View Full Version : Engine rebuild update, tuning question?

09-01-2012, 01:08 PM
So this was back last year from one of my first threads:
"I have a redtop sr20det, 440 injectors, t28 with internal wastegate, Greddy type RS BOV, headers, turbo back with a cat-delete. Its a s13 hatchback with a veryyyyyyy annoying cold start problem. fires right up when warm (after i used starting fluid to make it fire).
Recently had a new: 02 sensor, water temp sens, complete wiring harness, stock sr ecu w/ map, z32 maf.
But still hessitates to start when cold..Compression was down a little also, but was perfect like a month ago before i put it in the shop to have my wiring harness done. So i dont know what to think besides having my injectors cleaned out. Also, 3 of my plugs are fine, but my 4th was coated in oil.....?"

So i had my engine rebuilt at my local shop that my family has known for a while and who do quality work.. Looks like i had a chip in my 4th piston due to over reving from the guy i bought it from which answers my compression loss.. Ha. Found out my cylinder walls are fine. I had the block hot tanked, balanced and a valve job. Bought a complete engine rebuild kit including
Forged CP pistons. 86mm 9.0.1
Clevite connecting rod bearings
Clevite main bearings
Clevite thrust bearing
OEM full engine rebuild gasket kit
Apexi head gasket 87mm T=1.5
OEM Sr20det timing chain, tensioner, guides, guide bolts
OEM water pump
ARP head stud kit
and OEM oil pump, and timing chain cover.

So the chip in my #4 piston explains my cold start issue: loss of compression.
I have a TURBO SX dual stage boost controller and i want to run 8lbs during my engine break in process, and after about 1500 miles, hook up the 2nd stage switch to 12lbs.
My question is, how do i turn down my boost and how do i check its level?
Other question is, i have a mapped SR ecu that is running my 440cc injectors, and about 12lbs. Will that be fine with my setup? I'm going for daily driving, but also a healthy reliable engine that will handle some aggressive driving at times, but not all the time. This car is my baby! Ya'll know how it is..
Thank you guys for your feedback i really appreciate it. especially on such an old thread..

09-02-2012, 10:43 PM
Bump help????

09-03-2012, 12:46 PM
Who mapped the ecu? Need more info than just 440s and 12 lbs. To lower boost pressure, adjust the boost controller, that's what it's for. If you have the stock wastegate, run it without the controller for break in. Should be around 7/8 psi. To check pressure you'll need to hook up a boost gauge.

09-03-2012, 01:53 PM
you can break it in on 5 billion pounds of boost if you want, it doesn't matter how much boost you are on when you break your motor in cause the motor won't even see full boost unless u take it there, which you shouldn't, 1500 miles is rather excessive, after starting it and letting it warm up you can take it from 35mph to 55mph on half throttle about 10 times to put it under a load and seat the rings, then just drive it like you normally would stop and go traffic for about 200 miles then change your oil then drive it normal letting it see a bit of boost here and there for another 2 or 300 miles and then you can let her rip, for such a basic low boost set-up theres no need to go overboard on the break in process, although thats just my opinion you can do whatever you please obviously, you cannot turn your boost lower than what the spring is rated to in your wastegate, if it's stock then its 7lbs theres no need to go any lower than that, in fact you should keep it on 12 because that is round about factory boost with the oem boost solenoid, and you need a boost gauge to check how much boost you are on

09-05-2012, 12:12 PM
Okay thanks this helps! Yeah i have a boost gauge in my car along with oil pressure. And I have my ECU mapped for 4400cc injectors and a Z32 MAF. So i think turning down my boost just to like 9 should be fine for the first 800/1000 miles. I will post pictures of my build soon.