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View Full Version : Tune with race gas, then use tune for WI?


bishiboy
16-02-2005, 06:30 AM
What if I tune my Evo VIII with race gas then use this tune for WI?
It would solve the problem of WBO2 readings. Generally the race gas tune would have the same settings, leaner mixtures (12.5:1), increased boost and more timing.
I think if you do a conservative tune on race gas and use it for WI it should be pretty close.
Any input on this?
By the way, I have a UTEC. I already have a good 91 octane tune on map #1. I can set up a race gas/WI map in another slot. If I run out of water, I can switch maps.
By the way...I love this UTEC.

hotrod
17-02-2005, 12:31 AM
Your race gas map would be a useful reference point, but will not be a plug and play replacement for a proper WI tune.

To get best performance out of a WI system you will typically, need to lean out the mixture far beyond what is possible with high octane fuels. You will also probably end up with different ignition timing than the fuel only map.

When running WI you have two opposing effects that tend to change ideal ignition timing. Leaner mixtures ( near peak power) tend to burn faster and need less ignition advance, and water injection tends to slow down the early part of the combustion process due to the cooler cylinder conditions.

I'd still work up the WI tune from the pump fuel map but it would be useful to keep the race fuel map specs handy as a reference so you can refer to it as you make your WI changes.

Larry