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Project Megajolt


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Thanks for starting this thread. I thought I'd add what I've done as well with a Megajolt project on my '85 Esprit turbo as well.

I've touched base with Jeff over a year ago, and he sent me some useful photos

I had a custom crank pulley and separate trigger wheel built for me by an experienced machinist near Houston that has done many of these fro different cars.

I thought I'd spread the word, because his product has proven itself in my install, and you might be interested in his services.

He has developed fully dimension CAD drawings of the parts, and now has experience the Esprit. I sent him the OEM pulley to work with, but now he has the dimensions.

I can provide some pictures of the aluminum pulley, steel trigger wheel (which bolts to the front of the pulley with slotted hose to allow fine-tuning of TDC position), and a sensor mount which bolts to the front of the engine using two longer front cover bolts). I could provide the drawings as well, but it would seem fair to ask the machinist. Don't look at this as a plug, because it's my actual experience.


His (Jason Miller) website may not mention lotus, but it should. The cost for all this was very reasonable, and it bolted right in.

The '85 front pulley has a larger diameter for the alternator belt (the front-most pulley groove) than for the vacuum pump and air conditioning. I believe later models went with a single diameter for all three.

I made the choice to stick with the original equipment diameters. I also had an earlier model iron pulley that had all belt groves at the smaller diameter, but again, I chose to ignore that and use the 85's standard diameters. While it's too late for me, would any of you offer advice to others on that choice?

I am not actually interested in more power, but am interest in drivability and reduced maintenance. Frankly I hate the position of the distributor under the intake manifold. Both directly under the gasoline and very hard to access and adjust.

The main thing I am interested in now would be any experience you have with the MAP, or on-the-road lessons learned. Where would I get the best MAP for an '85 carbureted (turbo) today?


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Yes I did ask about other material, especially since the earlier model pulley I got from JAE was cast iron. Miller would have done one, but after looking at the original equipment crank pulley (that is already low mass, was reduced in mass from the earlier cast iron one, and has never had a harmonic balancer, it was decided to stick with billet aluminum. I realize that the very early 910 engine only had one belt grove so were even lower mass. I guess I essentially decided to not take on more R&D that Lotus themselves did. All of Miller's examples posted on his website seemed to either be w custom pulley from billet alum or a OEM pulley machined to accept a trigger wheel. Sorry I didn't get better pictures of my actual install, but I was pressed for time to get this car back on the road. Perhaps when it's on a lift, I can capture how well the crank position sensor mount worked out. The best thing about that is that you only have to loosen one bolt to give you the clearance you need to change belts. It is clean, essentially a aluminum rod with a large hole drilled and slotted to carry the sensor.

Do you have any Mega-Jolt MAP files?

Feel free to ask for anything you need. I can contact the machinist about his drawings. He's posted examples of dimensioned drawings for other cars (BMW, FIAT) on his site for free distribution, only stating that his name needs to remina on the drawings.

I myself belive he's good enough to simply enlist him to do the work.


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Very interesting! I'm pretty sure that I want to do something similar at some point, as I don't expect distributor caps & rotors to be available forever. Assuming of course that the engine lasts that long...

"If you can't fix it with a hammer, it's electrical." -somebody's dad

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I have maps. Email me when you get that point and I can send you some. You can also go to autosport labs website and find a few. Just search Lotus Esprit. I believe the one I am currently using is based off the one.


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  • 2 months later...

I have the VE and spark tables I used on my naturally aspirated 2.0L 907 motor in my Jensen-Healey. I am using a Megasquirt1 system with the MSnSE code loaded and I am using EDIS crank-fired ignition as well as the fuel injection. If anyone is interested I have a fairly complete list of parts I used to do the conversion. Since this was a naturally aspirated 2.0L engine, I used 21.3lb/hr injectors from a Dodge Neon and I am running the fuel pressure at 43psi.

If anyone wants to see the maps I used just drop me a note or pm.



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  • 2 weeks later...

Hi All,

This megajolt project is of great interest to myself and I am sure to all other owners of esprits.

Is there any chance of someone kindly putting together a full shopping list of everything required for this modification?



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  • 6 months later...

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