[VMZ432]

Originally Posted by seank

That is a good question. On my track car, I run a 30 degree lower thermostat. That being said, it does take longer to warm up (twice as long). The car runs 20 degrees lower on a 100 degree day. I THINK the difference is that it opens more, to allow more water to flow earlier. Earlier, allows more time before getting hot. The BMW radiators are more than sufficient at cooling, although some do not like that they use plastic.

I tried that. Does exactly what you say, it makes the car take longer to get to normal levels of heat. But does not reduce the maximum oil temps appreciably on the track. I think I will switch back actually, because when I take the Z4 on the street it's because I want to enjoy it, and waiting nearly 10 minutes for it to heat up really annoys me. Often the trip I'm making isn't much longer than that.

Originally Posted by gmd2003

Bottom line is if you plan on tracking this kit in a non Nordic country be prepared to add significant cooling capacity or deal with limp modes (on Track).

I disagree with that. In my experience over the past 6 years with and without FI I don't think the kit made the problem much worse, maybe just a little. The problem was already there bone stock, so bottom line IMO is the Z4M does not have enough cooling capacity for the track.

Originally Posted by gmd2003

So I'm going to try upgrading my radiator , adding the motorsport thermostat and running 100% distilled water with water wetter, before changing out the oil cooler I just payed big bucks for.

Let's hope there is still enough room for a larger radiator now that the intercooler is in there! Pretty sure that's the only thing in your list that will make a difference. I'll see if I can find someone who's done it.

Originally Posted by gmd2003

The afternoon sessions my oil temps continued to climb to the 260-270 range and i started having a limp mode kick in only at the end of the straight (after 12 seconds of full throttle acceleration. This could be avoided by short shifting into 6th gear but this considerably slowed me down.

If I were trying to avoid limp mode, I'd short shift every gear on that straight. Just a little in every gear should make more difference to limp mode and slow you down less. I'm not even talking about short shifting really, just changing your style to shift earlier by a couple of 100 rpm.

Originally Posted by gmd2003

I'm just happy I was able to run it enough to get it overheated lol.

Glad you had a better day than last time!

Originally Posted by gmd2003

I will keep everyone posted on how things go.

Please do!

One question. Have you EVER seem limp mode twice in one session? Me, never. Never ever ever. That is one thing (that and the lack of any codes being thrown) that makes me think the issue is not related to a specific temp range being breeched. Also, I bet there have been instances where you've gone into limp mode early in the session, before the car even gets to full track heat? That's what made me so hopeful for your fuel pressure solution. But I guess it's more complicated than that. It's like the ECU is making a judgement call based on a collection of measurements that have been adversely affected by rapidly increasing temps, rather than the temp itself. And because there is not one specific variable it can identify as the cause, it doesn't throw a code.

Sounds stupid I know, but that's what it seems like.