Track day with EFI

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mooreken
Posts: 612
Joined: Sat May 09, 2015 12:25 pm

Track day with EFI

Post by mooreken »

The Daytona TE day was my first event with the new Sniper efi. I have taken it to a tuner and he did a partial tune.
My fuel system would not handle WOT after around 5200 rpm so he didn’t do any full pull runs. I spent the week before Daytona getting and installing an in tank fuel module. I reset the rpm limiter to 6100 (the tuner had set it to 5200 to be safe) with the Holley software and up loaded it to the ECM. So cool.
With my 750 street hp carb I always had fuel distribution issues. When I would check the plugs the front two cylinders on both sides would show as nearly black rich and the one next to it be near normal
Nothing I did seemed to make any difference. I changed carbs and manifolds to no avail.
When I checked a couple of them at the track both look great.
The Sniper sprays fuel in all four barrels all the time and I think this has really helped with the distribution.
I am also thinking (after watching “Engine Masters” on motortrend TV) that the carbs were pulling extra fuel from the accelerator pump nozzles. And as I had increased the size of them that even made it worse.

I’m going to change the plugs and make another trip to the dyno to finish up the tune so I will be able to look at all of the plugs.
Here’s hoping for big Dyno numbers. :dance:
mooreken
Posts: 612
Joined: Sat May 09, 2015 12:25 pm

Re: Track day with EFI

Post by mooreken »

I have taken the Cobra to the tuner after Daytona and the fuel pump upgrade. He has dialed it in with the new pump. As this tuner has a different brand of Dyno the numbers from my first Dyno run really don't transpose to his. He had told me that his system reports about 15% less than the others.
With that being said as per his experience my corrected number is around 475 at the wheels with the sniper. (It was 465 with the carb on the first dyno)
When I built my first engine the tuner with on the engine dyno told me that the manual fuel pump would eat up 10hp. I didn't think it could use that much but when we ran the motor with my manual pump it showed almost exactly 10hp loss with the manual pump. That is about what the latest dyno shows with the corrected numbers as I have removed the manual pump and added the electric.
I don't think that I will spend the $100 to go back to the first Dyno just to see what it is doing now. I'm just happy that I didn't lose HP by going to the EFI. And it seems that I have not.

Now I need to run the Cobra a bit and recheck the fuel milage. It had dropped from 17 to 10. I'll post what the results are later.
I did a plug change between the Daytona track day and the trip to the tuner and the plugs are looking much better. Still a little distribution difference but much better than with the carb.
And now I can just get in and start it up and drive off. With the Carb and no choke, the foot dance to keep it running when cold has gone away.
I was using a small size Alternator (drag race style) as I have an electric water pump. It was a 100amp unit. After adding the in tank fuel pump with the water pump plus the fans, spark box, and now the fuel pump, the sniper display was showing that I was only getting about 12.5 or so volts while running.
The sniper really want 12+ volts so I upgraded to a 140-amp alternator. And of course, the increased size of the alternator and a slight difference in mounting I spent 2 days modifying the thing to fit into the space I had to place it. (As per Tom's experience that everything resists getting changed).
But as Chief Dan George said in the movie "The outlaw Josey Wales"" I endeavored to persevere" and all has worked out as expected.
So, I can say that so far, I am happy with the EFI upgrade. I like the ability to tune with the laptop and the cold start and run drivability.
Though I have to admit that with the Voltage and fuel upgrades it has been a little pricey.
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