93redFD

in other words hpw lean can we go???

peejay

Depends on the conditions.

I honestly don't believe that N/A engines can even detonate from lean mixtures. I've measured ".000v" on my )2 sensor under cruise conditions for thousands of miles with no problems other than excellent fuel economy. I've also run them at similarly lean A/F ratios under full throttle for many laps with no ill effects other than running a bit feverish. I've also run them at full throttle at mixtures so lean that the engine misfired heavily due to fuel restriction (rust in the fuel lines) and drove 30 miles home that way with no ill effects other than having a top speed of 35mph and burning out every gasket in the exhaust system.

I would not attempt this on a turbocharged car, however.

- PJ (Getting the trailing plug leads mixed up *will* cause an N/A to detonate at 1/3rd throttle, however... ignition timing of 196BTDC is a BAD thing)

82streetracer

iTrader: (1)

yeh, NA rotary are almost knock and preignition invincible

Kurgan

Simple answer, on a turbo car, a safe number would be around 11.1-11.8:1. You can go SLIGHTLY leaner, but anything more than 12:1 and you are pushing your luck BIG TIME.

DavidDeco

Depending on Boost level and RPM. You can run leaner if you are not boosting or barely boosting.

fastrotaries

at idle or under vacuum i've heard of people run stoich.

rx720bt

Most stock third gens I saw is in the low10's at full boost WOT on 4th gear run. I must say it's pretty rich. "Genearlly" for a turbocharged car 11.2 is good for best torque, on the rich side. And 12.5 is good for best horsepower, on the lean side. But the question is, would you want to run your 13REW on 12.5 AF? Probably as a margin of "security" it might not be a good idea.

twokrx7

iTrader: (1)

There have been some great threads on the single turbo forum in the past year, take a look.

peejay

What's good for best HP should be good for best torque. HP is just torque factored by RPM.

I agree, best to be on the safe side, unless it's totally vital that you squeak out that last 5hp at any cost