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Dynamometer session coming up

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plotkinc Catherine Plotkin
Edmond, Oklahoma, USA   USA
A the SCCA holiday party I won a session on a dynamometer. Any ideas on what to expect for a Convertible GT6 (Spit6) on one?

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Spitfirejoe Joe Guinan
Fremont, Nebraska, USA   USA
1980 Triumph Spitfire 1500 "The Phoenix"
No idea - depends a lot on what you've done to the engine. Cam? Carbs? Header? LOTS of variables... I think the GT6 was around 100 hp in stock form.

I'd love to work on some carburetion issues with a "Rolling Road" - trying different jetting, etc.



Joe Guinan
Fremont, Nebraska

plotkinc Catherine Plotkin
Edmond, Oklahoma, USA   USA
The session went well. She had a very flat torque curve (2000rpm to 3700rpm) at about 91.31ft-lb and peak hp at 66.37 to the back wheels.

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clshore Carter Shore
Beverly Hills, Florida, USA   USA
Did you get a graph from the session?
Assuming drivetrain loss of 10-15%, that's around 73-76 HP, 100-104 ft-lb at flywheel.

BTW, torque is measured, HP must be calculated from Torque x RPM.
An interesting byproduct of the units of measurement used is that the Torque and HP numbers will be equal at 5250 RPM.
So on graphs with an equal scale for Torque and HP, the curves will cross over at 5250 RPM.

Spec says 104 hp @ 5300 rpm, 117 ft.lb @ 3000 rpm

Sounds like your motor was running out of steam in mid and upper RPM range.
Did you fit new air filters before the Dyno session?

During an extended dyno session, you can optimize the ignition advance settings, and carb mixture settings for best power.

But if you have a iphone or Android, you can download a Dyno app that will calculate HP and Torque using the phone built in timer
and accelerometer, and then display figures and graphs.

Not great absolute accuracy, but useful for back-back testing of changes, like air filters, ignition timing, carb mixture, etc.

plotkinc Catherine Plotkin
Edmond, Oklahoma, USA   USA
Yes I got a graph.

I did not do any pre-tuning, I was just using it to see where I was with the car. Thank you for the input on the air filters. I have been busy getting the brakes and suspension where I want since they were the limiting factors last year.

Thank you for your feedback.


Attachments:
dyno.pdf    376.3 KB

clshore Carter Shore
Beverly Hills, Florida, USA   USA
Catherine,
Thanks for sharing the graph.

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