user 8202

97 Miata stock 1.8 running the full Mk turbo kit, 640cc FF injectors, ms3pnppro, diyautotune EBC running close loop boost control.

I had to set to 185kpa (12psi) and all was well. I am going to be rebuilding the engine in the fall and hopefully running an EFR6258. My bright idea was to turn up the boost to around 15 psi, just because I don't care if I blow the motor or not. Problem is I can't get the boost go above 184kpa and it only hit 184 in a 4th gear pull from 2k. any other gear and/or higher than 2k rpm it wont get above 175kpa.

Anybody know what the deal could be? I put my boost settings at 185 tapering to 195 above 5000rpm. looking at the log I have attached even when I hit 180 the boost actually tapers down instead of up like I have it set. I have read the Joe Perez sticky, but I am running an EBC and have the boost line ran just before the throttle body. I did a ghetto boost leak test by sealing the intake of the turbo and then blowing on a hose hooked to the intake manifold with the throttle body blade open. There was no hissing and I could feel all the pressure being held without leaking.

I have attached a log and my current tune.

Godless Commie

iTrader: (2)

What is your overboost protection (boost cut) setting?

WigglingWaffles

Whats your wastegate pressure? The exhaust gasses could be blowing the flapper open.

user 8202

The wastegate has a good bit of preload on it. Was doing 9-10 psi before the ebc.

Overboost is set to 205kpa

Skamba

Does setting your max ebc duty to 100% make a difference?

Also, the DIY autotune EBC frequency can be set to 39hz - although I don't think that matters here.

shuiend

iTrader: (24)

Unhook the vacuum line to wastegate. Go do some pulls and log it. Make sure you have overboost set for sure.

Morello

Boost leak? You're at 90% duty cycle in your log and not making any more boost. Only other thing I can think of is your solenoid settings might be off.

user 8202

I did a ghetto boost leak test by blowing through a hose on the intake while holding the throttle body open. It didn't leak but I'm wondering if i have a leak at higher than 5 psi levels

shuiend

iTrader: (24)

Silicone intakes online sells a great boost leak tester.