Getting the z4mc back from carbahn after the new year

[Z4M85]

On the dyno, the car was in the 10s for AFR and the audible pinging could be heard under heavy load between 2k-3k rpm. They always blamed the hardware. O2 sensors, spark plugs, TPS were replaced, and the VANOS was refreshed with Beisan parts and a valve adjustment. Lastly, they said it was the octane. Nothing changed after adding half a tank of 96. After all that, it ended up being the tune all along.

The car responded great in stock form and now with the new tune from PCT (Paul Claude Tuning), the fueling and drivability is excellent. It can be WOT at 2000rpm and it pulls no problem with no pinging all the way to redline. This is just the base map (calibrated on a dyno) for the setup the car has - no custom remote tuning or dyno tuning. Here is a thread of some of his work:

http://www.m3forum.net/m3forum/showthread.php?t=605681

Originally Posted by rueyme

Thank you. Yes carbahn did excellent work and through my interactions with them I can tell they did quality work and paid great attention to detail. I've always known steve dinan to care about reliability and they just didnt take my project to get it in and out of the shop.

I did get the karbonius intake installed and it is much higher quality. The strut bar is back on so now the hood is complete. One thing however was I had difficulty connecting the mount at the bottom of the box to the engine block, perhaps they had to bend the bracket in order to get the other box to mount up, so that's a small quirk I need to get fixed in the near future.

I will check out your tuner to see the difference if I have issues with ttfs. I have a dyno run to be scheduled around 2 weeks which is after I get the car corner balanced and 1200 mile oil change. Supposedly the mss70 ecu is more advanced according to ttfs so it handles alpha n better than the mss54. I'll see what we get on the dyno in a few weeks and go from there. The can tune he gave me to run on so far seems to have no issues as far as smoothness but I do on occasion on idle hear pinging. How would over fueling be detected?

[rueyme]

Just a latest update. Finally got the break in done on the engine and had the dyno and tune scheduled with frank smith of ttfs last night. Bad news the engine is starving for fuel at around 7000 rpm it is hitting 14+ afr which frank said is dangerously lean at full load and that high rpm. You can see on the graph how it was building up power then falls off like a cliff at around 7k rpm. Hes running the injectors at 92% and he said rather than run close to full load it's better to address fuel issues from the pump to injectors to eliminate any future problems and to correct the issue properly especially since so much was invested into doing this build correctly.

The good side is be mentioned the build is really good, and he gave hats off to the builder of the motor. Carbahn supposedly did really well in putting the motor, he never seen this configuration push this much power without a dialed in tune on the dyno. Perhaps the underdrive pulleys plus the lightened flywheel also is helping reduce some minor parasitic loss in hp.

While I have the fuel system being worked out I decided to do some more cosmetics and chassis improvement by way of weight reduction.

[racerbruce]

So great the fuel starvation was ID'd and is being addressed - leaning out a brand new bespoke engine build would be tragic.

Tell us about the weight savings w/the Recaros and the CF top - how many lbs were trimmed??

[rueyme]

Originally Posted by racerbruce

So great the fuel starvation was ID'd and is being addressed - leaning out a brand new bespoke engine build would be tragic.

Tell us about the weight savings w/the Recaros and the CF top - how many lbs were trimmed??

The seats are sparco rev. I believe with mounts and rails it comes to approx 22 pounds each when I weighed them. I got at least 50 pounds total weight savings on that mod. The roof is a 10 pound savings as the carbon fiber is 6 pounds vs the factory is around 16.

I will need to reweigh the car soon last I weighed with just the seats was 3120 with half tank of fuel. But much has changed since that weigh since I put the 2 piece rotors and bbk and added stuff like the wing and diffusers. I want to reweigh once I get the differential build since that's the last major component that will be changed. Most likely however this weight range is the best I can do unless I remove things like carpet or get carbon fiber body panels. At this stage I'm not so ready to turn the car so bare since I still take it to car meets and shows

I'll post more once I get the fuel issues resolved.

[racerbruce]

Awesome - currently @ 3,120 lbs and advertised weight is 3,230 lbs....the 110 lb savings will be enormous since much of it will be rotating mass (brakes/wheels) and taking 10 lbs out of the top of the car positively affects CG.

[rueyme]

Originally Posted by racerbruce

Awesome - currently @ 3,120 lbs and advertised weight is 3,230 lbs....the 110 lb savings will be enormous since much of it will be rotating mass (brakes/wheels) and taking 10 lbs out of the top of the car positively affects CG.

I also put a 10 pound lithium ion battery so that shaved off a good 30 pounds. Everything as you said adds up. I will post updates as they come just so current and future owners can get some ideas for upgrades going forward.

[racerbruce]

Originally Posted by rueyme

I also put a 10 pound lithium ion battery so that shaved off a good 30 pounds. Everything as you said adds up. I will post updates as they come just so current and future owners can get some ideas for upgrades going forward.

....we are very interested in the progression of this Coupe - this is a real-time evolution of this beloved BMW Z4MC.

A note to us all....our beloved rides (Z4M Coupes & Roadsters) are not....and will not....be produced again; we have the last of the S54 B32 propelled cars....with refinement(s) at the top of the design and performance curve - significant parts from the E46 such as incredibly designed brakes for a production car, suspension, differential, etc....and we are the benefactors of a very low production vehicle....i am grateful.

[Z4M85]

Originally Posted by rueyme

Just a latest update. Finally got the break in done on the engine and had the dyno and tune scheduled with frank smith of ttfs last night. Bad news the engine is starving for fuel at around 7000 rpm it is hitting 14+ afr which frank said is dangerously lean at full load and that high rpm. You can see on the graph how it was building up power then falls off like a cliff at around 7k rpm. Hes running the injectors at 92% and he said rather than run close to full load it's better to address fuel issues from the pump to injectors to eliminate any future problems and to correct the issue properly especially since so much was invested into doing this build correctly.

The good side is be mentioned the build is really good, and he gave hats off to the builder of the motor. Carbahn supposedly did really well in putting the motor, he never seen this configuration push this much power without a dialed in tune on the dyno. Perhaps the underdrive pulleys plus the lightened flywheel also is helping reduce some minor parasitic loss in hp.

While I have the fuel system being worked out I decided to do some more cosmetics and chassis improvement by way of weight reduction.

Any update on the tune and Carbahn engine build?

[Daemonblitz]

Haha, when I started scrolling down through the first picture I had to do a triple take, thought it was my car

Good taste in mods!

[RvsBmw]

Looks good, indeed curious if the car still in progress .

[Rekla]

OP - are you in CA? Just wondering if you are, I am wondering if the Carbahn upgrades lead to troubles at the time of smog testing?

[ctdriver86]

What headers and exhaust are you running, great build!