PF Tuning

TR8 Haltech-ectomy
Written by Peter Florance   
Sunday, 14 February 2010 03:08

Today's subject was a 1981 Triumph TR8  SCCA race car. The car had a Haltech E6K engine management installed a few years ago. The Haltech was distributor triggered from its built-in ignitor. Since then, the car had suffered from reliability problems.

The Haltech box had been sent back to Haltech but nothing was found. The owner was led to believe that this paticular product did not always perform well with distributor-trigged systems.

The owner of the car brought it to our local race shop and asked them to take a last look at the installation. Interestingly, they called me to quote them on a MegaSquirt installation. Their idea was that even if the problem was in the car or installation, it would be easier to diagnose with MegaSquirt's better software tools.

A quote was rendered and accepted. As the harness looked pretty good, my idea was to make an adapter harness to connect the MegaSquirt MS2 system to the Haltech E6K harness.

Today, we installed the harness. My check list (see Resources section) came in handy and gave me the confidence to procede. With the exception of a minor problem in the assembled V3.0 board, the installation worked like it was supposed to.

Tomorrow, we tune on the dyno.

Update: we ran into a few issues.

  • The alternator didn't work. After several runs we flattened the battery. Once we hooked up a charger, we realized we had tuned so far out to the edge of the injection-time battery voltage correction-curve that we had to re-tune AFR's. Grr...
    We sent the alternator out of rebuild and it came back working great. Unfortunately a working alternator also cost us about 7 HP which was politically hard to swallow, but no one was going to win a race with a dead battery.
  • As part of the Haltech installation, the distributor pickup had been welded down at a point that yielded a trigger angle that was problematic for a V8 basic trigger. We needed either 35 (too small) or 125 (too large). Rob (Abacus) recommended they re-phase the rotor. Unfortunately the screws were all red loctited down and one was broken. I had to scramble to find an M3.5 screw quickly. Abacus Racing's machine shop eyeballed the phasing and got it within 9 degrees of ideal, which is amazing. We ended up with a trigger angle of 69 degrees which worked great.
The car did fairly well after that, making more tq than hp (predictable for stock Rover V8) and drove well at the first event. Second event it died on the track and could not be restarted. It appeared that the distributor was at least 90 degrees out (crankshaft relative) but it seemed impossible to happen.
The next couple of weeks were tense for me until the owner called me to let me know that the cam gear was stripped and the distributor had jumped timing! A cause and fix were determined and we're looking for big things.