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Author Topic: Safe to put 95/97 ron fuel in '99 ron car'?  (Read 1006 times)

Offline Jons1001

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Safe to put 95/97 ron fuel in '99 ron car'?
« on: September 29, 2021, 02:56:48 pm »
Anyone know if this will be ok for a tank or 2? The car is originally from Japan so always been ran on 99 ron fuel (says it on the fuel cap) but has also been mapped and only had Tesco Momentum 99 in it since. Would it do any damage to put a tank of normal unleaded, or 97 ron (Sainsburys, BP) Cheers

Offline garrardrj

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Re: Safe to put 95/97 ron fuel in '99 ron car'?
« Reply #1 on: September 29, 2021, 06:41:47 pm »
Won’t do any harm. It will run poorly until the ecu gets used to the lower octanne.
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Offline GVK

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Re: Safe to put 95/97 ron fuel in '99 ron car'?
« Reply #2 on: September 29, 2021, 09:23:41 pm »
I'd drive it, it wont explose , but wouldnt thrash it.....

Offline pudding

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Re: Safe to put 95/97 ron fuel in '99 ron car'?
« Reply #3 on: October 01, 2021, 11:03:23 am »
If it's been mapped for 99, it will likely run into detonation if you drive it hard.  Just tread carefully with the throttle until you can get 99 in there again.

I don't know why tuners mess with the ignition timing.  They should just leave it as VW set it, which gives you more scope for running lower octane fuels.



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