Too lean ?
Re: Too lean ? Yes.
It depends on your WOT advance. If you bump your WOT timing to 15 deg you could lean your car our VERY lean before you noticed any KR at all.
It is best to make those kind of adjustments with a wideband operating.
It depends on your WOT advance. If you bump your WOT timing to 15 deg you could lean your car our VERY lean before you noticed any KR at all.
It is best to make those kind of adjustments with a wideband operating.
Re: Too lean ? Your method will error on the side of the car being lean. Typically, a car with no KR will hold peak power for a/f ratios from 12.8 to around 13.8. In my experience for a car with timing in the high 20's KR is usually seen around the 14:1 mark. With that said you will probably end up with an a/f around the mid to low 13's. Which isn't bad and should provide peak / near peak power.
There is no rule for this though. There are just too many factors that can cause your car to ping at WOT. On a cold day with some good gas you may end up parking your a/f around 15:1 which would end up costing you power.
Good Luck,
Kevin
There is no rule for this though. There are just too many factors that can cause your car to ping at WOT. On a cold day with some good gas you may end up parking your a/f around 15:1 which would end up costing you power.
Good Luck,
Kevin
Re: Too lean ? Timing is pulled at 4500 rpm because of peak torque. Torque is related to cylinder pressure, and the more cylinder pressure, the more likely the car is going to detonate.
Sooo, peak torque = less timing.
It is very important to keep this dip. If you get rid of it your car will most likely ping all the way till you let off.
Sooo, peak torque = less timing.
It is very important to keep this dip. If you get rid of it your car will most likely ping all the way till you let off.
TECH Apprentice
Joined: Jul 2002
Posts: 388
Likes: 0
From: Batlimore, Maryland
Re: Too lean ? Interesting comment NoGo Timing is pulled at 4500 rpm because of peak torque. Torque is related to cylinder pressure, and the more cylinder pressure, the more likely the car is going to detonate. " Could that expalin why my HPP3 made my car ping like crazy from 4,500 RPMs up until I shifted at 6,000 rpms? As a result of the ping i removed the power programming. I called Hypertech and they gave me a line about my car breathing to free and that's what cause the lean condition that resulted in the ping.
Re: Too lean ? It is very possible.
There are alot of pitfalls when you add a set value to the entire timing table.
Most setups are very sensitive to ignition advance at peak TQ with the a/f properly dialed in. If you properly dial in your timing for no KR at peak TQ, you probably can run the same advance at peak HP that the hypertech originally intended (stock +3).
Good Luck,
Kevin
There are alot of pitfalls when you add a set value to the entire timing table.
Most setups are very sensitive to ignition advance at peak TQ with the a/f properly dialed in. If you properly dial in your timing for no KR at peak TQ, you probably can run the same advance at peak HP that the hypertech originally intended (stock +3).
Good Luck,
Kevin
Thread Starter
TECH Regular
Joined: Mar 2002
Posts: 433
Likes: 0
Re: Too lean ? OK, how likely would that be around 27 degrees ?
Yes, I would do wideband but where I'm going I may not have the luxury.
Would this work at all ?
I increse WOT timing slightly
Lean it out until I get minor KR
Step back a bit and put timing where it was
BTW, that dip in the timing curve around 4500 RPM, is it because knock is most likely to happen there or something else ?
Yes, I would do wideband but where I'm going I may not have the luxury.
Would this work at all ?
I increse WOT timing slightly
Lean it out until I get minor KR
Step back a bit and put timing where it was
BTW, that dip in the timing curve around 4500 RPM, is it because knock is most likely to happen there or something else ?
