Martyn's Z4M Coupe

Vanne · Post by **Vanne** » Fri Feb 24, 2023 10:26 am

hmm yeah kinda hard that, well not hard, just very time consuming for such a easy job really..

hows work on MAXXecu coming along? iam currently re-wiring the whole lot with deutch connectors after nearly buring down the car over last weekend with a doddgy brother thermo fan connection

theres something to be said for open fuse boxes...

Martyn · Post by **Martyn** » Fri Feb 24, 2023 10:58 am

Yeah, I could of probably done it in 10 mins without the SC and stuff in the way lol.

Maxx stuff is currently on hold until I can book some dyno time, I mapped the car on the road for off and low boost but I was struggling to road tune the higher boost stuff, really need a steady state dyno to do it properly with the Maxx.

Deutch connectors are so nice to work with!

RMB · Post by **RMB** » Fri Feb 24, 2023 12:13 pm

Hi Martin,
Great write up thank you, watching with interest.
For me one of the very best looking cars ever made with one of the very best engines.
Would you recommend the quick jacks? I’m looking for similar so that I can quickly swap wheels in my garage.
I’m local and running a Mr Z plate too. I just need the car now to match!
Hope to see/hear you on road!

Thanks
Rich

Martyn · Post by **Martyn** » Mon Mar 06, 2023 5:49 pm

RMB wrote: ↑Fri Feb 24, 2023 12:13 pm Hi Martin,
Great write up thank you, watching with interest.
For me one of the very best looking cars ever made with one of the very best engines.
Would you recommend the quick jacks? I’m looking for similar so that I can quickly swap wheels in my garage.
I’m local and running a Mr Z plate too. I just need the car now to match!
Hope to see/hear you on road!
Thanks
Rich

Thank you!

The quickjacks are great!

I'll keep an eye out for you!

Couple of small updates on the car.

I got round to pulling the plenum off and switched out the super noisy Tial Q blow off valve with a Vortech MaxFlow Race diverter valve. I only threw the Tial on as the Greddy unit was bleeding boost so it had to go!

Here's the new MaxFlow Race unit next to the nasty Greddy unit.

Whilst the plenum was off I started removing bits so I could get to the alternator. Here's the offending alternator bolt which I a massive pain in the ass!

You can't remove the alternator without removing this bolt, and that's as far as you can remove it before it hits the cross brace

Needless to say it's a massive pain in the ass, you either have to tilt the rear of the engine up or remove the front end to remove/install the bolt, last time I ended up removing the front end, this time I drilled a hole in the cross brace to all the bolt to come through the frame

New alternator fitted and my BSD faults have gone! I threw a new supercharger belt, and top idler pulley on for good measure whilst I was there too.

Next ball ache was getting the plenum back on, and getting the hose on the outlet of the bypass valve on to the the inlet pipe on, the supercharger outlet hose on and all 6 throttle body boots on at the same time.

All is back together and working well again.

Vanne · Post by **Vanne** » Thu Mar 16, 2023 2:59 am

Ive got a Maxflow on mine, youll love it!

not sure ive seen one like that Greddy before?

pokeybritches · Post by **pokeybritches** » Sat Mar 18, 2023 9:12 am

Martyn wrote: ↑Fri Feb 24, 2023 10:58 am Yeah, I could of probably done it in 10 mins without the SC and stuff in the way lol.

Maxx stuff is currently on hold until I can book some dyno time, I mapped the car on the road for off and low boost but I was struggling to road tune the higher boost stuff, really need a steady state dyno to do it properly with the Maxx.

Deutch connectors are so nice to work with!

Hey Martyn, great work!

What tuning strategy are you using for the Maxx? You can't use normal speed density tuning due to the ITBs. The manifold is constantly boosted at higher rpm, and speed density requires the MAP sensor to be placed post-throttle body. The air pressure within a single silicone coupler post-throttle body is not stable enough to get good MAP readings, so a common rail MAP is required for speed density to work. However, the common rail MAP setups tend to suck on S54s.

The better strategy is to use a modified alpha-n technique. Place the MAP sensor in the VF manifold, pre-throttle bodies. Create two alpha-n tables (airflow and ignition timing) which mimic a naturally aspirated Z4M, and then apply two correction tables based on MAP readings- one for fuel, and the other for retarding ignition timing. The alpha-n table doesn't have to be 100% accurate, and the original MSS70 ECU file actually has an alpha-n table already built into it. You can copy this table almost verbatim into the Maxx. You may have to do some conversion of units depending on what the Maxx likes to see.

You should be able to estimate additional fueling needed based on boost pressure (just make sure your lambda targets are correct and also decrease with boost). For example, at 1 bar of boost you would need a 2.0 fuel correction. With no positive boost pressure, you would need a 1.0 correction.

For ignition timing, you can use the stock timing for the base table. Pull the boosted timing targets from your logs of the last tune I sent you. Then interpolate between the two to build your MAP correction table.

This tuning strategy works especially well for turbo engines with ITBs... S54s, RBs, you name it. If you decide to put a turbo on the engine in the future, you'll already be 80% tuned to support it. Feel free to reach out if you get stuck.

Martyn · Post by **Martyn** » Sat Mar 18, 2023 9:59 am

Hey Josh,

I'm using AlphaN on the main fuel VE table with TPS as the load source, then I have an additional fuel table which adds a percentage of fuel based on MAP (102KPA to 190KPA).

Ignition and Lambda tables are MAP based.

Cheers

Martyn

pokeybritches · Post by **pokeybritches** » Sat Mar 18, 2023 10:20 am

Are you using the MSS54 table KF_RF_N_AQ_REL as your base alpha-n table for VE?

Martyn · Post by **Martyn** » Sat Mar 18, 2023 10:29 am

Na, I had previously run the car on the Maxx when it was N/A so I used that as my base. When it was N/A I roughed out the VE table then fine tuned it via the logs.

pokeybritches · Post by **pokeybritches** » Sat Mar 18, 2023 10:39 am

Makes sense. Well hopefully the dyno goes well

Martyn · Post by **Martyn** » Sat Mar 25, 2023 2:23 pm

pokeybritches wrote: ↑Sat Mar 18, 2023 10:39 am Makes sense. Well hopefully the dyno goes well

Cheers Josh.

You guys sparked my interest to have another bash at getting things dialled in on the Maxx, turns out a slight change of strategy was all that was needed, I dropped the ignition table on from 100KPA onwards down to 5 degress and just concentrated on getting the fuel dialled in without worrying about knock. I hope to have this sorted in the next few days if it stay dry, then I can tweak the vanos PIDs, then finally ignition.

Whilst trying to dial the MaxxECU in the starter motor decided to crap out a couple of times, so I had to pull the inlet off (again) and swap that out, I also changed both TPS sensors whilst it was off. The new starter is a 1.4kW unit so spins the S54 quicker than the old unit.

I also fitted a new battery for good measure as the existing one was a little tired too.

Martyn · Post by **Martyn** » Sat Mar 25, 2023 7:44 pm

Now we're getting somewhere!

I ditched the additional fuel table for boost and let the Maxx calculate the VE based on MAP itself, this is after 1 round of tweaks to the VE table and the lambda controller disabled but the total target fueling error is down to +/-5% in most areas now.

~180kPA / ~11.5psi at 8K RPM

I'm still yet to work out where the inbalance is coming from between cyls 1-3 and 4-6 as I don't appear to have any boost leaks between the head and the plenum. I was seeing a similar inbalance with the MSS70 too.

Plenty more work to do!

Martyn · Post by **Martyn** » Sat Mar 25, 2023 9:30 pm

And this is one of the reasons why I love the charge cooled setup!

Air straight out of the charger at the top end of the rev range is hitting 90*C, yet the air entering the engine is sub 30*, when you're not on it the temps recover super quick too!

Vanne · Post by **Vanne** » Sat Apr 01, 2023 2:56 pm

bloody lovely mate

Martyn · Post by **Martyn** » Sat Apr 01, 2023 3:36 pm

This morning I went to visit the legend that is Ray West, of West Tuning over at Thruxton, he allowed me use of his dyno so we went about doing some testing.

First couple of runs were on the MSS70 stock ECU.

This yielded a result of 561.2 flywheel horsepower, and a peak of just over 400lb/ft of torque, resetting the adaptation did nothing and the car repeatedly pulled similar figures.

I then switched back to the MaxxECU and dialled in the fuelling some more, the car was putting down ~500 flywheel each time, I then worked on inlet and exhaust vanos and then re-visited the fuelling again and then finally bumped the ignition up from the 5 degrees i'd set for road tuning.

The result was 578.5 flywheel horsepower and just over 400lb/ft of torque. I believe I left a decent chunk of power on the table but I wanted super safe ignition targets so I left it at that.

I did over 35 dyno pulls without a single issue, not bad for a motor with 143K miles on being force fed 11.5psi

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