[Finz]

A local tuner advised me not to do the cold start delete on my M2C. They said that it often results in the engine having up/down idle speed for the first approximately 20 seconds - something to do with oxygen sensors. Also that this is widely known within the tuning community.

First, I had not heard that before.

Second, that might be an OK trade off.

For those who have done cold start delete, what is your experience?

Bill

[PopeDoomDoom]

Had cold start deleted for about ~6 months, first on stage 1 bm3 and now on stage 2 bm3. Never had any problems at all or any problems with idle speed at startup. Also running the GTS startup. Had cold start delete on different exhaust setups including stock midpipe and downpipes and now on catless downpipes/midpipes, still no issues.

[tropicatango]

On my f80 m3 i had BPM sport stage 1 tune with catless downpipe

When temperatures were below 6-7 degrees celcius, when i started the car i could not just leave in the seconds , the car was stalling (my car was manual 6 speed)

I had to wait, or simply giving more gas to be able to release clutch pedal to roll...

Once the car roll for the first time from cold, it's ok and no problem after that even 10 seconds after at a stop.

When it was warm, it was not doing that.

Now i drive m2 competition with the same engine, the s55 and i leave the exhaust as it is. This engine is very powerful and with a tune you can get high power numbers with oem cats, so not really worth it for me.

Catless downpipe add sound for sure, when i installed the catless downpipe, i was already stage 1 and i did not really feel a difference in performance

What i wanted is the turbo whistle sounds in the exhaust like my old Porsche 996 turbo but the turbo spooling whistle sound wasn't at the Porsche level, i was a bit disappointed

[6speed_M2]

I'm not sure if it's bad for stock downpipes. I wouldn't imagine it is but I have no clue. I know it's meant to warm up the cats so if you're catless it shouldn't make any difference. Other then that it's fine. I ran my car like that when I was catless for a year or two.

I'm on a high flow cat now & I'm using the cold start again

[stefan]

It's possible it could cause issues with the o2 sensor which will be expecting slightly higher flow rates if not calibrated. But in most implementations like bm3, it takes this into account and it's not an issue. If you are concerned about DPs you can always heat wrap them but again it's not a problem. What will happen is that the cats will operate at sub optimal conditions for the first little bit but this is still really minor in my opinion. The cold start procedure is mainly there to satisfy regulators for a very minor decrease in emissions assuming the driver idles for a bit. If you start driving right away I bet the difference is almost nothing. Cold start is obnoxious and pointless.

[Finz]

Thanks for the replies. I get the sense that most people doing the cold start delete are also going to catless DPs. Although I plan on staying with stock DPs, I have been experimenting with different midpipes and mufflers - most of which make cold start and GTS roar even more obnoxious to me. I have found no data, only theories, on potential damage to the cats by doing the cold start delete - and it is telling that no one jumped in to say they had the issue of uneven idle speed. At this point my concerns are minimal.

[stefan]

Originally Posted by Finz

Thanks for the replies. I get the sense that most people doing the cold start delete are also going to catless DPs. Although I plan on staying with stock DPs, I have been experimenting with different midpipes and mufflers - most of which make cold start and GTS roar even more obnoxious to me. I have found no data, only theories, on potential damage to the cats by doing the cold start delete - and it is telling that no one jumped in to say they had the issue of uneven idle speed. At this point my concerns are minimal.

The uneven idle sounds a bit dubious. The exhaust hardware on these cars are basically the same from when we didn't require cold starts. The idle issue sounds like a tune problem to me.

[Robin_NL]

I have the cold start delete with my MHD GTS tune and I just wait '20s' or so @ cold start. No worries.

As already stated in this thread, the idling is a bit wobbly at times and driving away instantly results in almost stalling(I have a DCT box). But I don't care about that.

Cheers
Robin

[mike@x-ph.com]

i did the cold start delete for the entire 3 year lease period on my F82 M4, no issues.

I plan on doing it on my new car as soon as a flash tune allows me to do so