COP 4 cylinder - 924s/944 & other content - Very Long Po

Show off your Megajolt installations, vehicles and action shots here!

Moderators: JeffC, rdoherty, stieg, brentp

Post Reply
Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

Let me know if you need anything. I spent alot of "quality time" LOL messing with that to get it to work corectly. At some point I would like to see just how small a trigger wheel it would work with.
Respectfully

Dean

dr.occa
Posts: 243
Joined: Fri Feb 23, 2007 10:52 pm
Location: TX

Post by dr.occa »

Dean924s wrote:Let me know if you need anything. I spent alot of "quality time" LOL messing with that to get it to work corectly. At some point I would like to see just how small a trigger wheel it would work with.
You would start losing definition Dean UNLESS the pickup/VR sensor used a something like a rare-earth magnet.

Ultimately, I'd like to have my 12A Rotary running off of MJLJ
AUTOSPORTLABS
NonStop Tuning
www.86garage.com

"Poverty is not a virtue."

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

dr.occa wrote:
Dean924s wrote:Let me know if you need anything. I spent a lot of "quality time" LOL messing with that to get it to work correctly. At some point I would like to see just how small a trigger wheel it would work with.
You would start losing definition Dean UNLESS the pickup/VR sensor used a something like a rare-earth magnet.

Ultimately, I'd like to have my 12A Rotary running off of MJLJ
I would agree!!! The pickups for the RX7 have very very strong magnets in them. I have taken them apart to swap how the sensor mounting arrangement is to allow for better mounting of the sensor relative to larger trigger wheels and getting them back together is a lot of fun due to the magnets being so strong. The trigger wheel in an RX7 is very small. Pony about 1.5 inches in diameter. However it has much fewer teeth. I am betting you could get down to about a 2" trigger wheel with this sensor with out issue especially if you were going with a 32-1 wheel. As I am using a 72-2 it would be interesting to see if it would read that at 2" diameter.
Respectfully

Dean

dr.occa
Posts: 243
Joined: Fri Feb 23, 2007 10:52 pm
Location: TX

Post by dr.occa »

With lesser teeth I don't see why not at those diameters.

According to my first gen rx7 fsm, the leading ignition timing at 500rpm idle is 0° while the trailing should be at 10°. Sooo, if there were 2 36-1 trigger wheels on the rotary eccentric shaft pulley with say the rear wheel staggered by a single tooth you'd have yourself an MJLJ setup! This would need 2 MJLJ units though.
AUTOSPORTLABS
NonStop Tuning
www.86garage.com

"Poverty is not a virtue."

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

My Megajolt has gone for 100,000 miles

Post by Dean924s »

Hay all just an update. By my calculations my Megajolt has now gone over 100K miles!!!!! I put it in in feb of 09. According to my GPS I average about 30-35K per year. So in Feb of 2013 conservatively my Megajolt will have easily got 100K.

Actually correct that. I swapped it over to the MJ in Dec of 08 so in Dec of 2012 it will have probably gone closer to 120K !!!!! Who would have thought!!!!


Big thanks to Brent!!!!! Proof again that it is a great product!!!!!
Respectfully

Dean

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

I have not been here in a while but again nothing to report. I have had no issues. The 924s is still my DD racking up between 30k & 35K a year. This I think puts me close to the 180K mark using the MJLJR.
Respectfully

Dean

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

Well I have had my first hiccup. Car was parked on July 4th. We had a heavy rain and on the 6th it would not start. Testing found no spark. So I have done the following

Tested the coil and the primary side it was just a tad above spec so I replaced it with a new one.

Replaced the EDIS unit with a known good spare.

For the heck of it I disconnected the MJLJr unit (not that it would matter in terms of spark).

Checked compression (Ya I know nothing to do with spark)

Checked Timing to make sure that something was not messed up with the cam and the timing belt (All was good)

Verified I had Fuel and all the injectors are working properly. (Again nothing to do with spark but wanted to make sure)

Plugged in the Computer to the MJLJr and did a quick log while cranking. I found that I don't have any RPM signal but the MAP is working.

Also of note I am not getting a RPM signal out of the EDIS unit on the test lead.

So I suspect that either the wiring from the pickup or the pickup its self have failed. The next step is to open up the wiring and check continuity from the sensor to the EDIS box. If this checks out I will replace the sensor.
Respectfully

Dean

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

AND it Lives!!!!!! Checked the wiring from the sensor to the EDIS unit and there was a poor connection where I had spliced the wires from the sensor to the lead from the EDIS unit. Looks like fatigue from vibration caused the problem. So the Fix is to affix the wires and the splice connections to the engine so they more with the motor or in effect remain stationary and let the wire from the EDIS box take the flex / movement from the motor.
Respectfully

Dean

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

AND if anyone needs any more convincing that the MJLJr is not a great product it was only because of my being to take a log with the car cranking so I could see that there was no RPM signal that it made the diagnosis simple and fast. I could not have done that with a standard EDIS system
Respectfully

Dean

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

Well more than 200,000 miles later and the car has been stored away due to low oil pressure. I really am surprised that I got more than 250K on this motor!!!! And more than 200K of it was with the MJLJr. For now the car is going to be stored away and I am pondering my options in terms of motors and what not.

I have had a forced induction project in the works for a REALLY long time. It involves a hybrid M62 supercharger that I cobbled together using the back housing from an early C230 Kompressor and the front snout from a early Buick Riviera.

I also have a 3.0l block in my basement that I have been considering putting to good use. All this means is I have a project!!!!!

Unless Brent has something to sell me that is better than my trusty MJLJr it will be supplying the ignishen control for what ever the project ends up being.

It has been a GREAT seven year's of MJLJr on my car and there will be more to come once I sort out the new power plant for my toy!!!!
Respectfully

Dean

brentp
Site Admin
Posts: 6061
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi Dean,

Thanks for the report! I hope you get your car back on the road soon, don't forget about it in the corner :)
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

Thanks Brent!!!

I had been considering just slapping a new set of rod bearings into the car as these are considered maintenance items in these cars and it would be the "quick fix". Compression is fine in the motor so this is an option BUT with such high millage I really need to do some long over due maintenance like the front end seal's on the motor as well as the rear main seal. The other thing that occurred to me is that the clutch is the unit I put in the car back in the 90's and it has seen well over 250K miles as well so that really should be done. In short it really is time to take the motor out and do a major refresh.

I hope to get it back on the road in some form by the spring. We will see.
Respectfully

Dean

odonnell
Posts: 2
Joined: Wed Nov 18, 2015 7:18 pm

Post by odonnell »

This thread gave me a lot of thinking material when I was looking into standalone management on my 1983 944, I first read it about 6 months ago.

Dean, I've actually cited your install on a few different Porsche forums, as I'm a huge fan of this approach. Guys over on Rennlist and Pelican are coming around to seeing the benefits - the problem is, we don't really have many documented installs. I think this build deserves a summarized write-up over on Rennlist, with a testimonial about the fact that it performed great for 200,000 miles.

I'm personally running a Microsquirt, full standalone. I can confirm that the GoingSuperFast crank wheel works as intended with our cars. I'm using a single hall effect sensor to trigger the MS (wasted spark ignition via LS1 coils), but I have a friend with the same wheel on his crank, and he uses the Ford EDIS VR sensor and it works flawlessly as well. So for that one, safe bet. Installation was under 10 minutes - and besides the wheel all you need are some M6x1.0mm bolts that are 16mm long (got mine from local Fastenal) - the additional 3mm of the trigger wheel demands slightly longer bolts.


Image


We seriously need more documented builds around - the Motronic parts aren't getting any younger (and even new, are lackluster). It goes to show that even junkyard parts from a Ford sedan are a substantial improvement... for not a lot of money. It's ridiculous that this hasn't been snapped up by more 944/951/etc enthusiasts. FWIW the crank wheel requires no welding, so it makes the project more accessible to the average weekend mechanic (like me... with no welder... yet).

Dean924s
Posts: 228
Joined: Fri Nov 07, 2008 2:57 am
Location: USA - MA

Post by Dean924s »

Thanks!!!!

The way I did it was a huge success. With the EDIS you need a 72-1-1 wheel on the cam so if you could find a trigger wheel that would be a better install on to the cam that would make this install much easier. You have to remember that when I started this it was new ground and MS2 was still state of the art and access to computer controlled CNC machines was big $$$$$. Now days you can mail order custom CNC parts by just emailing a CAD file and a paypal $$$$ and a matter of a week or two your part will arrive in the mail. Back when I started this this was only a dream that cost as much as my car was worth so I had to go with what was already on the shelf and adapt it to my car. Why I ended up using spur gears. Yes the welding and waht not was a nuisance and it was only done to lock the position of the gear to the cam so it could be taken apart adn put back in the exact same position but that could easily be done using scribe marks.

Another thing back when I started this. I was concerned about the added rotational mass on the cam and it could cause issues with the cam bearings. I tried using the smallest gears possible. It was also why I used the sensor from an RX7 and it was used with a trigger wheel that was much smaller than the OE ford one. But now 6+ years later I realize that the cam has all the force of the cam belt pulling on it so the small additional rotational mass added to put a trigger wheel on it really is nothing to be concerned about and 200K miles and 6+ years of trouble free service later kind of proves this.

With my setup it would be simple to convert over to a MS2. You would have batch fire injection but like COP it is a cool idea on paper and that extra 1-2% of performance will never be felt by the driver. It adds a level of complexity and cost that is just not needed on these cars. Why I abandoned my original cam fired COP idea using a EDIS8. In theory it could work but in reality completely unnecessary. Better to do the tried and true and be enjoying your car than have a very large piece of garage art.

Anyway If there is anything I can do to help anyone that is considering this conversion they should drop me a note here. I am more than willing to share what I know and help others enjoy these cars. This modification was the single best mod I ever did to that car. 2nd only to putting Koni Sports in it.
Respectfully

Dean

odonnell
Posts: 2
Joined: Wed Nov 18, 2015 7:18 pm

Post by odonnell »

Dean,

The stock 944 DME actually already uses batch-fire injection, it fires 1/2 and 3/4 together. It's like wasted spark but for injectors. With MS you can install a cam sensor - when coupled with a crank sensor, you can do full sequential fuel and spark (COP). However I 100% agree with you that it's a waste of time and the benefits just aren't there for the average guy.

But there is an in-between... semi sequential injection. It's the same as batch fire but instead of holding the injectors open for "x" milliseconds, it splits it up into multiple smaller opening. So like EDIS multi spark. This gives a noticeably smoother idle and is a little smoother all around at low RPMs. No extra hardware required (as there would be for the switch to sequential/COP).

On my 944 I use that setup. There are no speed/reference sensors, only that one sensor on the crank trigger wheel. That sensor alone sends enough info to run the coils in wasted spark (exactly the same logic as your 72-2 cam wheel) as well as run the injectors in semi-sequential. With that being said I admit it's a big project - I've dropped links to MegaJolt Lite on a couple RL threads because it's dramatically less work and a lot cheaper. The real gains IMO come from the ignition map, and the fact that the stock coil runs short of dwell time after 4500 RPM or so. After that, there are huge gains to be had after you dump the AFM. I want to get my car on the dyno soon for a real tune, but the subjective butt dyno is indicating 165 bhp (I have a cam and some other mods).

Post Reply