Retune needed after new OEM motor?
 

I have the BP kit installed on my car currently.

If I got a new motor from Nissan, would I need to retune it again or is it just a simple swap of the motor, fire it up again, and give it hell?

One of my friends said that every engine is different. And while I agree, I don't think an OEM motor would be so far different that the engine AFR's would vary enough to need a whole new retune on the dyno.

Thoughts?

I would advise a re-tune, or at the very least a 'touch up' of the current tune for any variances.
Also, with a new motor you probably don't want to go full tilt for a little, maybe after 500 miles do an oil change and then slap it back on the dyno for a touch up tune.

I'd retune it

Back up the truck....did you pop your motor?

Now to answer your first question. Was it just the motor or was the ECU replaced also? The tune is linked to that specific ECU Vin# so they would require a retune.

I agree with Dreamer and DE, I would recommend getting it back on the dyno just to double check everything.

depends on the differences between them the biggest one is going to be compression, if you were tuned on an old tired motor you may end up with detonation on the new one due to it having tighter rings. If the tune was mad when your current motor was still fresh it won't be that far off. I would say swap them, drive it easy and break it in, then go in for a dyno pull just to have them make sure it isn't doing anything it shouldn't be.

Yeah my engine let go. I lost grip at redline and went slightly above, maybe 300 over. Piston head blew in half. I think I ran out of fuel up there.

I am the buyer of that fresh 109 miles motor that was for sale here. The guy selling it lives here in CO. It was wrecked by a guy transporting it from one dealership to another.

My motor had 10K on it when I installed the kit and had it tuned. The ECU will not be swapped.

What did you pay for this motor? Unless it was a steal, I think I would have went built since you were running E85 already.

What power level/psi were you running when it let go?

Ouchies, Do you have some sort of fuel system on the car? Or are you running the stock setup? I know with that E85 you guys have you got to spray alot of it in there to keep things happy.

Well I can tell you that I paid $4,000 less than I would have had I gone the built bottom end route.

I was on 11lbs. But again it wasn't the power that did it. It was fuel.

A contributing factor was the fact that I added a boost controller after I had been tuned. IT was a spring style MBC. It held boost a bit more up top which is why I think I must have leaned out some. This combined with the higher HP I was making around 7,700 rpms, is what caused it.

Going from one stock engine to another will warrant considering special attention to the tune and logging, but I wouldnt be so dramatic as scheduling a tuning appointment before first start up and test driving, etc.

However, since this is following an engine failure... regardless of why I believed the motor failed, I would take into consideration the possibility that the existing tune may have contributed... and for that reason I might consider getting in position for tuning/logging before pushing the new engine hard under boost.