UNDER THE SCOOP
Fuels and Dynos can be so Confusing.
Sometimes you just stumble upon a discovery. We were dyno testing and comparing our SV1 against all other carburetors to see how well it performed against four barrel carburetors.
It was a horsepower/torque comparison plain and simple. But the thing we found as we averaged horsepower output from run to run (we would do three pulls and average them) was that the SV1 was unbelievably repeatable. It would repeat average numbers that were 70 percent tighter than any four barrel carburetor. If you get a chance check out our SV1 dyno results. But although thats a great discovery…it wasn’t amazing. It was kind of expected due to its design parameters.
The amazing thing was the SV1 exposed something that we were all unaware of. During a typical dyno pull since the dawn of dynos, we would always see the horsepower numbers rise and fall as the runs progressed. As the years passed we attributed this to dyno data acquisition systems. But if you’ll notice on the SV1 those rises and falls are almost completely wiped out (by about 70 percent). Which incidentally coincided with the tightness of the average horsepower/torque output numbers the SV1 produced.
I was having a discussion with Warren Johnson concerning these findings as he had already suspected the same thing. Forcing an engine to draw out of multiple barrels contributes to pulsey operation. However, by combining the pulses (using a single barrel) allows a more consistent draw from the system and better overall metering as a result (less pulsey in operation). The dyno results in these tests have unarguably proven this theory.
So all this time when we thought the dyno data acquisition was spikey in its recording processes, it was the four barrel carburetor causing these spikes. The dyno data acquisition was actually accurate all along. So the SV1 surprised us all by exposing that as we had never seen or heard that smooth of a pull before with any four barrel carburetor design.
Anyway, back to our test. We would like you to note some interesting things about fuels during these tests that you can apply to your program.
As you all know, E85 was showing itself to be the latest rage in fuels. It has high octane ratings and its cheap. But the downsides are its corrosive like Alcohol and makes less power than alcohol. So once you step the fuel system up to do E85 you are so close to being able to run alcohol and see the big power jump that alcohol gives you…you may as well take the step.
Lets for example a 360 c.i 700 h.p. engine on E85 it may gain 5-10 h.p. But now as an example a big block Chevy 468 c.i. 700 h.p. engine may gain 15-25 h.p. The lower h.p. per cubic inch engines will show the biggest percentage of gain.
But on alcohol a lower h.p. per cubic inch engine can gain 25-40 h.p. but remember fuel volume eats up corss section so there is a caveat there as well. A 2 h.p. per cubic inch and higher engines may see zero gain on alcohol. So fuels and their applications vary wildly.
So if you are driving your car on the street, E85 is a great fuel, if you are looking for a cheap race fuel for performance cars with a relatively non toxic exhaust emission that helps the car run cooler as well.
But it seems there is no clear cut winner when it comes to fuels. You have to weigh everything you need from your vehicle. Not in a million years would I run an alcohol car on the street. The fumes are toxic and on a hot summer day follow you around for miles. Some folks don’t mind the fumes though, so to each his/her own.
Now if we are going racing, oh man Alcohol is the way to go for sure. It’s proven itself to be the most consistent fuel on the planet….OOOPS maybe not anymore. VP Q16 is a gasoline, yes you read that right. A gasoline that can run with alcohol in consistency.
We dyno tested Q16 in an SV1 and the mirror repeatability was just amazing it was as tight or possibly tighter than alcohol. Here comes the downside, wow is that stuff (Q16) expensive and wow is that stuff corrosive. Possibly more corrosive than alcohol. But in our test it made as much power as alcohol without the big fuel system requirements.
So we switched to C12 as a comparator. The SV1 carburetor on C12 fuel was more consistent than a four barrel carburetor on alcohol OR Q16. Obviously a SV1 on Alky or Q16 was even better, but you get my point in that we have options. So in the end, in the consistency test you can have a combination that will run the number and win races and use a fuel that is not corrosive, not terribly expensive and available pretty much anywhere. The only thing you have to do is realize what your wants and needs are and then spend your money in that direction.
The fuels and the induction systems are out there, but there is no clear cut winner on choosing a fuel. Everyone is doing something different with their programs and has different things they will tolerate. Then there’s always the other factor….some like Blondes and some like Brunettes. I prefer whatever hair color my wife is wearing at the moment…was that a good answer honey?