35 replies to this topic

[Nev]

I went to Halfrauds this morning (*spit* ) and bought myself some octane boost, put the recommended quantity in the tank (mixed with Tesco 99 RON), swirled it around on some round-abouts and went out for a 100 mile blast.

WOW... it really does make a diff. Everything seems faster, turbo pickup, low speed torque improved, more noise (oooh, I love a visceral experience!), sustained high rev turbo boost seems to be 1 PSI higher somehow (though I only briefly got to look at the gauge and I have no idea why). My new exhaust must have been helping a good deal too I think. Managed to find a very clear bit of test track and got up to 165 Leptons before I completely ran out of gears and was too far in the red on the revs. Even so I think the engine was still accelerating. I can't wait till my next 2 mods are completed at Courtenays and I get on the Dyno.

I'd definitely recommend people try this stuff at least once. Looking on eBay the cheapest is £2.99 a bottle (to be mixed with 50 to 60 Litres of fuel), so the cost is fairly minimal really. I have already ordered another sample (diff manufacturer) off eBay and will test it as soon as it arrives. If it works well, I might attempt to negotiate a bulk buy off the eBay vendor at some discount (possible group buy?).

Incidentally, if you want +30 BHP in your car just by changing fuel (assuming its Stage 4 Turbo), read TMS's interesting article

On the assumption that increasing Octane rating from 95 to 99 provides +30 BHP roughly, adding the +2 octane boost would approx increase power by yet another +15 BHP. Although from reading about htis on Google, octane increase is not linear with power increase.

Thus you gain (approx) +45 BHP by using decent fuel and octane boost, and only for approx £5/tank more - that is excelent value for money IMO.

Pip pip VX Chums.

Edited by Nev, 14 March 2009 - 06:19 PM.

[VXJON]

Wow very impressive

[j0n]

Always wondered if its any good, might pick some up and give it a go.

[gazcaddy]

5th gear tested several fuel additives and found they made no difference

[slindborg]

unless you did it on a dyno (a good one) back to back, then its arse imho lol

[j0n]

hmmm, maybe I wont get any after all.

[cheeky_chops]

Incidentally, if you want +30 BHP in your car just by changing fuel (assuming its Stage 4 Turbo), read TMS's interesting article

On the assumption that increasing Octane rating from 95 to 99 provides +30 BHP roughly, adding the +2 octane boost would approx increase power by yet another +15 BHP. Although from reading about htis on Google, octane increase is not linear with power increase.

Thus you gain (approx) +45 BHP by using decent fuel and octane boost, and only for approx £5/tank more - that is excelent value for money IMO.

Perhaps you havent seen the thorney sponsorship list?

Here is a hint:

[Matt]

I tried different fuels and suppliers i.e. shell optimax, tesco 99, etc.... on an old car. I was very scientific about the whole thing using sight, sound and wet finger in the air!!! But using my crappy skills as a scientist i felt that shell optimax gave me a few more miles and a bit better throttle response, tesco 99 a few extra miles and all the other no difference. The temps and conditions were probably different every time but there definitely seemed to be a slight difference. Then again it could have just been my mind playing tricks on me, its the old story of spending hundreds on a mod, then you trick yourself into believing it actually did something.

Edited by Matt, 14 March 2009 - 07:50 PM.

[Yellow_or_black?]

I'm running 230bhp at the moment - so tomorrow I could be on 275 bhp just using the right petrol and buying some octane boost? Cool. No need to bother with a £4k Stage 3 then

[VXJON]

I'm running 230bhp at the moment - so tomorrow I could be on 275 bhp just using the right petrol and buying some octane boost?

Cool. No need to bother with a £4k Stage 3 then

Even better, buy 2 bottles and go for over 300hp at 2.99 a bottle it's got to be worth a go



/worth a try

Btw I've just came in to ownership of the 1st zambiawan repuplican bank and will need some investors. In order to make 4.56742million I need someone in the Uk to open an accout for the transfer to go ahead. Can you help? A fee of £4k would be enough to start proceedings

Yours

Dr vxjon

[Yellow_or_black?]

Dear Dr VXJON, Thank you for your lovely email. I'm unbelievably chuffed you picked me to invest - I feel so special. My Saturday started out so depressingly, but now - I am over the moon to have been hand-selected to contribute to the future of Zambia (I have to admit - I had to look in at Atlas where that was! Ooh, silly me!). I must say, your email couldn't have come at a better time. I was 5p short of the £4000 I would need to get a Stage 3 on my car (a VX220) - this would make it go very fast indeed. But I have now found out that I only need to change my fuel and buy a £2.99 bottle of magic stuff (totalling £5), so I have £3994.95 that I no longer require. Please supply me with details of how I can donate this amount to a worthy cause. Ooh - I feel so wonderful. Thank you for bringing light to my life. Mrs Beryl Blatworthy Kent, UK

[boghouse]

LOL...YOB....Quality

[Nev]

Thankyou Beryl Indeed, I had no scientific proof other than the boost guage being a bit higher than normal. It is tempting to do pre/post additive run on Courtenays dyno next week, but at £95/hour on the dyno its a jolly expensive experiment. Also if I added any additive, it needs to be thoughly mixed, so Id have to come off the dyno ramp, drive round some round abouts and then get back on the ramp BTW, some of you may or may not know that Motronic 5.1.1 advances the ignition in steps until the knock sensor detects pre-ignition of the fuel (and then retards it back a bit). This is why our engines (and many other modern ECUs) desire cold and dense air and higher octanes, as their ability to perform this auto calibration on the fly can take advantage of the dynamics in the environment and fuels. This alone (in theory) advocates the use of higher octanes for more power. But I do admit this is all therotical and does need dyno proof... Oooh, and I am aware the Jon Thorn is an astute business man with fingers and allegiances in other pies...

Edited by Nev, 15 March 2009 - 06:48 AM.

[Cookies220]

We are a sarcastic bunch aren't we.

[Nev]

I am trying to hold back tears at the moment Why do you all hate meeeeeeeeee ????? Argghhhh !!! LOL

[VXJON]

Mrs Beryl Blatworthy

[slindborg]

Motronic 5.1.1 advances the ignition in steps until the knock sensor detects pre-ignition of the fuel (and then retards it back a bit). This is why our engines (and many other modern ECUs) desire cold and dense air and higher octanes, as their ability to perform this auto calibration on the fly can take advantage of the dynamics in the environment and fuels. This alone (in theory) advocates the use of higher octanes for more power.

this does require the ign advance/knock limits to permit you to go a nice way into better power... eg you could have got a fuel that lets you advance say 5degrees more, BUT the sofware limits stop you at 2.5Degrees

We calibrated the ign under normal conditions, and then went for MBT to set that limit, and then the detonation limit table too. so the knock sensor has the ability to dance about round those three tables etc, but never miles more than you desire.

And incidentally, since higher octane ratings mean slower combustion (hence the det resistance), with the SAME ign advance you are burning slower, meaning you are technically running a retarded ign, and "could" (without causing sensationalism) lead to higher EGT's and burnt out exhaust valves/turbines etc..... So mapping to the fuel is paramount.

maybe a wise investment would be a wideband lambda sensor and also an EGT gauge

[Lps]

Nev try sticking some Methanol in your tank at about a 10% ratio to however much gass you fill up with. That'll make it go like billy-o! Agree with slind on the wideband/ egt gauge. At least you'll know 10 seconds before your engine goes Chernobyl!

[Nev]

Stuart, yep, lovely slow burn waves in the chambers promotes torque, which we all love - in fact if I ever rebuilt the engine, it's a consideration to stroke it slightly to make the piston throw further to generate more torque. However I think it would require a specially ground crank - and they are prohibitively expensive and I don't know of anyone who has stroked a Z20LET... I guess having higher EGTs is why stage 5 onwards usually includes a sensible precaution of higher temp running exhaust valves and sleeves, I have it requested as mod for the stage 6 quote I am negotiating with Courtenays ATM in fact. Do EGT sensors simply screw into a threaded boss (like Lamda sensors), and where is it best to place them - just after the turbo presumably? Am off to eBay in 2 mins to look !! Also, when I'm up in Norfolk in a few days, I will ask Courtenays about wide band sensors for their stage 4 map, presumably they'd have to adust the Lambda input calibration curves, but I suspect they may be able to do this easily. They are fitting a 80mm MAF for me anyway (and doing a couple of other minor mechanical mods), so will have to put in the adjusted calibration curve for that as well. I can only presume from looking at Courtenays website, that their stage 4 maps are specifically written for 99 Octane fuel anyway, so increasing this (using octane booster) to say 100 or 101 octane should be within the scope of the dynamics of the volatile memory to adjust and take this into account... hence why subjectively I felt the improvement - but I will ask. Perhaps Stephans could write (or most probably has already has written) a set of base maps for standard running of 100 Octane fuel, as all the German cars he tunes will undoubtably be using the Shell 100 octane fuel (its higher octane in Europe but not the UK ) Also another question about ME 5.1.1, how fast does the volatile memory get refreshed with new data? Is it like 10 miles or 100 or 300 miles of differing/revs/temps???

[Nev]

I'd consider the methanol avenue if I had stronger internals, but I suspect that I may already be running upto 340 ft/lb of torque ATM, so my little engine is not likely to tollerate much more fuel abuse Sadly, this means that I am having to wrestle with the prospect of a full engine rebuild *ugg* if I want more torque. And if I rebuild the engine it would be stupid not to take full advantage and swap turbos/both manifolds/cams/remap etc etc... though this would make road driving (what I mainly do) not much fun unless I was really spinning the engine up all the time, as the torque band would be from 4000 to 7500 revs with Courtenays cams. Jon has already furbished me with the power/torque curves for a GT2871 and GT30 that Stephan used to drive round with in Germany with approx 400 to 450 BHP. I have taken my old map and super imposed it over these and can see the yin/yang reasons to move to a bigger turbo quite clearly with genuine data.... oooh deceission, decissions. And to top it off, I have lost my job, so I have to consider not having much money until I can get another Bummer.

Edited by Nev, 15 March 2009 - 09:53 AM.