7800 rpm

[hombre]

I've reset my rev limit to 7850 RPM, in preparation for a dyno run to 7800 on Monday. I need to see how close we get to the theoretical speed (by gearing) of 208 MPH in 5th gear @ 7800 RPM. If we can't do it on the dyno, we sure won't do it on the track.

Other SC R3 owners please note: DO NOT TRY THIS WITH YOUR BIKE!

My bike is specifically set up to make power at higher RPMs. I use much longer duration cams than stock, with much greater lobe separation, have an intercooler that halves my intake charge temps at 20 PSI boost, and a high volume fuel pump that can supply more than enough fuel for that boost. I'm also running 100 octane fuel (my own blend). A "standard" SC R3 will detonate at those boost levels due to excessive intake temps even if it has a high volume fuel pump. That's why the standard SC R3 has the IAT sensor before the supercharger (otherwise it would melt). Mine is mounted in the intake plenum just before the throttle bodies, where it does what it's supposed to.

All that said, she really ripped fine in the cool air this morning! She actually pulls harder from 6500 to 7700 than she does from 4500 to 6500. All that boost doing it's thang!

 

[warp9.9]

Looking forward to your Monday report Walt. Sounds to me like you will make your mark on the Dyno. Of course the bike having to move your weight might take a little out of her. Anyway just so she does not upset you, I will gladly take her off your hands

Just joking I to hope to hit them speeds sometime but as you stated and I agree. I will not atempt it till I get the intercooler From Richard, a set of cams and some head work. As I already know how damaged a engine can get.

 

[xhdskip]

Walt,
I admire the work you've put into your scoot.
Alot of forethought and ground breaking mods.
I for one (and I'm sure I ain't the only one) hope you make your
2 ton up record rocket run.

 

[snuffcityrider]

Best of luck!

Hope you hit that 200 mph mark, and then some. I wish that I had just a fraction of your mechanical ability( and your money).

 

[BigWillie]

Good luck on the run. I look forward to hearing that you made it. 200 is a huge milestone.

 

[travelguy]

good luck walt... dont know why but this reminds me of a jarhead avaitor that once commented to me that the f4 proves that given enough power even a brick can fly...

 

[Joker]

Good luck Walt, and don't worry, I won't be trying it on my bike. I'm nuts, but not that nuts....

 

[hombre]

Well, we learned beaucoup about supercharged R3s this morning. First the bad news; my R3 could not turn 200 MPH on the dyno even at 7800 RPM. All she had at that RPM was just shy of 197 MPH.

There was no valve float at 7800, and the engine suffered no ill effects from turning that RPM. However, my tune leaned out from 11.7 AF @ 7500 RPM to 12.2 AF @ 7800 RPM. Boost is in excess of 20 psi! The big news is that the 668cc Siemens injectors supplied by TTS are maxed out above 7500 PM. To properly tune a SC R3 over 7500 for speeds of 190+ MPH, larger injectors are required. I knew that larger injectors would be necessary at 8500 RPM, but didn't know just where the 668cc ones would max out. Now we know. We already knew that the "V-Stack" air filter pressurizes at 175 MPH, as it leaned out my AF by 1/2 point at that speed. I estimated that it would lean out by a full point or more at 200 MPH, so was hoping to tune for about 10.8 AF at 7800 RPM. That's impossible to do with the injectors I have now, so there's no point in trying for a 190+ MPH run when we'd run the risk of lean out at those speeds.

The good news is that I do know which injectors to use, and now know that I need the Carpenter valve train and forged pistons to reach 200 MPH... at some RPM over 8000.

 

[Joker]

Nice try Walt, sorry you didn't reach your target. At least you found the limits without wrecking anything (unlike little brother Warp), and now you know what you need next.

 

[RocketDaryl]

My goal is ride as SLOW as possible. I want all the wimmins to get as good of a look at my throbbing, ripped body and pretty face as possible.