Fuel ?

[jcorlew24]

I bought this car last week and the previous owner has been running the car on 93 octane with half a 32 ounce bottle of Torco to a full tank. I also ran it for the last tank and now have to order another couple of bottles.

The stuff is pretty expensive and it is a bit of a hassle to order it everytime you fill up. I have a fuel station that has 110 race fuel for around $5 a gallon just down the street.

The car was just tuned at Dynospeed in Memphis and made 585 to the ground on 16.9 lbs. of boost, on a conservative tune ( I had them run the stock pulley on the crank to get the boost down from about 19 just to be safe). I talked to the tuner and he said he would recommend running the Torco as a safety net, just incase I got a bad tank of gas.

The car is not a daily driver just a weekend cruiser. I don't plain on beating the absolute dog s*%t out of it either. So should I just run the 93 octane and add a couple gallons of 110? Also how much 110 should be added to a tank? This may be a dumb questions but it would be a lot easier than ordering Torco.

Here is a run down of the motor:

Kenne Bell 2.6H @17psi
Kenne Bell BAP
Kenne Bell Big Oval TB
60# Injectors
JLT CAI
SCT BA-2600 Mass Air
LFP Lower pulley kit(stock ring)
Billet Flow 100mm snub Idler
Billet Flow (3) 92mm idlers
Kenne Bell 3.5", 3.25", 3" pulley
LFP Heat Exchanger
LFP Radiator Resovoir
LFP Supercharger Resovoir
BBK chrome long tube headers
BBK shorty H-pipe(no cats)
Mac Stainless Catback


Thanks in advance for the all your help.

 

[Quick Strike]

Tune it on what you intend to run. Estimating fuel substitutions is a good way to hurt an engine. I run the same amount of Torco on my street tune. I buy a five gallon pail and then fill four 32 oz cans from that. You can find the pails for $250ish shipped if you look for a while. That is equal to $12.50 per 32 oz can or $6.25 per fill-up. It is a pain after a while, but after I fill four cans I am good for eight fill-ups before repeating. Be careful handling it if that is the route you go.

 

[MalcolmV8]

I agree tune on fuel that will be run. Switching fuels afterwards and hoping for the best is not a good way to go.

If you don't want to mess with torco just have your tuner pull a few degrees timing out of your tune so it won't knock. You're on 16.9 lbs of boost you say. That should be easy.

I'm running 20 lbs of boost on my 2.9 and tuned it myself on 91 pump gas initially. I just kept timing down.

It's actually more efficient to turn boost down and keep timing up but unlike turbo cars we have to change pulleys, belts and so forth so the reality is its much easier to just pull some timing.

 

[jcorlew24]

I must be confused. If the car was tuned to run 93, the reason for adding Torco is to up the octane. So if you are adding 110 to 93 shouldn't that be accomplishing the same thing. The car would be fine running on 93 the way it was explained to me. The reason for the Torco is just if by chance you get some bad gas. That's why I was asking because it would make things easier to run 93 and then add a little 110 to the tank to keep the octane up.

 

[MalcolmV8]

If the car runs just fine on 93 then just run 93. Adding a couple gallons of some other fuel may do nothing but I'd make sure A/F and all else is still in check.

 

[jcorlew24]

Did a lot of research and seems to be a lot of guys running mixtures to get the octane up. I don't have cats and my 02 sensors can easily be changed. So race fuel mixture seems to be the way to go until I retune to run on straight race fuel. If my race buggy sells I may decide to go E85. Will see.


http://www.svtperformance.com/forums/engine-tuning-214/714900-whipple-2-3-mix-race-gas-pump.html

 

[Quick Strike]

Different fuels require different stoich air/fuel ratios. When you mix fuels you change the what is required to maintain an appropriate air/fuel ratio to an unknown quantity unless this is how it is tuned. Even changing the air/fuel ratio requirements by .5 or .25 could be the difference between mean and lean. We have all seen the pictures of too lean by now!

For example: E85 has a much higher octane level then gasoline, but has to be at a 8 or 9 to 1 air/fuel ratio in our cars to prevent a lean condition. Regular gasoline has far less octane, but will not be lean in our cars even at an 11.5 to one air/fuel ratio. Now, if you were to mix them (hypothetically), your gasoline tune would be too lean even though you have blended in a higher octane fuel.

Adding Torco does not change the required stoich air/fuel ratio, but adds octane for increased detonation resistance. Mixing fuels is not bad, but it just needs to be done at the right air/fuel ratio for the fuel mixture. Tuning is the way to find the right ratio for your that mixture.

 

[jcorlew24]

Different fuels require different stoich air/fuel ratios. When you mix fuels you change the what is required to maintain an appropriate air/fuel ratio to an unknown quantity unless this is how it is tuned. Even changing the air/fuel ratio requirements by .5 or .25 could be the difference between mean and lean. We have all seen the pictures of too lean by now!

For example: E85 has a much higher octane level then gasoline, but has to be at a 8 or 9 to 1 air/fuel ratio in our cars to prevent a lean condition. Regular gasoline has far less octane, but will not be lean in our cars even at an 11.5 to one air/fuel ratio. Now, if you were to mix them (hypothetically), your gasoline tune would be too lean even though you have blended in a higher octane fuel.

Adding Torco does not change the required stoich air/fuel ratio, but adds octane for increased detonation resistance. Mixing fuels is not bad, but it just needs to be done at the right air/fuel ratio for the fuel mixture. Tuning is the way to find the right ratio for your that mixture.

Now that makes since. Guess I just need to order some Torco then.

 

[jcorlew24]

Well I guess my dumbass posted in the wrong section.