Thrillhouse

So here's my update after my experiences today.

I hit the performance cutback about 20 minutes into my first 30 minute session. At first it was just a gradual cutback of power. At the beginning of my session I'd easily redline 4th gear and go into 5th on the main straight. Later in the session though it was really slow to rev through 4th gear, clearly lower power output. On the next lap after that it felt like I hit a fuel cut at 6500RPM in 4th gear. I gave up and pulled off.

I found though that I can manage it a bit better to keep the cut from happening as quickly. If I short-shifted at 6500RPM and coasted the bulk of the main straight I could make it through a full 30min session.

I did hit limp mode on my last 2 sessions, but that's mostly because I started driving harder and faster. I still got a good 20min of very hard driving before I felt the major cut(provided I didn't redline the engine and coasted the straight).

I'm prety sure that it's some sort of hard limit in the ECU, because if I drove more slowly on the track for a half lap, I'd get full power again. My first guess is it's either oil temp or transmission fluid temp. I need to get a OBD reader to be sure I guess.

Anyway, I think it's fair to say it's a problem with all G37's. I was running with VDC off at all times, didn't miss any shifts, didn't over-rev the engine or anything. It just seemed to pull power as I ran for a longer period of time.

I'll make a full post in the motorsports forum complete with videos and pictures later.

Edit: Post with videos https://www.myg37.com/forums/motorsports-track/184098-august-12th-trackday-at-pacific-raceways-video.html

Lastchance

I tracked my car and had four separate 30 minute runs in 80 plus degree weather in california. I have a 5AT. I had no problems all day. But, I have had my car reflashed at Technosquare so its possible that the rev limiter may have been taken off during the reflash.

gshb

i ran a track day earlier this year (maybe feb?) at laguna seca and did not notice power loss of any type. my times throughout the whole day continued to drop. on the main straight i would always hit redline in 3rd and then bring in 4th briefly before i have to brake again. my car is stock and at the time it had 1000 miles. i have a 6MT w/ sport package.

edit: i just read some posts and noticed that thrillhouse is riding the redline on the straights? im not going to ask why you are riding the redline, but this is clearly something that the ECU could be designed to counteract. i cant say that the cars i previously drove had this type of function, but i wouldnt be surprised if this was the cars way of preventing engine failure because of the driver holding the redline for extended periods of time. can you chime in on how long you hold redline? this could be a oil temp thing or could be how long the car is held at redline for this to happen. if you can drive 15min with no problem doing the same thing then all of a sudden 5 more minutes in you get loss of power, it sounds like temperature related. high rpm for extended periods of time can dramatically increase oil temperature compared to someone touching redline all day but always shifting up.

Thrillhouse

No, I was not holding the engine at redline. I was just shifting at it. I found that if I shifted at 6500RPM instead of 7500, I could drive for a longer time before really hitting limp mode. I never once hit the rev limiter. The reason I'm not shifting during the second half of the main straight is because I was coasting most of it to give the car a chance to cool down, and I was in 5th gear which takes a long long time to rev out.

Staying in 3rd gear I believe probably wouldn't be enough to trigger it. Though the fact that lastchance was OK with a flashed ECU makes me curious.

bboysteele

Have any of you taken your car in for the TSB for the VVEL yet on the Autos? If you haven't, you might want to try this first.

alunserjr

Would a tuner be able to monitor the ECU and determine what is causing the cutback?

Also, I was shifting around 7K (not redline or rev limiter) when this was happening to me.

alunserjr

gshb, what do you think the temps were at Laguna in Feb?

gshb

the morning was overcast (and actually raining). by afternoon weather had cleared up, but it was still pretty cool. being near water, i doubt laguna hits 80s or higher. if it makes a difference, laguna was mostly a 3rd gear track. i would only hit 4th for a few seconds on the long straight and 2nd at one hairpin turn.

alunserjr

The weather history for Monterey (www.wunderground.com) shows temps don't get into the 70's until April. Feb is chilly - at or below 60. When I first ran in May it was in the 70's late in the day. I didn't have the cutoff until the last session of the day.

gshb

what is the redline anyway? i can go past 7500 and not get bounced back. ive never been bounced actually come to think of it. i always shifted at or around 7k.

alunserjr

Redline on the tach is 7500, I don't know when the rev limiter kicks in - I haven't hit it. I usually shift around 7000.

alunserjr

My G37S has a manufactured date of 12/07 and has the limp home mode. Can anyone else who has tracked their car list their manuf. date and if they experienced the limp home mode?

wiseman

All G37S's G35 6mts cut off engine power at high rpm. The G35s would cause like a rmm rmm rmmm kind of thing real quick and the G37s just cut off power. It should only happen near redline or else you do have a problem.

Kidcane

iTrader: (7)

Hitting the redline should not limp it though, just cuts the power.

wiseman

What the hell is a limp home mode? Never heard of this... Your all over the boards kidcane impressive...