SpecE30 and Megasquirt

#101

Being a newbie to the E30 forum, is the MegaSquirt legal or pending to legal? From what I’ve read, the stock ECU had to used. Getting into this, I would really like it if the MS was a legal option…

#102

[quote=“TrackRat” post=58160]Being a newbie to the E30 forum, is the MegaSquirt legal or pending to legal? From what I’ve read, the stock ECU had to used. Getting into this, I would really like it if the MS was a legal option…[/quote]It is not legal. There is virtually 0.0000000% chance that it would become legal. The rules are much more stable than this thread might lead you to believe!

#103

Hey Shawn…did you buy that car yet?

Mark

#104

[quote=“MadScientistMatt” post=57991][quote=“Ranger” post=57975]Having said all that, my theory is that the CPS isn’t so much a “crank position” sensor but a “top dead center” sensor. I have no proof of this, but I think that the critical piece is the gap in the teeth at TDC not the teeth themselves. Therefore, so my theory goes, the DME is looking at a rapid sine wave and then a gap in the sine wave. That would mean that a noisy sine wave wouldn’t matter, as long as the gap in the sine wave was clear.

My reasoning is this…the DME doesn’t need a sensor to tell it the position of the crank. As long as the harmonic balancer is spinning the DME can interpolate the crank’s position from the timing of the gap in the teeth. That would be easier from a design perspective then trying to keep track of the exact shape of the sine wave from the rapidly moving teeth.

Stating the obvious, the gap is there for a reason and it’s not to make it easier to get to a couple bolts.

I got this idea when I stumbled across a (non-M20B25) BMW reference to a TDC sensor that seemed really similar to our CPS.[/quote]

The gap is there for cylinder identification, all right, but there are a couple types of noise that can give the ECU problems. A piece of noise right where the missing tooth goes can make it lose track of the missing tooth and lose its cylinder identification, while noise in the sine wave between pulses could look like an extra tooth and get your timing off slightly if the ECU fails to filter out pulses. Here’s an example of someone capturing the first type of noise issue at around 4,000 RPM with a MegaSquirt set to log the CPS (and no other signals - many MegaSquirt code variants have special tools for troubleshooting CPS issues, beyond just watching the RPM signal).

This is for a Ford, not a BMW, but the idea is the same. You’ve got 36 teeth and one missing, instead of 60 teeth with 2 missing. What you’re looking at is a bar graph where the height of the bar represents the time between teeth, and there is one missing tooth so you get a double-height bar when you see a missing tooth. However, on one revolution, a noise pulse gets through the filter and makes the missing tooth disappear. (He fixed this with a change to hardware filtering, in case you were wondering.)[/quote]

Man, that just kicks ass. Getting that kind of data in order to identify the cause of less-than optimum engine management would be just killer.

It’s a bummer that this idea isn’t going anywhere, but I was figuring that it was going to be a hard sell. Make no mistake, I entirely accept the importance of rules stability. But I’ve fought so many engine management problems that this idea seemed to have real charm.

At RA last month everyone gained a couple car lengths on me on the back stretch. That didn’t happen to me with engine #9, but it is now with engine #10. Both those engines are cherry. Not “were” but “are”. Engine #9 was perfectly serviceable when I pulled it is now bagged in storage. I’ve chased down and seemingly resolved a number of engine management issues that plagued #10, but it’s still not as strong as 9, and it’s not because of the engine itself. It’s engine management.

Jim said it very well on the previous page. Steve earlier opined that the sort of problem that a MegaSquirt could help solve was minuscule (sic). I beg to differ. At the last event 2 cars out of 20 had problems that could have been instantly diagnosed with an MS. A good educated guess did fix them (this time), but that is still 10% of the field present at RA. Memory is a tricky thing, but my recollection is that I wind up working on one or more cars at most events trying to solve some sort of performance problem. I’d hardly cause that minuscule.

For those of you that are talking about any MS solution that would allow for different tunes, you’re not helping. SpecE30 is a conservative culture. The sure way to kill an idea is to suggest that there might be a way for someone to something differently. If you like this idea, currently a dead idea, help it win next year on the merits of it being a trouble-shooting aid, and a way to easily inspect that no one has a unique tune. If it can’t be accepted on those merits, it won’t be.

If it should be accepted one day, then you can try to convince people that letting them screw with the tune would be a good thing. Now that will be a hard sell.

[quote=“Steve D” post=58162]It is not legal. There is virtually 0.0000000% chance that it would become legal. The rules are much more stable than this thread might lead you to believe![/quote]Lol, I love ya man.

#105

I’m all for removing complexity to the cars. Only problem I have with MS is the tuning capability. I’m getting much better at tuning than I was before. For someone who just wants to show up at the track and race without spending a ton of time on the dyno fixing fuel and spark maps, it wouldn’t be nearly as fun.

Every engine is different, and so are the tunes…

Then again, if I can buy a MS system, remove a bunch of wires and tune it I’d be all in.

#106

The reason SCCA opened up the ECU rule is that it was unenforceable. Is for NASA, too. Not much trouble finding someone to flash a stock chip with a better tune.

So, allow the option of MS and people can do what they want to do. Makes about a 5hp difference on a chassis dyno and most any idiot can tune it. If you want you can leave it in closed loop mode, set your timing and F/A ratio (must use a WB O2 sensor) and forget it…just like the newer cars. No dyno trip, no muss, no fuss…just run. CB

#107

[quote=“cwbaader” post=58279]The reason SCCA opened up the ECU rule is that it was unenforceable. Is for NASA, too.[/quote]Just to clarify, SCCA has not opened up the ECU rule for Spec Miata. Many other classes are open, but I believe Spec Miata is a similar rule set that can serve as a decent guide for Spec E30.

I’ve often wondered how hard it would be to create a tech mechanism with a PC that plugs into the ECU, feeds known values for certain sensors, then reads output values. Seems like an easy way to sniff out chips. Surely cheaper to have one of those per region than have every SE30 driver spend $500-1000 on new ECU and tuning.

#108

I agree we should learn from SM’s mistakes (intake & exhaust of the month come to mind) so you should also include the information that SpecMiata just had to allow adjustable FPRs and open timing so the cars without the “special” ECUs were equal and negate the benefit of the cheaters.

Unfortunately it’s inevitable that as our series becomes more popular that this will be an increasing problem.

#109

You can buy a PNP kit for the e30 from DIYAutotune for $430.00…build it yourself…its not rocket science. They have sample tunes to get you up and running. That 430 is cheaper than going to the junk yard and buying enough ECUs to find a good one. Mandating the stock ECU is false economy!!

I do not know, but the ECU on a SM may not be hackable as easily as is the BMW.
Note, a MAJOR SM motor supplier in the SE uses only one ECU and harness to dyno test motors. I have seen a 15hp drop when a motor was installed in the car. YRMV. CB

#110

It seems as thought what we are really looking for here is a “painless” new harness kit for our cars, not a tuneable ECU system with datalogging.

#111

[quote=“cwbaader” post=58282]Note, a MAJOR SM motor supplier in the SE uses only one ECU and harness to dyno test motors. I have seen a 15hp drop when a motor was installed in the car. YRMV. CB[/quote]15 HP drop from an engine dyno to a chassis dyno? Sounds about right.

#112

I would guess that Chuck is talking about a 15hp drop when corrected for drive train losses. That would be a pretty significant difference from just the DME & harness.

#113

Chassis dyno to chassis dyno…same corrections/smoothing, etc. Totally unexpected. CB

#114

[quote=“cwbaader” post=58282]That 430 is cheaper than going to the junk yard and buying enough ECUs to find a good one.[/quote]If Pelican sells remanufactured ECUs for $300, why would you spend >$430 on junkyard units?

#115

[quote=“cwbaader” post=58282]I do not know, but the ECU on a SM may not be hackable as easily as is the BMW.
Note, a MAJOR SM motor supplier in the SE uses only one ECU and harness to dyno test motors. I have seen a 15hp drop when a motor was installed in the car. YRMV. CB[/quote]

It isn’t. There is only one company I’m aware of that has hacked the early Miata ECU on a commercial basis. One of their reps claimed on Miata.net that many Spec Miata front runners are (illegally) using their tuning. Not sure if that’s true or not.

#116

I agree we should learn from SM’s mistakes (intake & exhaust of the month come to mind) so you should also include the information that SpecMiata just had to allow adjustable FPRs and open timing so the cars without the “special” ECUs were equal and negate the benefit of the cheaters.[/quote]That is true. It was determined that it was cheaper and more practicable to allow competitors to exploit open timing (allowing slotted timing wheels) and fuel pressure (with AFPRs) than to than police cheated ECUs that were used to accomplish the same results.

I made those changes on my '99 and the cost was <$200 parts & labor.

Bear in mind that the Spec Miata class tries to equalize FIVE different cars (1.6 liter, early 1.8 liter pop-ups, later 1.8 pop-ups, 1999-2000 cars (brought slightly better suspension geometry to the party), and 2001+ cars with VVT).

Spec E30 is one-engine, one-chassis class. That takes away huge parity issues that SM deals with. SE30 has never permitted open intake. The exhaust (grumble, grumble) is at least a spec component.

If E30 ECUs are easy to hack, they should be easy to tech. Then again, you can probably tell how ignorant I am on the topic.:laugh: Or maybe we take a page from Spec Miata and open up timing and fuel pressure to minimize the gains to be had illegally?

#117

Crank triggers are only legal if your car came equipped with one from the factory. Distributors, however, are free, so you could change the insides to a Hall effect unit. A moot point for an e30 as they have a crank trigger stock. APFRs have been legal as long a I can remember (yesterday??), at least 7-8 years.

There is no guarantee that a 300 PP unit is going to make power. They repair what is on the board…I doubt they check the tuning on the chip, and that is where the power lies. The MS unit addresses all parameters of the engine and can be tuned in real time is you so desire.

Maybe Matt from DIY can weigh in here. If you want to police the stock unit, can’t a relative cheap interface (laptop) be generated to check the F/A map on the stock ECU?
Remember, if there is no rule enforcement, there are no rules. CB

#118

[quote=“cwbaader” post=58306]Maybe Matt from DIY can weigh in here. If you want to police the stock unit, can’t a relative cheap interface (laptop) be generated to check the F/A map on the stock ECU?
Remember, if there is no rule enforcement, there are no rules. CB[/quote]

It’s doable but probably wouldn’t be cheap (or something we’d be likely to make ourselves). You would need a hardware device that simulated the factory crank wheel and measured the fuel and timing outputs (timing is at least as important as fuel), and ran it through every RPM / load combination that you were likely to encounter on the track. As the R&D cost to develop such a gadget would only be spread over a couple dozen units, they’d be on the expensive side.

#119

I seem to recall that the ASA series, back when all cars went to spec LS1 EFI engines, handed out ECUs to all teams before practice/qualifying/racing and collected them at the end of those sessions. Electronic tuning and trickery were quickly eliminated, as the ECUs were randomly assigned. Maybe all SE30s in attendance at a race remove and pool their ECUs at the beginning of the event, and the one that you blindly pull out of the group (excluding your own or one from a team car) is the one you get to run all weekend. Write your names on them, and they all get returned to the original owners at the end of the event. At worst, officials could bring 1 or 2 spare ECUs as backups.

Maybe a “claimer” rule for ECUs would slow down some alleged shenanigans as well. Set the price for the current going rate for used ones at junkyards, on eBay, etc. Or, allow ECU “protest swaps” between drivers for only a nominal management fee. Or, just blow the door wide open and allow tuning the stock ECUs with basic chips.

Again, I see no problem with buying your own MegaSquirt and using it for diagnostic/troubleshooting purposes on your own time if you are one of a few drivers who is having problems; then, simply show up to an event with a factory ECU.

But, I’m not currently an SE30 driver…just Scott’s SE30 mechanic with an eye on this class when I move up to W2W.

Mark

#120

9.3.1.3.4. The stock fuel pressure regulator must be used.