Megajolt Install on L28 & 3x DCOE

[Lazeum]

As far as I know, I'm waiting for spring to show up while I'm fixing for good my fuel tank. I just know that my engine runs for now, nothing more! 

They wasn't a lot of info about megajolt in a s30, so I did this thread. I'm glad it could help people to take this route.

 

I also forgot to look at the tach when I've run the engine. I still don't know if it works... 

 

....and thanks! 

Edited March 21, 2013 by Lazeum

[Git-y-up]

Great CAD drawings Lazeum. I am one of the fortunate individuals with access to a Father in Law with a lathe and machining background. Hope you haven't patented this sensor mount design yet cause I am going to be a copy cat. If you would be so kind and make my life a whole lot easier, do you have the drawings for the TPS sensor bracket you fabed? Ill fedex you some good Canadian Beer:) LOL

 

You won't be disappointed!

 

If I am Its all your fault

[Lazeum]

Let me quick get a patent on it, I'll sue you and you'll send me a 510 or a RX3 from Canada in compensation   

 

Seriously, if you need some CAD files in whatever format you'd like, let me know and I'll put them on the board. I can even correct the mistakes I've made during my attempt.

Regarding TPS bracket, I haven't got any drawings or CAD. I took some measurements, I did some cardboard templates & I've reproduced it with steel afterwards. It took me 5 iterations to get it right - when you bend the metal, curvature radius makes the bracket not so easy to be right.

Edited March 22, 2013 by Lazeum

[EvilC]

Great to see you got it going!

 

Weather is slowly getting better here. I plan to get the tach working and some time in dialing in the tune with the MJ.

[Lazeum]

Weather is still unsure here... Today was nice but they expect some temp below 32°F soon again (with salt that goes with)

 

Anyway, I'm still fighting with my gas tank, so good weather can wait a little. In 2 weeks, it should be done!

[Git-y-up]

Nice of you to offer the cad files. All I own is CAD14. Nothing 3D capable. The drawings are good enough for me. How much correction was built into the crank bracket to line the sensor with the trigger wheel? Or did you machine the dampener to a line the sensor and trigger wheel?

[Lazeum]

Nothing like this.

 

It is just the 2 holes machined to hold the VR sensor are not at 6mm each. One is 6mm, the other one is 5mm.

To accept the sensor, the 6mm hole needs to have a counterbore of 9mm, 5mm deep.

 

The plate needs to have also one of the bean shape hole at 5mm wide instead of 6 to match the other piece.

 

On the picture below, left hole is 6mm with counterbore required, right side is 5mm with oblong hole.

If you've got a VR sensor handy, check it out and it will become obvious.

 

Edited April 7, 2014 by Lazeum

[Git-y-up]

Thanks Lazeum, Ill make the part and most likely will have an AHA! moment. How did you decide between 1st Gen and Second Gen Ford EDIS coil packs?

[Lazeum]

I've kept the 1st gen coil pack I had.

I've put some rubber pads to install it on the fender. they raise the coil pack enough to install it flat wherever you'd like in addition to dampen vibrations. You can even install the coil pack on head cover above spark plugs if you'd like - make sure pads can handle heat from engine.

 

 

For spark plug wires, you can reuse the stock edis wires; cut them to proper length and install new spark plug terminals, easy to source to make a custom install clean.

Edited March 25, 2013 by Lazeum

[Lazeum]

I've run the car today. Just for information, my tach is working flawlessly the way it is wired now. Tuning process will be able to start soon.

[Leon]

Now you're on to the fun part!

[Lazeum]

Here are the files modified with lessons learned since I've installed everything in the car to create your own VR sensor bracket.

 

 

I've also driven the car, it was very nice with no issue. Car is smoother than before, power is ok (same level than before with Dizzy) but map is not done yet, I've change it once only.

I've got "pop's" from the exhaust while going uphill under load, it needs more advance at low rpm & much more under load & low TPS angle.

I also had to raise idle speed whereas it was ok with dizzy. not sure why, I haven't touched carbs in the whole process.

Only mechanical change to the engine was e-fans instead of regular fan.

 

So far I'm running idle timing at 20°, max at 33° @ 3500rpm.

VR Sensor Bracket - Datsun 240z.zip

Edited May 15, 2013 by Lazeum

[Leon]

Nice! It would be interesting to compare maps once you've finished tuning.

[Lazeum]

Engine still runs strong and smooth. I did not make any progress in tuning yet but car is very driveable the way it is now.

 

Today, I was passing somebody on forest road, going WOT up to 4500-5000 rpm. When I was just passing the other car in a loud Braaap! Suddenly,the Z made a huge BANG! from the exhaust while still at WOT! I've probably scared the hell out of the other driver who did not ask anything (but he was slow, way under speed limit).

Car is still running strong with no side effect but I need to understand what happened. Next time, I'll plug the wideband and record.

 

From my list, it could be:

- too lean mixture (it was perfect at 12:1 before MJLJ switch)

- not enough timing - 1st suspect in my mind - I'm running 32° max for now.

- exhaust leak?

- I've set up soft rev limiter at 5000rpm (still breaking-in) - could it be the reason?

[JCan]

Matt - you have a pretty nice setup!   I know you have a new electronic ignition, + rev limiter, I also believe you have an electronic fuel injection, lastly we know that a bang in the exhaust is most likely unburned fuel passing from the engine to the exhaust pipe and igniting.

 

Given this knowledge, does your rev limiter stop ignition or fuel injection?  IF it only stops ignition (the way they used to work back 1000 years ago when I was a kid), is there a possibility that it kicked in and the unburned charge went from the cylinder to the exhaust pipe?  Maybe you can disable the rev limiter and see if that fixes the problem?

 

On the z that I just built, I seem to be having problems with the electronic ignition at high revs.  (still debugging)  If the above is wrong, do you think you may have the same issue?  A miss can also cause a bang in the exhaust pipe.

 

Intermittent problems are the most difficult!

 

Good luck!

[Lazeum]

From a fuel stand point, I'm running Triple carbs. It could be an issue with fuel but I would believe power would drop off with a ramp down before getting a bang. Wideband analysis would help.

 

The soft rev limiter in my ignition system is setting up advance at 0° when it hits the limit. At 0° advance, fuel might not be able to fully burn, resulting in deflagration when hot gases meet 02 from outside.

I remember at school to make noise with bikes, friends were revving up their engine to cut everything with ignition switch while at high rev. This was making some loud bang & flames from the exhaust tip. I could have experienced the same effect on the road.

 

Nice feature from Megajolt is I can datalog everything (but I need to enable it!). I can try to play with rev limiter at lower rpm and see if problemm occurs with same symptoms.

 

On my to-do-list, I need to check VR sensor mount and check if it is still holding tight. I drove the car another 20km afterwards with no problem. It is most likely not the problem.

Edited May 27, 2013 by Lazeum

[JCan]

I am not a fan of rev limiters.  You balanced your engine right?  My brother and I (in the day) would race through 8krpm without engine problems.  I vote you set it to 9k rpm and go back to your mountain road and try to repeat the backfire.

 

IF you still hear noise, sounds like you can enable datalogging.

 

All in all, it sounds like fun!

[Lazeum]

I did not balanced the engine while doing the build. Engine was already balanced from factory and I don't expect to rev the engine past 6500rpm. The cam is not made for high revs anyway.

 

I think I will try to reproduce the issue but at lower speed such as 4000rpm and see what happens. I'll report back but it will be next weekend.

 

...and indeed, it is fun. Much more fun than tweaking stuff in the garage. It is the rewards to all the hours spent working on it to make it good (hopefully, it will last!).

Edited May 27, 2013 by Lazeum

[Leon]

Great job Matt, it feels good to be on the road. Don't worry, I'm sure you've done a good job on the install. Given that, the system should be very reliable.

 

The bang was due to your soft limiter. Going WOT at 5k RPM and suddenly retarding timing to 0deg would definitely cause that.

[Lazeum]

I had a lot of fun today!

3 hours driving the Z in forest roads was fun. Especially when the car runs great! No issue at all!

 

First, I was able to reproduce the BANG, it is coming for sure from the soft rev limiter. So there isn't any worries there anymore

 

Then, I had plenty of time to play with timing. To support my tuning, I had my nose, my butt & a DIY detcan that works great.

I'm sure I can go further in tuning but I start to be close from the limit of the engine. Each change has produced positive results with no downfall.

 

Coolant temp while engine is running is good. With 75°F weather & cruising speed of 70mph (around 3000rpm), needle is right in front of the bar from "E".

 

Here are the progress I've made. You can see difference between maps to check what I've made.

Load is TPS%.

 

1st map, a conservative reproduction of what my Mallory dizzy was doing.

Timing is the same whatever load is. So TPS is not part of tuning yet. 

 

 

Since no knock has been heard, I've ramped up a little max timing. From idle to 3500rpm, slope is linear. I've used Excel to better see the shape of the map (even if MJLJ software allow us to visualize in 3D the map)

Still, no TPS tuning involved.

 

 

Car feels great, better than with Mallory unit. Power & torque are definitely above previous setup. 

Still no knock of whatsoever to spot even when going up-hill in high gears.

 

I started to play with TPS with next map. 

First attempt was really to check impact with TPS, so I've only modified one small area of the map while cruising at 50kph in villages & 100kph on roads. I've put the cell modified in blue.

 

 

Results were good, engine feels a little more responsive at cruising speed. Nothing crazy however; if somebody would have changed the map without telling me, not sure I would have noticed it immediately.

Since it was going towards the right path, still without knock, I went further. I've forgot one cell in the following map. I'll have to adjust it next time.

 

 

For this last map, I've changed load impact on entire rev' range (engine can go only up to 4800rpm for now with soft rev limiter)

I've noticed a good impact on engine output this time. Still no knock to report.

I still believe I can further but I'm getting close to the limits, a dyno could truly become useful now but I need a load controlled unit - not so common in France & expensive...

Progress are also during acceleration, car pulls faster while pressing down the pedal, I can feel more torque during throttle progression. It goes better from steady speed to full acceleration.

 

Something amazing happens also with the last map: Fumes smell issue with open windows is gone with the last map!!!! 

I wasn't expecting some impact here but it makes perfect sense, with better timing, efficiency went up, more fuel is burnt. (maybe instead of raw fuel, I'm breathing more CO & NOx now   )

 

Since I can literally smell AFR change, I need also to control AFR with my wide-band next time, something I haven't done yet. I did not change anything on carbs yet but they run flawlessly with no hesitation.

Edited June 1, 2013 by Lazeum