Poor running on Optimax
Poor running on Optimax
Author
Discussion

tvr5000

Original Poster:

391 posts

254 months

Monday 10th April 2006
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Anybody experienced poor performance using Optimax. Just got the motor back after 12k service and ran like a dream, having a mixture of BP super and standard unleaded. Stopped on the way back to the North and filled up with Optimax. Straight away it stuttered when hard pressed around 4500 upwards. Thinking back, It has run really well some days and not so others, and this seems to tie in with what I put in her. Going to keep experimenting with the fuel types but this seems to be a suprise as it is always promoted as the fuel for TVR's.

vixpy1

42,697 posts

288 months

Monday 10th April 2006
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Probably a bad batch, there seems to be alot of them!

Tesco 99 is much better

lew_boi

85 posts

244 months

Tuesday 11th April 2006
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Ive had the same problem over the past couple of days.
Was running fine on normal unleaded, tried optimax for the first time, it brought on the 'efi fault' warning on the display plus a slight missfire when being pushed hard. Spoke to a TVR independent and was told this should make no difference ! and that i should have the injectors cleaned. Have since gone back to normal unleaded and its fine again !

whitey

2,508 posts

308 months

Tuesday 11th April 2006
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could have been a bad batch, or stale fuel from a small station that no-one ever buys optimax from! Or you filled your tank to the brim and it did not allow the fuel tank to vent properly through the carbon canistor which can lead to stuttering for a short period.

tvr5000

Original Poster:

391 posts

254 months

Tuesday 11th April 2006
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I've bought the optimax from numerous locations and still the same result. Did'nt know about the overfilling theory. Still doing it now though after a 100 miles.

mr9lt

50 posts

247 months

Tuesday 11th April 2006
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I thought Optimax grade fuels were recommended for track days only according to a Y2K manual, the dealer also recommended not using it!

whitey

2,508 posts

308 months

Tuesday 11th April 2006
quotequote all
tvr5000 said:
I've bought the optimax from numerous locations and still the same result. Did'nt know about the overfilling theory. Still doing it now though after a 100 miles.


If thats the case it will not be a fuel problem. I would suggest getting the engine looked at, especially if it's just had a service. It should run fine on 95 or 97/98/99. The benefit of the higher octance fuel is only the additives added to help the engine run cleaner. The engine is mapped to run on 95 and a higher octane would only very possibly be beneficial in hardcore track driving but unlikely.

Can you describe the fault in more detail?

cheers
Whitey

>> Edited by whitey on Tuesday 11th April 13:06

>> Edited by whitey on Tuesday 11th April 13:08

andyvdg

1,537 posts

307 months

Tuesday 11th April 2006
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I get slightly different running depending on the fuel. Basically the best is with the same type of fuel that was in the tank when it was last serviced e.g. Optimax. Never made a very big difference though.

Cheers,

Andy.

Tuscan Six

40 posts

246 months

Tuesday 11th April 2006
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I have also had poor running on optimax and my engine is fine. I stick to BP 95 unleaded and it feels plenty fast enough!

G9eg

177 posts

251 months

Tuesday 11th April 2006
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Can anyone tell me what ron the BP ultimate is ,after racing at Santa Pod on Saturday with Optimax(done very well)coming home put in BP's finest and heard alot more popping and banging on overun.
Was it me or the fuel.

s6boy

1,789 posts

249 months

Wednesday 12th April 2006
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I was recently told that the speed six was originaly set up using Shell Optimax (not sure how long it has been around so can't claim this to be gospel) and advised that using a higher octane rating wouldn't necessarily improve performance. I'd agree you probably got a bad lot, but at the same time I've noticed a slight hesitation when running two different fuels ie BP Ultimate/ Optimax. When a full tank of Optimax has run through it clears. Don't think it's my imagination!?

CatherineJ

9,586 posts

267 months

Wednesday 12th April 2006
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When we had the Tamora the label above the fuel filler said 95 Ron only. That was a 2005 model car.

yzf1070

814 posts

255 months

Thursday 13th April 2006
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G9eg said:
Can anyone tell me what ron the BP ultimate is ,after racing at Santa Pod on Saturday with Optimax(done very well)coming home put in BP's finest and heard alot more popping and banging on overun.
Was it me or the fuel.


Most manufacturers standard unleaded = 95Ron
BP Ultimate = 97 Ron
Optimax = 98 Ron
Tesco Bio fuel (ethanol content) = 99 Ron

I recently read a test where a Scooby was tested on the rollers and the road. BP Ultimate indicated highest consistant BHP and torgue aross the curve, whilst all drivers thought the Optimax felt best when driving despite being overall behind the BP Ultimate. Tho it did hold on to the curve longer than BP Ultimate at max rpm. Tesco fuel was surprisingly behind those 2. But there was next to nothing in it. The 95 Ron fuels did adequately well. But the MPG was down in comparison to the higher octane fuels. The conclusion was that if your car has ECU management that can auto select the correct igniton map for the variances in fuel octane then it is worth using the highest octane fuel long term....


>> Edited by yzf1070 on Thursday 13th April 11:37

G9eg

177 posts

251 months

Thursday 13th April 2006
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Cheers Graham