My ST170 is mapped for 97Ron fuel, 99% of the time i run 95, is this going to cause damage? it is losing me power, is it worth remapping to 95ron or does it not matter that much?
The car is returning 21mpg on the motorway at the moment, around town it is as bad as 18mpg will a switch to a 95ron map help things

 

Normally I would say when the car's is mapped for XXX Ron, you MUST use that and nothing else, at least nothing lower. It could damage the engine severely when it's starts knocking at wot.
The only exception is when the car has a very good knock detection system, which would allow the use of fuels with different Ron. But if it hasn't got that standard, then it doesn't have it when remapped.

Otherwise, either use 97 Ron or better or get it remapped for Ron 95.

 

Why AREN'T you bothering to put 97 in??? SIMPLES......

 

Cost at the moment better fill up with 97 before something goes bad

 

id get it remapped for 95 if your running it on that

 

run i on what its mapped for otherwise dead engine.

also wat speeds are you doing on the motorway to get that?? in fact even the town millage is crap so i'd say you have something wrong with the car, may be something as simple as using the wrong fuel but could be shite map or something else has gone wrong...thats assuming your not booting it everywhere.

 

Your car should be MUCH better than that, unless a total lead foot, the vct works fantastic on these, even better on other mapped ecu's as well.
If it is mapped for 97 so long as you don't thrash it constantly it will be ok, it's mostly under severe load you will have problems, so just take easy, who mapped it ?
tabetha

 

21mpg?

if thats in normal driving, I would see that either the remap went wrong or you have a severe mechanical fault!

 

No word of a Lie, 21mpg motorway miles, i got 80miles for £20 of fuel the other day, filled up when light came on, 80miles later light was one again. I worked that out as 21mpg with a fuel price of 1.159!! i suspect it might be bank one lambda sensor getting a little lazy ? It was mapped using dreamscience.

 

Sounds terrible to me, get it onto a set of rollers and see what AFR it is running etc.

There MUST be something up with it to be that shit!

 

It is worse than terrible, i only drive the car once a week as it canes the fuel. Maybe i have a leak
Car goes like absolute stink though

Been considering trading it in for a RX7 as its almost as bad on fuel as one of them