I picked up some race gas today, 110 octane. I plan on building a race gas tune tomorrow and maybe running some people at the track. How lean is too lean? IIRC, I've read that 13.5:1 is ideal as long as you're getting no knock...but what about EGTs? I've added 5 degrees of timing to bring my car up to about 30-31 at redline and ran a solid 12.5 afr before with absolutely 0 knock, seemed like a huge difference in power but I was afraid to do anymore. How lean can I go without worrying about the EGTs skyrocketing? Is it safe to gradually pull fuel and get into the 13s as long as knock is being monitored and is at 0 counts?
Im not sure on what turbo your running??? If it was me.. and this is my 2 cents of course I would not go past a 12.5AFR.. I know both duster and PTP said that 13.0s are also fine as long as there is no knock.
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At the moment the stock turbo. Haven't got my bt setup pieced together yet. And I was thinking I read from duster that 13.0 was safe...just wanted to double check before I blew my car up.
Well since your on the stocker. I would go up with the boost before leaning it out to much. There have been crazy boost spikes from people on here making numbers and times. Hell if I still had my stocker I would spike 26psi on that sucker lol
12.5 (ish) is going to give you the most power, if you encounter knock due to temps you should cool the mix with a richer mix (11.5). I would assume in the 13's you will be loosing a bit of power
Well since your on the stocker. I would go up with the boost before leaning it out to much. There have been crazy boost spikes from people on here making numbers and times. Hell if I still had my stocker I would spike 26psi on that sucker lol
Yep that's what I'm doing. I ran 26 psi last time. Added 5 degrees of timing and leaned it out to 12.5. May run 26-27 this time and add some more timing if i dont get any knock.
At the moment the stock turbo. Haven't got my bt setup pieced together yet. And I was thinking I read from duster that 13.0 was safe...just wanted to double check before I blew my car up.
Yes 12.5-13.0 is fine with < 1.0 KR but 27psi on the stock turbo won't get you much gain over 24-25psi.
I'd keep the spike under 25psi and add up to 10 degrees of timing. Don't touch the MBT timing though, it'll act as a MAX cap in case the PCM adds a few more degrees on its own.
EGT will get high but higher timing helps cool things a bit by allowing more time for heat transfer. Also let the engine cool down ~5 minutes between WOT runs.
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Thats really pushing it running 26 pounds, what happens if it spikes up to 30 boom
We have spiked to 50 psi and nothing happend on the stock turbo. It doesn't move the volume of air to blow the motor.
27ish spikes is about all the higher you want to take the stock turbo. Any more than that and it hurts power in the TQ curve.
What you want is to have a boost system that is 100% leak free up to 25 psi (holds 25 psi). If you can achive this... you will have the power production that very few have ever seen with the stock turbo.
Well I didn't get to go to the track the other night because of rain. I'm hoping I'll get to go soon. Probably a good thing I didn't go because I didn't have a chance to check for leaks, going to do that Tuesday and hopefully go to the track on Friday.
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How lean is too lean?
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