Quiet Moments.....with Jim Conforti - Addressal of the 4k Power Dip

[danewilson77]

If anyone is in Florida I can update dme in about 20-30 min.

Awesome. Thanks for offering.

Fwiw...we have debated this quite a bit, so I'm interested in the longevity of the software fix. It has been said on numerous occasions, that the dip will come back, over a period of time, after software update. How long has it been since your update?

Keep us filled in. Thanks.

Sent from Williamsburg, VA USA

[danewilson77]

I am posting this for 3 reasons:

1. My dip is still prelevant at approximately 4k rpm.

2. I just got off the phone with Jim Conforti.

3. I wanted to share the info....with the Family.

He spoke with me for roughly an hour. It was an interesting discussion...that entailed training on DISA valve operations, adiabatic ignition, the 4k power dip, software tuning, Ferrari's, gasoline quality, NORAD and what his future holds.

With regard to the 4k power dip.....his impression is - As told by me (I need to remind you guys....that he only comes on the boards and says something....if he has run the numbers himself and has verified it to be true): I will never say it like he does, as he was feeding me knowledge from a fire hose. Basically there are two phenomina that contribute to the 4k Power dip:

1. Mechanical sticking / Operation of the DISA. This is normal operation.....as rpm's increase to a point (3750 rpm's) the DISA valve slams open. There is no slow progession through that "dipped" power range.

2. Knock sensor adaptations, regarding DISA. He has disabled the DISA in cars that he has supercharged. This did result in a bit of torque loss in that power range, but the car operated overall, smoother and more efficient with zero power dip. As far as he knows, tuning will not remove the dip. Tuning may reset the adaptaion values, so initially, the dip will not be there (or be less prevalent), but after fuel management system adapts to new limits, the dip will be back. I think this is the case for me. He additionally said altering the knock sensor adaptations on a street driven car was suicide.

As an aside.....we had an interesting gasoline discussion. He said that 91 octane from Sinclair (or any other gas station for that matter) and 91 octane from Chevron, with equal RM values, will not be the same gas. Mind blown.

So.....if you couple a tune (that alters the knocks sensors), with a tank of gas.....other than Chevron....melting a hole in your piston, could occur. Interesting statement here. For this sole reason, when he was performing dyno's, he instructed customers to only fill up at a Chevron, near the dyno shop (Then followed and interesting story about a kid not following these orders, which resulted in Jim chasing his tail for 5 hours on the dyno, and resulted in a full drain and purge of the cars fuel delivery system)

So....in a nutshell.....there is no, known fix.....in his opinion, for the dip. Remember...there's 2 issues here. One is mechanical. One is electrical.

As a favor to me (and the community), he will be asking his contacts at BMW, if they have addressed this issue with a fix yet.

When he replies to my email....I will post here, or he'll come on and update the thread with his thoughts and findings.

Jim...I apologize in advance for butchering what you told me on the phone. You were shifting gears pretty fast......between a myriad of topics, and I could not fully wrap my head around some of the concepts. At this point....I hope all is well with you, and I appreciate you taking my phone call.

~DW

Bumping for Jim.

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[terraphantm]

For anyone who is uncomfortable updating the DME themselves and doesn't want to pay the dealer rates, I can flash it on my bench if you mail it to me.

[330i ZHP]

The DISA being a problem makes sense - since I do not have one and do not have the dip. But I do remember it from when the ZHP was NON-FI

[derbo]

The DISA being a problem makes sense - since I do not have one and do not have the dip. But I do remember it from when the ZHP was NON-FI

Did you just put a block off plate?


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[BCS_ZHP]

Stuart's "Wagone" is supercharged, a whole new & different intake manifold set-up.

Plus recall the intended job of the DISA. At rpms below 3750-4000, it stays closed so that your air-fuel mixture is only traveling thru half of the volume of the intake manifold - some a/f traveling to the front 3 cylinders and the remainder traveling to the rear 3 cylinders. Above that rpm level the engine needs a/f quicker, the DISA opens so that the air-fuel is being fed as fast as it can be, you're trying to get power at that point so efficiency isn't the main goal. On Stuart's set-up, you're compressing & forcing air/fuel into the engine all the time, the faster the s/c spins the more a/f it compresses and sends to the engine.

[330i ZHP]

Well said

[Hermes]

every time I see this thread I think of Deep Thoughts with Jack Handey

[GreatFrog]

OK... Great. I honestly think the "gas discussion" we had was only applicable, regarding engine damage, if you had a tune that altered the knock sensors.

Sent from SIGFest 2012, via TTv1.5.4

So it is not applicable to Shark Injector? I cheap out on Kroger's fuel all the time ever since I discovered the $1.00/gal off trick . Was a loyal Shell customer before that... I googled around before switching, people were saying the base fuel is the same for all local gas stations, the difference is in the additives. Especially intriguing given the fuel point partnership between Kroger and Shell.

[danewilson77]

So it is not applicable to Shark Injector? I cheap out on Kroger's fuel all the time ever since I discovered the $1.00/gal off trick . Was a loyal Shell customer before that... I googled around before switching, people were saying the base oil is the same for all local gas stations, the difference is in the additives. Especially intriguing given the fuel point partnership between Kroger and Shell.

I think it is applicable to any tune. He was very exacting and descriptive in his explanation of the beautiful blue and quality of flame at the spark. I don't think cheap gas saves you enough to justify it imo.

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