For analytical purposes, this would pertain to a bone stock '95 RX7.

Short of blowing the motor, how would an FD respond to bad or contaminated gas? Would it backfire or sputter under load? Would it still drive but feel very sluggish? Would it automatically put the car into limp mode? Is there a difference with the ECU's for each year of the 3rd gen RX7 from '93-'95 to where newer ECU's are programmed to respond a certain way for safety purposes to protect the motor from damage? Is there no way for the ECU to detect the bad fuel and would it just create a poor mixture and knock until it popped the motor? Would there be any specific check engine codes displayed? Etcetera etcetera...?

When giving your response, please state whether it is from experience or in theory.

Thanks

 

I would guess it would be similar to piston engines, the gas would burn extremely quick and lots of liquid (mostly water) out of the tailpipe. Of course you don't want to drive it like this and it could possibly cause something bad to happen. People put water in their engines on purpose to steam clean, if the engine gets up to temp it would just burn the fuel and spit the remaining unburnt solution out of the tailpipe. Where it would get bad is the fuel lines, filter, etc. This is of course theory and it could have worse impact on a rotary than a piston engine.

If you suspect the gas is bad you shouldn't drive it no matter what type of engine so no real need to even discuss it. Also do a tune up afterwards as with any engine.

 

Modded or not a bad gas as in lower octane than intended causes detonation. A modded car is lot less forgiving though. Detonation mainly occurs under load and some peole describe it as marbles colliding with each other, to me it personally sounds like the clicking of a solenoid. With rotaries, without warning you can be fine second WOT and loving life and then *boom* your ballon is popped lol. Just like that blown...

IMO the only thing you can do to save yourself from a bad tank of gas scenario is to add A.I. Detonation occurs when the gas in your motor self ignites due to the high temps in the chamber (compression). That is why higher octane is needed with high compression engines.

 

Old gas (as in 4 months old) caused my car to stall sometimes right after I started it up. The car always restarted.

The problem never occurred with fresh gas, or with similarly aged gas back before the ethanol content. Whether that's due to a difference in my car or the fuel I can't say for sure.

 

i put fuel stabilizer in my tank and then fill up full, drive around for a bit to circulate it through the whole system and then store it for winter (6 months). after taking it out i dont run full boost on the first tank of gas just to be safe, but i havent had any problems yet

 

Ethanol collects water which is why it wasn't a huge deal before they started adding that crap.

 

1 gallon of Toluene added to every tank. It will effectively bump your octane rating to about 100 and help protect you from bad gas. Helps defeat the corrosive properties of the added Ethanol and helps keep those injectors running free.

I buy 5 gallon cans from Sherwin Williams for around $55.

www.kaboodle.com/reviews/octane-booster-test

I will still use this when I turn up the boost with water injection. The stuff works great.

 

For those of you that missed the bit where he said he increased the boost:

Bumping the octane level without having a tune for it will likely make your throttle response kind of laggy.