Finally got my 8 on my 08

[Draco1340]

OK, so I kind of cheated.

I have been working at getting closer and closer to getting an 8 second pass all year with my Gen II with no motor modifications but a pipe, power commander, air shifter, 87 octane pump gas, and 6" stretch.

By summer I was running 9.2s. I lost 20 pounds (down to 178 lbs) to go even faster.

By fall, I was consistently in the teens. Since September, I have been running 9.0s.

On Saturday I ran 9.05, 9.03, 9.03, 9.07, 9.03, 9.04. AGGHH. No 8!lease:

Screw it. On goes the bottle, with a very small 15 to 20 HP shot. BINGO! First pass: 8.98 with a crappy 60 ft. I later jacked up the pressure to get me 158.8 mph.

 

[boosta1395]

Great. Congrats! Your bike looks bad a$$ weight never goes out of tune.

 

[Wheelie]

are you using a spraybar? I have a feeling my 08 will have an ezbutton by Spring.


wee

 

[BusaWizard]

Mine too.

 

[PADEROLIS]

Bada$$ photo! Congrats on your passes!

 

[BA BUSA]

Congrats

 

[Draco1340]

are you using a spraybar? I have a feeling my 08 will have an ezbutton by Spring.


wee

No spraybar. I'm using 2 15HP jets in the 2 inlets to the airbox for a very soft hit in second gear. My pressure pro N2O regulator was set for about 550 PSI, and I later turned it up to 700 PSI for a 158 MPH pass. I recently purchased a USB hub for switching maps on the fly, and hopefully this will help. Right now the bike is running super rich in first until the spray kicks in in second, and then runs a pretty steady 12.5 A/F through the rest of the gears.

 

[Raced Guy]

Great job, what are you set at on your lowering links with the 6inch arm. Im trying to figure out if i need a longer tail. Looks like the guy in the other lane had a good run also.

 

[Draco1340]

Great job, what are you set at on your lowering links with the 6inch arm. Im trying to figure out if i need a longer tail. Looks like the guy in the other lane had a good run also.

Mine is -3" in the rear, but I need to go lower. In the lowest position you will hit with the stock tail if you are stretched more than 3" (with a GenII).

 

[Raced Guy]

I was thinking that would be an issue, oh well just have to plan on more parts then !

 

[justa-busa-girl]

thats awsome and great pics too!!! now how did you loose that 20 pounds lol?????

 

[Scar]

Why the 87 octane? I know the Gen2 calls for premium unleaded...

How is it you're running the lower grade?

I'm really looking for a square answer here...no 'scarcasm' at all inferred or implied.

 

[Draco1340]

Why the 87 octane? I know the Gen2 calls for premium unleaded...

How is it you're running the lower grade?

I'm really looking for a square answer here...no 'scarcasm' at all inferred or implied.

Good question. Couple of different reasons:

The emperical answer - because I have run pump gas from 87 to 92, to 100, tuned 13.0, and have always made more MPH on 87. If tuned properly, its worth about a 1/2 mph. I also have noticed more of a tendency to detonate at anything over 13.4 with the 87, so tuning is critical. I wouldn't run 87 without an Innovate or equivilent. A well designed head (12.5:1 I think) can use that low an octane only if you don't lean it out.

The practical reason (and probably the best reason)- Because Dave Owen and Brock would / will both tell you to do it. In fact MR9 and MR11 race fuel are low octane, and thats the prefered fuel if you can get it in your state. I can't, living in the communist state of MA.

The scientific reason - Octane doesn't make power (obviously), BTUs do. To take advantage of octane you need compression and to deal with compression, you need timing. Running stock compression, you can get away with lower octan. Also, the dirty secret in the industry used to be that the cheapest way to increase the octane in pump gas is to increase the alchy content, and this does drastically cut the BTU/lb. Yes, you can tune for that by fattening it back up, but in general there is a slight energy content hit when going to higher octane. Thats slightly offset by the free oxygen content that alcohol has, but there is a net loss, albiet small. There is huge variation from pump to pump, and even between different times of the year, so again, you need to tune your motor with a datalogger. I did my graduate studies in the 80s working on fuel research "mule" engines, so if there was sincere interest I could direct you to specific SAE papers I refererenced or wrote, on how different energy content impacts power output. I'm not really doing combustion engineering anymore, so I point you back to the practical answers above.

BTW, with nitrous, all bets are off, and you run highest octane you can get.

 

[dadofthree]

Nice ride and very nice times.