Low gear boost

[Joshw0000]

I'm not sure if I'm having an issue or if it's always been this way, but recently I noticed that I'm getting no boost at all in 1st and 2nd gear. Even if I drive in manual mode and shift at higher RPM's than auto would, I'll be in vacuum and essentially get right at 0 boost but I never see any positive amount. 3rd gear and up I see (with my SCT Tuner) decent amounts of boost.

I've read that for some cars this is pretty common but haven't seen anything specific for the SHO. Do you guys get any boost in 1st and 2nd gear?

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[krewat]

Is it tuned or stock?

 

[yaycandy]

I that same issue before and it ended up being the blow by oil clogging up the boost control solenoid valve...whatever they call them? Lol. The box thing with 3 hoses. They can be cleaned but its better to replace

 

[Joshw0000]

It's tuned for 93 octane, 3 bar MAP, CAI, cooler plugs and thermoststat, and a catch can (if that matters).

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[Joshw0000]

I that same issue before and it ended up being the blow by oil clogging up the boost control solenoid valve...whatever they call them? Lol. The box thing with 3 hoses. They can be cleaned but its better to replace

I just checked mine and all of the hoses are connected (it seems the one without a clamp is notorious for coming loose). The part seems cheap enough to replace if you think it'll help.

So do you now make boost in 1st and 2nd gear? I get plenty of boost from 3 to 6...as much as 19 PSI. I just don't get any in the first 2 gears and I'm not sure if I'm supposed to. The car does feel a little slower than it used to but that could be a placebo effect.

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[yaycandy]

I just checked mine and all of the hoses are connected (it seems the one without a clamp is notorious for coming loose). The part seems cheap enough to replace if you think it'll help.

So do you now make boost in 1st and 2nd gear? I get plenty of boost from 3 to 6...as much as 19 PSI. I just don't get any in the first 2 gears and I'm not sure if I'm supposed to. The car does feel a little slower than it used to but that could be a placebo effect.

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No i ment oil clogging up the inside of the contraption. Or sticking it open, there cant be a boost leak if the boost works at higher gears or higher rpm. Clean it, see if it helps. If not we can figure to look else where to the wastegates. That wastegate controller will dump boost if its gunked up

 

[Joshw0000]

No i ment oil clogging up the inside of the contraption. Or sticking it open, there cant be a boost leak if the boost works at higher gears or higher rpm. Clean it, see if it helps. If not we can figure to look else where to the wastegates. That wastegate controller will dump boost if its gunked up

I'll pop it off and take a look.

I should have boost in those low gears, right?

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[yaycandy]

If you are actually getting a full boost reading in gears 3 or 4 and none or little in the other gears then its gotta be something thats controlling the boost by the computer

 

[skyshadow07]

I should have boost in those low gears, right?

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Of course, I can't see why you purposely (i.e. tune) wouldn't

 

[Joshw0000]

I just wasn't sure as I read somewhere that typically boost is limited in lower gears for [some reason I can't remember]. It wasn't our cars; I think it was a WRX forum. And since I seemed to be getting full boost in higher gears, perhaps it's perfectly normal for the SHO? I don't see any issues with my solenoid and I reflashed my custom tune and seem to be getting low boost in 2nd gear now (~ 3 PSI) but still none at all in 1st gear. I don't recall ever seeing any boost in 1st gear. I've only owned it for a year and it had 60K miles when I bought it so I've only logged about 15K miles on it.

I'm still driving it daily, but not hard, until I figure out if/what is wrong with it. As I mentioned, I don't hear any noises or "feel" anything out of the norm.

If anyone has a gauge or tuner and can confirm how much boost they're getting in 1st/2nd gear, I'd really appreciate it.

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[stripSHO]

I get 15 psi from about 3500 rpm in 1st at WOT. I got the impression that you're just cruising but shifting higher, in which case you're not going to see boost in low gears because you're not putting a load on the engine.

If I'm mistaken, some other things I'd look at are wastegate percentage, throttle angle actual, tip prs boost kpa, tip prs boost kpa dsd, and torque source. Those should give clues on where the problem lies.

Boost can be limited by gear in the ECU, but I can't imagine why any tuner would do it to such an extent as that would essentially neuter the car.

 

[802SHO]

Any time you throttle it (WOT) you are commanding full target boost that your car is tuned for regardless of gear. That amount is determined in the tune and will vary depending on your specific mod list and tuner.

I don't think I've heard of a No Boost issue in certain gears only, in this instance 1st and 2nd. If you have a boost problem you'd think you would have none...period. And extremely odd it's consistent to 1st and 2nd only.

Like StripSHO mentioned, you should definitely take it out, do a datalog. I would do 3 datalogs. A 3rd gear pull from 2k rpm to 6k, a 2nd gear pull same way, and a 1,2,3 pull. Send to your tuner for review and as you wait for a reply, look over the logs yourself. Take a screen shot of boost and perhaps share here.

 

[FiveLeeter918]

Agreed with 802SHO...