Liam's Z4C race car project

[Liam22]

Quick update on winter upgrades.

Have always felt like the engine is strangled at the top end, and disappointed with the 250bhp peak power. The exhaust manifold and downpipe are really comprised for right hand drive vehicles. Partly because there are 2 catalysts packed in there, and partly because the steering column gets in the way.

My budget won't stretch to a custom tubular manifold but here's the next best thing.



Retaining only the 3-into-1 collectors, the rest of the system is all new. Comes into a 3" single pipe as soon as possible, with a race cat to meet regulations.



A single high-flow silencer in the middle and single 3" pipe all the way to the exit. No rear silencer.



Took it for a power run at the same rolling road I used before. +17bhp and a very healthy 267bhp at 6900rpm. Peak torque from 4500-6000rpm.

Happy with that. I also have a Superchips tune to try but wasn't able to apply it today.

 

[axelleveau]

Once again Liam your approach to go for best value for money is impressive! That welding is nice on here
Even if you do not want to go that way now, doing full manifolds in the future could just be a modification on top of that system :roll:

I just have one request: Can you post a video of it so we can hear how it sounds? :evil:

 

[lucasxdiniz]

Happy with that. I also have a Superchips tune to try but wasn't able to apply it today.

No sound clip?!

 

[jamesdi]

WE NEED A SOUND CLIP OF THIS BEAUTIFUL SPECIMEN!!!

 

[1536Z4]

Nice Liam and a good increase in performance .

What cell race cat have you used ?

Where did you have it made ?

Cost if you don`t mind giving me an idea ?

Thanks

 

[enuff_zed]

Looks good Liam
How does that fare in the scrutineering sound checks?
ie. Will I know you're at Snetterton from my living room 3 miles away

 

[Wursle]

Quick update on winter upgrades.

Have always felt like the engine is strangled at the top end, and disappointed with the 250bhp peak power. The exhaust manifold and downpipe are really comprised for right hand drive vehicles. Partly because there are 2 catalysts packed in there, and partly because the steering column gets in the way.

My budget won't stretch to a custom tubular manifold but here's the next best thing.

FB_IMG_1643834697625.jpg

Retaining only the 3-into-1 collectors, the rest of the system is all new. Comes into a 3" single pipe as soon as possible, with a race cat to meet regulations.

FB_IMG_1643834791781.jpg

A single high-flow silencer in the middle and single 3" pipe all the way to the exit. No rear silencer.

FB_IMG_1643834716304.jpg

Took it for a power run at the same rolling road I used before. +17bhp and a very healthy 267bhp at 6900rpm. Peak torque from 4500-6000rpm.

Happy with that. I also have a Superchips tune to try but wasn't able to apply it today.

Epic work as always Liam! a cheap modification that might be worth looking to for those extra HP is some MILVS. not massively expensive and can add a fair amount of Torque and power across the entire rev range. A company in the states StageFP do the custom mapping for these and have seen 250whp on our engines with very similar modifications to what you have already done!

They are also able to raise the redline to 7200rpm.

https://stagefp.com/product/sfp-n51-n52-tune/

https://www.bimmermilvs.com/

 

[1536Z4]

extra HP is some MILVS.

Don`t want to hijack Liams post so I will ask this same question in a separate one here https://z4-forum.com/forum/viewtopic.php?t=134439

Hi Wursle

I have been thinking about doing this for a while and have read through the 39 page thread here https://www.e90post.com/forums/showthread.php?t=1329840 . Not in a financial position to go ahead with it at the moment as you also need the tune done remotely and I have already paid out for a remap . Have you done the mod yourself ?

 

[Liam22]

Wow - the MILV stuff is very interesting.

I had a cheeky shakedown race at Silverstone GP on Sunday. It was a last minute thing which meant going on last year's worn out tyres and marginal brake pads. A new race series for me, Snetterton Saloons (on an away day to Silverstone at a Britcar meeting). I was in the 2.5-3.5l class.

Damp qualifying, but the car felt great and noticeably faster. Unfortunately the ABS pump started to fail which meant I went from having ABS to not having ABS. Given that all my warning lights are already on (because disabled steering angle sensor) I didn't see this coming, resulting in a trip to the gravel trap...

I pulled the ABS fuse for the race but it meant learning the brakes from scratch. Thankfully it was dry, and I had a few locky moments but no real issues. In the dry, the car is now hitting 130mph at the end of the Hangar Straight :evil: and 2 seconds a lap quicker than the last time I drove Silverstone GP.

My son made a cool video https://www.youtube.com/watch?v=ySmZa22xDiQ
[youtube]ySmZa22xDiQ[/youtube]

A few things to fix before its next outing:
1. ABS pump repair (I have the classic fault codes)
2. New RHS driveshaft circlip (same problem I had last year with the LHS). Driveshaft is popping out. Perhaps the diff/subframe is flexing???
3. Wheel alignment (getting dragged out of the gravel was brutal)
4. Replace bonnet badge (don't know where it went!)

 

[Zedebee]

4. Replace bonnet badge (don't know where it went!)

They are so expensive, someone probably nicked it!

Cool vid.

 

[1536Z4]

2 seconds a lap quicker

Nice video . Sounds great and quicker too

 

[TheDan]

Looked awesome, I love the Silverstone GP track!

3. Wheel alignment (getting dragged out of the gravel was brutal)

What alignment (camber) settings do you plan to aim for?

 

[Jahmez]

Love these types of threads.... Looking forward to seeing it all pan out...

 

[sars]

Just awesome

 

[Wursle]

Wow - the MILV stuff is very interesting.

I had a cheeky shakedown race at Silverstone GP on Sunday. It was a last minute thing which meant going on last year's worn out tyres and marginal brake pads. A new race series for me, Snetterton Saloons (on an away day to Silverstone at a Britcar meeting). I was in the 2.5-3.5l class.

Damp qualifying, but the car felt great and noticeably faster. Unfortunately the ABS pump started to fail which meant I went from having ABS to not having ABS. Given that all my warning lights are already on (because disabled steering angle sensor) I didn't see this coming, resulting in a trip to the gravel trap...

I pulled the ABS fuse for the race but it meant learning the brakes from scratch. Thankfully it was dry, and I had a few locky moments but no real issues. In the dry, the car is now hitting 130mph at the end of the Hangar Straight :evil: and 2 seconds a lap quicker than the last time I drove Silverstone GP.

My son made a cool video https://www.youtube.com/watch?v=ySmZa22xDiQ
[youtube]ySmZa22xDiQ[/youtube]

A few things to fix before its next outing:
1. ABS pump repair (I have the classic fault codes)
2. New RHS driveshaft circlip (same problem I had last year with the LHS). Driveshaft is popping out. Perhaps the diff/subframe is flexing???
3. Wheel alignment (getting dragged out of the gravel was brutal)
4. Replace bonnet badge (don't know where it went!)

Mega mega mega as always Liam!

Also look into the N54 Manifold swap for a cheap way to pick up extra horse power with the MILV's as it will rev all the way to 7400!

How are the Megane calipers and M3 discs holding up now? are they still going strong and is there any desire for more braking?




This sounds absolutely nuts now!

 

[Liam22]

What alignment (camber) settings do you plan to aim for?

Same as I've been running for a while. Will post the settings the next time I see my setup book.

I was going to get the ABS pump repaired to cure the 5DF0 and 5DF1 error codes (£190). But I was told that the E92 M3 ABS unit has a compatible pump and I was able to find a low mileage one for £150.



I separated the pump unit from the electronics and tested the motor with 12V.



Pulled the old unit from the car and noticed it has been repaired before. Even better to replace it then!

Simply bolted the E86 electronics onto the E92 hydraulics and put it back on the car. Did a quick test with ABS bleed and it made all the right noises. Will do a full bleed this week.

 

[Liam22]

Also look into the N54 Manifold swap for a cheap way to pick up extra horse power with the MILV's as it will rev all the way to 7400!

Any evidence for this? I had a quick look but seemed inconclusive. Also some question on throttle body sizes.

How are the Megane calipers and M3 discs holding up now? are they still going strong and is there any desire for more braking?

Pretty well. They've been through 2 sets of pads now and starting to show signs of micro-cracks. They'll certainly do another season, probably two.

 

[Liam22]

Fitted the MILVs today. I've previously replaced the cam cover gasket, so remembered pretty well how to remove the cover. That's a 30 minute job in itself.



Marty's instructions are pretty good. I was able to get a 22mm ratchet on the crank from above, through the gap by the expansion tank. I found the best position for each cylinder was to "point" the cam lobe away from the engine, perpendicular to the deck. I also thought it was a good idea to pre-lube each support with clean engine oil.



However, I'm not that clever, because I over-tightened the support bolts on cylinder 1, shearing one of them. No harm done, but I'll need a new pair from BMW before I can refit the cam cover. Here's the job half done with temporary bolts on the no.1 support.

 

[1536Z4]

I over-tightened the support bolts on cylinder

Hi Liam,

Did you use a torque wrench or just hand tight plus a few degrees .

Did you use a different method for the other bolts .

Thanks

 

[Liam22]

I got confused by "in lb". Set my torque wrench to 14Nm for the rest!