98 Ron Can Cost You Power

[luckydip]

The car:

Stock healthy RB20Det.

Only mods were:

2.5" CAT back

AVO muffler and catless (no dump)

Good air filter element (no pod)

Iridium plugs

Simple solenoid boost control

+ 3 deg timing.

Stock BOV, Fuel pressure, injectors, intercooler, coils and ECU

The car was set up for Targa 04 category 7 (1982-90) L2 (Lightly modefied). It produced 139.5 rwKw at stock boost (10 psi). At + 3 advanced 145.5 at stock boost. At 12.5 psi and the timing it was 150.0rwKW on the dot. All done on a DYNO DYNAMICS DYNAMOMETER by Bradd Sherrif in Launceston on a mild April evening.

One year later - after a whole season on the circuit and a Targa Tasmania - the plan was to get 170rwKW. So 13.5 psi and 98 RON plus a little bit more timing was the go.

After run 1 in old set up all got was 141kw. Put down to weather conditions, old plugs and engine a bit worn? Put boost up to 13.5 psi - got 145.6kw.

Emptied out PULP fuel and put in 98 - and lowered boost to 10psi just in case. 128kw was result. SHOCKED. Put boost up tp 13.5, resulted in 137.5kw - even more SHOCKED. Bradd was in disbelief. Did 2 more pulls, same result.

Conclusion: The standard RB20DET likes PULP and the ECU is obviously set up for it.

Further info: It has since been mentioned that the ECU works on FUZZY LODIC and is in constant re-tuning mode which takes time and probably would have produced better results if run on 98 fro a while. Also if we had disconnected the battery for a while it may have done the same thing.

While I'm no expert on this - facts are facts. But - with a programmable ECU (the HALTEC here now) and the same set-up with 98 I would expect my 170rwKW.

Kerry

[eMsta]

so does this mean we are better of going 95 ron?

[ferni]

I'll be suprised if your make less power on 98, but to take advantage of 98 you're car has to be tuned for it. That may mean getting your ECU to relearn what it knows if its stock...? Fact is higher RON rating means it can take more heat and you can wind more boost/timing into it before it starts pinging....

[t01-100]

Kerry is not the only person that is experiencing this. I have contacted BP, but not responce yet.

[stricko]

I reckon if ya reset the ECU and go through a couple of tanks of 98 then get it back on the dyno it should make more power.

[grandmasterb]

Kerry is not the only person that is experiencing this. I have contacted BP, but not responce yet.

After speaking with a few people over the last few weeks since its introduction there have been mixed results with 98RON and re-tuning.

One thing i have noticed with most people's varied results was that they all still retained the stock ECU and was just running a SAFC/AVCR or manual boost control.

I will retune my car to 98RON with the new motor (being done in Melbourne by Dr Drift) and hopefully i will see better results (more torque ) so its even better to slide!!!

[TasR32]

my SR 180 lacks power on 98.

ive gone back to 95.

[sav man]

didn't xrated say he had to pull some timing out of his tune on 98? Did we get a bad batch?

[t01-100]

I ran Sunaco GT Plus (102) at the hillclimb on the weekend instead of chancing it with Ulitmate.

[al_r33]

Thanks for the info mate.

so in my case it looks like a combination of the 98ron & the Turbo giving me a shitty 138rwkw but thats with a PFC thow.

Edited August 22, 2006 by al_r33

[Bov]

ferni is right.

98 RON has a higher knock rating hence you can run higher cylinder pressures and resultant heat before you get knock. Mixture is a very important component and maybe the standard ECU's just dont provide enough movement in the tune specs.

After market ECU and try again.

If you still dont make more power which logically you should then maybe the 98 RON aint quite the 98 RON we expect??? Big question to BP then eh?

My two bobs worth.

Cheers

Greg

Stu, who supplies Sunaco GT Plus (102). Might be good in a boosted 4age eh?

[frigjam]

Japan's regular unleaded is 98RON and most of my imports i've owned (or still own) have 98RON fuel stickers on the fuel flap, so I'd say there is more to it. As mentioned above, the ECU may need a reset as it does "learn" to a certain degree, although shouldnt have a huge impact. Also, is the fuel from the bowser really 98RON???

[DJRIFT]

i think it logicly has to be the ECU needing to re-learn. which isnt a big deal, ither run a few tanks of 98 or disconect the battery and try again wich sucks.

but this raises another question, is the 98 realy 98, how would the average person know as they pumped it in, its all in the mind that your car is going better and as proven by kerry its not, at least not on the first tank.

as for me im still running PULP and i cant realy see the point in paying more for the product yet as it only drives from a to b and hardly hits boost.

another experiance i had a few weeks ago was i accedentaly put normal unleaded fuel in (it had been a long day) and i didnt notice one bit of difference. not saying this is a good idea just i cant tell what fuel im running.

[frigjam]

another experiance i had a few weeks ago was i accedentaly put normal unleaded fuel in (it had been a long day) and i didnt notice one bit of difference. not saying this is a good idea just i cant tell what fuel im running.

agreed with there, i have used normal unleaded at times and not noticed a fricken difference. but the car would have been fairly stockish and far from its limits. having said that, the engine can be pinging without you knowing it, obviously when you ARE aware its pinging then its pretty serious at that point.

[luckydip]

Thanks for input guys.

From what I've read and heard.............

Octane rating, RON (Research Octane Number)

The most important characteristic of gasoline is its octane rating, which is a measure of how resistant gasoline is to premature detonation which causes knocking. It is measured relative to a mixture of 2,2,4-trimethylpentane (an isomer of octane) and n-heptane. There are a number of different conventions for expressing the octane rating therefore the same fuel may be labeled with a different number depending upon the system used.

Energy content

Gasoline contains about 32 megajoules per litre (MJ/l) or 131MJ/US gallon.

Volumetric energy density of some fuels compared to gasoline:

From this, an amount of petrol regardless of RON has the same amount of energy or BANG as any other RON petrol. From other info - I think the higher the RON, the slower it burns. A higher RON won't give you more power - but the ability to tune a motor to give more power. I suppose somewhere there is info on ratios of flame speed/burn, compression, piston speed etc. From here in it's getting into a black art.......that I leave to the engine tuner.

Any info on after market Jungle Juice appreciated:

1. Name, info on it

2. Distributor + ph no.

3. Price.

4. 1st hand experience with it.

Kerry

[t01-100]

Greg & Kerry I'll email you details re Sunoco.

[ferni]

If i didn't run 98 i think my engine would ping way too much... never done it so will never know

[Young GT-R]

anyone tried it with an aftermarket ecu?

[Jays_5000]

My experience is the same as Tasr32's. Chewed the shit aswell, barely even got 300kms to a tank on a relatively stock RB20DET. I can get about 400 on Shell PULP and it runs really well also.

[grandmasterb]

My experience is the same as Tasr32's. Chewed the shit aswell, barely even got 300kms to a tank on a relatively stock RB20DET. I can get about 400 on Shell PULP and it runs really well also.

Its funny how people have an opinion that 98RON is worst than the 95RON PULP that they use at the moment on there stock car!!!!

REMEMBER that your car hasn't been tuned to 98RON and there are a number of factors that can influence performance gains with tuning.

Just filling the tank up with 98RON instead of 95 isn't going to give you magical perfromance gains.

It does seem that the first impressions of some people that have had there cars tuned to 98 is a little disappointing considering the rest of Australia dont seem to have these problems that we are experiencing here in Tassie at the moment.

Having said that i run the 4X4 on PULP (was running a worked 202 now has a 454) and i found that once we got the 2nd float running right in the carbs and replaced the pick up that the truck ran better on the 98 than the 95 and its not reving as hard as it was original when we had a load on.

Now this is a little different given its not forced induction, its not EI and we run a set of 34's with cruiser diffs and now a different box, so the ratio's are different and i know that contributes to the rev factor, but while towing a load it does seem to run better on the 98.