Hello everyone,

So my remote tuner, whom I trust calls for datalogs where I start at a speed under 10 mph in 3rd gear and WOT until the rev-limiter. This involves lugging the engine quite badly until 20 mph or so. My worry is that by going WOT at such low rpm in 3rd gear, I am lugging the engine quite badly and could cause pre-ignition which would not be good. So my question is, how worried should I be about pre-ignition and premature engine damage from lugging the engine this way? Is this normal tuning procedure to start in 3rd gear at such low speeds?

Would really appreciate input from some experienced tuners here like Gernby or other people with experience and knowledge in engine performance.

Thank you.

 

Lugging a motor isn't good, but the benefits of a good tune far outweigh the impact of a few lugs. I prefer starting the 3rd gear pulls around 1800 RPMs with the pedal to the floor, preferably NOT going up a hill.

EDIT: After thinking about how 10 MPH converts to RPMs in 3rd, that does sound too low. I wouldn't be worried about knock, but I would be concerned about low oil pressure. It could be hard on the bearings.

 

Thank you Gernby for the response. I just did the gearing calculation myself, that means I was starting out under 1k rpm which sounds terrible to me. I have only done this twice now but both were uphill so that has me very worried about whether I have done any damage to the engine just from these two runs, i would hope not.

Will the flashpro datalog capture oil pressure and would my tuner be aware of whether its too low at those engine speeds and alert me of that?

I may ask my tuner to let me start out at a higher speed, maybe 15 mph (which is close to the 1800 rpm mark you suggest) so that I can ease my mind a little bit.

 

Honestly, don't concern yourself about the past. What's done is done, so there's no use in dwelling on it.

I would let the tuner know that you don't feel comfortable starting that low in 3rd, and see what he suggests. Starting in 2nd would be much easier on the motor, and the rate of acceleration will be so low that the data should be fine. The tune really just needs to be "safe" below 2K, since it should always be at or above 2K while driving.

 

Just spoke with him and he is fine with starting the run around 15 mph. I also think I made a mistake last night doing the two runs on highway on-ramps which were noticeably uphill so that probably didnt help at all.

He also said that he has the AFR pretty rich down low on these tunes to protect against knock, so I probably have nothing to worry about, I just tend to overthink everything and my engineering background has me second-guessing and trying to understand everything.