Having some problems boosting over 15psi....

[td06hkiko]

Ok here we go. I normally run 15psi on low boost and 20-22psi on high boost. I tune with pocketlogger. And I have checked for boostleaks. I have already pressurized the intercooler system along with the intake and no leaks. Now the problem is, boost over 15 psi car starts to stutter? I tried hi boost and right now wont boost over 16psi. Could it be the WASTEGATE ACTUATOR? Or the 34mm flapper? Turbo is still new no shaft play and spins freely. I did find the vaccum hose connecting the actuator to the boost controller starting to crack from the heat. so I changed that. Still the same problems. Anyone wanna take a shot at this one.?????

 

[CanadianTSi]

Plugs and or Wires could be bad.

 

[td06hkiko]

Ok. I checked the plugs and wires, disconnected the battery, and also at the same time removed the pin from the shaft that connects the flapper door on the wastegate. Now, by hand I can open and close the wastegate and there is nothing obstructing it. I can move it freely ie.. OPEN and CLOSE. Works fine. Now I take the car for a test drive and I am hitting 15 psi solid and no stuttering what so ever, that was Lo Boost. Now when I punch it in Hi boost I only saw 17psi and my profec-b dial setting is about 2 O' CLOCK. Normally at this point I'm supposed to be at 21 psi. I dont know anymore. I am like WTF?? Has anyone experienced this prob? And can anyone help.?? Thanks

 

[92awddsm]

Sounds more like a boost leak than anything else. Make a leak tester and you will probably find your problem.

 

[Sk8er07999]

Sounds more like a boost leak than anything else. Make a leak tester and you will probably find your problem.

Dude did you even take time to read his very first post? Guess not.

I think it's a fuel related problem. My friend had that same problem. Adjusted the afc slightly and no more stuttering. Just need to fine tune it now if we can figure our how.

 

[Trctnless]

I had similar conditions under acceleration last week at the strip. Bad Studdering and Hesitation as the Boost was hitting hard. I Was also making the same age old mistake of throwing more fuel at it to lower EGT's /// I still think i'm tuning around a boost leak somewhere..

Wires were fine...
Checked my plug Gap.. It had increased to .031 since the last time I checked

I was also running WAY Rich 1.06V and getting pulled to 6deg and getting no more than 18deg TMG up top.

Cleaned and ReGapped the 7's to .028
Leaned it out 10% more @ WOT

No more hesitation/studdering o2's to .94 and got 21 deg @ 7000 (B28@ 15 psi)

1/8 mile wise that tuning took me from a 9.7@75 to a 9.2@80.

Good Luck.

 

[td06hkiko]

I leaned out the afc some and some of my stuttering went away. I am running SAFC 660cc denso injectors. My LO map is set at -18 1k -24 2k -24 all the way up to 7k for LO Map. Trims are within + minus 5 really close. Now for WOT HI MAP. i have -18 1k -25 2k -35 3k -35 all the way up to 7k. My timing is not getting pulled but when I reach 5k rpms, timing slightly tends to drop. My normal timing at the end of Redline is 17-18 degs. I am using Pocketlogger to tune. I think what really fixed the problem was Removing the wastegate shaft and making sure the 34mm flapper was working right. Before I put the shaft back on the flapper, I made some adjust ment to the shaft. (closed it up some).

 

[td06hkiko]

I leaned out the afc some and some of my stuttering went away. I am running SAFC 660cc denso injectors. My LO map is set at -18 1k -24 2k -24 all the way up to 7k for LO Map. Trims are within + minus 5 really close. Now for WOT HI MAP. i have -18 1k -25 2k -35 3k -35 all the way up to 7k. My timing is not getting pulled but when I reach 5k rpms, timing slightly tends to drop. My normal timing at the end of Redline is 17-18 degs. I am using Pocketlogger to tune. I think what really fixed the problem was Removing the wastegate shaft and making sure the 34mm flapper was working right. Before I put the shaft back on the flapper, I made some adjust ment to the shaft. (closed it up some).

Also found that Greddy Profec B took a shit on me. I switched to a TURbo XS MBC and bypassed the Profec B solenoid and started making some boost again. Now I am still tuning around some minor boost leaks. Still having alittle suttering around 4k rpms when the boost first hits and then it smoothens out from 5k rpm all the way to 7rpm. I guess I am leaking up to 16psi.

 

[td06hkiko]

Plugs and or Wires could be bad.

It wasnt boost leak after all. I pulled the sparkplugs out and re-gapped them to .28 The whole time, its been fouling up coz of the wrong gap. I had it gapped at 32 and now it's set to .28 now its smooth and no more studdering. I am back up to 21psi and the logger shows 17 degs of timing advance at 6500rpms.