Dyno Session and Rear End Rebuild

By: Bob Goodson
May 12, 2020

I had been very careful not to drive the car too far if at all.  I did drive it to Ponies In The Smokies a show in East TN which is local to me.  But I was very careful not to take it above 2500rpm.  It was also raining when I drove it up.  The underside needs a massive detailing so that didn’t bother me.  

I was able to tow the car up to Blue Oval Classics and get the rear end fully rebuilt and the 3.55’s put in.  All new bearings and seals in the axle.  I was excited to do the gears as they’ve been on the shelf for years.  And the plan was to have Beau do that and set up a day to run it on the dyno to set the fuel pressure and make sure the air/fuel ratio was safe.  This car is being managed in the old school way with an FMU (Fuel Management Unit) and a Pro-M with the matching injectors.  I’m not looking for maximum power out of the combo.  It’s too easy to get caught up in the race for more power.  The goal all along was to have a 400hp motor on a safe “tune” with the parts. 

We’ll just say… we’re close. 

 

You can hear Beau in the video say “it’s too lean” at the end. That pull was very short.  The very first pull stopped at 2200.  The a/f ratio was 15.5:1.  So it was a good thing I didn’t push things too hard when driving the car up to the PITS (Ponies In The Smokies) show.  

In the end the car put down 314hp and and 367 ft/lb of torque.  At 4000rpm the dyno readout went wonky and the fluctuation of the torque curve was like a mountain range.  According to Beau, when this happens its either spark blowout or the belt slipping. In this case it could be both.  The belt is original to the Vortech kit which was made in 1996. And the spark-plugs are a couple of ranges cooler than stock.

The plan is to get a new belt, a hotter coil, and one range warmer spark plug and go back up again.  The spark plug may not be necessary as we used 104 octane to tune.  With that fuel having a slower burn rate than 93 it may not be necessary to swap plugs because the reality is that I’ll be running 93 octane in it. Either way, there’s a good bit of horsepower left on the table. And that all will be done tuned the old school way with the Pro M Mass air meter with the matched injectors and the proper FMU (Fuel Management Unit) disc.    

Note the yellow chevron is gone.  I had to remove them and get some made because the original ones were bubbling and peeling.  NOS decals just don’t survive the age of time. 

2 Comments

  1. Lee

    NOS decals, while nostalgic, are a waste of money unfortunately. Great update.

    Reply
    • Bob Goodson

      Ain’t that the truth! At least they made it through the World of Wheels and PITS shows!

      Reply

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