[Stubok]

Originally Posted by bahasad

I think I read somewhere that the stock 8AT trans in the 328I is built to a limit of around 350 ft-lbs. With these tunes, you are hitting that limit easily.

Ive also heard and read that the 8AT is being used in the 335 and other autotrans cars, so it should be good for way more than 350lbft.

[f30kid]

He also has the Sports transmission which shifts differently than non , although same trans it just coded to shift differently

[GSR Technik]

Originally Posted by goon

Just to confirm mine was RWD not xdrive.

Copy that. For some reason I thought it was x-drive. We've also confirmed with the guys we are working with over in Indonesia that they are experiencing the same thing across all N20 based cars. As torque moves well into the 300 wtq range it's happening which seems to be when people are getting that little extra umf with the addition of a downpipe. The 228i we are going to be testing out here in the next week or so is a stage 2 auto car so we will see what we find. If we don't run into the issue we can just keep adding octane to bump up the numbers and see at what torque levels it starts to trigger the torque limit.

[GSR Technik]

Originally Posted by Forgiven

GSR Can you do something to my activehybrid 3? I live right next to you guys.

So that's the N55HP motor right? That is a question I'm going to have to go to our CTG (Chief Tuning Guru) Matt Bekam to answer. Let me forward to him and get his assessment given that I assume there is a crap load of extra code in there to control the activehybrid systems.

Nick...

[GSR Technik]

Originally Posted by Dippydo

So the next question is if you hit the torque limiter, is that logged and now does the dealer see that in the data giving away there was a tune?

If we can replicate it our here on a car that we have direct access to we might be able to answer that question. If we can find the binary that controls that torque limit and raise it we might be able eliminate the problem all together - it happening and it logging anything.

[bahasad]

Originally Posted by Stubok

Ive also heard and read that the 8AT is being used in the 335 and other autotrans cars, so it should be good for way more than 350lbft.

They are different variants of the same transmission - the internal components can be quite different between a 328, a 335, and other 8HP equipped cars.

And for proof here it is:

http://en.wikipedia.org/wiki/ZF_8HP_...F_8HP_variants

450 N*m = 331 ft lb.

[Forgiven]

Originally Posted by GSR Autosport

So that's the N55HP motor right? That is a question I'm going to have to go to our CTG (Chief Tuning Guru) Matt Bekam to answer. Let me forward to him and get his assessment given that I assume there is a crap load of extra code in there to control the activehybrid systems.

Nick...

Yes it has the N55 motor.
I'll give you a call, thanks

[f30kid]

Originally Posted by bahasad

They are different variants of the same transmission - the internal components can be quite different between a 328, a 335, and other 8HP equipped cars.

And for proof here it is:

http://en.wikipedia.org/wiki/ZF_8HP_...F_8HP_variants

450 N*m = 331 ft lb.

According to that and Realoem its the same exact parts except for mounting bolts , im not seeing any difference ?

[bahasad]

Originally Posted by f30kid

According to that and Realoem its the same exact parts except for mounting bolts , im not seeing any difference ?

The F30 328 and F30 335 share the same 8HP45 product #, there could be differences between them.

Either way, it is rated to 331 FT-LBs for the 3-series, 1-series, and chrysler products. The 328 with all these bolt ons will easily surpass that, therefore causing potential issues/failures. There is a reason why BMW put the safety-factor in the calibration for the Trans.

I'm not even going to argue the fact that the con-rods for the 328 motor and are only built to about 331 HP.

Tuning is great and all, and I highly support GSRs work. I'm just saying this tune is exceeding the limits of the Powertrain.

Just my 0.02cents.

[GSR Technik]

Originally Posted by bahasad

The F30 328 and F30 335 share the same 8HP45 product #, there could be differences between them.

Either way, it is rated to 331 FT-LBs for the 3-series, 1-series, and chrysler products. The 328 with all these bolt ons will easily surpass that, therefore causing potential issues/failures. There is a reason why BMW put the safety-factor in the calibration for the Trans.

I'm not even going to argue the fact that the con-rods for the 328 motor and are only built to about 331 HP.

Tuning is great and all, and I highly support GSRs work. I'm just saying this tune is exceeding the limits of the Powertrain.

Just my 0.02cents.

I guess that's the whole exercise of the progression of tuning. Finding the limits and figuring out if there are reasonable solutions to keep progressing. I think we are finding the upper limits and need to find a nice sweet spot. Ideally we'd like to bump up the torque limit up 10 or 20 ft/lbs because cars with DP and 93 seem to need just a little bit more room to run consistently. The manual cars seem to be doing fine at those torque levels as far as the motors. The question does remain if we bump that torque limit say just 5% will we still be in a safe operating range for the trans. BMW is usually pretty conservative so I'm guessing a 5% adjustment would still be within operating design parameters.

[bahasad]

Originally Posted by GSR Autosport

I guess that's the whole exercise of the progression of tuning. Finding the limits and figuring out if there are reasonable solutions to keep progressing. I think we are finding the upper limits and need to find a nice sweet spot. Ideally we'd like to bump up the torque limit up 10 or 20 ft/lbs because cars with DP and 93 seem to need just a little bit more room to run consistently. The manual cars seem to be doing fine at those torque levels as far as the motors. The question does remain if we bump that torque limit say just 5% will we still be in a safe operating range for the trans. BMW is usually pretty conservative so I'm guessing a 5% adjustment would still be within operating design parameters.

True, there are 335s and M235s that are out there running mods obviously pushing closer to 400s on the same trans.

[Stubok]

Originally Posted by GSR Autosport

I guess that's the whole exercise of the progression of tuning. Finding the limits and figuring out if there are reasonable solutions to keep progressing. I think we are finding the upper limits and need to find a nice sweet spot. Ideally we'd like to bump up the torque limit up 10 or 20 ft/lbs because cars with DP and 93 seem to need just a little bit more room to run consistently. The manual cars seem to be doing fine at those torque levels as far as the motors. The question does remain if we bump that torque limit say just 5% will we still be in a safe operating range for the trans. BMW is usually pretty conservative so I'm guessing a 5% adjustment would still be within operating design parameters.

Absolutely. The Germans always highly (over) engineer drivetrain parts.

In my experience automotive parts like this will have a 1.5 to 2 and higher safety factor built into the design.

So it's probably failure tested to 700+ Nm or over 500lbft.

I would be very comfortable running my trans at 500Nm - 368lbft (10% more).

If you can figure this out Im in.

[Stubok]

Originally Posted by GSR Autosport

Copy that. For some reason I thought it was x-drive. We've also confirmed with the guys we are working with over in Indonesia that they are experiencing the same thing across all N20 based cars. As torque moves well into the 300 wtq range it's happening which seems to be when people are getting that little extra umf with the addition of a downpipe. The 228i we are going to be testing out here in the next week or so is a stage 2 auto car so we will see what we find. If we don't run into the issue we can just keep adding octane to bump up the numbers and see at what torque levels it starts to trigger the torque limit.

Nick, Could you let us know what you found with the Stage 2 - 228i?

[GSR Technik]

Originally Posted by Stubok

Nick, Could you let us know what you found with the Stage 2 - 228i?

Stage 2 test car got delayed a week. Coming in next week - Thursday. It's the VMR Wheels 228i.

We put a more aggressive tune in the 28 AT Stage 1 test car with a few additional changes to see if we can get it to the torque limit but nothing yet - running normal. We need to get it back on the dyno and see what kind of torque it is making as we didn't dyno it before we sent in back into the wild.

Nick...

[CalCarNut]

Any updates on goons car anomaly @ rpm?

[GSR Technik]

Originally Posted by SoCalDave

Any updates on goons car anomaly @ rpm?

Still haven't got another x28 AT car back on the dyno that would make +350tq > we're going to have to find someone who is willing to put a little 100 oct in their car to test.

[FSociety]

goon any updates

[goon]

Originally Posted by ROBNYC

goon any updates

You would have to ask GSR Autosport I flashed back to stock and went with an afe scorcher module. It does not compare to the ecu tune, but I feel better and safer these days.

[Stubok]

Guys, I'm starting to wonder if there is an interaction between the tune and downpipe that may be causing the hesitation/misfire issue. That seems to be the common theme with the cars that experienced this.

I don't even think it is the 93 octane. I have stage 1 with DP cel delete, and I'm also getting the occasional stutter. An easy to replicate stutter is going 60mph up hill (so under mid to heavy load), in 6th gear (8AT) - 2500rpm and firm acceleration. Almost always stutters around 2800rpm. Once passed 3000rpm it doesn't come back and goes smoothly to redline.

[alohasurftoad]

i put a down payment for a stage 1 gsr tune however (stubok) your misfire issue is a bit disconcerting. hope more people with gsr stage 1 chime in.

[Stubok]

Originally Posted by alohasurftoad

i put a down payment for a stage 1 gsr tune however (stubok) your misfire issue is a bit disconcerting. hope more people with gsr stage 1 chime in.

I have also had a cel - P0234, which is an overboost code. Apparently that is now been fixed in their flash so sending in the ECU for that change.

In addition, I may have a boost leak, which if so is more than likely contributing to the stuttering. I never got it with the piggyback, so I'm assuming it's a result of the flash.

Wrinkles that will be resolved I'm sure.

[FSociety]

Stubok Seen a lot of issues with DP + Aggressive tunes on N20/N26.