Race Fuel!

[cOoTeR]

Today I picked up a 5 gallon pail of VP racing fuels Q16. It's listed as a 120+ Octane (116 Mon, 120+ Ron), leaded oxygenated fuel. Next Friday I'm taking the bike in to get 2 tunes. It has already been tuned on 91 Oct for the stock setup with a Sprint air filter and went from 164hp at the wheel to 213whp. Now the bike has a full exhaust system. I'm going to have F power mode tuned for 91oct then when that's done were going to take the fuel out and put in the Q16 and tune M mode for it. I can't wait to see the gains. I kind of took a gamble going straight to the Q16. As long as the stock fuel system can pump enough fuel it should pay off though.

[Drnick]

Leaded?

[cOoTeR]

Leaded?

Yes.

[FJR919]

Why leaded? I thought the only benefit to lead as an additive was to protect exhaust valve seats in older engines (usually pre-1972) that don't have induction hardened valve seats.

[Champ87]

Why leaded? I thought the only benefit to lead as an additive was to protect exhaust valve seats in older engines (usually pre-1972) that don't have induction hardened valve seats.

Lead was added to fuels to increase octane rating to reduce detonation. Damage to unhardened valve seats was one of the effects of detonation but other components can suffer as well. Pistons and rings can be prone to damage from severe or sustained detonation - an effect witnessed by those of us who have raced tuned two-strokes (fortunately never on my bikes).

Hard to see what the benefit of lead might be in an H2 SX - it's my understanding that similar performance benefits can be had from unleaded race fuels. Maybe buying that particular race fuel is more to do with cost/availability. That's just me guessing so maybe cOoTeR can fill us in on his choice of that particular fuel.

[XcelleraThor]

I trust you already removed the kat, otherwise the lead in the exhaust will kill it and render it useless.

We have compulsory technical inspections of vehicles here every two years and I don't think I'd pass one without a kat under the bike. It would either be visually obvious or show up in exhaust measurements.

Unfortunately :-(

[cOoTeR]

Why leaded? I thought the only benefit to lead as an additive was to protect exhaust valve seats in older engines (usually pre-1972) that don't have induction hardened valve seats.

I contacted a few LSR and drag racers who run boosted motorcycle engines as well as a few tuners and race shops. E85 or C85, C16 and Q16 were the what was recommended for my set up. All said that E85/C85 were the best bang for the buck but were most likely to need an upgraded fuel system. With the inconsistencies if pump E85 in my area I would prefer to go with a race fuel brand which would negate the cost savings. All said C16 and Q16 would make the best power across the rev range with Q16 being better as long as the fuel system can keep up. VP racing says Q16 normally requires a 4-6% increase in fuel flow. I'm hoping that the fuel system has the ability to cover that without being maxed out.

With the static compression ratio of the H2 being 11.2:1 and running about 16psi of boost (based on bike showing 220% atmospheric pressure with 100% atmospheric being 0 psi of boost. Atmospheric pressure is around 14.7 so 120%of 14 is 16.8). The effective compression ratio becomes 22.8:1 to 23.4:1 depending on the altitude in my area. With that high of an effective compressing ratio I figured the more resistant the fuel is to detonation the better.

Also there is a shop near by that has Q16 readily available.

[cOoTeR]

Stock tune and exhaust the bike did 164hp to the wheels.

De-restricted and tuned the bike did 213hp to the wheels. About a 30% gain.

Full vandemon exhaust with tune for stock pipe bike did 217hp.

Tuned for full exhaust on pump gas bike did 221hp to the wheel. About an additional 4% gain for pipe and tune.

We put the race fuel in and as expected it lost power, down to 212. We tuned it richer and gradually advanced timing until we were 7 degrees over the pump gas tune. It made 237 at the wheel. But back to back runs the power dropped to 231 as it got hotter. We pulled 1 degree of timing from up top and it made 233hp to the wheels and stayed there for multiple runs. So the race fuel tune gained about another 5% gain in power with a safe tune. If I was racing for money or glory I'd keep the extra degree of timing and risk it. But I'd rather have a safer tune and more consistent bike.

The tune for the stock exhaust was done in temps about 10-15 degrees F warmer and less humidity. Today's temps were in the low 80s and humidity was over 45%. I'll get the graphs posted later when I have better signal.

I can't wait until November 5th. Some friends and I rented out a near by track so I'll get a chance to burn off the 3 gallons of race fuel I have left.

[cOoTeR]

A side note. The H2R style muffler is really loud! My son and I went to eat about a 1/2 mile away, a little closer as the crow flies. When we left the restaurant I heard what I thought was a bike hauling ass down the street. Then I realized the sound wasn't getting closer just louder. It was my bike on the dyno. It also puts out a lot of heat at the top of the rev range. About 6 ft away it felt like standing by a bonfire. The bike is really dirty because it was raining this morning when I was taking it there. Here is a video from the back side of the bike filmed from behind the door frame. Sorry for the poor audio quality, my phones mic couldn't handle the sound.

[cOoTeR]