Breaking up in higher boost/rpm

[Sallymae]

Hey y’all,

currently trying to figure out what direction to go.Twin turbo bottom mount gen 3. Car begins to break up in any setting past wastegate (7psi) it’ll do it at about 7k+rpm’s. Car runs great on wastegate no break up or anything. No codes at all. Plugs are brisk rr12’s gapped to .018 and I even switched over to ngk 6510 with no luck. Stock motor besides valve springs and no exhaust turbos are dumped. Any ideas what to check or possible issues ?

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[SheepDog]

Plugs are brisk rr12’s gapped to .018

Why such a tight gap? You want as large a gap as possible, while still preventing spark blowout. even .025 is plenty for 7 or even 10 PSI.

Another thing to check would be damaged/backed up cats, if you are running them

 

[Sallymae]

Why such a tight gap? You want as large a gap as possible, while still preventing spark blowout. even .025 is plenty for 7 or even 10 PSI.

Another thing to check would be damaged/backed up cats, if you are running them

That is what my tuner wants them at. Car sees max 14psi. No cats,no exhaust at all just turbos dumped straight down.

 

[daSNAK3]

That is what my tuner wants them at. Car sees max 14psi. No cats,no exhaust at all just turbos dumped straight down.

Who is tuning it?

 

[K4fxd]

.025 to .028 is what I'd gap them at.

How many miles? you might need valve springs.

Would need to see logs to make sure the tune is on point.

 

[Sallymae]

.025 to .028 is what I'd gap them at.

How many miles? you might need valve springs.

Would need to see logs to make sure the tune is on point.

I was thinking it could possibly be valve float but the springs have 1000 miles on them, and the exhaust is almost as open as you can get. I’ll try gapping the plugs up a bit and see if that works.

 

[SheepDog]

I was thinking it could possibly be valve float but the springs have 1000 miles on them, and the exhaust is almost as open as you can get. I’ll try gapping the plugs up a bit and see if that works.

I doubt that it's valve float. Centri cars that keep making more and more boost as RPM increases, do not suffer from this. Not at 14 PSI anyway. You said the valve springs are new- are they OEM Springs?

 

[HKusp]

I agree with Dax, you're not getting valve float at 7psi unless you have some goofy spring set-up. what brand springs are they?

 

[K4fxd]

Shouldn't be springs with only 1000 miles on them.

 

[Sallymae]

I doubt that it's valve float. Centri cars that keep making more and more boost as RPM increases, do not suffer from this. Not at 14 PSI anyway. You said the valve springs are new- are they OEM Springs?

PAC 1281X springs, I agree seems weird for it to be springs but doesn’t mean it’s not a possibility.

 

[Sallymae]

I agree with Dax, you're not getting valve float at 7psi unless you have some goofy spring set-up. what brand springs are they?

well it runs great at 7psi but any setting above that even 8psi no good. PAC 1281X springs

 

[Sallymae]

Here’s a quick video of it on 9psi

 

[SheepDog]

What kind of boost control are you using? Sounds to me like the waste gates are opening prematurely

 

[Sallymae]

What kind of boost control are you using? Sounds to me like the waste gates are opening prematurely

Eboost 2 with a mac solenoid. Hmmmmm I haven’t tried checking any of my gates or plumbing to them. I’ll check that out also. But it’s hitting the target boost and holds when I turn it up so I don’t see how the gates would be prematurely opening.

 

[SheepDog]

Eboost 2 with a mac solenoid. Hmmmmm I haven’t tried checking any of my gates or plumbing to them. I’ll check that out also. But it’s hitting the target boost and holds when I turn it up so I don’t see how the gates would be prematurely opening.

Yeah check for leaks in the lines, or incorrect routing

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