Machine shops & STI engine rebuild...

[Dean]

Much happier. Hesitation gone, boost mostly controlled or over controlled still a bit, but better.

Anybody have the cobb stage 2 '07 STI wastegate table for comparison? I remember I am using a VF43 with an '07 pill so the '04 VF39 larger pill tables are not quite in control. Still sticking at 9PSI at times but getting through it in 3rd and 4th and 5th mostly fine. 6th hits 9PSI like a wall. or was it 5th and 6th?

I think the problem was a combination which is why it was so weird. Closed loop delays were probably a big part of it and wastegate teh rest with maybe the solenoid cleaning helping a little.

It was really weird having the car cease to accelerate for a second or what seamed like an eternity.

Thanks to those who offered their stock solenoids but looks like I don't need them.

[knucklesplitter]

Originally Posted by Dean

Anybody have the cobb stage 2 '07 STI wastegate table for comparison? I remember I am using a VF43 with an '07 pill so the '04 VF39 larger pill tables are not quite in control. Still sticking at 9PSI at times but getting through it in 3rd and 4th and 5th mostly fine. 6th hits 9PSI like a wall. or was it 5th and 6th?

The 07 STI has a small 0.8mm pill that usually needs to be changed out to the earlier size (1.2mm) in order to control boost properly with a aftermarket downpipe. I think Cobb even recommends or requires this with their 07 Stage maps. You are playing with fire using the 04 wastegate tables with an 0.8mm pill.

[knucklesplitter]

Originally Posted by knucklesplitter

The 07 STI has a small 0.8mm pill that usually needs to be changed out to the earlier size (1.2mm) in order to control boost properly with a aftermarket downpipe. I think Cobb even recommends or requires this with their 07 Stage maps. You are playing with fire using the 04 wastegate tables with an 0.8mm pill.

http://www.cobbtuning.com/info/?ID=3476

[Dean]

OK, will grab the '04 pill. Was thinking that might be easier. Will probably just swap hoses. I think I have them.

Looking at logs, the knock sensor appears to be wonky... It throws out random knock under little or no load and even under deceleration negative rel. pressure, teens throttle position. WTF???

Do forged pistons cause enough noise for the knock sensor to go off? Dropped my damn multiplier all the way to 0. Do they go bad?

[cody]

You sure you don't want to run a MBC, Dean? Everyone who tries the Hallman Pro with an appropriate tune loves it. I've run one for years.

[Dean]

I have a turboXS MBC lying around and may end up with a MBC tune at some point but not now.

Changing to that will make no difference if I am getting random knock signals stealing my timing.

[knucklesplitter]

Originally Posted by Dean

OK, will grab the '04 pill. Was thinking that might be easier. Will probably just swap hoses. I think I have them.

Looking at logs, the knock sensor appears to be wonky... It throws out random knock under little or no load and even under deceleration negative rel. pressure, teens throttle position. WTF???

Do forged pistons cause enough noise for the knock sensor to go off? Dropped my damn multiplier all the way to 0. Do they go bad?

False knock is a PITA. Never heard of forged pistons doing it (and those KB's are pretty quiet anyway). Usually it is something rattling like a loose or broken heat shield, or a loose part tapping against the block/heads/manifold. Sometimes raising the knock correction thresholds above the offending load or RPM can help.

Knock sensor is unlikely the culprit but I have one you can try out to see for sure.

This may be why you are running into the hesitation. When the IAM drops below .35 (or whatever it is set to) or feedback knock correction exceeds a set threshold the ECU will go to wastegate boost momentarily or until the knock goes away for a while. Also you can feel it when a lot of timing is pulled.

[Dean]

This morning I am going to make sure the knock sensor is oriented correctly and properly torqued.

Yes, apparently that makes a difference.

The harness should leave the sensor at a 60 degree angle to the right rear off a front to rear line and torqued to 17.4 ft-lbs.

[Dean]

I wonder if the knock sensor basically being completely loose would do it?

Not even finger tight. What idiot put that on? Oh, yeah.

I wanted to put on the turbo heat shield and big intercooler anyway, right?

let's go see...

[Dean]

Well, that did it.

I do still need an 0.043" '05-'06 STI restrictor pill/hose. I guess the one from the '04 went with the cracked VF39 Turbo.

[knucklesplitter]

Originally Posted by Dean

Well, that did it.

I do still need an 0.043" '05-'06 STI restrictor pill/hose. I guess the one from the '04 went with the cracked VF39 Turbo.

Stop by. We have a bin full of the 1.2mm pills.

[sperry]

Originally Posted by Dean

This morning I am going to make sure the knock sensor is oriented correctly and properly torqued.

Yes, apparently that makes a difference.

The harness should leave the sensor at a 60 degree angle to the right rear off a front to rear line and torqued to 17.4 ft-lbs.

If you were to take a microphone and pound it on the floor, what do you think the audio recorded it would sound like? A knock sensor is really just a mic bolted to the block, right? Bouncing it all around would totally make the ECU go crazy trying to figure out what it's listening to!

[Double Phister]

Congrats Dean on your success. I just swapped out my own block too (ralispec). I just passed 1200 miles. Still have my paranoid ears on. Did the hard break in thing this time.

[cody]

Originally Posted by R4ND0M_AX3

Congrats Dean on your success. I just swapped out my own block too (ralispec). I just passed 1200 miles. Still have my paranoid ears on. Did the hard break in thing this time.

Time to update your mods list linked in your sig.

How'd you like the Cobb Stage II motor?

[Double Phister]

Originally Posted by cody

Time to update your mods list linked in your sig.

How'd you like the Cobb Stage II motor?

Woops. updated.

The cobb block was good. I got about 60K miles on it. It was noisy from day one but ran great and didn't burn excessive oil. It started eating oil bad (1 qt/500 miles) after about 50K miles. Consumption had worsened to 1 qt/200 miles by 60K. Compression was low but even. I suspect oil rings are toast. No smoke from oil fill. Exhaust smoked from hard accelleration. Didn't smoke on boost alone with artificial load via brakes. I thought it might be the stock turbo (I was near 100K miles and a 19psi tune) so that got upgraded . Still smoked so I pulled the motor and took my time gathering parts and started assembling. New block is quieter than the cobb. My cobb block was louder than other cobb blocks. If they still made them I would have gone with them again.

50K seems to be the limit for built blocks with few making it that far.

If I have to build another one I'll adjust my goals towards longevity. Perhaps longer skirts and tighter than 'normal' P/W clearances.