Montego

iTrader: (1)

Now this does not seem like boost creep at all. Since it only happens in one gear. 3rd gear that is.

Saturday I installed a RB dual tips in place a magnaflow muffler. The RB flows much better. I had to turn my set gain **** down a couple of notches on my EBC. Note that I do have a straight through exhaust and my turbos are ported (not the wastegate).

Anyway my boost pattern is as follows now:

Boost controller off:
1st gear: 7 psi
2nd gear: 7 psi
3rd gear: 11 psi (holds steady at 11.0-11.3. and it is not a steady rise either, basically third gear = instant 11 psi)
4rth gear: 7 psi

Boost controller set at 10 psi:
1st gear: 10 psi
2nd gear: 10 psi
3rd gear: 11 psi (same as above scenario)
4rth gear: 10 psi

Boost controller set at 12 psi:
1st gear: 12 psi
2nd gear: 12 psi
3rd gear: 12 psi (anything set above 11 psi works as it should)
4rth gear: 12 psi
at all gears the boost is constant 11.9-12.4 psi

so what gives? it's the classic signs off boost creep (boost controller has no effect) except that it does not do it in 4th gear and it stays constant at 11 psi. Which is what has me stumped.

To be honest it really is not a big deal since it's only 11 psi but I am still curious.


mods in sig

DaveW

What RPM did you get up to in 4th? If you only got to 5K or so, maybe it didn't get to the point where it crept, and in the lower gears, maybe you were not in them long enough to see it.

Montego

iTrader: (1)

Well I didn't redline 4th but I got to almost 7k and the boost was a constant expected psi level (7 or 10). Unlike 3rd gear where it instantly goes to 11 psi, as I said earlier it's not a slow creep either. basically BAM! 11 psi as if I had set it on purpose.

For the lower gears:
Actually judging by the quick response in third gear, I am long enough on second to see it up to 11, but it does not. The boost stays very consistent at 7 or at 10 psi no higher just like in fourth.

I have a greddy profec B spec II electronic boost controller. So I can actually see differences in boost to 1/10 of a psi. So I can tell you for sure that my boost is not creeping (or over boosting) in all of the other gears.

weird

scotty305

iTrader: (2)

Montego, did you ever solve this problem?


A friend of mine has the following power mods:
intake, IC, downpipe, midpipe, exhaust


He's running the stock ECU and a piggyback handling fuel, and an electronic boost controller (HKS, I believe). I know he should upgrade his engine management, but I want to talk boost control not EMS here. He's measured AFR's on the dyno and they're pretty safe.


He's done the following:
With the wastegate solenoid disconnected, the wastegate spring limits boost to 7psi. There is no creep at all. This tells me that the stock wastegate opening is capable of venting enough exhaust flow to limit boost.


With the stock ECU controlling things, he's seeing 14-15psi on his boost gauge (don't know which gauge, but let's assume it's accurate because it's reading 7 psi with the wastegate solenoid is disconnected). Same thing with the boost controller, he's not able to lower the boost.


I'm assuming that his problem would be solved if he can find an electronic boost controller capable of decreasing boost (by limiting the duty cycle to the WG solenoid) rather than just increasing boost. I could probably build one but I'd rather not if there's already an existing product out there. It looks like your Greddy Profec would be perfect.

-s-

Montego

iTrader: (1)

Scotty,

My problem was solved by replacing a couple of vacumm lines (I'm non sequential so it was no big deal) and making sure that there were nice and tight. I also reprogrammed my EBC. Now I my car actually creeps to 11 psi but that I can live with it since I know what causes creep. . What I'm thinking that happened was that during the same install of the RB I also did some things in the engine bay. I'm thinking that I f'ed one of the vacuum line hoses while I was there but failed to notice at the time.


now as far as your friends problem:

Basically he is unable to lower boost with his EBC and you have proven that his it is not creep. Now I don't know anything about HKS EBC so I can't comment on that at all. From what you say I gather that this EBC is only good for increasing boost not lowering. Correct? If that's the case then I would not use it on my car.

The Greedy profec B spec II is certainly worth the money, because you can actually limit the boost to 7 psi (as long as you aren't creeping) and above (43.5 psi). And it's limits boost by lowering the duty cycle of the wastegate solenoid (as you already guessed). This EBC worked great for me and many others I don't see why it wouldn't work for your friend.



rather than taking my word for it check out Greedy's manual and down load it.

http://www.greddy.com/tech/PROFEC_B_SPEC2.pdf

See page 16 regarding SET "This feature controls the duty rate of the Valve Unit which controls the boost"

scotty305

iTrader: (2)

Thanks, that's just the info I was looking for.

-s-

Montego

iTrader: (1)

you're welcome