Silvia Club of NSW

I don't really know a lot about this, but my understanding of this is that pinging and detonation are the same thing. My car has recently started and it sounds really minor but I know it is not good for the engine. I think it was brought on by using crap fuel, because it never did it before. until i used this particular brand, I only put it in twice. I have a JDM S15. How bad is it for the engine and how do I fix it?

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mmmmmmmmmmmmm Silvia

Are you still using the dodgy fuel? Or have you ran the tank near to empty and put in good fuel and the problem is still there?

If it is only when you use the one type of fuel my car experiences the same thing. If I use Optimax it'll ping, I drove the car very lightly and didn't push it until the fuel was used.

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The Gazelle, looks good from afar but far from good.

Pinging and detonation are the same thing and are caused by bad fuel/fuel starvation. It is pretty bad for the engine and AFAIK can damage a whole shitload of internals and the block if it's not corrected immediately.

My suggestions are to sick to 98 (or more) octane fuels - NOT optimax becuase it's crap (and only 96 anyway). And if you can, go to unigroup or somewhere similar and get your car on the dyno to check the a/f ratios.

Just another thought - are you running stock boost?

I am at the end of my current and last tank of crap fuel so it is still doing it.But I will fill the car up with BP or Mobil next and see if it does it then.

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mmmmmmmmmmmmm Silvia

cypher 1024 I have the usual and it is currently running 12 psi. I haven't had the car dynoed yet but I think I will be sooner than later

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mmmmmmmmmmmmm Silvia

If you can hear the pinging, that's very bad. It can be happening even if its not audible.

If you're getting pinging and you don't want to drain the tank and get rid of the shit that's in there, at least wind the boost down.

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Tips for being fooli sik:

Go chrome or go home
Sneezin's Pleasin'
Da flutta is bred and butta
NOS is boss
Try to be different, just like everyone else
No boost? Ya just loost

shouldn't you have a knock sensor that retards the timing when it detects pinging??


also i was led to believe the actual cause was hotspots in the cylinder (which may be caused by shit fuel/lean mix) but the hotspots result in unequal crazy explosions and the piston get's all rattley.


Cars will ping more as they get older, til they finally just die


But I'm no expert.

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"If you can stand to look at that car all the time and not throw up then maybe you should buy it"

-- DumHed

i thought the 'pingometer' worked under 4k, then there is too much engine noise for the ecu to tell what is ping and whats not

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M35 Stagea.info @ http://www.m35stagea.info/

who knows!

depends what rpm he's getting pinging at?

if it's low maybe his 'pingometer' doesn't work.

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"If you can stand to look at that car all the time and not throw up then maybe you should buy it"

-- DumHed

whats wrong with optimax ? its what i use all the time, and as far as i know its 98ron

my car doesnt ping... if you have a jdm s15 then i believe the tuning is different to the ones here as there tuned for a higher octane fuel hence the problem of pinging if you have crappy fuel

edit: what fuel are you using by the way ?

turn the boost down till you get rid of the fuel.
or at least try some octane booster..

As far as i know the knock sensor is of very limited value anyways. The quality of fuel will matter but on a nearly stock car, even a JDM model even 95 octane is probably good enough. Normal japanese cooking grade fuel is 95 octane and all the stock standard cars in japan are probably designed to run on it (sounds logical to me anyways), probably some of the reason all jap turbo cars run uber rich. My S13 SR20DET powered gazelle is quite happy with 15psi and a moderate sized front mount cooler on optimax and stock ecu. My mates stock 1992 180SX with 98 octane fuel pings it's head off after a few good blats up a hill. As soon as there is some heat in the cooler it really falls over. I reckon your cooling makes a heaps bigger differance than the grade of your fuel on a near stock car. He's running 12psi not 15 as well.

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1996 180sx
1990 Silvia

My car started pinging after i put on exhaust/front pipe. a/f ratio was rich enough, temperature was cold enough. The reason of the pining was because of the ignition timing being too advanced in the mid range - i dunno why - I had to either get my ecu remapped or retard the whole ignition timing a bit. For now, I am driving with the timing retarted a little bit by adjusting the initial timing.

My car doesn't ping but I do get much better economy on Optimax. A few months ago I found out the local BP station in Canberra was selling BP Ultimate 98 so I decided to give it a try and see what happens. For two years I have run exclusively on Optimax and got between 450 to 490 from a tank and when filling it up used between 45 to 49 litres and it was virtually always about 10L/100km. After using two full tanks of BP Ultimate I had got only 390km from each tank. The petrol consumption for the first was 11.58L/100km and the second 11.86L/100km. I am not that happy as I was hoping for better economy from the BP Ulitmate as it is a denser fuel but I am using about 17% more fuel and considering coles has a 4c voucher for Optimax it means my fuel bill is up by 20%. I phoned up BP technical help to ask why my consumption is worse than optimax and hoped to get a good answer.

According to BP it is the car has a build up of toluene within the fuel system. Dimetri from BP said they buy fuel from all other suppliers for testing as part of their own research. He said what happens is when a car runs on Optimax for a long time it builds up a level of toluene within the fuel system. Once this has built after a few months it is continually being mixed and replaced with the petrol. If Optimax is being used then the level of build up stays the same but if you swap to another petrol like BP Ultimate or Mobil Synergy 8000 then the toluene deposits slowly disappear. While that is happening the toluene mixed with the BP Ultimate makes a mixture that is about 10% less powerfull than BP Ultimate without the toluene mixed in.

If you keep running a car on Optimax once the toluene has built up to a maximum level the deposits keep mixing with the petrol and the car will generate about 3% more power on optimax than is it was running on optimax without the build up. Therefore if you want to use Optimax it is better to keep using it. He said many people do that and he believes apart from more damage to the environment the car will be fine and will run better than swapping from one to another.

If you don't want to use Optimax all the time then you are better running anywhere from 3 to 7 tanks of BP Ultimate or Mobil Synergy 8000 to clean out the build up of toluene. He then said you can use any of the fuels including Optimax but be careful to not use more than two tanks of Optimax in a row or the toluene will start to build up again. He suggested I give Bp Ultimate a few more tanks to remove the toluene buildup before deciding what to use.

Other interesting things he said.
1. BP Ultimate and Mobil Synergy 8000 are both very similar in make up of additives etc and are virtually identical as far as you car is concerned.

2. BP Ultimate and Mobil Synergy 8000 are both refined only in Queensland and WA and have been available in those states for much longer than anywhere else. I think from his other comment that BP is refined in WA and Mobil in Queensland and they sell to each other so in NSW/Canberra maybe we are buying Mobil Synergy 8000 from the BP Ultimate pump.

3. Shell Optimax has a higher level of Toluene than what is allowed in two Australian states so has been taken off the market in those states (didn't tell me which states). Toluene causes more UV from the sunlight to penetrate which is the main reason it is banned in those states. Shell are currently researching how to update their refineries to change the formula for Optimax and he expects in two years for it to be very similar to BP Ultimate.

4. Caltex Vortex Gold is only 95 (which I already knew) but was developed for racing use where the cars are not using special fuels. Dimetri said he believes it is the best 95 fuel around and if your car is designed to run on 95 then it is what he would use.

I found his comments very interesting, especially the Caltex Vortex comment as he works for BP. My plan is to keep using BP Ultimate for another few tanks and see if my milage can get back to what I had with Optimax. Once it has then I assume all the toluene build up has dissappeared and I can start experimenting again. I might then give Vortex a go and see what economy I get to see if it is a cheaper option.

I tried four tanks of Ultimate and the consumption has been about 11.5L/100km overall. I got about 11.2 for one tank that was from Phillip and about 11.5 to 11.8 for the other fills from Chilsholm. I am not convinced that Phillip has better Ultimate but more likely that I filled it up a bit better there so it gave a bit more but also explains the 11.86 I had from the tank before Phillip.

Based on an average of 11.5 for Ultimate and 10.0 for Optimax and no real difference in the feel of the car Optimax is working out a fair bit cheaper but rather than just switch straight back to Optimax while I was experimenting I decided to try Woolies Premium.

I know you are all amazed I would consider trying it but I heard something very interesting about woolies petrol. The standard 91 is imported petrol from Italy, quite a good petrol but due to the extra transit much more chance of being contaminated with water etc which is why it is probably best to avoid it. The premium is supplied by Caltex to woollies. This news was quite interesting firstly considering that the BP technical help guy said that Caltex Vortex is the best 95 in his opinion, secondly I doubt Caltex would make a special petrol just for Woolies, and thirdly the Silvia is supposed to run on 95 or above it should be ok to give it a go.

The car still felt quite responsive to drive. The consumption was also 390km for a tank which waqs the same as BP Ultimate. I have switched back to Optimax and so far 400km and still 1/8 of a tank left and the car is running great so I am expecting 450 top 490 like before the experiment.

So from my test that took three months I am now going to use Optimax based on price and performance. If anything the car runs a bit better on Optimax and is certainly cheaper. I normally do 10,000km a year and based on 450km from a tank of optimax and 390km for BP Ultmate or Woolies premium, prices of $1.10 for BP Ultimate, $1.06 for Optimax after a voucher and $1.00 for Woolies after the voucher my petrol bill for the year will be $1060.00 for Optimax, $1150 for Woolies Premium and $1265 for BP Ultimate. At least now I know my car will run ok on all three without pinging and which one gives much better economy and probably the most responsive acceleration.

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Convertibles Rule

The fuel that I am refering to is Caltex. I have only put it into my car twice and at the begining of the second tank it started to ping so never again. I do have advanced timing but the car was fine and did not ping until the fuel change, so as a result I believe this to be the cause but we will see. I am running 12 psi with exhaust and huge front mount.

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mmmmmmmmmmmmm Silvia