What to expect from tune after lowering compression
Thread Starter
Staging Lane
Joined: Jul 2015
Posts: 81
Likes: 1
What to expect from tune after lowering compression Hey guys, I'm inching closer to getting my engine running in my car. I have a supercharged ls6 that was previously running ported 243 heads with pac 1218 springs and a 220/.581 lift cam.
The performance changes while doing the rebuild have been going from 10.5:1 compression to 8.1:1 compression through putting dished pistons and 317 heads that are not ported. I will be swapping over the pac 1218 springs over to the 317 heads. Also my prior tune was done at 6000ft ASL and I'm now at 1000 ft ASL.
My question is from a tuning perspective am I going to need a base map to be able to break in my motor for 500 miles before taking it in to get dynotuned? Would you expect it to idle be driveable or will it be pig rich from the lowered timing and added fuel for the higher compression tune that was previously getting run? Thanks.
The performance changes while doing the rebuild have been going from 10.5:1 compression to 8.1:1 compression through putting dished pistons and 317 heads that are not ported. I will be swapping over the pac 1218 springs over to the 317 heads. Also my prior tune was done at 6000ft ASL and I'm now at 1000 ft ASL.
My question is from a tuning perspective am I going to need a base map to be able to break in my motor for 500 miles before taking it in to get dynotuned? Would you expect it to idle be driveable or will it be pig rich from the lowered timing and added fuel for the higher compression tune that was previously getting run? Thanks.
Last edited by tommypenguin; Feb 24, 2018 at 02:53 PM.
Launching!
Joined: Jan 2018
Posts: 283
Likes: 0
being much lower in compression it will take significantly more timing to burn the fuel efficiently. at 8;1 it will probably break down under boost with too little timing and rich AFR.
go for a gentle drive around the block and look at what the STFT do to begin with. adding or subtracting that percentage is a good place to start.
go for a gentle drive around the block and look at what the STFT do to begin with. adding or subtracting that percentage is a good place to start.
