I have a few ideas...

#1 you can run more ignition timing with race gas.
#2 it atomizes much better
#3 (i run leaded race gas) its fights against nasty knock.
#4 somehow it burns at a faster rate, yet wont prematurely ignite...and exerts more force on the piston.
#5 you can run leaner mixtures


the big thing that gets me.... I see people making like 500 on pump and 700 on race gas. Thats 200 whp that JUST appeared. I dont get it.

 

People don't just make more power on race gas. First they add race gas and then they turn up the boost like crazy because now they can do it safely.

 

timing and boost

 

Racegas burns at a slower rate NOT a faster rate.

 

Pump gas will make more power than race gas most of the time, but will detonate much easier, resulting in having to run less timing and boost. The added power with race gas is from more boost 90% of the time, with a little more coming from more timing. There's alot more to it as to why, but that's the simple explanation.

 

short answer, its resistance to knock. From there you can derrive more power through other means; boost, compression, ignition timing, nitrous (or all of the above )

BTW, "race gas" burns slower, more controlled.

Edit: sorry for the repost of already mentioned info, about 10 minutes spanned between hitting reply and submitting post as a user needed help...

 

how did I miss Boost....I thought people were simply changing fuel and adj their timing maps to pick up 200 whp hahhaah. left me thinking what kind of gas are they running?!?!!



Any tony...if you would like to get into the physics of the fuel feel free...I'd love to know a lot more than the basics if you would feel inclined to inform me. Thanks

 

1 British Thermal Unit is the amount of heat required to raise the temperature of one pound of water one degree F..

 

Isn't octane a measure of stability, not necessarily burn rate? Granted the two are probably fairly closely related, but they are not the same.

From my understanding, fuels can be formulated to a particular octane rating but have greatly different burn rates. I've been trying to find out information about burn rate more then octane lately, as I have ran a couple different 110 octane fuels and found significant difference in power, detonation resistance and optimal tuning.

Is there anyway to compare burn rate between fuels with the data sheets given by the fuel manufacturers?

 

im still confused a little about race gas vs pump gas on timing...

if race gas burns at a slower rate then pump gas..then you would have the timing for the spark plug to ignite earlier then pump gas rite?...so it burns completely and most effectively when it finish its stroke...so wouldnt race gas have less timing then pump gas since it burns slower or am i on the wrong page here?

 

more timing means more "advance" before TDC. So... you're basically giving the mixture more time to burn.

I'm no expert though, and I'm half drunk at that. So maybe Tony1 will chime in.

BTW, Ben Strader's efi101 class goes over all this. I highly recommend it.

 

ok so any sparking before tdc is advance timing....and any timing after tdc is retard timing correct???

 

(Chem student chiming in) Octane is simply a measure of the gasolines resistance to detonation. On a molecular level, the more "branches" of hydro-carbons, the higher the octane. (On a side note, nothing is going to resist detonation as much as lead would). The more branches of hydrocarbons, the more heat is required to break them apart to form new bonds with the incoming air. Hope this helps.

Kyle R

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tRaCeBuStA &raquo;</TD></TR><TR><TD CLASS="quote">damn 975 post and u still dont know this yet?</TD></TR></TABLE>

damn, since i have 4000+ posts, i think i should know everything huh?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by herecomesboost &raquo;</TD></TR><TR><TD CLASS="quote">(Chem student chiming in) Octane is simply a measure of the gasolines resistance to detonation. On a molecular level, the more "branches" of hydro-carbons, the higher the octane. (On a side note, nothing is going to resist detonation as much as lead would). The more branches of hydrocarbons, the more heat is required to break them apart to form new bonds with the incoming air. Hope this helps.

Kyle R</TD></TR></TABLE>

he only has 3 posts, yet he probably know more than anyone else on this board lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tRaCeBuStA &raquo;</TD></TR><TR><TD CLASS="quote">damn 975 post and u still dont know this yet?</TD></TR></TABLE>
Since when does post count raise your knowledge?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">Since when does post count raise your knowledge? </TD></TR></TABLE>

i think you can find your answer here : https://honda-tech.com/zerothread?id=1339765

 

I've been a member since 2002. So I don't post a lot. I built my engine and car by myself, fabricated all of the parts, and tuned it myself. I didn't pay Mase to tune my car. I run C16 to help fight knock... I've never taken any classes or gone to any seminars for tuning EFI cars. I just simply go off of EGT and Wideband.

You can call me an idiot if you wish, but if no one asked quesitons what would we all learn? In this case it was something as simple as a difference in boost pressure... I simply did not think of it...nor did I rack my brains trying to figure it out. Its a fairly obvious thing that I SHOULD'VE picked up on... but oh well.

As far as burn rates etc. I would think a fast burn high octane fuel would work much better than a slow burn high octane fuel due to the rpms at which we operate. Im sure a fast burn would mean you would have to run less timing in the long run, but would be a MORE consistent burn and predictable in the CC.

 

good question b/c I don't know a lot about fuels! i guess that makes me a retard!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tRaCeBuStA &raquo;</TD></TR><TR><TD CLASS="quote">im not saying ur a idiot because u dont understand how fuel work, u make yourself sound like a idiot by what you said.

I dont get how some people make 250hp on a stock gsr motor and how some people make 500-600hp off a stock gsr block. I guess i'm a idiot for building up my motor and wasting all that money when i could of hit around 600hp leaving my motor stock.</TD></TR></TABLE>

You sound like an idiot.

 

like I said before... The guy made 500 on pump and 700 on race gas. He didn't specify how he was making more power...and most people dont specify that they turned up the boost 10 more psi. They just say, " i made 400 on pump and I made 500 on race gas" leaves me thinking wtf is race gas doing for them that its not doing for me. I was simply asking for an explanation as to how 200 whp just appeared....it was simply answered by saying they cranked the **** out of the boost. Not hard to grasp really.

 

wow

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tRaCeBuStA &raquo;</TD></TR><TR><TD CLASS="quote">i would think u know something like this by just being on the forum so much. Its not something only a rocket scientist can figure out. If you really were into racing/modifying cars you should know basic stuff like this, if not then i think this isnt gonna work out for you unless you bring your car to a mechanic all the time. And i can understand if you dont know the difference from pump gas vs race gas, but the extra 200hp for race gas doesnt make any sense at all. Thats something i would expect to hear from wanna be racers going to local parts store to get a can of nos octane booster because they think it'll make their car faster</TD></TR></TABLE>


Some people just go on the forum and post *****. And just because you are into modding cars doesn't mean you have to know everything. I'm all mechanical and at times I get lost with how timing is critical when tuning a car whether it be NA or FI.

I admit, I do it seldomly---but I don't abuse it. Well, this one infact is a post ***** (def. the person above me too )since it's not contributing to the thread.

 

you've got to realize that alot of race fuels are oxygenated as well, which would account for some additional power.. its likea very small nitrous shot in the fuel. but mostly, its becuase it allows higher boost without detonation

btw, i've always wanted to ask this RTErnie.. but is it just me or does 394whp@27psi sound kind of low for a 2.4L? I've seen a 1.7L destroked LS make 525whp on 30 pounds, and thats without a VTEC head...I mean, not that its not great, and you run great times, it just seems to me like you should be making more power?

 

Try building a turbo car that doesn't have the ability to rev all that high or make power at higher RPM and 390 WHP might not seem AS bad. He's probably making more torque with HIS motor then that destroked 1.7L you've SEEN of SOMEBODY ELSE'S.

I've heard of a 1.5L making 1500 WHP, 525 out of a destroked 1.7L is WEAK. The point being, "it's all relative."