Problem with xHP and manual mode when hitting rev limiter?

IQraceworks

Sergeant
Jul 7, 2020
262
153
0
Missouri
Ride
07' BMW 335i
I’ve got a weird thing going on with my transmission when in manual mode on the xHP stage 3 tune (it’s done this ever since I’ve had xHP for the last few years). If I let the RPM’s get a little too high before I shift so that the motor hits the rev limiter, it’s like the transmission will lock in gear for 2-3 seconds before it actually shifts gears. Even if it shows the next higher gear on the dash display, the transmission still pauses for 2-3 seconds before it shifts.

Example: I’m in 2nd gear, I stomp on the gas, RPM’s start to climb up past 5K, tires break lose, tach blazes past 7K, hits rev limiter for a split second, I click the shifter back to shift to 3rd gear, dash display shows 3, transmission holds 2nd gear and doesn’t shift, I let off the gas and click the shifter back to shift again, dash display now shows 4, rpms are still crazy high and the transmission is still in 2nd gear, then after 2-3 seconds the transmission finally shifts…into 4th.

It’s like when the motor hits the limiter, it’s preventing the transmission from shifting, or the DME just has too many things going on at once between the rev limiter and request to shift the transmission.

I’ve tried raising the max shift points in manual mode up to 7,800…..same problem

I tried dropping the max shift points in manual mode down to 6,500…and then it just shifts on its’ own when it hits 6,500, and I don’t want that…..I want it to shift when I want it to, no matter if it accidentally hit the limiter or not.

No issues with shifting in sport mode, or D more, or even Manual mode...unless I accidentaly hit the rev limiter. The car has ran 10.90's at the track and it shifts perfect...but it's a prepper track, so I'm not breaking the tires lose and hitting the limiter, I'm shifting at around 6,800rpms.

Any ideas? Anyone else experience this issue with xHP?
 

Motown65

Private
Sep 12, 2022
31
3
0
What car is this? I take it its dct? I believe ive had this happen in first gear using launch control on my f82. Shoot me a pm
 

IQraceworks

Sergeant
Jul 7, 2020
262
153
0
Missouri
Ride
07' BMW 335i
What car is this? I take it its dct? I believe ive had this happen in first gear using launch control on my f82. Shoot me a pm
This is an 07' 335i with N54 and 6speed Auto HP21 transmission.

I got word back from the tech at xHP. He's telling me that hitting the rev limiter is "less than optimal", and can cause issues with shifting because the DME has a hard time getting the correct torque vaules from the transmission in order to command the shift? Sounds overly complicated. Stage 3 is supposed to have the "Race Cal" setup so that in manual mode it's not going to aumatically shift at all, it will hold a gear all the way to the limiter......so why have it set up so that when/if you do hit the limiter.....it's going to cause issues with shifting?? Sounds like an xHP software bug to me...
 

W8ivit

New Member
Mar 21, 2023
9
5
0
I had similar problems this weekend . At the drag strip my car refused to shift into 5th gear when I was at 100 mph or so . No matter what I do manual or sport mode everytime it was supposed to shift it wouldn't and the car would just eventually slow down because i was redlining the car.
 

N54gasm

Sergeant
Feb 6, 2017
350
234
0
New Freedom
www.spoolnmotorsports.com
Ride
2008 BMW 135i
Experienced this as well over the weekend while at the drag strip. Hitting rev limiter can mess with the dme/trans and mess with the shift logic. Idk what your rev limit is but mine was 8k, and it would do it everytime my car spun ans hit the limiter. Lowering the limiter to 7300ish seemed to have worked for me.
 

IQraceworks

Sergeant
Jul 7, 2020
262
153
0
Missouri
Ride
07' BMW 335i
Glad I'm not the only one who's had issues with this. I talked to a tech at Xhp.....at he made it sound like there's just too much going on at one time, and the DME can't process the inputs fast enough in order to get the correct informaton to the transmission. For those of you who have had the issues....are you using the option on xHP to set your own shift points? I think that might be some of the issue. As soon as I get my car running again, I'm going to set it back to the stock shift points and see if that makes a difference......even though in manual mode, it shoul ddissreguard the shift points all together.....but the option is still there to set them for some reason. I think it's a bug in xHP......