So now that I have a few days on the 91 no Ethanol with the 91 Tune V8. I can say that the car runs a lot better. It even idles smoother, the only real issue that it is pulling more timing than I would have expected. With the above statement I guess it also applies to non ethanol blends. Today it's only 4C (39F) so it's chilly. Running the 91 V8 Tune on 94 Petro (with 10% E) the car ran like a bag of crap once the temp dropped below 10C (50F). Still winter blends I guess, I have gone over the logs from last year. Track runs in May of last year Temp at the time was only 8C and the car ran really strong. I got one of my best runs at 12.737. FRP was a solid 2200 psi the whole run (this was on 10% E). I wonder how different must the winter gas it to cause this difference in the car and tune. LMS has sent me a V7 with the cold weather tweak. I will be trying this over the weekend with some 10% Ethanol 94. More to come.
Hesitation and high KR Cold weather issues?
- Thread starter ShoBoat
- Start date
Loaded up V7 CW 91 Tune. It was time for a fill up so I went with 94 with 10% Corn. Initial results are interesting. I was actually surprised, KR is reasonable (we still have winter gas up here) And its cold, only 4C tonight. I couldn't feel any hesitation or misfires at all. I will do some data logging and confirm. The car pulled really strong. So strong that it roasted the tires right through first gear and part way through second. (the cold and summer tires are partly to blame for that) but it still felt really cool.
Ok so a bit more driving and testing. I was sure it was gone at first. Not so...... So from a standstill the car pulls great all the way through to the end of 4th. From a roll at 30 mph to WOT down to 2nd gear no problem pulls great again well into 4th gear. Now here is the kicker, at 55 mph and WOT same issue as before. Hesitation and misfires. WFT?? FRP drops to below 800PSI. On the other runs it holds well above 1500. If was a mechanical issue for example pump you would think it would do it all the time, not just from a 55 mph roll. I have sent the latest logs to LMS for their thoughts.
See below for the charts, first is 30 mph 2nd is 55 mph.
See below for the charts, first is 30 mph 2nd is 55 mph.
Are you logging boost level when it is sputtering and missing? It sounds like maybe you are just boosting really high momentarily then fuel pressure drops causing sputtering, missing, KR.
Don't ask me why but I can get boost where I want it and think I'm making good progress with my tune then out of nowhere boost will be lower and or higher in places than I had it...It has more to do with the commanded torque I think....The boost is an arbitrary thing, the car is attempting to give you the torque you are commanding and the boost is what it is. It's weird and I'm still learning it but my point is that boost spikes can happen inadvertently and when fuel pressure is low the door is open for sporadic behavior.
I wish you could log in livelink gen 2. I'd send you the config file with what I log and I'd love to take a look at some of your WOT pulls.
Did you say that it happens right after you floor it at a downshift for wot? Boost could be spiking pretty good there....I've had high boost tip ins with multiple tunes including tunes that I paid for.
Don't ask me why but I can get boost where I want it and think I'm making good progress with my tune then out of nowhere boost will be lower and or higher in places than I had it...It has more to do with the commanded torque I think....The boost is an arbitrary thing, the car is attempting to give you the torque you are commanding and the boost is what it is. It's weird and I'm still learning it but my point is that boost spikes can happen inadvertently and when fuel pressure is low the door is open for sporadic behavior.
I wish you could log in livelink gen 2. I'd send you the config file with what I log and I'd love to take a look at some of your WOT pulls.
Did you say that it happens right after you floor it at a downshift for wot? Boost could be spiking pretty good there....I've had high boost tip ins with multiple tunes including tunes that I paid for.
Unfortunately I don't have live link, but I can send you the logs in Excel format. It will give you the idea. It takes a bit after the downshift, maybe a second or two. It's really weird. Send me a pm with your email address and I can send you the logs tomorrow.ajpturbo said:
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When you did the 50mph roll with the low fuel pressure it looks like the car didn't down shift....Were your RPM's low? It's hard for the hpfp to make pressure when RPM's are lower, that's when mine suffers as well.....I've ran well over 20 psi and rail pressure stayed over 1500 as long as I was over 4500 RPM's