Z4 M Coupe mods, the ongoing tale...

"New" pics of the Z4 and my buddy's 325/S52 from a Malibu shoot for Bimmer and Performance BMW earlier this year:
http://www.bimmerfest.com/forums/sho...=1#post5580767

Day one at OCRC went well. I learned that the heat shield I made does reduce oil temps for a little while, but starves the radiator and raises oil temps drastically soon after. The peak oil temp was the same as before the diverter valve was installed, but it got there more quickly overall, and water temp got up to 247! So that was a fantastic failure.

I pulled the heat shield after two quick sessions and went back out. Oil and water temps were a lot lower (oil by about 20F), so it would seem that the diverter valve is indeed beneficial. The track configuration this time around is all 3rd gear with only one turn at part throttle. So it's very hard on the car's cooling system (lots of load and limited speed) compared to Willow or Streets, etc. if driven as hard as possible. Still, my oil usually peaks at about 285F there, and I don't think it passed 265F today once the heat shield was removed.

HOWEVER...something strange did happen and I'd like some input if anyone can answer my question. During a couple of sessions today the yellow oil light would turn on at only 245F instead of the usual 260F, and the red oil light which usually comes on at 280F would come on at 265F instead. Nothing was changed on the car or how it was driven, there was only 3F change in air temp today, and the runs during which the lights would turn on "early" were not consecutive! What is causing this???

p.s. I noticed that my oil is a little overfilled (reached the top of the red part of the dipstick), would this matter?

Day 2 at OCRC went well. Had a lot of fun right-seating for new students and being a ring taxi. Scatha did pretty well too. I got one session that was fully uninterrupted with regard to catching slower cars and I could flog Scatha as hard as possible. This basically means running in 3rd gear WOT up to redline 5 times per lap in addition to being WOT to about 7k RPM 3 times as well - all this in about 1:40, for 20 minutes!

With the diverter valve and no heat shield my oil temps climbed steadily to about 260, then creeped to 265 and pretty much stayed there. One time during that session the oil touched 270, and a few times it dipped to 260, so I think it's safe to say that I found the point at which it will not climb further. This is a 20F improvement over the previous 285 that I would see at OCRC and Cal Speedway, so the diverter valve swap works! Unfortunately my water temps were just as high as when my oil would hit 285, so the hot air coming out of the oil cooler is still superheating the radiator. This might explain why the yellow and red oil temp warning lights sometimes come on much earlier than usual (although I'm still waiting for an expert to chime in on that, hint, hint) relative to oil temps.

The limp mode, as far as I can tell, is gone. It didn't happen at all on Sunday, even with the highest temperatures Scatha is likely to see from here on. The context of the two instances on Saturday have convinced me that said limp mode isn't related to ESS or their programming, but is a residual BMW code that triggers when the car thinks it's in danger (heat+throttle load+RPM). Which means it's a good thing, since I shouldn't be running the car that hard that hot.

I made the mistake of not checking my track pads before I went to swap them prior to the weekend, and they only had about 3mm of pad left. Oops! So this time out I put a spare set of HT-10s on the front and left the street pads on the back. From a safety standpoint it was fine, but I wouldn't do it again. The rear pads warmed up to operating temperature more quickly than the HT-10s, and this affected the brake balance for a time. Then I discovered that the HT-10s are just not quite enough pad (at least without HT-10s on the rear too) for that track and my driving, as I encountered pad fade at two points on the circuit per lap once temps were up. Of course if I had proper race-style brake ducts that would be a different story. And that may happen at some point. Until then I'm going back to my HT-14 front/HT-10 rear setup.

One last comment: The StopTech 1mm Ti brake pad shields work AWESOMELY! This marks two events in a row with ZERO fluid fade, on a track where I would routinely get fade at one, if not two, braking sections. For the money they are a fantastic improvement and you can get them (or another brand's) for any BMW caliper.

I'll post pics and vids as soon as I can process everything. You're not going to believe one of the cars that showed up (but didn't track). It's a one-of-one.

Subscribed. VERY interested in the sidemarker upgrade. Will you be producing these? Please PM me. THANKS!

Originally Posted by 08E86M-475

Subscribed. VERY interested in the sidemarker upgrade. Will you be producing these? Please PM me. THANKS!

-I won't be producing the side marker. The one I have is hand-built and they are only functionally relevant to a supercharged M that sees a LOT of hard track duty. To mold the piece would be very expensive and the market doesn't exist in sufficient quantity.

Pics and vids from the OCRC event: http://www.bimmerfest.com/forums/sho...d.php?t=499822

Scatha will be at Auto Club Speedway with Speed Ventures this Saturday.

Originally Posted by Palantirion

Pics and vids from the OCRC event: http://www.bimmerfest.com/forums/sho...d.php?t=499822

Scatha will be at Auto Club Speedway with Speed Ventures this Saturday.

I'm sorry that I missed OCRC this time - we were out on a vacation roadtrip that week (but at least with the M!) Do you know when Nathan's next event is scheduled?

Are you going to be running Fontana Friday or Sunday, now that SpeedVentures cancelled Saturday?

Originally Posted by CalRick

I'm sorry that I missed OCRC this time - we were out on a vacation roadtrip that week (but at least with the M!) Do you know when Nathan's next event is scheduled?

Are you going to be running Fontana Friday or Sunday, now that SpeedVentures cancelled Saturday?

-Sorry for the late reply, been spending the last week rebuilding/migrating to a new OS after a serious RAID/XP failure. Just now got my email back up.

I don't know when Nathan's next event will be, but OCRC holds events roughly quarterly.

To answer your other question, I went to Sunday, and saw you, so you knew that already. Thought I'd type it anyway :P

Well, the holiday season has be VERY busy for me. Took a 9-day trip to Tahiti (I may post pics later) and am working on a new race car livery (details to come). I also relocated the ESS-supplied oil cooler from in front of the radiator to in place of the driver's side bract duct. I expect this will drastically reduce my water temps and still effectively keep oil temps under control. The only question in my mind is what, if any, effect there might be having different front brake cooling rates. I'll find out on the 15th, OCRC's next track event:
http://www.bimmerfest.com/forums/sho...81#post5758681
http://www.ocracecraft.com/

FYI: The same weekend Speed Ventures is running a two-day HPDE at Auto Club Speedway.
http://speedventures.com/

A pic of the oil cooler in it's new position:

Originally Posted by Palantirion

Well, the holiday season has be VERY busy for me. Took a 9-day trip to Tahiti (I may post pics later) and am working on a new race car livery (details to come). I also relocated the ESS-supplied oil cooler from in front of the radiator to in place of the driver's side bract duct. I expect this will drastically reduce my water temps and still effectively keep oil temps under control. The only question in my mind is what, if any, effect there might be having different front brake cooling rates. I'll find out on the 15th, OCRC's next track event:
http://www.bimmerfest.com/forums/sho...81#post5758681
http://www.ocracecraft.com/

FYI: The same weekend Speed Ventures is running a two-day HPDE at Auto Club Speedway.
http://speedventures.com/

A pic of the oil cooler in it's new position:

I'm going to go out on another limb and say I have a poor outlook on this fixing it though it may help a little. I wish you would believe me when I tell you your efficiency is being killed by your cats. You either need to DRASTICALLY increase the CAPACITY of your cooling system (you slightly increase the efficiency of it with this mod but it will be nothing like a capacity increase) or remove the cats.

You would not believe the changes in temperatures in high horsepower cars before and after removing cats.


It's so easy to swap the headers at least just TRY it once, takes less then an hour to swap headers if you're good. Buy a set of ebays (normally I wouldn't suggest this), even paying for install you might be out 500$ if it doesn't work. I'm sure thats a fraction of the time and cost you have in the problem already.

If that doesn't work nothing else but capacity is going to stop your car from overheating as much as it is.

DONE!

It's fixed, problem solved, mission accomplished, etc.

Same track, hotter than the previous two events (ambient = 85F vs. 70F), driving as hard as ever.
Previous oil temp (after diverter valve swap): 265
Highest oil temp today: 230!
Previous water temp peak: 243
Today: 209!

I also noted a significant reduction in AIT, from an average of 3-5F over ambient to 8-10F below.

Good news on the engine cooling; I am guessing you did not feel much difference in the brake feel/ability with the differential cooling?

Originally Posted by pal

Good news on the engine cooling; I am guessing you did not feel much difference in the brake feel/ability with the differential cooling?

Pal - biggest concern over FI is now a non-issue. If Nismo gets too fast I am pulling the trigger on the VT-1 system...

Originally Posted by pal

I am guessing you did not feel much difference in the brake feel/ability with the differential cooling?

-Nope. I had a little fluid fade twice, which may or may not have been due to the oil cooler move. The track was a little different than last time and since I was the designated "ring taxi" for OCRC I was running balls-out, sometimes deeper into corners than usual. It's nothing that concerns me, as there was no obvious negative effect from the move.

Originally Posted by tnsbruce

Pal - biggest concern over FI is now a non-issue. If Nismo gets too fast I am pulling the trigger on the VT-1 system...

-The good news for VT-Series owners is that the versions that come with replacement oil coolers mount them in the brake duct. So no one should have any temp problems at all.

Thanks Palantirion. That's great news that your issue is resolved and that VT owners may not have to go through the process you went through. Most of us don't have the resources you do/did to even get through issues over time.

Originally Posted by tnsbruce

Pal - biggest concern over FI is now a non-issue. If Nismo gets too fast I am pulling the trigger on the VT-1 system...

Nismo is getting a racing limited slip diff this winter so he will def give us a run at the track. 2011 should be great - cannot wait for track season. Wish I was in California.

Got new tires mounted this morning. I'm switching, at least for now, to Kuhmo V710s. Even though they have less tread depth than the NT-01 they are supposed to physically wear better. They also come in sizes that slightly reduce the overall diameter, and I would like to see if I can keep my current ride height without shaving down part of my front fender liners. The V710s are also VERY light, 24.3lbs for the 285/30R18 and 22.3lbs for the 245/35R18. So mounted they are around 40-43lbs/corner. Not sure what my next event will be, probably Cal Speedway with Speed Ventures.

If anyone has tracked these tires before I'm interested in feedback and pressure suggestions.

Hey if you don't mind me asking how much does you splitter stick out on the sides from the bumper? crfine88 is putting together a group buy with APR for a splitter very similar to yours and I really love the way yours looks.

Originally Posted by F360C

Hey if you don't mind me asking how much does you splitter stick out on the sides from the bumper? crfine88 is putting together a group buy with APR for a splitter very similar to yours and I really love the way yours looks.

-Without measuring it I'd say around 2". It doesn't stick out quite as much as the 245 tires, but it's close. At some point I am going to add a fence, for reasons discussed on crfine88's thread. My concern with that proposed splitter is the mounting hardware. We have to build reinforcement plates to anchor the splitter to the bumper cap, which involves some VERY careful fabricating. I wouldn't consider that part of the installation a DIY unless you have prior fabrication experience. Getting a splitter made is really easy, designing the mounting system so that it can be a proper DIY installation is something else entirely.

Originally Posted by Palantirion

-Without measuring it I'd say around 2". It doesn't stick out quite as much as the 245 tires, but it's close. At some point I am going to add a fence, for reasons discussed on crfine88's thread. My concern with that proposed splitter is the mounting hardware. We have to build reinforcement plates to anchor the splitter to the bumper cap, which involves some VERY careful fabricating. I wouldn't consider that part of the installation a DIY unless you have prior fabrication experience. Getting a splitter made is really easy, designing the mounting system so that it can be a proper DIY installation is something else entirely.

The mounting shouldnt be to much of a problem. I have already had the bumper off and have a good idea of how I am going to mount this to be very strong. I am going to try and not use the bumper for most of the support but instead have some "hard points" mounted to part of the frame. Hopefully it works out like I have it planned in my head.

In your post about the tires so you mean Hankook V710s? I can't find a Falken V710. I have been toying with the idea of giving the V710 a go so I am very interested to hear your review of them.

Originally Posted by F360C

The mounting shouldnt be to much of a problem. I have already had the bumper off and have a good idea of how I am going to mount this to be very strong. I am going to try and not use the bumper for most of the support but instead have some "hard points" mounted to part of the frame. Hopefully it works out like I have it planned in my head.

In your post about the tires so you mean Hankook V710s? I can't find a Falken V710. I have been toying with the idea of giving the V710 a go so I am very interested to hear your review of them.

-Actually I meant Kuhmo! Edited previous post. Thanks for catching that. TR link to the tire: http://www.tirerack.com/tires/tires....del=Ecsta+V710

Originally Posted by Palantirion

-Actually I meant Kuhmo! Edited previous post. Thanks for catching that. TR link to the tire: http://www.tirerack.com/tires/tires....del=Ecsta+V710

I have run these before and found them very good. I currently like the R888's better because they last a little better. The Kumho's had more grip but I went through them in less than 4 track days. The Kumho's seemed to have a little (not much) better turn in. For the money the R888's are the dog's bollocks...

Originally Posted by Duncan17

I have run these before and found them very good. I currently like the R888's better because they last a little better. The Kumho's had more grip but I went through them in less than 4 track days. The Kumho's seemed to have a little (not much) better turn in. For the money the R888's are the dog's bollocks...

-What pressures did the V710s like? And what suspension were you running with them?


Btw, Scatha is now on Car & Driver's Backfires. Think of it as Facebook for car guys, kind cool. http://backfires.caranddriver.com/ph...ums/272/photos

I'm on there as Earl Shepherd.

The photos look really good! The one where you were behind the vette, did you pass him or did he pass you?

Originally Posted by STIHLBOLTS

The photos look really good! The one where you were behind the vette, did you pass him or did he pass you?

-LOL, a C5 Vette is no match for an M Coupe, even N/A.

Do they run the same class as you do?