95 only ,MAD7BOY said:I think running on 95 is a false economy. You'll get less power, hence you'll have wasted good money on a performance car that you won't get good performance out of. And there is a good chance that the engine will be damaged (as others have said) due to detonation, again costing you cash.
I think 97ron is the minimum that they are designed to run on, just pay the extra 2p!!! (Evo's arn't supposed to be cheap!) [NB: I've not been to Dublin, but I assume that 97 is availible over there.]
As far as I was aware, that is how standard ECUs work. After a reset, I've occasionally see some knock at high load / revs while the ECU backs off the timing to adjust to Optimax.burgers22 said:Hi
I think you might have misunderstod that thread, it often take me quite a time to understand what johnbanks posts, him being a clever bugger and all.
Yes Evos have two sets of maps, low and high octain for fuel and ignition, but the low maps are used only after the ECU detects knock ( detonation), this will lower a peramiter called octain number which will eventualy lead to the values for fuel and ignition being read from the low maps.
This is not ideal as your engine has already suffered knock. It would be much better to get the car mapped for the fuel. Usualy the timing is retarded as a starting point, the JDM maps tend to be quite agressive in the ignition maps.
surely the lambda sensor would tell the ecu when it was running lean and adjust accordingly?johnbanks said:The biggest problem is with continuous knock, and the stock ECU (at least on my IX) seems superb at supppressing knock even when you suddenly restrict the exhaust and reduce the octane. I think the danger points would come with running lean because the ECU has no sensor to tell it that the mixture is lean on full throttle. The ECUs are good and save a lot of engines, but I still think it is wise to measure what is going on if the conditions are likely to encourage det (eg airflow restrictions, tuned engine, low octane fuel). Widebands are now about $200, and datalogging cables are under $100, of course you have import duties, shipping etc, but compared with the cost of an engine they are very cheap indeed.