Compare 89 leaded gas to 91 10 percent ethanol

[tjs44]

Taking a 9.5 CR iron headed engine to dyno.They have 89 leaded and I will be running 91 10 percent ethanol in the car.Is it worth me taking 10 gal of my pump gas with me or use the dyno gas.The operator suggest a one step colder plug.Tom

[enigma57]

I would suggest dynoing the engine running whatever fuel you will run it on in your car. And if the dyno room is set up (not all are) so you can run whatever exhaust you will run in your car as well, so much the better.

Good luck with your build,

Harry

[FC-Pilot]

I agree, take what you will end up putting in your tank. There is no point in finding the sweet spot on something that may be very different than what you will end up using. Now if you are just planning on getting an idea of the curves so you can get the right converter built or something like that, and then plan to do carb tuning in the vehicle then ok. But I still would prefer to tune it on the end result fuel.

Paul

[Alaskaracer]

When I had my junk dyno'd my guy wouldn't even supply fuel unless I was running what he had in stock. Told me to bring what I was running in the car....