Low boost? Wastegate opening to early?

Re: Low boost?

I vote leaky recirc valve.

Re: Low boost?

Its a Forge. Blue spring. Maybe needs a shim?

[quote author=angryRotarian link=topic=139022.msg2996269#msg2996269 date=1237166534]
I put the red spring in and took a run. Same issue. I setup the log to get more boost-related indicators. Two of them are tracking the same boost ( I wanted to see if they were the same ).

It seems the wastegate starts to open when not at 15.6 to around 33%. I'm assuming 100% is closed. Is this normal? It doesn't make sense, as if I am not at target boost, that should be closed. Could this be the culprit?

And more importantly, what could cause this?
[/quote]

Your second graph indicates no problem whatsoever.
The DH is not monitoring the wastegate itself (not possible), but rather it is monitoring the wastegate control valve.
The wastegate control valve should be at about 50% with full boost.

Here is one suggestion: Try not to go WOT in a higher gear (3rd or above) with the engine RPM below ~3000. According to your graph, you went full throttle at about 1700 RPM. Try the same datalog with part throttle (no boost) up to 3000 RPM, then go WOT.

[quote author=GT1 link=topic=139022.msg2996746#msg2996746 date=1237185000]
[quote author=angryRotarian link=topic=139022.msg2996269#msg2996269 date=1237166534]
I put the red spring in and took a run. Same issue. I setup the log to get more boost-related indicators. Two of them are tracking the same boost ( I wanted to see if they were the same ).

It seems the wastegate starts to open when not at 15.6 to around 33%. I'm assuming 100% is closed. Is this normal? It doesn't make sense, as if I am not at target boost, that should be closed. Could this be the culprit?

And more importantly, what could cause this?
[/quote]

Your second graph indicates no problem whatsoever.
The DH is not monitoring the wastegate itself (not possible), but rather it is monitoring the wastegate control valve.
The wastegate control valve should be at about 50% with full boost.

Here is one suggestion: Try not to go WOT in a higher gear (3rd or above) with the engine RPM below ~3000. According to your graph, you went full throttle at about 1700 RPM. Try the same datalog with part throttle (no boost) up to 3000 RPM, then go WOT.
[/quote]


So, you're saying that this level of boost is normal? That would mean that the dashhawk reads low, as I should be seeing 15.6 in 3-6.

I have another graph that shows a 1-4 gear run. It shows low (10-11 psi) in first, and then the same 13.5 or so psi in 2-4. Its almost as if the car thinks its in second in these higher gears.

If somebody else could post a DH graph with boost, it would be a big help!