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Discussion Starter · #1 ·
I'm relatively new to the Evo having only owned one a couple of months now and have read about some people using Octane booster additives on some forums.

As a complete eejit when it comes to things like this I thought I'd ask what everyone thought of them?

So, what EXACTLY do they do?
How does it improve the car (both in performance and maintenance)?
What is the best booster to use?
How is it best applied? Added? Whatever!
Where do you get some?
How much is it typically and how often does it last?

Any help would be appreciated.

Thanks guys

Davy T

Discussion Starter · #2 ·
The engine control unit on the EVO which controls the fueling ,ignition and to some degree the boost, is mapped or programmed for the engine to run on 100 octane fuel which is what is used in Japan. Most super unleaded petrol available in this country is 97 octane, recently Shell have started selling Optimax which is 98 octane, which means the octane rating is 2-3 points lower than the ECU is designed to run. This means the engine is more likely to detonate, (Pre-ignition, knock or pinking) which is an uncontrolled explosion of the fuel/air mixture in the combustion chamber instead of normal combustion at ignition. The worst case senario of this would be a holed piston. The engine has a knock sensor on it and if it detects detonation the ECU will try to stop it by retarding the ignition timing at that time, which will also reduce the power output.

Octane booster additive boosts the octane rating of the fuel when mixed with it. There are many different octane boosters on the market, I will use 'Millers octane plus' as an example. One bottle costs around £3.00 for 250ml, this treats 50 litres of fuel (one tankfull) and boosts the octane rating by approx 2 points, so 98 ron would be boosted to 100 ron.

Some makes of octane booster cannot be used if you have a catalytic convertor fitted because of the chemicals they use would damage the convertor.

Personally I have used octane booster and super unleaded since new. At last weeks Tuning Japanese rolling road some cars which were not using octane booster had detonation detected while running on the dyno. Normally when driving on the road you would not hear it.


Discussion Starter · #3 ·
Clive-What an informed posting,Thanks!
My standard E7 was one of those at the Aldershot R/R day, and I was doing some tests as well with Mark Shead. He could hear my car start to det around 6000 rpm on full load (road-test) when running on Esso SUL, EVEN |PLS| Millers at the rate you have proposed. The standard ECU was quickly retarding the ign timing, so athough onset could be heard thro head-phones, it was not considered to be a major risk, but still highly undesirable!! Next test will be with Optimax |PLS| Millers, now that it is available.... I hope this works, or we have a problem!
I believe that this is more of a problem with Standard E7s than with standard E6/5s because the standard MAX BOOST ON THE SEVEN IS 1.25-3.0bar--do all you new 7 owners know this??? You are getting 300|PLS|bhp and good torque as standard, but the use of octane booster would seem to be obligatory for long engine life!

Discussion Starter · #4 ·
I'd like to start using Octane boosters but I'm worried about the additives that are included and the effect they have on the engine, are they actually safe to use? How often do you use them? Will they damage the engine or is it more likely that not using them will damage the engine?


Discussion Starter · #5 ·

It's worth reading the thread about octane boosters in the Technical Section about two pages back. You will see the response I had from Silkolene about how mush booster to use and some good info from HH6 just to get you thinking!

Discussion Starter · #6 ·
Thanks all, I'll check out the tech forum for some more info.

Especially thanks to CliveW, so much info, cheers, much appreciated.

Davy T

Discussion Starter · #7 ·
I import, sell and use Nitrous Formula - the only EVO owner I know off who has used this is Kevin Atkins - I think he's pleased with the results.

Any Octane Boosters used in the incorrect doseages will leave quite heavy deposits on the plugs - use correct concentrations and it will be a slight brown residue - generally.

On a few test cars and engines on RRs and engine dynos, the results have been very good, partucularly to the engine temperature and removal of det.

Cars which benefit most are those with remappable ECUs - some customers are prepared to have their car specifically mapped for SUL and NF to get the most gains - for example on a Subaru, an extra 4 degrees advance is regulalry achieved with zero det.

I use NF in mine - on road I use the minimum doseage of 1ml per litre and get zero det - on track days I tend to use a whole bottle - expensive for everyday use but a small price to pay for a greater safety margin on track.

This has been tested back to back against Toluene (at 20-30%) and achieved higher increases in RON.

Discussion Starter · #9 ·
Best figures of 3 runs were: 309 bhp (Corrected DIN output at the engine) @ 6670 rpm and amp; 282 lb-ft @ 4570 rpm.
Worst data was 303 bhp and amp; 269 lb-ft.
I think all the 7s on the day gave good outputs over 300 bhp.
Cheers! Austin

Discussion Starter · #10 ·
Hi Guys

I have tried and tested quite a few octane boosters now, the results vary from type to type. IMHO the best so far is the NF Formula that Deadscoob mentioned, after that Wynns 10|PLS|. All tests are carried out with detonation headphones throughout the rev range in each gear. By the way my VI dets on straight 97 super.

Rgds Kevin A
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