builds boost slowly...

[mikesim]

here's my setup: greddy fmic, greddy mbc (placed 12" from turbo), hks gt2530 .64 a/r turbo, s-afc II, stock mafs, dsm injectors, 255lph walbro pump, NGK copper BKR7E gapped .028"

this is my problem: when clicked down to .6 bar/8.7psi, boost comes on steady and reaches max at 4,000RPM. but at a larger amount like say .8 or .9 bar/11.6-13psi, boost still comes on steady, but sticks at .6 for a second and builds to fulll boost at nearly 5,500rpm.

i've checked vacuum lines over and over again, finding two unplugged connections, but that's only helped the idle. i've checked the FMIC piping, but all the clamps seem ok, and they've never slipped off.

what i am guessing right now is since we clocked the turbo a bit, and my friend shimmed the wastegate, it's causing it to stick because it looks slightly cocked.

also, people have been telling me the MAFS would max out by 12 or 13 psi on this turbo, but it doesn't. it gets to 88-91%.

any insight on this would be really helpful. thanks.

Mike

[c-rad]

You check the compressor blades to see if they're jacked up at all? When shaft play causes the compressor wheel to contact the housing, the turbo starts taking longer and longer to build boost until it won't make boost anymore.

[rico05]

The fact that you get good response at lower boost and worse at higer levels, there seems to be not be enough vacuum pull on the wastegate. 2 things: when I shimmed my wastegate, I would get max 10psi, but it would take FOREVER to build. Now, with a proper mbc, I see full boost (10psi) by 2800RPM, and above that, it builds instantly on throttle.

Try unshimming the wastegate, and try again. You have a boost controller, so either get a wastegate that is designed for a higher level of boost (HKS) or let the MBC do all of the boost regulation at the higer level you are running.

[89'ClubK's]

If you're keeping the factory MAF, try cleaning it out really good by using an air compressor. Worked for me for awhile. Good Luck!

[float_6969]

Ditch the shimmed wastegate, and move the MBC as close to the turbo as possible. You always want your vac lines for the wastegate to be as short as possible.

[mikesim]

thanks guys, i'll be able to take a look at it this weekend. i'll let you know the results.