Low RPM Hard Acceleration - Pre-detonation

[tdott]

Originally Posted by Scharbag

Hmm, that is a neat website address

Google bmwlogger

[DetroitP]

OP,
Were you ever able to obtain an updated calibration/tune from the company they tuned your vehicle?

Since you eliminate the issue by reverting back to the OEM tune, then it sounds like the calibration may need to be tweaked.

Unfortunately, many tuners care about WOT performance, and completely ignore the low speed work.

[Scharbag]

Originally Posted by DetroitP

OP,
Were you ever able to obtain an updated calibration/tune from the company they tuned your vehicle?

Since you eliminate the issue by reverting back to the OEM tune, then it sounds like the calibration may need to be tweaked.

Unfortunately, many tuners care about WOT performance, and completely ignore the low speed work.

Chatted with the tuner - low end was not aggressively changed. The pre-det actually would happen with the stock program as well as time moved on. I am pretty sure it was a bad set of O2 sensors. Since changing those, and my x-pipe, I am getting better mileage and not having pre-det. Pretty sure I was down on power before too.

Cheers,

[kyrix1st]

Originally Posted by Scharbag

Chatted with the tuner - low end was not aggressively changed. The pre-det actually would happen with the stock program as well as time moved on. I am pretty sure it was a bad set of O2 sensors. Since changing those, and my x-pipe, I am getting better mileage and not having pre-det. Pretty sure I was down on power before too.

Cheers,

Did it happen with stock cats or catless x pipe?

I had this issue as well but running ESS DME solved it for both stock cat and catless setup.

Maybe my O2 sensors are bad as well..

[Scharbag]

Originally Posted by kyrix1st

Did it happen with stock cats or catless x pipe?

I had this issue as well but running ESS DME solved it for both stock cat and catless setup.

Maybe my O2 sensors are bad as well..

All the issues started one I welded my stock cats back in instead of test pipes. Stage I and Stage II tunes (with cats) pinged. At the beginning, stock tune did not ping but at the end, it did.

Now that I have a new RKP HFC X-Pipe AND new wide band O2 sensors, running on a stage II tune, the pinging is gone and the car seems to be peppier. Fingers crossed that issue is over. I am leaning towards failing O2 sensors. Never set any codes, but FML it caused me some issues.

Cheers,

[DetroitP]

Originally Posted by Scharbag

Chatted with the tuner - low end was not aggressively changed. The pre-det actually would happen with the stock program as well as time moved on. I am pretty sure it was a bad set of O2 sensors. Since changing those, and my x-pipe, I am getting better mileage and not having pre-det. Pretty sure I was down on power before too.

Cheers,

Good, glad it worked out for ya. I would guess and say the lower back pressure from eliminating the Cats had fixed the issue for u.

[De_Cruelz]

Scharbag was the detonation you experienced previously anything like what the OP posted here: https://www.m3post.com/forums/showthread.php?t=1659505

[Scharbag]

Originally Posted by De_Cruelz

Scharbag was the detonation you experienced previously anything like what the OP posted here: https://www.m3post.com/forums/showthread.php?t=1659505

Hard yes - that clip where he is slow and you can see the bushes at 20 seconds is exactly the shit that I am still dealing with.

It is WAY better than it was since I replace my O2 sensors and changed the X-Pipe to a new HFC version. But I still get some terrible clattering when I accelerate hard in too high of a gear.

Grrrr... But miserly loves company.

[De_Cruelz]

Originally Posted by Scharbag

Hard yes - that clip where he is slow and you can see the bushes at 20 seconds is exactly the shit that I am still dealing with.

It is WAY better than it was since I replace my O2 sensors and changed the X-Pipe to a new HFC version. But I still get some terrible clattering when I accelerate hard in too high of a gear.

Grrrr... But miserly loves company.

Oh man, I was hoping that you resolved the detonation issues completely with the new O2 sensors and x-pipe. I suppose if it's only in high gear that isn't too bad?

I had detonation issues which were far worse and easily audible with the windows slightly down and could never figure it out for the longest time. Recently I had brake vacuum issues and long story short had the sensor and pump replaced. What I did not expect though was the detonation reduced significantly for me. All the mechanics were puzzled as we couldn't determine how it would be related. Now I have slight detonation issues like in the video and have O2 sensors on order. Just need the time to get it replaced. Thanks for responding!

[Scharbag]

Originally Posted by De_Cruelz

Oh man, I was hoping that you resolved the detonation issues completely with the new O2 sensors and x-pipe. I suppose if it's only in high gear that isn't too bad?

I had detonation issues which were far worse and easily audible with the windows slightly down and could never figure it out for the longest time. Recently I had brake vacuum issues and long story short had the sensor and pump replaced. What I did not expect though was the detonation reduced significantly for me. All the mechanics were puzzled as we couldn't determine how it would be related. Now I have slight detonation issues like in the video and have O2 sensors on order. Just need the time to get it replaced. Thanks for responding!

Yeah, I only have it now when I bog hard. Say 6th gear at 2500RPM and floor it in my 6MT. It is really loud and angry sounding. But it I am in a proper gear, the pre-det is gone regardless of my fuel choice.

[De_Cruelz]

Originally Posted by Scharbag

Yeah, I only have it now when I bog hard. Say 6th gear at 2500RPM and floor it in my 6MT. It is really loud and angry sounding. But it I am in a proper gear, the pre-det is gone regardless of my fuel choice.

Thanks mate! Would be interesting to see what the O2 sensor voltage readings would be with an OBDII reader. I think the Carly app may have something. I'll take a look later or tomorrow if I can.

[Tellmee]

I have this issue in my car as well when running alpine tune. I am thinking about trying to go back to ESS tune and see if it happens with that too.

[Audioslave686]

Originally Posted by Tellmee

I have this issue in my car as well when running alpine tune. I am thinking about trying to go back to ESS tune and see if it happens with that too.

I have a similar issue running alpine tune. I already replaced O2 sensors, Idle control valve and low-pressure fuel sensor and still experiencing the same thing - hard acceleration under 2500 RMP.

let us know if ESS tune helped solve the issue

[Scharbag]

So I thought I had solved this per-det issue. Running Shell 91, I still had it a bit.

So today, I went to a dyno, hooked up a knock-box, and did some figuring. Here is what we did:

Stage II Tune - bad knocking under 3500 RPM - and I mean BAD

Factory 241E Tune - some very light knocking under 3500 RPM (only audible with knock-box)

Stage II Tune (winter gas tune - modified to pull timing a bit) - some light knocking under 3500 RPM

The revised tune was WAAAAAAAAY better after the changes.

Then, for grins and giggles, we added 2 gallons of E85 (tested to be about E55 - was a bit old) in the tank and tried again. No knocking at all on the revised Stage II tune.

So, the only thing I can think of is that the fuel here on the island is truly garbage. Dyno shop says they have seen more and more vehicles having knock issues around here.

Anyway, I am going to run this revised tune and try different fuels to see if any work better.

On a positive note, car pulled 382RWHP

Cheers,

[eriktufa]

Originally Posted by Scharbag

So I thought I had solved this per-det issue. Running Shell 91, I still had it a bit.

So today, I went to a dyno, hooked up a knock-box, and did some figuring. Here is what we did:

Stage II Tune - bad knocking under 3500 RPM - and I mean BAD

Factory 241E Tune - some very light knocking under 3500 RPM (only audible with knock-box)

Stage II Tune (winter gas tune - modified to pull timing a bit) - some light knocking under 3500 RPM

The revised tune was WAAAAAAAAY better after the changes.

Then, for grins and giggles, we added 2 gallons of E85 (tested to be about E55 - was a bit old) in the tank and tried again. No knocking at all on the revised Stage II tune.

So, the only thing I can think of is that the fuel here on the island is truly garbage. Dyno shop says they have seen more and more vehicles having knock issues around here.

Anyway, I am going to run this revised tune and try different fuels to see if any work better.

On a positive note, car pulled 382RWHP

Cheers,

Mind clarifying the revised tune you got from Alex?

[Scharbag]

Originally Posted by eriktufa

Mind clarifying the revised tune you got from Alex?

Basically he said it is a "Winter" tune. So, not exactly sure how drastic the timing changes are but it helps.

Cheers,

[GORDON.M3]

Honestly, the "best tune" is the OEM tune if you aren't running catless... These engines are so high strung already, there are so many people who claim they are tuners but really just "whore" out the same thing to everyone. There aren't many tuners that "dyno" and constantly improve their tunes on this old platform, they are too busy making money from burble tunes to really care.

There are only a few tuners that truly know what they are doing and I can say BPM Sport is one of them. Surely Mike has a reputation on the forum but his tunes are A grade. I would look into it if you are continuing to have some issues with knock.

If you have INPA or BMW Standard Tools it would be nice to see what your DME adaptations are looking like right now.

[Scharbag]

Originally Posted by GORDON.M3

Honestly, the "best tune" is the OEM tune if you aren't running catless... These engines are so high strung already, there are so many people who claim they are tuners but really just "whore" out the same thing to everyone. There aren't many tuners that "dyno" and constantly improve their tunes on this old platform, they are too busy making money from burble tunes to really care.

There are only a few tuners that truly know what they are doing and I can say BPM Sport is one of them. Surely Mike has a reputation on the forum but his tunes are A grade. I would look into it if you are continuing to have some issues with knock.

If you have INPA or BMW Standard Tools it would be nice to see what your DME adaptations are looking like right now.

I have inpa and ista-d. Not exactly sure how to check adaptations. Could you talk me through that? I would be happy to share.

This tank still has some E85 in it. Going to go to empty then try chevron 94 again.

And I have no primary cats. So I need a tune. And I dislike the cold start cycle. And I want 8600 redline cause I am dumb.

Cheers,

[DetroitP]

inpa & ista-d are diagnostic tools from what I read, so you can't see the actual tunable maps such as spark and fuel, can you?

[eriktufa]

Originally Posted by Scharbag

Basically he said it is a "Winter" tune. So, not exactly sure how drastic the timing changes are but it helps.

Cheers,

I've got this recently from him as well to try.

Any difference in HP when you compared the old tune vs stock vs new tune?

[Scharbag]

Originally Posted by eriktufa

I've got this recently from him as well to try.

Any difference in HP when you compared the old tune vs stock vs new tune?

We never actually pulled to redline with the first tune as it was knocking. I should have done a pull with the stock tune but I did not. Oops.

May I ask why you also need the winter tune?

[eriktufa]

I'm pretty sensitive to noise so I thought the car is knocking. In hindsight, it could be the exhaust rattle/metallic noise that I heard from 3000 rpm onwards.

I don't mind a safer tune though.