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Updated tune with weird results

2493 Views 15 Replies 6 Participants Last post by  evolizzee
So BNR made an aggressive tune for me with the recent install of the ZZP downpipe/Forge BPV and it runs great. I went to open her up one day for the first time, a week after datalogging, and hit a wall at 112mph. The governor kicked in and the car nose dived...The info center said "speed limiter reached" or something along those lines. So BNR created a tune to up the limiter a bit and informed about proper tire selection. I installed the tune and shortly after engine start the info center went off saying "Engine Power Reduced". The car still idled fine. I then reloaded the tune, started it up, and went for a drive to see if it would do it again. Again, only a minute into driving the alarm went off "Engine Power Reduced" I felt no change in performance. The car drove smooth, TP sensor read nominal, and power came in as usual. So I went home, loaded up the aggressive tune that still had the factory speed limiter setting, and the "Engine Power Reduced" alarm has yet to alarm. At least 5 engines starts and a couple hundred miles since then and no alarm. The boost still spikes to 20.5psi and tapers to 18-19psi. AFR's are still mid 11's. No KR and the car pulls like it should. Did the car not like the updated tune with the speed limiter raised or could it be something else? Has anyone had a similar case?
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Honestly, I have lived in triple digits myself and I would not feel in the least bit comfortable 115+. How fast do you need to go or are you drag racing ? Maybe the speed limiter is more of a protection than anything else! If you really want to go that fast you bought the wrong car. But interesting findings, I don't believe anyone else has found such results.
I can not stress, make sure your tires speed ratings are up to the limiter.
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Honestly, I have lived in triple digits myself and I would not feel in the least bit comfortable 115+. How fast do you need to go or are you drag racing ? Maybe the speed limiter is more of a protection than anything else! If you really want to go that fast you bought the wrong car. But interesting findings, I don't believe anyone else has found such results.
I have a weekend car that I can enjoy real speed with. I just wanted it bumped to 130. I have no problem with speeds over 100, or over 150, for that matter. All of my previously owned vehicles (daily or hobby) have been tuned and the tuner automatically bumped the limiter up if they were set close to 100-130. Some didn't require a limiter adjustment...like my Camaro. CincySpeed said it was already set to 160ish... which I haven't even reached yet.

Its just kind of odd to have an alarm like that pop up just from taking the same tune, and the only adjustment made, was increasing the limiter... especially when that is a pretty serious alarm.
I can not stress, make sure your tires speed ratings are up to the limiter.
Thisthisthis.

I have a feeling it's going to take you quite some time to get to 130mph. My Cobalt takes a little bit of time to get there, since it's in overdrive (which you will be), but I have closer to 300 HP at the crank in a much lighter vehicle.
Its just kind of odd to have an alarm like that pop up just from taking the same tune, and the only adjustment made, was increasing the limiter... especially when that is a pretty serious alarm.
I'm not questioning your "need for speed so don't get me wrong, it is quite odd for a tune to have an alarm as such! I have not heard of anyone else mentioning a speed limiter before I would be curious to see what RPM you are at, at that speed I know GM has a rev limiter on the engine also but it is not an alarm
But interesting findings, I don't believe anyone else has found such results.
Yes, generally a regular speed limiter just simply stops letting you continue going any faster without any kind of a message.
Houston, we have a problem.
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It wasn't alarming the "Reduced Engine Power" just when trying to reach top speed. It would alarm about 1 min after engine start. No matter if it was sitting still or putting around back country roads. Luckily, just the aggressive tune with the factor speed limiter in place doesn't activate the alarm, so I'm just gonna stick with it until I hear back from BNR. They've been more than helpful!
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I would quit beating on your car until you have an answer.
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I would quit beating on your car until you have an answer.
Yeah, BNR responds pretty quickly to emails. Hopefully, they might have an idea. The car drives smooth as can be without any issues on the current tune though.
https://youtu.be/-nIbl_CidiE

Thisthisthis.

I have a feeling it's going to take you quite some time to get to 130mph.
She doesn't do too bad. I bet it'll push to 140mph with proper tires and possibly turn a low 15 sec 1/4 mile. She'll never see the track to prove that theory. I doubt my LS buddies will ever let me live that down if I did show up to Beech Bend with it lol!! However, I do plan on buying better performance wheels and tires after the factory ones wear out...
She doesn't do too bad. I bet it'll push to 140mph with proper tires and possibly turn a low 15 sec 1/4 mile. She'll never see the track to prove that theory. I doubt my LS buddies will ever let me live that down if I did show up to Beech Bend with it lol!! However, I do plan on buying better performance wheels and tires after the factory ones wear out...
We've taken plenty of goofy **** to the drag strips before - I mean, I've run my Cobalt there on numerous occasions, including once (as a baseline) when it was stock. No shame in running anything there.

I've been meaning to get back there again now that I have tires with grip (I had them on the last time I went, but didn't take my sub out, and had a thing in the tune that was accidentally turned back on when I had the speedo adjusted for the different tire size) and see what it does.
It's normal to see all kinds of weird messages right after a flash. If you only saw it the one time and it didn't come back, it's not an issue. If it continues to come up every time you start the car, the speed limiter may have been raised too high and car doesn't like it. It's a weird message to display when it's grumpy about the speed limiter, but I've seen it before.
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Maybe we should try a lower speed? 130-140? Do you happen to remember what you raised it to? If all else fails, I'll be fine with leaving it at the factory limit. I'm just not used to ever hitting the speed limiter in any of my past cars or my current weekend warrior. It kinda surprised me when I hit it lol!
It's normal to see all kinds of weird messages right after a flash. If you only saw it the one time and it didn't come back, it's not an issue. If it continues to come up every time you start the car, the speed limiter may have been raised too high and car doesn't like it. It's a weird message to display when it's grumpy about the speed limiter, but I've seen it before.
Well, I loaded up your revised version of the raised speed limiter tune. I had to update the firmware first. So far, after about 5 engine starts and 120 miles there have been no weird alarms on the info center. I think that did the trick. Thanks for the troubleshooting help.
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