911

Engine spec soon:
Sti v3
Apexi FC + 3 port boost controller
Gruppe S headers
3'' decat
550cc + Walbro
Sti 8 TMIC + water cooling
Andy F hybrid TD05 20g turbo

What difference in power/torque if the car is Andy F mapped with straight Optimax verses Optimax with heavy dose of NF?
I hill climb the car, and fuel addatives are actually banned!

Any real life experiences?

911

john banks

40 BHP.

911

!
I know you don't kid about John, but 40? That's about 15% ish.
Better keep buying the NF, in bulk for next racing season this time....

Must admit that the car didn't seem more powerful (stock engine @ 1.31 bar) when I added NF, but it revved much smoother; however, I flowed the stock headers also..

911.

john banks

Try increasing the boost and advancing the ignition to get a 10% gain. I was thinking, ***** out you would go from about 390 to 430 BHP with that setup, depending on rollers, but for competition use if you don't want to be rebuilding the engine, less may be better.

Pavlo

For competition I would go for race fuel, and a T into the fuel return line to bleed off a proportion of the returned fuel, so you can empty the tank by running the pump. But you want to still keep some fuel returning to make the jet pump in the tank suck the fuel from the non-pump side.

I think the safety and consistency offered by proper race fuel is worth it for the small amount you would use in competition.

Paul

Andy.F

Paul

Additives are not allowed in this class, so race fuel is a no no !

But as you and I know, regulations don't really stop the use of this stuff so it's a gamble and Graham needs to decide if up to 15% more power is worth the risk ?

Andy

911

In the sports car class above me there is an 800 bhp 2.2 L Audi Quattro that smells funny, if you know what I mean!

I would rather keep to Optimax + NF as a max, some scrutineers are fussing over water injection a few meetings ago.
Likewise ALS are becoming very anti social on the hill climbs, frightens the Horse Stables...especially if it is a GEMS system, BANG...BANG...BA...

Bigest worry is the 5 speed Sti trans.........Bang!

Thanks for the comments everyone.

But, why did I feel no improvement when I flowed the cast headers and added NF?

911

Andy.F

To fully utilise the higher octane you need to advance the timing and/or increase the boost.
If your Sti is running det free on optimax then octane booster will make no difference.

I'd recommend using the FC Commander to add some timing if/when you use octane booster, this way you have the choice. Have it mapped for optimax and bring along some NF to find the advance limit for your engine at the end of the mapping session.

If the "coast looks clear" with regard to scrutes, then add the NF and dial in the extra advance prior to the run......sorted !
Also consider adding some methanol, standard in most USA winter fuels, you could then argue you bought your 'pump fuel' in the states

911

Yeh, as if I could get one past them!

Running a stock ecu and leaving the boost @ 1.31 bar with /without nf then you obviously are correct!
I've got an Apexi FC with Commander on it's way cheap (new/not used) so that will allow the 'trick' which is totally legal!

Hill climbing seems to be about laptops all of a sudden....

Andy, can we map safely on my 5 speeder as I'm not sure if I will have the 6 speeder in place at the same time?

The AUDI does run race fuel but is not road driven, but does have an MoT!

Very interesting reading, thanks to all for showing the interest 911

Andy.F

Yes, the Sti3 box is better than your average UK anyway FWIW I've never seen a broken 1st gear and I've done a fair few launches on sticky tyres The fact that your gearbox oil temp will be fairly low may also be an advantage.

I think I mentioned before but well worthwhile spending time wrapping and double wrapping your headers, turbine housing and downpipe and also ensuring a good isolated cold air feed to the turbo, particularly as you will not have any airflow through the engine bay prior to your runs.

Andy

911

Thanks Andy. The wrap is on the bench and thinking of using a heat 'blanket over the turbo. Really want to fit a sports cat in the down pipe, but will wrap that too.
Standing in the que waiting for the run to the start line soaks everything, hence ice in the TMIC reservior and quenching/drowning the TMIC just before going to the start line.
Will do a cold air duct as Carl did via the fog lamp location.
Did you drag race on Avon slicks with a 5 speeder and 330 lbft though? Trans temp would be ambient from the start (more power losses..)
I can just see the trans letting go just into the season...
Maybe I do worry too much!

911
911

Pavlo

Race fuel is allowed, but additives are not.

Seing as unleaded racefuel meets the BSI spec for pump unleaded fuels, unless the Blue book or series regs specifically state a max octane for fuel, the race fuel is allowed.

Paul

stevebt

iTrader: (8)

why not try and wrap your turbo ive done it to mine and when it heats up the turbo really does feel like its pulling better

Andy.F

You sure Paul ? It's a while since I raced in that class but the regs stated only pump fuel at that time, I assumed that to mean comparative octane, I've no idea if they check octane or not ?
If not, then way hey

Andy

911

I doubt that the hill climb scrutes I know would test octane.
To the best of my knowledge it has to be pump fuel.
Methanol is allowed, you just need an orange disc on the car to warn the fire marshals of an 'invisible' flame.
You cannot add Nox, and as before, water injection has raised some eyebrows too recently.
The Blue Book is the Bible, but local Championship regs can over-ride them except for safety items.ie no turbo restrictor.
Pump petrol with NF will be ok, unless you are beating everyone by miles and someone 'snifs you out'!
Looking at the TD05 FE, getting a wrap effectively around the hot end looks tricky..

911

stevebt

iTrader: (8)

pmsl if you think the td05 is big wait until the td05/06 is under your bonnet i got harvey <cough> dawn to fit my turbo wrap and he ahem did a great job didnt you harvey

stockcar

"blur book" rules normally specify 'pump' fuel, however this doesn't mean you have to buy the supermarket stuff...............MSA regs are normally 100octane (dependant on class/ category) and specifically outlaw any additive's other than a 'lead replacement lubricant"!!

technically speaking your NF is out, and if any of your competition reads this then they will know!?!

Millers CVL gets around this as it is primarily a "valve seat lubricant" and is specifically blended to conform with MSA regs!! just so happens to add 3+ RON............LOL

alyn - asperformance.com

Pavlo

Unleaded race fuel is 'pump' fuel. You can even get it out of a pump at Santa pod. SO unless there is a specific octane limit (and this varies accross class/ car type) a race fuel should be legal.

Check the Blur Book as Alyn says!

Remember the rules are your friend

Paul

911

There are no Octane 'max' numbers I know to, just 'pump fuel'.
NF Millers etc are all technically out, inc water injection.
This is why I want Andy to map on straight Optimax.
If I'm squeeky clean then good reason to pop at the others who bring their 'racing petrol' in Jerry cans for some reason.....

If others try to tweek the 'Blurrrrrr Book' so be it , there are greater factors to a fast hill climb than the fuel benefit I think, tyres being the greatest!
Interesting replys though!

911

Pavlo

If there are no max octane limits, then unleaded race fuel is 100% legal for your class, provided it conforms to the british standard (and the popular ones do).

Please do not accuse anyone of cheating or bending the rules by using race fuel, it's legal, it's gives an advantage, and if you don't capitalise on the same advantage that's your mistake.

£20 worth of race fuel per meeting (max) is a cheap 30hp if you ask me.

Paul

craigdmcd

iTrader: (2)

Elf Turbo fuel and the others are all classed as pump fuel as they come out of a pump at silverstone, it's just not cheap though.

Craig

911

Take your point Paul.
Racing starts when the rule book arrives (McLaren's Tech Director quote I think)

It's all tricky when the car is driven on the road to the meetings (it is a Road Going class after all). Separating the fuels could be done with separate (small) tank/pump though.
Need about a gallon for a hill climb, ie a big swirl pot!

That is legal.

911

Peanuts

iTrader: (15)

with paultry 3degs. advance on the commander and a 5ml/l dose of NF I managed a jump of approx 20bhp.
need to get the octane up a bit more though to resist det at the top end as I had to abort the run.
when we (the hants-scoobies mob) go to power engineering in february I should be able to get a full 4degs. without issue (or det!)

will report findings in the new year

911

Make sure you do! Glad I bought the commander now.
911