I agree with Mustang. You need a tuner with 02 sensor to map for fuel adjustment, timing, temperature, and altitude. On both my RZR800LE and 570 Ace I use a CommanderV with the Auto Tune. With this set-up you don't have to guess or struggle with re-mapping. The auto tune continuously adjust to ambient conditions. I have been very pleased with the improvement in power, throttle response and overall improvement. I use only alcohol free 90 octane fuel. I have a cold air intake system on the RZR but think the Ace has an adequate air intake for the 570 engine. I use the stock spark plugs which appear to do the job well. I believe you will pick up 3-4 hp and 2 or 3 ft pounds of torque which is a lot considering the engine size. Overall it makes your machine more fun!
Just my opinion.
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