About a month ago before I went to the drag races to see what my car would run I changed the oil and transmission lube. I put in Havoline synthetic 10w30 motor oil, I drove 90 miles to a nearby track to race my car. The week prior to the races my car was crapping out at anything above 3000 rpm. At the track the car ran horrible only managing a 17.00 with a 75 shot of nitrous. I've previously run a 15.40 with no nitrous at all amidst gobs of tire spin out of the hole. It has been three weeks since the races and my car still runs like a turd. In the mornings when the car is cold it runs hard like it used to before I had problems, as soon as I get out of school and drive it again or it gets warmed up it doesn't move at all at wide open throttle, I mean it barely breaks the speed limit. Would a putting a code scanner on it find the problem or am I just screwed. If any body Has any suggestions I would greatly appreciate them. Thanks

 

Well as to the oil thing, 10W30 should be used only if the engine is seeing temps under 30F. So if you have been driving at temps above 50 degrees, you were using the wrong weight of oil and that could be causing problems.

And the only two synthetics that have been proven to have a low flash point (point of when the oil burns) are Royal purple and Mobil1. The flash point on both of those is under 550F. Some synthetics have a much higher flash point which would then sludge or leave a high ash content in your motor's combustion chambers and seals. You should check with the oil manufacture before using any synthectic in a rotary motor.

Please note that Mazda does not ever recommend the use of a synthetic in the 13B motor, just because of those sorts of problems.

 

I recommend not using Valvoline Synthetic. From what I gather the reason Mazda originally said to not use synthetic oil is because of the high ash count in older synthetics. Ash count is directly related to carbon build up. A while back my friend had Valvoline send some data sheets for their synthetic and organic oils and had Mobile 1 send the synthetic data sheets. The Valvoline synthetic had much higher ash than even their organic, it was more than double I think. Mobile1 was quite low, possibly as low as 1/10 the Valvoline organic oil. As for why your car runs like a turd I don't know for sure, but I would change the oil.

Oh wait, I just saw that you said Havoline, I don't know what their ash count is but may be worth changing oil.

Do a compression tes and pray you didn't blow an apex seal.