TXCAMSS

iTrader: (60)

I am sitting in a hotel out of town and a thought hit me while driving. Is there a race fuel that will provide an increase in HP in a NA LS1 engine?

I have found from personal experience that I actually lose a few 100ths when I run a higher octane race fuel such as unleaded Sonoco 104 over my normal pump 93 octane pump gas.

I use a higher octane race fuel as insurance to fight off detonation during hot weather conditions or where I might be force to hot lap the car and low ET isn't the primary goal such as brackets or an index race that I am a little quick for.

My question for you gurus is: Is there a fuel available that can actually provide a HP increase and improve ETs in a NA application by even a fractional amount rather than slowing the car down?

This question is targeted for an application that is built for pump gas with a SCR of say 10.5-11.8 that is not detonation sensitive and is tuned conservative.

Adrenaline_Z

You can get quality race fuel with the proper octane level for your motor.
IE: VP racing fuels

It's a little pricier, but it might get you another tenth instead taking away a
few hundreths!

TXCAMSS

iTrader: (60)

A tenth improvement with a fuel change alone? OMFG

Please tell me you're not yanking my chain


9s here I come!!!!!!

427

iTrader: (3)

If your engine is set up for pump gas, it won't run faster on higher octane. It will probably slow down. If your car is running on racing gas with high compression, then VP makes an all motor fuel that will give you faster et's. It is a fuel that is used alot in comp eliminator, call your local VP rep to order. Have your credit card ready, its going to hurt.

Kurt

GOaT Cheese

87 Octane. 87 Octane makes the most power, due to the fact that it has the highest BTU rating, but power robbing detonation may occur with 87. The higher the octane rating, the less BTU's (which equates to less thermal expansion, and less power) helps prevent detonation because it is harder to light and is less volatile. But, if you gain 30 h.p. by running the proper spark timing, you are willing to give up 10 h.p. by running high octane fuel. But if your engine can run at optimum spark timing on 87 octane, then that is the combo that will produce the most h.p..

J-Rod

You can add some race additives to gasoline that are oxygenates. They aren't particularly good for your fuel system, but on the dyno we saw about 5 RWHP with them.

The best over the counter additive you are going to find that I know of is Coxoc. Its made by Klotz. Coxoc brings an additional 37%
oxygen into the fuel mixture. This improves combustion efficiency and allows more gasoline to be burned. According to Klotz, you can see about a 6-7% increase in HP. It depends on mix ratio. It uses nitropropane which will mix with gasonline, unlike nitromethane. Depending on the sanctioning body, it is not a legal additive in some sanctioning bodies.

If you want to mix some, I'd mix it the day I was going to race, and then after I was done, flush the fuel system. It doesn't have a lot of shelf life.

If you need custome blended fuel I have a guy that does that too.

miami993c297

iTrader: (6)

That's right.

In the early 90's, when fuel regulations where open in F1, at certain point the octane was as low as 85 (may be less) on engines turning already around 16500rpm (not for all...).
The philosophy and conception of the engines was balanced with and around the specificity of those different combustions law.

A lot of "DIENE" (ex: norbornadiene, dicyclo-pentadiene + / + etc...) was used in the formulations that was drastically dragging the octane numbers down, but so much calories and so much energy produced by a high specific mass "fuel" (some numbers where over 0.935 !!!), the price to pay was finding solutions to dissipate the temp...and also create a way to spray this liquide before entering the engine...

Christian

Armageddon

iTrader: (41)

I've always thought about it this way. Say you've got a motor setup for 93 and you put some 10-something in it. Higher Octane with more of a resistance to detonation burns slower. If your fuel is burning slower how is that effecting your timing? It's not necessarily your fuel that's causing you to gain ET's. It's the flame front finishing it's propagation while the piston is further down in the cylinder. If you advance your timing with higher octane you allow the fuel the time it needs to combust fully in the chamber without letting the pressures drop off.

engineermike

One of the magazines did a test on this a while back on a 9.5/1 motor. They went from 87 to 93, then up to 110 leaded gas, dyno tuning every time for best power.

Believe it or not, they made the most power with the 110 race gas. Even more surprising was that the 110 race gas made the most power at reduced timing advance. The reasoning was that the race gas is further refined and, thus, burns faster, requiring less spark advance and making more power.

The octane number had nothing to do with it.

Mike

GOaT Cheese

It has to, octane rating directly effects the BTU's (energy capacity) of a given volume of fuel. I'm not saying the article was wrong, but perhaps scewed on a bias? For instance lets say VP pays $30,000 to HotRod magazine to do a heads up comparrison with its fuel compared to "pump gas".Is the publication that just got greased, gonna say "sorry, the cheapest pump gas available makes the most power", or are they gonna say "With proper dyno tunning, VP fuels make the most power over anyone"? Both statements would be accurate, however, keeping a large contributor/advertiser happy is worth quite a bit.

engineermike

Yes, well, it has to do with more than just BTU's also. Methanol has a very low BTU content, but the Stoichiometric ratio is half that of gasoline. Even though the energy content is lower, you burn alot more of it. So, even though 110 has a lower BTU content, you need to enrich the mixture and burn more of it. However, the power gains had nothing to do with BTU's or A/F ratio, and everything to do with rate of burn.

Mike

Adrenaline_Z

What these articles might be omitting is the tuning and timing involved to make
the fuel produce better numbers.

Simply changing the fuel type without adjusting the timing is going to
throw the combustion pressure off of from the optimum crank angle and
continuing power stroke event.

Ignition timing is likely the most critical power maker while tuning.

engineermike

Exactly! The article had details on the jetting and ignition timing. I'm going off of memory here, but I believe that the optimum power on 93 was something like 34 (SBC) and on 110 it was more like 28 - 30. Again, due to the quicker burn.

Mike

engineermike

I can't believe I spent the last hour digging up some old dyno test. . . but I did. Here are the details:

Hot Rod magazine, December 2001, "Octane Shootout"

Engine: 360 Mopar at 10.4/1 compression.

87 octane: 396.0 hp at 36 deg timing.
91 octane: 402.1 hp at 36 deg
100 octane unleaded: 403.5 hp at 37 deg
114 octane leaded: 408.3 at 31 deg

Each dyno run was performed at 31, 34, 36, and 38 deg timing.

If the article was sponsored by a vendor, then it was "104+ octane booster" because it was tested also. I left out the octane booster results because they only muddy the water.

The following is a direct quote, ". . . most of all, we discovered that our presumption that higher-octane fuels burn slower than lower-octane fuels is largely incorrect. There are too many other fuel-formulation issues at work to assign a general rule about octane. . . note that we made the best power with 114 octane with the least ignition lead, indicating it had the fastest burn time."

Mike

Maggie

wow...this post takes me back to a time when I actually earned a living as an engineer... Aliphatic hydrocarbons with NO2-groups attached directly to carbon atoms was one of my pet projects.
The nitropropanes/nitroparraffins are 'true' power adders.
There is more to this group of power adders than just O2 ballance. They will produce a greater bubble value (volume of gas from enthalpic reaction) and provide a higher spicific energy than most other "oxgenates" with similar molecular weights and O2 balance.

miami993c297

iTrader: (6)

Just a quick note with your permission, in term of Fuel Engineerie everything can be done and % as low as 0.01% of one of the ~ 250 components of this chemical product is changing (a lot) the final result.

In fact each engine is reacting differently to a specific sort of fuel and it is related to so many parameters that I can't elaborate here, but always keep in mind the dissipation of calories.
And an engine producing a poor specific power with huge difficulties to keep cool the peripherals of the combustion chamber is not the best example about debating of fuel performance.

At the end of the story if you want to obtain a rule (the best laboratories are working on it everyday since so many years) about the equation FUEL=POWER you will want to work with engines around 200 Horse power by Liter or 200hp/1000cc, less than this is NOT working in absolute ...

It is just making fuel, which is a HUGE BUSINESS.

Christian

GOaT Cheese

We were discussing the best performing fuel with a set specific pattern. No other alterations. If you start to change consumption rates (jetting) and types of fuel (alcohol) the entire debate changes gears. If the question at hand, is which fuel makes the most power, without changing anything but the octane rating, not timing, or jetting, or any other factor, then the lower octane fuel will be the best choice. You know as well as I do that you cannot simply start running Methanol in your engine, why? Because it wouldn't even start, due to the very low energy content of the fuel. To run alcohol you need to crank the compression through the roof, or add forced induction, whereas both of these factors by themselves drastically change the rate at which the flame front propogates, and the power producing capability of the engine. I simply must disagree with you on this.

engineermike

Well that's just silly. . . why would you handicap a fuel that's capable of making more power by screwing up its tune? That's sort of like comparing cars to airplanes but saying that they both have to travel on land. . .

GOaT Cheese

The whole point is NOT screwing with anything, but simply which fuel makes more power in a fixed environment, without altering any other factors. For example, engineermike has a very nicely tuned Camaro, runs very good, and he doesn't want to alter its configuration in any way (screw with it). But , he is interested running the fuel that makes the most power, again without altering his tune because it took so long to get it just right. Engineermikes Camaro will make the most h.p. with the lowest octane gasoline that does not cause detonation.

TXCAMSS

iTrader: (60)

I sure had no intentions of stirring up a hornets nest, but this is great info. Please keep the ball rolling!!!!