There are numerous differences between leaded and unleaded fuels, and between different leaded fuels. Leaded fuels can achieve considerably higher octane ratings, so as to reduce detonation and permit considerably more aggressive tuning (e.g., timing and boost). For example, VP109 (unleaded) is 105 octane (r+m/2), whereas C16 (leaded) is approximately 118 octane (I do not recall the precise rating). The additional 15 octane points permits far more aggressive tuning, including more timing and more boost, which translates to substantially more power if done correctly (e.g., 20% more power). Moreover, leaded fuel burns cooler, so as to reduce intake temps and increase power. The performance differences between C16 and VP109 on a properly tuned car are very noticeable. On the negative side, leaded fuel destroys cats (I removed mine) and, over time, also damages sensors, thus adding certain maintenance costs.

There are also meaningful differences between high octane leaded fuels. C16 burns substantially slower than C12 (approximately 114 octane) and, therefore, C16 has a tendancy to create deposits in the cylinders resulting from unburnt fuel -- this does not always occur with C16, but is a recognized risk if C16 is used over an extended period. VP suggests C12 as a better daily race fuel because it burns much faster and, therefore, is less likely to leave unburnt fuel and deposits. After speaking at length with VP's national technical guru, I took his advice and switched from C16 to C12.

Hope that helps,

Craig

 

im running sunoco gt 104


racegas.com

tim

 

gunther i run sunoco gt104, great stuff

 

Leaded will ruin you emmision equipment like your O2 sensors and catalytic converters.

 

what are you paying for these 100-109 octane stuff compared to 93 premium pump gas?

 

A 5 gallon can of the GT104 Sunoco is $7.40 per gallon. The VP 109 is $8.89 per gallon. At least here in Virginia. Not sure about the rest of the country or in larger sizes.

Sunco 94 is about $4.29 currently.

 

$10 a gallon for vp 109
$4.50 per gallon for 91

On our last run, I was getting 7.8 miles to the gallon.
I usually put 5 gallons per week in my Turbo.
Last year I spent $1900 on VP 109 and that is all I run.

 

I run Sunoco 100 octane from the pump the majority of the time, unless I have a reason to run 93 (mostly for comparison vids...or doing 93 octane 60-130 runs). For those rare occasions when I want to run full boost, I run a mix of Torco 116 and Sunoco 100.

I hate running 100% leaded fuel. Boost response is never as good on 100% leaded as it is on unleaded or an unleaded/leaded mix.

 

I am running a tune from Proto on K24/x50 setup with Ti exhaust, 200 cat cells. I have been running the unleaded 100. This is pump fuel at a gas station - I feel a huge difference in mid range power. Car is running very clean, no blue smoke at start up. The following site will provide you with the local station information. I am paying about $6.60 per gallon here in the bay area at the station in Sunol, CA.

http://torcoracefuels.com/content/view/74/26/

 

How dangerous is it to mix leaded gas with unleaded gas?

 

I got sunoco 100 for the first time today and my car seems to love it. It's running very smooth and cool. I paid $8.00 per gallon at the pump.

 

Remember the 100 octane gas has a motor octane of around 95. Look for motor octane gas above 100. I started with 100 pump then went to VP MS 103 and then to 109. You will see the difference in every jump. It is unreal!

Take her up to redline in 4th gear for me and tell me how fast she will go. I think the 05 TTS Cabs have different gearing than the coupes.

 

My stash!

 

No smoking in Robert's garage!

 

How much does 109 cost? I paid around $7.50 for 100 in CA last month.