Chysler 440 (7.2L) EFI conversion (Jensen Interceptor)

[PhilipL]

Hi All

As to be expected I see there is a lot of Rover V8 activity in this section (which I've had my share of...) so how about something different?

I present here a summary of my EFI conversion of the Chrysler 440 cubic inch (7.2L) engine in my '74 Jensen Interceptor. Pics below.

Summary of the conversion:
1) Edelbrock PRM intake manifold modified to accept injectors;
2) Edelbrock EFI throttle body with TPS and PWM idle valve;
3) Discovery 2 V8 EFI submerged EFI pump;
4) Jaguar XJS surge tank with EFI pump inside;
5) Dual EDIS-8 coil packs with HT wires made by Magnecor;
6) Ignition module consisting of 4 BIP373 transistors, controlled by Megasquirt;
7) EFI control (fuel and spark) by Megasquirt-2 on a V3 board;

I have a downloadable PDF file of the project here: https://dl.dropboxusercontent.com/u/152 ... 202013.pdf

A very comprehensive thread on this conversion can be found here (I suspect you may have to register to view it): http://www.joc.org.uk/phpBB2/viewtopic. ... 540ed030e2

This is what it looks like after the conversion:

[v8250]

Philip, that's a very interesting conversion. Could imagine the UK Interceptor chaps cringing at non-originality...but good on you for doing this. I have a friend who works for JensenR here in the UK, he took me out in one of the new super Jensen R's some weeks back. These cars are very impressive. I've always had a big 'thing' for 541's and CV8's...they're such great cars and have in mind to convert a 541 to a V8 with manual box in the future. Again, the purists won't like it but a 541-V8 will make a wonderful toy!

[PhilipL]

Again, the purists won't like it

Yep. Well, stuff them. I want to drive and enjoy the car to the max while I have it. And to run a 7.2L at 3000rpm doing 120Km/h will surely kill the earth in less than 20km!!

Besides, everything is bolt on and can be reverted back to original. I kept all the original bits.

[DaveEFI]

Lovely job. ISTR seeing an Interceptor with port injection at the Ace Cafe?

[PhilipL]

Lovely job.

Thank you!

This may come as a surprise, but if I were to get another Interceptor (and I hope I do), I would NOT repeat the EFI conversion. I had the car running 99% fine on the Carter carb, compliments of excellent videos on Youtube (starting here: https://www.youtube.com/watch?v=fzNhCLg9veg). Only issue that bothered me still l was overfuelling while auto choke was active. The EFI is lovely but the gains are perhaps not worth the cost. The real reason I won't repeat the EFI is about the sound though. I preferred the SOUND the car made with the carb, not that the EFI sound is bad, its just not quite the same and I preferred the carb'ed sound.

I would however again remove the dissy and replace with ECU mapped distributorless ignition and I would again do the 4L60e conversion.

[Eliot]

The EFI is lovely but the gains are perhaps not worth the cost. The .

EFI alone wont give you much of a power increase, mapped ignition probably helps more. But you should find the start, idle and general around town is far better.
Once i had all fuel and ignition under the control the very next upgrade was a pair of Turbos!

[PhilipL]

EFI alone wont give you much of a power increase, mapped ignition probably helps more.

Quite so! I did not do the EFI conversion for the sake of power but for the sake of refinement and economy.

I first implemented the wasted spark ignition on its own and this brought about a MAJOR improvement in the way the engine behaved over the dual point dissy (with an MS6A)

But, while I was waiting for all the EFI parts to come from the US, I decided to have a go at the carb and that is when I realized that the Carter Thermoquad is actually a very good carb. Once you know its quirks and once it works well it does a very good job. I have a Youtube video (https://www.youtube.com/watch?v=L8iLbZo-Er0) to show how good it was running after I had sorted all its issues and had it tuned well. But I was committed to the EFI conversion and so completed the project.

[minorv8]

Excellent reading ! I am currently converting my Rover V8 engine to EFi using factory Efi intake, two Bosch coils (same as factory RR) and Haltech ECU. The plan is to first do the ignition, check that it works with a carb and only then change the fuel part. Of course, all this necessitates moving other components around so there is even more work.

[DaveEFI]

I too did my conversion in stages.

The car (SD1) already had Lucas flapper injection which had never been quite right from new. Mainly a luck of grunt at low revs.

The MegaSquirt 2 fuel only got it running as it should have been from the factory. I then added EDIS later.

Can't say there was a massive difference. Except that it no longer has good and bad days.

Next stage is an MS3 and sequential injection. Have all the bits made waiting to be fitted.

[Cobratone]

Next stage is an MS3 and sequential injection. Have all the bits made waiting to be fitted.

Me too on my 383 SBC, trying to work out where to put the LS3 coils, don't like them on the rocker covers

[PhilipL]

Excellent reading ! I am currently converting my Rover V8 engine to EFi using factory Efi intake,

If I may make a suggestion:
1) if you want a high revving engine with lots of top end power, use the LUCAS type EFI manifolds with 3.9 or 4.6 cast into the top of the plenum;
2) if you want a low revving engine with lots of low rpm grunt (torque), use the EFI manifold from a Disco2 V8 or P38 Range Rover '99 onwards (THOR engine, Bosch engine management).

[DaveEFI]

If anyone wants a complete top end from a 4.0 Thor, have one here. Or rather think it's everything apart from ECU.

I thought it might look nice on the SD1 - before being told I'd lose out on the top end.

[DaveEFI]

Next stage is an MS3 and sequential injection. Have all the bits made waiting to be fitted.

Me too on my 383 SBC, trying to work out where to put the LS3 coils, don't like them on the rocker covers

I'm going to stick with EDIS, since it seems happy enough at the peak revs on my 3.5.

MS3 allows EDIS and sequential injection with the addition of a cam position sensor.

[PhilipL]

If anyone wants a complete top end from a 4.0 Thor, have one here. Or rather think it's everything apart from ECU.

Yep, the THOR was designed with low end torque being the objective and basically peters out above 4500rpm.

The Lucas unit only really gets going above 3000rpm.

For a thor EFI to be "complete", you need:
1) The lower and upper efi manifolds with throttle body with all relevant bolts
2) the fuel rail with THOR injectors with bolts;
3) Throttle body with TPS connector and pigtail with bolts as well as the throttle cable mount on the front of the top manifold with 2 bolts;
4) Bosch idle valve with clamps and screws and 2 rubber pipes and connector and pigtail;
5) Both THOR tappet covers with bolts
6) both PCV rubber pipes coming from the tappet covers to the manifold;
7) if you intend using the cabin heater then both THOR heater pipes should also come with along with their bolts;

I have found the the large diameter clean air feed pipe that fits to the throttle body is also useful (for the idle valve clean air) in a custom installation.

Hope I remembered everything...

[PhilipL]

I'm going to stick with EDIS, since it seems happy enough at the peak revs on my 3.5.

Wise. It will be a very special RV8 to test the upper limits of an EDIS-8 ignition system (>7000rpm).

I used dual EDIS-6 ignition systems on my Jaguar V12 implementations. One could use dual EDIS-8 on a 16 cyl engine.

One of my dreams is to Megasquirt a Merlin (terrestrial use). Not that I would find any lying around in South Africa of course....