boost problem

[OnlyNeed4]

Ok, i used to have an autometer boost gauge which worked fine, and read about 13 - 13.5 psi. then i got a blitz turbo timer with digital boost gauge and sold the autometer. But the problem is, the blitz reads 1.33 hkpa (correct me if im wrong, but converts to roughly 19 psi) I dont understand why it reads that much boost. And sometimes i see all the way up to 1.5 hkpa and other times down to 1.1 hkpa. I dont even have a boost controller hooked up so i shouldn't be anywhere near 19 psi. I have no idea whats going on here but if you have any comments let me know. thanks.

 

[ddavisaf]

Ok, i used to have an autometer boost gauge which worked fine, and read about 13 - 13.5 psi. then i got a blitz turbo timer with digital boost gauge and sold the autometer. But the problem is, the blitz reads 1.33 hkpa (correct me if im wrong, but converts to roughly 19 psi) I dont understand why it reads that much boost. And sometimes i see all the way up to 1.5 hkpa and other times down to 1.1 hkpa. I dont even have a boost controller hooked up so i shouldn't be anywhere near 19 psi. I have no idea whats going on here but if you have any comments let me know. thanks.

Bolt-On Modsbig 16g w/ 34mm wastegate, K&N filter, dejon 3'' intake, turbosmart mbc, apexi n1 3" turbo-back exhaust,ported 02 housing, modified smic, dejon upper and lower ic piping,walbro 255 pump, b&m fuel pressure modifier, ultra stiff shifter bushings, Blitz dual turbo timer, autometer air/fuel ratio gauge.

Sounds like you have one to me. Looks like you're creeping to me. Turn the boost down until you get it to where you want it.

 

[OnlyNeed4]

yes, i do have a boost controller and i did list it in my mods page. but like i said, i DON'T have a boost controller hooked up right now. so therefore i should be running around stock boost levels, not 19psi. anyone else have comments?

 

[ddavisaf]

After you hit 1.33 hkpa does it drop down to normal boost levels? Or does it hit normal boost levels and increase to 1.33 hkpa?

 

[OnlyNeed4]

it pretty much spools too 1.33 kpa and holds. But 1st and 2nd gear pulls i only see around .9 kpa which is were it should be. 3rd and 4th gears i reach up to 1.33 but run out of fuel because its so high.

 

[ddavisaf]

Just boost creep. First and Second gear pulls are exactly where they should be, 3 gear and up there's much more of a load on the car so the boost starts creeping up wards. Get that mbc in and you should be able to control it a little better. Also, a little bit of port work and you should be able to control the creep better also. If you'd like me to find you the post on creeping and porting I'd be happy to. It explains what to port to try and counteract the boost creep.

 

[oldman]

What psi were you running before the removal of the mbc? .9kpa=?psi ?

 

[OnlyNeed4]

thanks for the info, i'll just hook the mbc up and turn it down a notch or so. i just never hooked it up due to the lack of fuel mods so i wouldnt be able to turn it up. and thought i can't turn it down either since it should be running at stock levels. thanks tho

 

[OnlyNeed4]

What psi were you running before the removal of the mbc? .9kpa=?psi ?
__________________
Bruce


.9kpa is about 14psi, what i was running, i've never actually turned the boost up due to no fuel mods

 

[oldman]

it pretty much spools too 1.33 kpa and holds. But 1st and 2nd gear pulls i only see around .9 kpa which is were it should be. 3rd and 4th gears i reach up to 1.33 but run out of fuel because its so high.

I suggest that before you decide that it's boost creep, I would run more tests because this does not sound like boost creep. With that said, it's pretty hard to detect boost creep with a digital display so first thing you should do is to T the vacuum source to the turbo timer and reinstall the Autometer boost gauge and test run with both gauges. Two things to pay attention to. 1. Boost creep = hitting a lower level first then creeps up as rpm increases. 2. Check the accuracies of both gauges against each other. Post back with test results.

One more question, how is the actuator hooked up now that the mbc has been removed?