Triumph TR7 16V installation

[jeffremj]

I added this as a story, but it is hard to find, so I have posted it as a forum topic.


I have fitted a version 2 system to a 2 litre 16V engine. The fitment is the same for a standard TR7 8V.

Highlights are a 500rpm setting at 30 degrees advance - this is an anti-stall feature that is useful with a cold engine that still has a manual choke. The next rev point is 800 and the normal timing resumes. So, if the engine starts to die, it is given a kick to 800rpm!

I have also added a 48 degree advance at high vacuum at the peak torque area (3500 rpm). The car now cruises with minimal throttle openings.

The final item is that the last rev column is at 7100rpm and the timing is backed off to 5BTDC. This works like a rev limiter - the power just fades. I tested it at 6100rpm to be on the safe side! Using this method also makes the wiring simple.

I feel this rev-limiter is needed because the car still pulls beyond 7K!!

Note that as the car still needs the distributor to be in situ, I have used it as my tacho drive (replacing the old coil with a 1K resistor) so that all the car sees by way of wires is a new is a 12V feed.

More information can be found here:

http://mjjfar.servehttp.com/triumph/edis.htm

The Megajolt Lite Jr is the best thing I have added to the car!!


Update:

I have since had a quick run on a rolling road and the power/torque seems about 1-2% better at 140bhp at 6200 and this is probably due to the better spark. This better spark is also manifested in power now remaining strong to 6500 and extending beyond 7K, hence my 'red-line' at 7100!

I also tested the air fuel ratio at 3500. At high power it is 10:1, medium 13:1 and low 21:1.

In summary, the megajolt lite Jr. gives me, over and above a distributor ignition:

1) good idle control
2) rock solid timing
3) extra 'oomph' at 1500rpm in top gear
4) a simple rev limiter that needs no wiring to cut off spark power
5) very good mpg at 70mph (up to 21:1 A/F ratio!)
6) no drastic power drop above 6200
7) tweaking fun

[Oliver Sedlacek]

I've been curious about the idle speed stabilisation capabilities of the megajolt. It's nice to know something simple works!

[jeffremj]

In the past, I had to blip the throttle at every stop (when engine was not fully warmed up) to keep the car from stalling. The 500-800 bucket now does an equivalent of my blip, automatically. It is a must for all cars with a lumpy idle that has a tendency to stall.

[klj895w]

First off I'd like to say congratulations, and thanks for posting up the pictures. I have a Dolomite Sprint. I've had my assembled board for around 2 years now and haven't installed it yet! Your info has given me the impetus to get on with it at last.
I have a couple of questions though:
Did you make some kind of spacer to go between the trigger wheel and the crank pulley, to stop the trigger wheel pressing against the rubber part?
Do you have a drawing of the trigger mounting?
What carbs, cam, etc are you running? I noticed the tubular exhaust manifold (header) which doesn't fit in a Dolomite engine bay, but I wondered if you'd done any other mods.

I like the extra features in your map and now I really want to get it up and running.
Regards,
David

[jeffremj]

>Did you make some kind of spacer to go between
>the trigger wheel and the crank pulley,
>to stop the trigger wheel pressing against
>the rubber part?

No. I decided that is wasn't a problem

Make sure you bolt onto the inner part of the crank pulley.

>Do you have a drawing of the trigger mounting?

No. The best route is to use a simple angle iron around 4mm thick. This should also be strong enough to mount the triggerhead through a simple hole, rather than a sleeve.

>What carbs, cam, etc are you running?

I used standard TR7 HS6, with richer needles, on Sprint inlet manifold. A fast road cam was also fitted. More info here:

http://mjjfar.servehttp.com/triumph/geo ... 6vconv.htm

Rolling road vid here:

http://www.youtube.com/watch?v=ncpEtvBk9CM

HTHs.

[rich]

hi , i am thinking of fitting this system to my sprint and and wondering how you overcame fitting the plug leads to the ford coil as the sprint has those long tubes , i've recently fitted magnecor leads and hope to utilse them as they were 65 quid!


rich

[jeffremj]

hi , i am thinking of fitting this system to my sprint and and wondering how you overcame fitting the plug leads to the ford coil as the sprint has those long tubes , i've recently fitted magnecor leads and hope to utilse them as they were 65 quid!

Hi, I just cut the covers off the Ford items and dragged/pushed them through the 16V ends. Nothing clever...

[Yvan]

Hi Jeff. I am curious, you have 30 deg. advance at 500 rpm. Is there a risk of a detonation? 30 is quite a lot of advance at 500 rpm. I have trouble with stalling at idle when the engine is cold, and I am thinking about trying your anti-stall method.

[jeffremj]

Hi Jeff. I am curious, you have 30 deg. advance at 500 rpm. Is there a risk of a detonation? 30 is quite a lot of advance at 500 rpm. I have trouble with stalling at idle when the engine is cold, and I am thinking about trying your anti-stall method.

It seems OK. I got the idea from a Renault ignition map as seen here with 30 advance:

http://mjjfar.servehttp.com/triumph/ren ... on_map.jpg

As I now use the proper rev limiter, I have used the extra bucket at the lower end. I have 30 at 500, 20 at 600 and 12 at 700rpm. Normal tickover is 750rpm.

[Yvan]

I thought that you do not need to set advance low at rpm limit, as you have set at 10 @ 7000 rpm here:

http://www.btinternet.com/~triumph/TR7finalmap1.jpg

It is enough to set rev limit option, and ignition will retard to 0 deg 100 rpm before your limit.

Also, you do not need extra bin at 600 rpm, I think that advance does not jump from 30 @ 500 to 12 @ 700, it changes gradually, so you will get ~20 @ 600 without setting bin at 600. Perhaps you can use that bin somewhere else.

Anyway, thank you for the info, I might try your anti-stall method, perhaps I'll try lower values first.

[DannyP]

Yvan, I was thinking the same thing.

Also, some engines like some retard at high rpm. I have a very highly tuned type1 VW aircooled, 2165cc, 170 hp.

I was told to retard the timing 4 degrees per 1000rpm above 4800rpm. I haven't tried it yet, am soldering up the harness tonight