323 BA ECU/PCM

**Posted:** Fri Dec 10, 2004 3:09 pm

Dont think you should be using LRP fuel - should be unleaded 95+ RoN - most garages have a premium unleaded of 97 or 98 RON - Shell, BP, Sainsburys etc....

**Posted:** Fri Dec 10, 2004 5:50 pm

Yeah, Dan's right - I think you'd you'd need to adjust your timing for LRP.

There's a at least one BP selling 'Ultimate' (97RON) in Yeovil. About 93p/L though!!! :shock:

Mark

**Posted:** Fri Dec 10, 2004 6:12 pm

There's always a trade-off

**Posted:** Mon Dec 13, 2004 10:57 am

Did anyone see topgear sunday? They had the EVO8, and it requires 97RON to run properly! lol

**Posted:** Mon Dec 13, 2004 12:01 pm

No, Tom - he said runs only on Optimax - 98RON!!

Smart ass Mark.T

**Posted:** Mon Dec 13, 2004 12:22 pm

ooo

I do apologise. 98 RON.

I stand corrected!

**Posted:** Wed Dec 15, 2004 10:26 pm

So how does the 1.5 '98 engine control knock, and it sounds like i'm just wasting money with the optimax then, unless there are other more long term benefits that i've not seen yet.
If the ECU doesn't control knock, then how can i adjust it when i use the lower octane petrol?

Nick

**Posted:** Wed Dec 15, 2004 11:36 pm

I'm 99% sure that the 1.5 doesn't have a knock sensor, so knock is not monitored/controlled. If the engine is in a sound state of repair, not heavely (ooer spelling) modified and a good quality fuel is used knock should not occur anyway

**Posted:** Thu Dec 16, 2004 1:26 am

I think that the RON rating is probably the best indication of the QUALITY of fuel and that it doesn't do any harm to use the best your wallet will allow.

I ran my 1.5 on Optimax and it was a happier car for it. The diference in cost wasn't that much in the end: it came to £2 more per tank; I could easily spend that on a chocolate bar, packet of crisps and a drink at the station shop!

....I just remember how awfully it ran in comparison when I stuffed supermarket petrol in it once.... (The ZXi I have now complains bitterly if I stick 95- RON supermarket car-juice in it!) :roll:

**Posted:** Thu Dec 16, 2004 9:43 am

think you could be right there Wai - but I use BP Super or whatever its called and its 93p per litre - Tesco normal fuel is about 10p cheaper I think so you are more looking more at £4 per tank full or there abouts. Anyway I am still using BP

**Posted:** Thu Dec 16, 2004 11:57 am

[quote="Roadster Robbie"]I'm 99% sure that the 1.5 doesn't have a knock sensor, so knock is not monitored/controlled. If the engine is in a sound state of repair, not heavely (ooer spelling) modified and a good quality fuel is used knock should not occur anyway

[/quote]

Thanks for that, although my 1.5 is not modified (apart from leads and K&N) it still develops a knock at about 4000rpm if i'm putting my foot down, and i'm using the highest octane petrol i can find.

Nick

**Posted:** Thu Dec 16, 2004 12:01 pm

excuse me if im being thick... but what do you guys mean by knock?

**Posted:** Thu Dec 16, 2004 5:54 pm

..knock;

Who's there!!! :lol:

:P

**Posted:** Thu Dec 16, 2004 9:33 pm

Dunop

**Posted:** Thu Dec 16, 2004 10:22 pm

"Knock" or "Detonation" is when the air/fuel mixture burns to quickly (for whatever reason) and maximum combustion pressure occurs before the piston has past TDC. This has the effect of trying to force the piston back down the cylinder as it is trying to rise up. This causes a "Pinking" sound and is extremly damaging to your engine

**Posted:** Fri Dec 17, 2004 2:23 pm

Dunop Who?

...Hmmm.. something doesn't smell right here.... :roll:

**Posted:** Fri Dec 17, 2004 2:58 pm

Oh Wai, you haven't have you!!!

Mark

323 BA ECU/PCM

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