Hi all,

i was hoping to find out if the 2.0 Gen 3 coupe had a knock Sensor.

Its my understanding that for optimaz/bt ultimate to take effect properly, the engine must have a knock snesor, so that it can retard the ignition timing, to take advantage of the higher octane fuel. Obviously, if the engine does not have a knock sensor, higher octane fuel will be a waste of money.

Thanks for any info

Higher octane fuel is most definitely not a waste of money for me on my Gen 1 (which obviously doesn't have a knock sensor). I used to be lucky to get 260 miles from a tank, now i can easily get 330+ on Optimax.

Double post, delete please

you can delete yourself Serj. When you have I will.

Well, if it doesnt have a knock sensor, the engine has no way of knowing that it is using higher octane fuel, and can therefore adjust the ignition timing to suit.

The only benift i can see from using Optimax on an engine without a know sensor, is the cleaning propertys, but the effect from this would be minimal.

What im saying, is there is no scientific reason, why fuel economy would be any better. unless your engine was very gunked up, and optimax helped clean it.

THe hyundai coupe hasnt got a knock sensor, so therefore has no way of adjusting to use the higher octane fule. Power output will be exactly the same.

check this out.....

I followed the link..its poor when people post to prove themselves more knowledgable. Its got to benefit everyone if they keep an open mind. If you are more knowledgable, its good to share your knowledge in a way thats helpful. Its harder to accept information thats offered to prove you stupid. Anyoldhow thats a gripe about what was happening on the New Tib site.
Serj says he gets 90 mpg more with Optimax and I dont suppose he's guessed that, so whatever any guide may say, his fuel mileage is improved.

Glynn

According to the HMA site, the coupe is fitted with a Knock Sensor, so who knows?

Does anybody know what ECU coupes use? Is it Bosch Motronic? if it's 5.1 then I dont think it has a knock sensor if its running 5.2 then it should.


As for an improvment of 70 more miles from a tank, just by switching to optimax, I find this hard to believe! Not trying to insult anybody's intelligence here, but how did you conduct this experiment?

Did you drive along exactly the same roads at exactly the same speeds, how did you know the tank was empty? Were you using the gauge as a measure? Or did you fill the tank to the brim, then when it was empty, refill it using the same pump, and note how many litres you had used and how many miles you had done?!?

Thanks

Ben


P.s How the hell do you manage to get 20MPG out of it?!?!? You must driver like an absolute loon!

Forgive my ignorance hear, whats the HMA site?

im genuinely interested about this, i dont mean to put anyone down or rubbish there own ideas..

good points benje,

Ive always started with a full tank, then calculated the mileage from the distance travelled and fuel required to refill at the same pump. The more distance travelled the better. If you used a similar method serje then I'm glad I already use Ultimate(cos the handbook recommends detergent fuel).
I 'm making no fuel or power claims cos I havent done any checks.

Glynn

I use standard unleaded and get a relatively consistent 400+ miles to a full tank (~55l) with a resulting rolling average of 34mpg over 40k+ miles. I've also done some limited (4k miles) testing with Optimax, in the hope that this would improve (hence any bias was likely in its favour) further and repay the additional cost, but concluded it made no difference whatsoever. My figures and testing method can be seen at .

With regards to any potential performance benefits of using Optimax I've never even been near any form of rolling road or similar test apparatus and so am unable to comment.

Mathew

Mathew thats a fantastic chart. So optimax is just a word, you were chased by the police throughout June 03 and its cheaper for you to live in France, or have I interpreted it badly?

Excellent graph.

Glynn

Nice conclusions!!

It's interesting what you say about France - if you look at the graph for Sep/Oct '03 you'll spot another general peak - this too was on holiday in France where travelling North to South on cruise is certainly good for conserving fuel!

My Optimax testing is far from conclusive however from what results I do have it's certainly not looking beneficial. I might give it another go - perhaps 6 months or so - if funds allow!

Mathew

They did a test of different of petrols in Evo mag using a golf gti and BMW, the difference between the worst and the best petrol was about 20bhp for the golf, the top 3 are below, can't remember the rest

1 BP Ultimate Best, top end and midrange
2 Tescos, equal best mid range, lacked a little top end
3 Optimax, just lacked a little every where

What was interesting was the drivers were asked to rank accord to how the car felt and the ranked them in reverse order, those results came from a rolling road test

I forgoet to mention they tested racing fuel, 125 octane in the golf, the jump in power was huge, so bassically the higher octance you can get the better

Nice one gdanski,

Heard of a guy who ran a race team, his drivers kept pleading for more BHP so one day he set up two Escorts, one the same settings as usual one with 55bhp more. After the guys did a couple of laps each in both cars they both chose the same car, the one they had always used (170bhp). The other car ( 225bhp) wasnt as good out of the corners and up the hills of Oulton Park. Both drivers were 2.5 secs faster in the more torquey car. BHP is not the be all and end all.(the highest bhp figure is always up in the screaming region it seems.) Anyway thats all torque....

Glynn

there was big improvement in torque to, the results were still in that order, but i can't remember the figures, if i've still got the mag i'll have a look tonight