E30 M3 S54 Project

[jvh]

I originally put this in an email to Neel but he asked me to put in on the forum. Here it goes...

I wanted to start a new email thread to start discussion/planning for the electrics for a car I'm in the midst of building. I'd like to work with APEX on the design of the system and depending on time/capability (mine) and cost, purchase the various tools/supplies/components from you at a minimum, if not complete harness(es).

I actually really enjoy doing wiring, so if I have the time (and capability) I'd like to do as much of the work myself as possible. It's fun for me and should help with the budget, especially since component locations are still being determined. This car is being built as a showcase for Elephant Motorsports and will be my personal racecar competing mainly in NASA GTS as well as BMW Club Racing. This is not a cost no object project, but I do not want to skimp or "make stuff work"--the cost in $ and time for a race weekend is too high to be messing with fixing stuff. I'm sick of spending too much time fixing things rather than tuning things (suspension/driver!) on valuable race weekends.

The racecar is a BMW E30 M3 chassis that has been fully stripped/dipped and caged. There is some further fabrication to be done to the chassis before it will go off to paint largely dealing with location of the engine (moved rearwards) and firewall modification required for that as well as the welding in of brackets/structures for fuel cell, dry sump tank, etc. The engine is a Fletcher built GA S54 with dry sump. I picked up a low hours engine and is currently sitting at Fletcher awaiting a refresh of the top end and the install of cams. Intake will be a CF airbox. The suspension is E46 front struts with Mcoupe rear end and will use an electric PS pump.

For engine management, the easy answer is to go with Motec since that is certainly common on S54s and there is lots of support out there not to mention we (Elephant) can get them from one of our suppliers at a discount. I know you are very keen on the Pectel system--what are the major pros/cons vs the Motec?

For the engine, I plan on retaining the DBW and dual vanos control. I don't know if dual lambda is needed/recommended or if an external CDI box is needed. I need to lean on APEX/Fletcher for recommendations. I know we spoke about reusing/splicing into a stock engine harness, but given that I don't currently have one (looking currently) I'd prefer to build a harness from scratch unless it is prohibitively expensive. As far as tuning the engine, it depends on timing of everything. If it can be done at Fletcher on an engine dyno, great, otherwise it could be done locally (Chicago) at either Fall-Line, SpeedLab or anywhere else you or Fletcher would recommend.

As far as wiring, the plan is to rewire the car from scratch as the only "stock" system currently in the car is the rear brake lights. I really like the concept of the power control modules such as those from Motec and OBR. Having lost a race due to a blown fuse I've vowed to not have them in any car where I can legally get rid of them!

Future plans for the car involve incorporating "no lift" shift and traction control. We're working with some sequential transmission suppliers in UK/NL on transmission options but that many be pushed off to next year depending on budget. I would like to look into traction control sooner rather than later given the HP/WT ratio of the car and the relatively small tires that will fit under the E30 chassis.

For ABS the current plan is to use the M3 CSL system--I currently have the pump/brain as well as all the sensors. If there are other ABS options that integrate better into a traction control system, that could be changed.

As far as data acquisition/dash, I've been using the Racepak IQ3 in the current car and may carry that one over to the new one. That said, after attending the Fall-Line open house and spending some time with Rob May playing with the Motec software I realized how good the Motec SW is and how lacking the Racepak software is. I guess you get what you pay for I'm open to options on this wither it be Motec or something else, but again I might have to stick with the IQ3 for now and move to another system when the budget allows. For the dash, I do need something as there won't be a stock cluster or dash in the car and whether that is from the engmgmt system, DA system or something else I don't care.

Hopefully this message was understandable and not too rambling I tried to cover all the things that have been floating around in my head and I hope to work with APEX to get it all sorted, planned and built!

[Neel]

This sounds really exciting. I want to put some time into my response, but in the meanwhile does anyone else want to jump in and give their 2 cents worth?

[jvh]

Neel--

I forgot to ask--do you have any experience with the Magneti Marelli ECUs? I spent some time talking with Danilo at PRI and it was very interesting. From what I understand, they work much like the Bosch and Motec M1 series ECUs where the engine is "modeled" in the programing rather than just tuning the data in tables. I may be wrong about how it works, but given the price point of the SRD is in line with the M800 and SQ6, it might be something to consider. I was just wondering your thoughts...

[Neel]

The Marelli's you speak of are the Marvel series - they go for $15k+ and that price doesn't include programing tools. They are very high-end ECUs best suited to teams who want to write their own code. The SR-series ECUs are very limited. We did an evaluation of one with Marelli's support last month, and decided against carrying it because we felt, in its present form, its neither cost or feature competitive.

-neel

[jvh]

Well, that was easy enough. I'll scratch them off the list...

[Neel]

Yeah, sorry to be a bummer. We try very hard to be neutral about ECUs and base our evaluations on our experiences. We won't support a product just because we're a dealer - which means we butt heads with our suppliers from time to time. Truth is, I like MOTEC for some applications, Pectel for some, VIPEC for some - and if I run into a brand I don't sell but it works better than anything I have now, I try to get my hands on it to try!

[jvh]

Not a bummer at all, just something I forgot to ask. I don't know enough about the subtleties of the various ECUs on the market to make a truly informed choice, hence the reason I'm here talking to the experts

[jvh]

Any initial thoughts? I'd to start doing a little research/reading!

Thanks!

[Neel]

We recommend one of 3 ECUs for E46 M3's:

VIPEC V88 - for cars that don't want/need traction control, advanced data logging or more than 2 maps per car.
Pectel SQ-6 for cars where you may want to add launch control, traction control, have 4 maps per ECU, advanced knock control and more.
MOTEC M800 - for cars where you also have a MOTEC ADL dash and have complex traction control/data acquisition systems and/or need wireless Telemetry.

The VIPEC is the budget choice, but works well for many. Expect to spend about $3k plus harnessing and any sensor options.
Pectel is the most popular - about $4500 plus harnessing and sensor options.
MOTEC tends to be in the Pro cars - ALMS or Speed World Challenge. The benefits here are not in the ECU but how it integrates to a MOTEC dash if you have one. You'll spend around $6k+ harnessing and sensors.

Whichever direction you want to go, we've done cars with all three and are here to help.

-Neel

[jvh]

Thanks Neel.

I've seen the Motec dash and software and it sure is impressive but at $8k for the dash, it's hard to swallow. How does the Pi dash options and the data analysis software compare in both features and cost?

[Neel]

The Pi is the best value for most of our customers. The dash has multiple pages, alarms, a backlight and just about everything else that you'd want in a display, and at $1945 its a great price. The reason its so cheap is the logging is actually done in the ECU - Pectel's SQ-6 can handle up to 2GB with optional expansion and logs channels at 1000hz. What is doesn't do is user-defined CAN, conditional alarms, math functions and other types of advanced functionality you may want for serious suspension or aero analysis.

The Pi hardware is what was used in Formula Atlantic, British F2 and many World Rally teams, and its very well proven.

-Neel

[SAD_Man]

Pardon my posting on your project thread

I have to say that I have used Marelli ECU's / Data loggers on and off (thankfully more off than on) over the last 20+ years and every time I encounter them I come away underwhelmed. My experience is more aligned to using them as data loggers than for engine mapping but it seems the 'issues' they had in the early 90's are still present.

Just yesterday I was running a race car at a track and the same old issue reared it's ugly head:

Track length - Every time a race car completes a lap then it is bound to have a slightly different track length as measured by the wheel speed sensors, this is due to wheelspin / lock ups / slightly different lines taken and can be 10 - 20 metres of difference typically for a saloon type car (i.e. low downforce) The Marelli system seems capable of no more than placing that error all in the area from which it originally came. When you try to overlay data from one lap to the next it is nearly impossible to make sense of genuine differences in speed etc... Sure you can shift the data manually to try and align different bits of the lap but you are on very thin ice to try and draw any valid conclusions. It's easy to spot as you see the point at which the speed traces no longer overlay and on closer inspection it usually coincides with a lock up or similar.

In the same period I have used Pectel ECU's (SQ6 /T10 / T6) & PI Research data loggers ranging from System 4+/5/6, Daytona, Sebring, Delta, Sigma using the original Pi analysis, to Toolbox lite and Pro and from day one they haven't shown the same kind of problems. The lap distance error has never been an issue, even using split beacons to minimze errors in track length it is difficult to tell the lap traces apart. Clearly Pi has some kind of algorithm in place that deals with these errors much more robustly. The Marelli analysis software in isolation isn't too bad if it weren't for the existance of toolbox and it's capabilities.

On top of the lap distance errors, I had 1 ECU that refused to download due to a ethernet issue which I had to keep swapping from car to car to get it to download and the CAN driver for a road car based steering angle sensor hasn't worked properly for the last two years despite complaints to Marelli about this

Sorry just my 2 cents

Cheers