So after hours of headache because my K04 and GIAC J31 being limited to 7 psi boost, I found that my N75 was not connected, nor was there a MBC...

I hooked it all back up how it should be, but am having an issue.

When I go WOT, it pulls hard.. until about 15 psi.. then it shudders like mad (still maxes my boost gauge at 25 psi)..

I have an Exhaust and FMIC (no 5 bar FPR)

I am also getting a flutter on my turbo (havent been looking into that.. not sure if its related)

I read this could be a boost leak (but im still making high PSI..) or something with the boost sensor?


I am thinking about putting in a MBC so I can limit it to 18-20 once it runs smooth, 25+ scares me haha..


Any thoughts/Help?

 

You shouldn't be boosting 25psi on stock injectors for one thing. For another, what gap and composition are your spark plugs? A typical chipped-boost setting requires a .028 gap and can run on stock plugs. Running 25psi, the turbo may be going into surge and is sure as hell giving very high cylinder temps. You should turn down the boost to 16psi or so and see what happens for one, and to err on the side of caution, a colder heat range on the plugs would be a good idea.

 

That is why I am thinking of putting a MBC in it, so I can "Turn it down".

I know I shouldn't be boosting that high, I am not trying to.. That is the point of the post haha. But it should still run smooth up to like 20? I want it to sit around 18.. But it shudders at like 15.

For plugs I have BKR6E (I think) capped to .032

 

Lol I realized that Your shuddering is bad ignition. Even for 15psi you should have gapped the plugs down to .028". .032" is too wide - boost can basically blow out the spark like a candle on a cake.

 

So try to smaller the gap, or am I gonna need new plugs? Also are BKR6E okay? I know it calls for 7. And these aren't iridium or anything fancy. Just plain ones

 

If they're not wicked old, you can just gap the old plugs down. Tap them gently on a hard, clean surface checking occasionally with a spark plug gap tool or feeler gauges.

 

They have probably less than 100 miles on them.. It was one of the things I replaced when my FMIC hose came off and my car was having a fit, since I had no idea what was going on I went for the cheap stuff first.

Think this sounds like the problem? Something as easy as spark plugs?

 

In large part, yes.

 

Alright, thanks for the help! All I kept hearing prior was larger problems, fuel related or coils and such. I will try spark plugs tonight and let you know the results!

 

Always start with the cheap, easy stuff first!