While I harp on getting the tune correct vs close enough I'd thought I share a 30K mile result of having the tune really close to correct and what it can do for you.

Right after I got my car, I had to yank the engine cause the crank dampener wasn't torqued down correctly after the last owner did a cam swap. The Dampener, chewed up the end of the crank. So in an effort to get the car running dropped in an old engine I had sitting in the garage. From talking to past owners of the donor engine car, it was rebuilt 60K miles before I got it. I figured to just use it as a mule engine and learn what I could using it.

For the next 30K miles, I spent lots of time over 20 PSi of boost, and ran alot of experimential code, and tuning stuff on it. toward the end of it's life #4's injector had some full rich and full lean problems, and that torched the piston. And all of the last year and a half non-intercooled. So when it died, it was of absolutely no surprise, and I was amazed that it even lasted that long.

A couple days ago, the machine shop called to let me know everything was fine, to include the bore sizing. AND that the first rebuild was with some econo rebuilders cast pistons.

Now, I just wonder how long it would have last if the injector problem hadn't happened.

While I'll readily admit to being picky about tuning, I think that these kind of results are nothing short of great. 30K miles, at 20+ PSI of boost on 93 octane, is just neat in my book. Not to mention that it was as a faulty injector, and harness problem that killed the motor.....


And while I'm at it, you might have heard that Barney got hurt. Barney being the new engine, cause it's purple.
Well, yes, a prolonged 25 PSI session did make a noise worse, so I'm getting the old engine patched up, to install while he goes back to shop for further analysis. It looks like a F/M intercooler is in the future for Barney.

 

I have also learned the same thing, it's hard to blow an engine by tuning the ecm, unless you don't know what you are doing. I have ran my engine at 13.9 a/f ratio down the entire 1/4 mile, under 95* ambient temps and it ran great. Ran 39* of timing, didn't blow my engine. It burned the plugs up though.

Sounds like you could have just replaced the piston, if it was forged. No sense messing with junk cast. The engine didn't really even die,ha. That is cool. Thanks for sharing your story!


Tim

 

What type of motor was the donor motor? 305, 350, what year? just curious. Great job man, this is very interesting.

pj

 

I'am a little curious as to what compression that engine had to be taking so much boost for so long. Do you know?

 

He's referring to his GN. 231 ci turbo 6 cyl from the factory (if u didnt know). Stock compression was 8.0 -1 and most rebuilds should be at 8.0-1 or slighlty higher due to overbore.
later
Jeremy

 

yeah well i melted 4 pistons cuase i forgot to check my gas gauage recently. ha ! what do you think about that ?i got 50k out of that motor. and its just getting fresh pistons and a clean up valve job from the plasma aluminum spray of melting pistons.

but yeah i get what your saying. the first GM honda conversion i did has been running 100k now with crappy 87 octane fuel on a motor that had 200k on it when i converted it and i did a compression test it was 160 at evey whole. either honda builds some fantastic engine ( which is true ) or i did a good job tunning it.

But Grumpy is right. Getting the tune right will keep the engine living a long time.