djtimodj

Just a gew questions about using race gas such as C16 or VP import (120MON rated) for motor safety.

I know most poeple run race fuel for more power to allow extra timing/boost but Im looking to try doing some tops speed and standing mile events soon and im looking at running the car on 99ron shell V power UK fuel mixed with VP racing C16 to boost RON/MON content to add some det protection.

Im looking at a 50/50 mix of pump to race gas as this should give me 110 octane fuel. How much safer is this vs. stock pump fuel? Top speed runs will stress the motor and add tons of heat so I want to make every effort to stop det.

Thanks people!

Cass007

iTrader: (34)

The mix is part of the fail. I was advised by my tuner to always purge the tank or baby the car when coming off the Q16 because you never know where the oct rating is for sure.

str8dum1

iTrader: (11)

if you keep the same pump gas tune, but mix in C16, thats a good idea. Its a good bit safer

I'd usually mix in some C16 on top of my pump gas when i went to the strip during the summer.

djtimodj

As str8 below has said mate, this is not going have a race gas tune. I would be running my pump gas tune but using race gas just for its anti-detonation property's.

So no worries about mixing and no knowing octane numbers.

DaveJackson

iTrader: (5)

Would adding a water/meth kit be on the table as a viable option?

rcdash

iTrader: (18)

WI is a great detonation suppressant, so yes.

djtimodj

is water meth as good as race gas?? My intake temps are low so would adding water meth do much??

What sort of octane is pure meth? Also would I need to tune for meth as its just like adding extra fuel??

str8dum1

iTrader: (11)

the gas mix is a better option. you have to tune for meth. you could do straight water injection for cooling and not have to change the tune. but race gas mix would still be safer.

Resmarted

iTrader: (2)

There are some misconceptions between octane meth and water injection.
Higher octane means 'slower' to burn/ more resistance to combustion. That's why we used to have lead in our fuel, it increased the resistance to ignite before the spark.

Meth (in comparison to water) doesn't really do much to increase octane, and doesn't do much to stop detonation INSIDE THE COMBUSTION CHAMBER. What it does do is lower air intake temperatures and act as extra fuel. That's why water meth kits are used on stock cars, you can crank the boost up on a stock car past the efficiency of the turbo and effectively enlarge the efficiency islands by cooling the intake charge with meth, then go past what the oem fuel system can support with more fuel (meth).

Water doesn't change intake temperatures as drastically, but is a much stronger detonation suppressant. Also water keeps valves clean, which can lengthen the life of the seats dramatically (no carbon build up to be slammed into the head). But it doesn't add any fuel (to some adding fuel is the last of their worries, others running a little richer is a bit of insurance).

Mainly what determines what these two liquids do are their chemical structures. H2O needs much higher temperature to turn from a liquid to a gas than any alcohol, where as meth can evaporate at room temperature (yes water does evaporate at room temp too but much slower). So the water kind of absorbs excess heat in the combustion chamber and gets changed into steam. Part of why I don't like meth, and ethanol is that they are naturally corrosive and don't have lubricating properties traditional petroleum based fuels have. My engine machinist also likes water injection a lot (he has worked on everything from big blocks, 4g63's, and even top fuel motors). Now I'm not saying meth injection is bad, because it's not, but I personally believe in all water injection for detonation suppression. And for me it's cheaper/easier to get distilled water than methanol...


and what str8dum said is partially true. Depending on how much meth you inject you will have to tune your car, but in theory you really shouldn't have to retune for just a small amount of water injection. Worst case scenario with water injection you will get a bit of a hesitation when the water starts spraying (like its running really rich). And if you get a boost dependent stepping water injector its likely that you won't even have that. It still would be best to retune the car, but it really shouldn't be difficult to retune it. I believe you are supposed to just reduce the target fuel by a few tenths, although I am not 100% on that.
IMO you should go with water injection over buying race fuel. Yes it is another thing to keep watching/refilling but (for me at least) it's a lot simpler insurance than constantly getting race fuel. I've heard that running 10% (of your total fuel flow) water injection (you don't want run more than that) has the same amount of detonation as running super pig rich (seriously sub 10-1 afr).

DaveJackson

iTrader: (5)

Thanks for that post Resmarted!
I think that by "slower to burn, etc" you mean higher flash point, though. Once it starts burning, I don't think it burns slower at all, but it resists pre ignition and detonation etc because it takes more energy just to get the explosion started.
The water cooling thing is due to "latent heat of vaporization" if y'all want to Google that. It might take only one degree to vaporize something, but that single degree takes a ****-load more heat to get to than the previous degree did.

jerryd87

iTrader: (4)

also depending how much you run it will raise octane slightly methanol has 89 mon 109 ron octane so (r+m)/2 method the U.S. uses gives it a octane rating of 99. on top of that you also have to remember methanol burns a little colder then gas which can be seen on exhuast gas temps, combined with lower IAT make for a cooler combustion chamber, or if you wanna run it on the ragged edge more timing to have the same combustion chamber temps. so while water will cool more in the combustion chamber, the properties og meth make it very controversial on which is actually better. things to note however is that some classes dont allow meth which requires pure water, but if you run pure meth you have to have the tank outside the passenger compartment or surrounded by a firewall which is why alot of people run 50/50.

Dynosty

iTrader: (27)

Your best bet is making sure your tuner is aware of what style racing you intend to do and that your tune is setup for it. Adding race gas, partially mixed or 100%, to a tune that is not setup for it will likely make you run slower.

str8dum1

iTrader: (11)

please explain how he will run slower with a mix of pump and race gas?

midz350

iTrader: (4)

Quoted from a different forum.

http://ls1tech.com/forums/fueling-in...-you-down.html

Resmarted

iTrader: (2)

+1

Basically higher octane has more crap in it that doesn't burn... funny right?

except its not crap obviously... bygmmfp (but you get my mother fackin point)

wizard

Tim,

I'm looking at meth / water injection myself. It's certainly going to be cheaper then running race fuel mate... I've heard the c16 fuel can clog up your injectors because it's considerably leaded. Anyone have any knowledge on this?

str8dum1

iTrader: (11)

that is rrrreeeeaaallly stretching.

the air pressure in the tires or the weight of the motor oil used would cause a much bigger effect than an effective 97 octane in the tank.

thats all benchtop math, just arguing semantics. Until someone posts data, i call BS. Thats basically saying your 87 octane daily driver is slower with 93 octane in the tank.....

InjectedPerf

iTrader: (15)

Watch air fuels when you change from Q16 to VP Import without retuning...

str8dum1

iTrader: (11)

both Q16 and VP Import are oxygenated fuels, so like the guys at Injected have mentioned, those could possibly need a tune touch up. (also need to watch you injectors as the newer high Z bosch's have seals that swell with oxygenated fuels)

C16 is not oxygenated, so a mix would not change the AFRs

InjectedPerf

iTrader: (15)

Str8dum1, where are you getting your information? You are saying if you mix C16 with 93 octane you won't need to change your tune to compensate for the new fuel mixture?

I have changed out Q16 to VP Import (both oxygenated fuels) and AFR dropped by over 1.5 points. You don't think you would lose power with that rich of an AFR?