to the valve.

boosted k20

do you have a dump tube? How are the bends on the pipe? I had one dump tube that had a sharp 90* bend close to where it was bolted onto the gate that would make the boost spike to 20+ psi. I took the dump off and it stayed at 10psi, where it should be.

catsman50

sounds like the wastegate isnt hooked up right make sure your using the right vacuum port

TheShodan

iTrader: (14)

The vacuum port that should be used is the SIDE port for the manifold, and the top one for the boost controller. you need 2 lines, not one.

http://www.tialmedia.com/documents/w..._wginstall.pdf

met

If all your doing is running off the spring no need for two tho :p not that anyone i know does this but for testing it doesn't hurt.

catsman50

Never heard of someone using the top for a bc I've always seem them inline with the one going to the manifold

TheShodan

iTrader: (14)

For a boost controller like a Greddy, yes, you need to use the Top and the side ports

Page 11, boss.

http://www.jdmlegion.com/Assets/PROFEC_B_SPEC2.pdf

VTC_CiViC

The controller is setup as per instructions, but I did bypass the controller and ran a line from the manifold straight to the bottom port of the WG with the same issue. I'm going to disassemble the WG tonight and see if the diaphram is damaged or what..

Muckman

iTrader: (2)

It sounds like the wastegate isnt able to bypass enough exhaust. What kind of exhaust manifold are you using and how is the wastegate neck situated?

VTC_CiViC

Full Race ramhorn w/ a 44mm Tial V-band

runs11's

The ramgirn style manifolds aleats creep because of the design the was the air flows through em mine does it as well my tuner told me its the ram style manifold i know he was able to fix it when i was running a lot if boost but this last dyno it eould creep at the end too

Muckman

iTrader: (2)

Thats not creep, thats uncontrolled boost.

runs11's

Sorry for the spelling it was from my phone. Oo ok i thought maybe he was getting creep

VTC_CiViC

Update: Applied a hand vacuum/pressure pump to the WG, opened at the right psi. Going to open it up tomorrow and have a look inside and see if somehow something isn't put together correctly. I tried running a small line straight from the turbo compressor housing nipple to the WG, no more than a 12-14" line, still creeps as the rpm increases and spikes around 7500..

TheShodan

iTrader: (14)

Turbo compressor housing to side nipple to wastegate? Not the TOP, correct?

VTC_CiViC

Yes..

VTC_CiViC

Update #2: Just about reached the conclusion this has to be a wastegate/overflow issue. Aside from the 44mm on the car, I've got a newer 38mm laying around as well, so I rigged up a tester and swaped springs out of both units to see if there was an obvious issue. Both gates produced the same results with the same springs as far as opening pressure and 'full-open' pressure. Attatched is a video of the 44mm opening and closing with applied pressure on a 'small yellow' spring.

http://www.youtube.com/watch?v=ulIrSe258_c

Based on the behavior of the pressure creeps and spike, it's looking more and more like this is a case of the wastegate unable to bleed sufficient pressure to keep the boost in check. I noticed that, particularly with the smaller spring, the boost will come up to 7psi and hold pretty well, it's not untill well into VTEC that it starts to creep upwards of 10psi and then finally around 7500 it shoots up pretty hard. I'm gonna have to bite the bullet and weld up an extended DP and bolt it up to an exahust and see what happens.. stay tuned lol!