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Please help, Installed new 4.10 diff. and rebuild transmission with 2400 stall converter. Car shifts great until I try to run it wide open and it hits the rev limiter. I have tried many different changes with the same result.
I am thinking that maybe something is off with the auto configure that I did for the new gear ratio. The 1st and second gear ratios have changed because of the Sonax 2.84 gear installed in the trans. Any help would be much appreciated.
Thanks in advance
I'm sorry for not being up on my knowledge for doing the gear ratio/tire size change stuff in a vette calibration to make sure it's right, but have you tried doing anything with the shift mph settings?
I noticed the 100% throttle cell on normal is not the same as the full throttle shift mph table next to it. One is like 35mph and the other is 39mph. Each of the other gears is different as well.
I will look at those again. I have found things I have missed in a couple of areas as I have been checking the program and comparing it to my previous set up.
and yes I have tried lowing my MPH and RPM shift points with no luck. I am sure it is something simple.
Thank you for replying,
Seen this, might help...https://forum.hptuners.com/showthrea...hlight=bluecat
How far have you dropped the MPH shift for 100% on the part throttle table and WOT tables? With a little stall and the 4.10 they probably need to drop 25+%. Since the PCM needs a moment to OK the shift after reaching the MPH mark (+trans processes) I usually set the two tables at least 5-7 mph below when I want my WOT shift and let RPM dial it in a bit. Even with the 2.84 first, the 4.10 is going to give pretty fast rpm rise in first so the PCM might need a little earlier notice. The closer the gear/tire/speedometer is to accurate, the closer you can usually set your MPH but I usually still need a gap.
When you see people need to drop shift MPH all the way down to 5 or 10 in order to get it to shift the speedometer related settings must be off....still dropping the MPH way down can at least prove to you if your trans is working. Also fresh 1-2/3-4 bands need several shifts to break in and start to grip the drum.
Thank you for your reply, I will try the 25% drop on the MPH and the RPM in relation and see what it does.
I am hoping to have it dialed in by the weekend. I will post how it goes.
Thanks again for the advice.
You should be able to leave the RPM pretty close to where you want it.
To everybody who gave input to my post, THANK you.
Everbody's input helped. I ended up having to lower my speed inputs by 15 MPH.
It is shifting great at WOT. Couldn't ask for more....
There are a couple of simple changes the gear change wizard doesn?t fix.Quote:
Originally Posted by kwest
This is for anyone reading this trying to figure out why they’re hitting the rev limiter after gear change and gear wizard. Reply here and I’ll tell you how to fix it.
Lowering shift speed is often a good move when diagnosing why a car is bouncing off of the rev-limiter before completing a shift. It is not always the answer but is a helpful tool when you need to figure out what is causing that issue.
Truly the gear change wizard is not perfect. It cannot take everything into account. It can get you into the ballpark but once you mess with a few other factors like converter and power it requires a bit of actual tuning to find a good balance.
People who never changed gears or tire size also get this issue (bounce off of the limiter at the top of a gear). It usually arises when the engine has more ability than the factory factored in to their "lead time" for shifts and/or a looser converter. That is why the genius who came up with BlueCat has a function for lead time. The factory also varies the speed that they initiate a shift based on the combo. It is one of the factors in the bigger equation.