Pump gas vs racing gas

[Tristicus]

So just noticing something while I browse forums and threads, lots of people say (mainly with really high HP setups with FI) they get something like 1100hp on pump gas yet 1600 on racing gas (C16?). Why is there so much of a difference between the two?

 

[punjabiplaya]

higher octane means you can run more advanced timing

 

[jlee]

higher octane means you can run more advanced timing

And more boost, for forced induction application. I should be at 285whp on 91, 300whp on 93, and 330whp on race gas (16/17/20psi respectively).

 

[punjabiplaya]

sounds good. no knock, crank up the boost and timing = win (until you vent a rod to atmosphere)

 

[Elfear]

What the others said. More timing can make a huge difference in FI applications. It's generally a trade-off between running more boost and running more timing. You can only run so much boost and timing at a given octane level. Increasing the engine's resistance to knock will allow you to run more of each.

 

[Zivic]

So just noticing something while I browse forums and threads, lots of people say (mainly with really high HP setups with FI) they get something like 1100hp on pump gas yet 1600 on racing gas (C16?). Why is there so much of a difference between the two?

Like everyone already stated, more boost, more timing...

I think the thing to note is that now days C16 is being ditched for E85 in a lot of cases. Around me, I haven't heard of anyone doing a "race gas" map any more, everyone just tunes for E85.

to give you an idea of the difference.

Pump gas, I can push to 26 psi. Beyond that, there is too much detonation.
on E85, I can run 33 psi. Take a look at the difference in power that 7 psi, more timing, and running a tad leaner AFRs will get you

Pump gas

E85

 

[KentState]

Doesn't the fuel system have to be designed for race fuel or E85? Can you run just any car on either?

 

[punjabiplaya]

Doesn't the fuel system have to be designed for race fuel or E85? Can you run just any car on either?

modern/new cars can handle it usually. if you're doing that much to your car, you've probably upgraded the pump anyways

 

[JCH13]

Doesn't the fuel system have to be designed for race fuel or E85? Can you run just any car on either?

Race gas, no problem, as fuel delivery is the same (except when boost is increased, but even then it's only marginally higher) but E85 requires nearly doubling the volume of fuel delivery, which may require significant modification and a different tune.

 

[Zivic]

Doesn't the fuel system have to be designed for race fuel or E85? Can you run just any car on either?

with E85 I needed a larger pump and injectors. to really push it I added a boost-a-pump. in most FI apps, you are already replacing these components when you up the boost, so the increase in costs is minimal to nonexistant.

I also want to point out, the mpg is only about 15% better on pump vs E85

 

[exdeath]

I want to do a 800 RWHP E85 Kenne Bell Mammoth setup, but E85 pumps are non existent around here. :'(

 

[jlee]

I want to do a 800 RWHP E85 Kenne Bell Mammoth setup, but E85 pumps are non existent around here. :'(

There are apparently a few stations in Tempe, Mesa and Scottsdale...makes me think... :hmm:

 

[caniroc]

Dont forget about Meth injection--an alternative to rasing octane levels while still running on pump gas so that boost can be dialed up as well.

 

[KentState]

Dont forget about Meth injection--an alternative to rasing octane levels while still running on pump gas so that boost can be dialed up as well.

That's something that my tuner also suggested. My only concern is a failure of the delivery of methanol can be catastrophic while E85 would be more consistent.

 

[punjabiplaya]

for locating e85: http://www.afdc.energy.gov/afdc/ethanol/ethanol_locations.html

 

[Zivic]

Dont forget about Meth injection--an alternative to rasing octane levels while still running on pump gas so that boost can be dialed up as well.

I have dealt with them in the past. I feel they over-complicate things. Just one more thing to go wrong. they definitely work.... until they don't

 

[Gillbot]

or more spray 🙂

Be careful though, many "race gas" formulas are leaded which will foul O2 sensors.

 

[Tristicus]

or more spray 🙂

Be careful though, many "race gas" formulas are leaded which will foul O2 sensors.

Wait people use those?

:awe:

 

[exdeath]

Wait people use those?

:awe:

Uhm yeah...

Even if you run catless and delete the rear O2s, the front's, and often an aftermarket wideband, are essential.

Not just closed loop idle and cruise, but even open loop WOT relies on the trim values previously learned from the factory O2s in closed loop as a ballpark base for WOT trim.

 

[JCH13]

or more spray 🙂

Be careful though, many "race gas" formulas are leaded which will foul O2 sensors.

Yay for 100LowLead Avgas!

Tetraethyl lead is a great octane booster/anti-knock agent, but so bad for everything else. I think the same guy invented both TEL and the first CFCs... what a dick.

 

[punjabiplaya]

pretty neat article on F1 engines: http://www.formula1.com/news/features/2011/9/12524.html

since the engines are all locked down and homologated, where to find extra power? in the fuel and oils

I'd love to see the new turbo engines running on e85

 

[Gillbot]

I know a lot of guys that run leaded anyway since it's cheaper to replace o2's and run leaded than it is for unleaded.