Honda 600cc F4i Engine versus 600cc RR Engine

[Justin Hodge]

Has anyone had luck converting from the F4i engine to the RR engine?

[Ryan Schoffer]

define 'convert'

the only big difference is the higher rev limit - i think the other differences are some internal forged vs cast parts, and perhaps slightly different head design

what im saying is, you could probably get most of the power of a RR motor out of a standard F4i, but dont expect it to last

at those high RPM numbers, the restrictor is going to really hurt you, so IMHO its a waste of time since you will get the best power down lower

[Charlie]

Its a totally different engine. It has some similarities to the R6 design, which some claim can shorten your wheelbase. I disagree. Its the same weight as the F4i, with what looks like a higher CG. I wouldn't be suprised to see a couple in Detroit.

Not sure exactly what you mean by your statement, 'having luck converting' either.

[vinHonda]

Definintely looks like a higher Cg. It's definitely a totally different motor.

But what are you going to gain? A few more revs? Too bad we don't race in F1.

Vinh

[Justin Hodge]

What I'm saying is that we have been running the F series motor for a long time and my team thinks the RR is a better engine. I have heard rumors that it's .7kg all the way up to 11 lbs lighter than the F4i. The pistons are forged and I believe the crank is lighter. I perosnally see no problems with the F4i engine.

[Charlie]

Its been awhile since I researched the RR engine, but its definitely not 11 lbs lighter. The difference is negligible, a pound or two at the most.

If they think its the better engine, ask them why? http://fsae.com/groupee_common/emoticons/icon_wink.gif Sounds like they don't know a whole lot about it. http://fsae.com/groupee_common/emoticons/icon_razz.gif There is some good info on the web about this engine and lots of pictures. Decide for yourself, it might be a good choice for your setup.

[Justin Hodge]

Well we have one in our possesion and we will put it on the Dyno shortly.

[Ehsan]

Interestingly, the F4i and 600RR have the same claimed dry weight from Honda. Its listed at 370 pounds. The RR motor has a few more horsepower and a slightly higher redline, which is almost certainly due to slightly better internals. Overall though, the motor is not the big change between the two bikes. Its the chassis. The F4i was not much of a departure from the previous generations of 600cc Honda sportbikes.

The RR on the other hand is based very closely on the RC211V MotoGP bike. The big key here is the Unit Pro Link Rear suspension that puts the top shock mount within the swingarm, thereby reducing bad forces entering the chassis. Thats the big difference with the F4i and the RR. More so than the motor anyway. Like Charlie said, there's a ton of info about the two online. Find it and make a decision based on your own needs and requirements.

[Ryan Schoffer]

i think one of the biggest benifits to running an F4I is the amount of parts avaliable from motorcycle recyclers, off ebay etc. as well as being able to get help from about 70% of the other teams in terms of both technical help and spare parts both on these forums and at competition

[aniLD]

Are there any teams that use the RR?

Is there any advantages you found with this motor?

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Charlie:
Its a totally different engine. It has some similarities to the R6 design, which some claim can shorten your wheelbase. I disagree. <HR></BLOCKQUOTE>

I disagree with you Charlie. You may be right if you install the engine in it's stock orientation but it's fairly obvious how to change the installation to obtain the shorter wheelbase.

We managed to take about 100mm off the front of engine to rear axle centreline distance, about half was from the engine and the other half from a clever driveline design. In the end we didn't use this to reduce the wheelbase rather to recline the drive within the same wheelbase to lower the CG further.

Ben

[Charlie]

Well all our cars are very unique. In our case we are totally limited by sprocket orientation. The R6 sprocket to exhaust distance is approximatly the same as the F4i. It is perhaps a bit shorter, but less than a half-inch or so. For us this means it does not allow a shorter wheelbase, only results in a higher CG. We have run a much different final drive than most teams, which means we struggle to get enough chain wrap. If this is not your limiting factor then the R6 may be more beneficial.