Low RPM Hard Acceleration - Pre-detonation

[wyatth]

^ So what changed with the revised tune again? Back to OE vanos adjustments?
I just wonder why/how your car can be more sensitive, and what the modified vanos settings are doing to the rest of us. I have no pinging or pre-det, but I am on comparable crappy CA 91 octane. Needing a "winter blend tune" seems crazy. I trust Alex/Alpine, but want to make sense of this. I just can't fathom why your car needs a special tune, your gas can't be much worse than ours.

[SoCalRPM]

Originally Posted by wyatth

^ So what changed with the revised tune again? Back to OE vanos adjustments?
I just wonder why/how your car can be more sensitive, and what the modified vanos settings are doing to the rest of us. I have no pinging or pre-det, but I am on comparable crappy CA 91 octane. Needing a "winter blend tune" seems crazy. I trust Alex/Alpine, but want to make sense of this. I just can't fathom why your car needs a special tune, your gas can't be much worse than ours.

I think you're asking the right questions. I'll have to leave it to people with more knowledge than me to offer the correct answers.

For me the revised tune was supposedly everything the same (servotronics, optimized throttle control in m-mode, and temp protection in cold start) and now an OE vanos setting.

Was this the answer to my issues? Not sure yet - haven't uploaded the new tune yet to find out.

My car is too mint to experiment with unknown factors until I know more. Especially considering the limited benefit of stage 1 - compared to needing a stage 2 if I had a catless exhaust.

[ItsGary]

Hey guys, I have an update for you.

I requested a 91 Octane Stage 2 file from Alex, I received it the other night and flashed it on last night. The rattle for me is gone for the most part. The only time I got trigger it was under the most drastic condition. IE; 7th gear, 1200-1400rpm & going up a hill. Other than that the noise is gone.

I originally had a 92 Octane Stage 2 file flashed on as I get my gas from the US and the pumps are listed as 92 Octane. I'm wondering if it's really 92 Octane or something less. It could also possibly be the winter blend as the sound isn't really there during the summer time.

Anyways I hope this update helps. I'll be testing some more on my way to work.


Also cause =/= correlation

[wyatth]

Does your 91 octane tune use modified or factory vanos settings/adjustments?

[ItsGary]

Originally Posted by wyatth

Does your 91 octane tune use modified or factory vanos settings/adjustments?

I didn't request the no vanos change however this is what Alex said after I emailed him.

I doubt the fuel is of an issue. With the updated map I have full ignition timing of my regular tune just no vanos changes. These cars are aging and with it comes these issues. You can probably have the same house if you run stock.

[eriktufa]

I think we sort of conclude that vanos changes contribute to the issue or/and fuel.

I'm pretty sure ItsGary map is without vanos adjustment i.e. stock vanos setting.

[91foxbody]

That noise sounds a whole lot like the exhaust shield rattle on my car (completely stock, no tune).

[Scharbag]

Originally Posted by 91foxbody

That noise sounds a whole lot like the exhaust shield rattle on my car (completely stock, no tune).

Oh I wish that it was... But, switching back to stock ECU programming does not fix exhaust shield rattles - but it sure gets rid of this sound for me.

Cheers,

[91foxbody]

Originally Posted by Scharbag

Oh I wish that it was... But, switching back to stock ECU programming does not fix exhaust shield rattles - but it sure gets rid of this sound for me.

Cheers,

Glad you got it sorted. I just got my cable in the mail for my Alpine tune, I'll be sure to request a winter tune for our crappy 92 mix here.

[eriktufa]

Originally Posted by Scharbag

Oh I wish that it was... But, switching back to stock ECU programming does not fix exhaust shield rattles - but it sure gets rid of this sound for me.

Cheers,

Are you running stock tune now (or should I call it flash first)?

I'm thinking of doing the same now and sort of now wanting to run catless now.

[ItsGary]

Anyone have an update now? Been a while.

[SoCalRPM]

Not the update you're necessarily looking for but since reverting back to the OEM tune over a month ago I have not experienced any issues at all.

I'm still planning to upload the revised tune (no or minimal adjustments to the VANOS)and see how that goes.

[eriktufa]

I think the consensus is that stock tune eliminates this issue.
I'm going to try running a 95 RON tune / 91 PON tune for US fella and see if it makes any difference.

[Scharbag]

Originally Posted by eriktufa

I think the consensus is that stock tune eliminates this issue.
I'm going to try running a 95 RON tune / 91 PON tune for US fella and see if it makes any difference.

Well, yeah.

I have run into a few people on the island that have experienced some pinging with the shite island fuel we have on stock tunes. The S65 is a sensitive beast.

In my case, running the Alpine 91 octane stage II tune with the VANOS adjustments removed has mostly eliminated my low RPM knocking noises when accelerating hard at low RPM. I continue to use Chevron 94 but have tested Shell 91 and both fuels seem good. The rare time I will get a slight knock when really bogging the motor, but not always and nowhere near as bad as before.

If you live in an area with crappy fuel, it is likely best to use the modified VANOS tune from Alpine.

Cheers,

[s0ldats]

i mixed 1/2 tank 100 and 91 from 76. ping/rattle went away completely and car RIPS.

went back to stock tune on tank of only 91. car does not ping/rattle

[ItsGary]

Originally Posted by Scharbag

Well, yeah.

I have run into a few people on the island that have experienced some pinging with the shite island fuel we have on stock tunes. The S65 is a sensitive beast.

In my case, running the Alpine 91 octane stage II tune with the VANOS adjustments removed has mostly eliminated my low RPM knocking noises when accelerating hard at low RPM. I continue to use Chevron 94 but have tested Shell 91 and both fuels seem good. The rare time I will get a slight knock when really bogging the motor, but not always and nowhere near as bad as before.

If you live in an area with crappy fuel, it is likely best to use the modified VANOS tune from Alpine.

Cheers,

I'm on the same tune, however I still get it at low RPMs.

Thought I'd give you guys an update also. I had my BMW tech friend come check out the car and take it out. He said the noise is 100% coming from bank 2 (Driver Side) which he said is good or bad.

We will look into it further. Considering I'm getting a code for PreCAT(Bank2) O2 again. I'll do plugs also. My VCGs need to be replaced so it would be a good time to look at the gears.

[ItsGary]

Another little update. We looked at the values and it seems bank 2 is running a bit lean. Only by a degree and a half.

[eriktufa]

For everyone who has been running a tune and having the same knocking issue, after experimenting aftermarket tunes and stock tune, my early conclusion is that stock tune is not as aggressive as aftermarket tune (thanks captain obvious) therefore you may or will not hear the knocking noise or should I say this is safe for your car.

In the past few days instead of running the normal 98 RON (93 PON), I have been using 95RON (91 PON) normal tune (meaning it is the tune with modified vanos and normal fuel blend (not winter blend)) and the knocking noise (detonation noise) is gone for now. At the same time, I have also switched to a lower grade fuel (95 RON) as it is a bit pointless running 98 RON although I may try running higher grade fuel with lower grade tune in the future.

I don't know what you guys can make up from my experience but it seems like the 98RON (93 PON) tune with 98 RON (93 PON) fuel is too aggressive for the car and running a lower grade tune with a higher grade fuel seems to solve the issue. Otherwise, adding octane booster may help.

I hope this post is not too long and clear to understand.

[lve2xlr8]

I've gotten this noise in two stage 2 tuned m3s, both with very low mileage. I just avoid lugging the engine and it doesn't seem to be a common occurrence. Occasionally on hot days, climbing a hill it's sort of unavoidable. Agree that it's absent on the stock tune.

[ItsGary]

Another update; finally tried the stock 240E map. Sound is completely gone. Tested it in every area I would have the rattle come up in.

Sucks that removing the tune is what fixed it.

Scharbag What was the options you requested in your map? I guess I should use the map options you have since the sound is gone for you also.

[Scharbag]

Originally Posted by ItsGary

Another update; finally tried the stock 240E map. Sound is completely gone. Tested it in every area I would have the rattle come up in.

Sucks that removing the tune is what fixed it.

Scharbag What was the options you requested in your map? I guess I should use the map options you have since the sound is gone for you also.

Ask for intake VANOS to remain stock. That is the tune I am running and it seems to be good.

Cheers,

[eriktufa]

I suggest avoid running any 93 PON tune. My gut feeling is still the same that the advance timing is way too aggressive.

The 91 PON does not exhibit any noise (even with modified VANOS and normal blend fuel).

I highly recommend 91 PON tune even if you run higher octane.

PS: I am only running stage 1 tune therefore I can't comment on stage 2 tune.

Good luck everyone