Member Contributer kostritzer Posted August 13, 2009 Member Contributer Share Posted August 13, 2009 I've been curious about this for some time. I know that the RC45 has a completely different crankshaft and firing order, but I've heard that 5th gen VFR heads were used on some race RC45's, and that the overall engine architecture is basically the same. What I'd like to know is what the camshaft lift and duration is in comparison, as well as compression ratio, throttle body size, valve diameter, exhaust primaries and port diameter and anything else that is "different". Basically what I'm getting at is, why can't the 5th gen motor be tuned to near RC45 power levels? I know that the firing order is completely different, but I always thought that was to help rear tire traction and not neccessarily to increase power. Any thoughts? Larry? Link to comment Share on other sites More sharing options...
Member Contributer fastrc46 Posted August 13, 2009 Member Contributer Share Posted August 13, 2009 :fing02: Link to comment Share on other sites More sharing options...
Member Contributer kostritzer Posted August 13, 2009 Author Member Contributer Share Posted August 13, 2009 I had a feeling popcorn would be the first reply! Guess I'm not the only one who's curious eh? Link to comment Share on other sites More sharing options...
Member Contributer sa1713 Posted August 13, 2009 Member Contributer Share Posted August 13, 2009 .... .BLS..... Calling BLS..... Link to comment Share on other sites More sharing options...
Member Contributer fastrc46 Posted August 14, 2009 Member Contributer Share Posted August 14, 2009 I'm pretty sure I know the answers, but, Larry is the RC45 expert. I suspect the short answer will be the fact that the firing order is different. Thus any HRC kit part for the RC45 is not a swap. Crank, cams, fi, computer etc. Though I have read something about the stock heads being the same or similar. On the surface the two engines seem to be almost twins but, the differences are more than skin deep. That and the cost of the HRC parts, if you could even get them. I'm sure Larry will elaborate. Link to comment Share on other sites More sharing options...
Member Contributer kostritzer Posted August 14, 2009 Author Member Contributer Share Posted August 14, 2009 I'm sure Larry will elaborate. Thats what I was hoping for! I don't see how the firing order could make a major difference in the overall horsepower numbers, but maybe I'm missing something. I've built a few high performance car engines, and the power is pretty much always made with the cylinder head(cams, valves, porting etc.) and ecu tuning. I know a lot of people are using power commanders, but has anyone tried using an actual stand alone EFI system with these motors? AFAIK, the power commander is unable to control ignition timing on the VFR, and thats usually a good way to increase power on most engines. I'm sure thats part of why the RC45 makes more power. Of course our engines are designed to run on 87 octane, but if you take that out of the equation... Link to comment Share on other sites More sharing options...
Member Contributer Ryanme17 Posted August 14, 2009 Member Contributer Share Posted August 14, 2009 I'm sure Larry will elaborate. Thats what I was hoping for! I don't see how the firing order could make a major difference in the overall horsepower numbers, but maybe I'm missing something. I've built a few high performance car engines, and the power is pretty much always made with the cylinder head(cams, valves, porting etc.) and ecu tuning. I know a lot of people are using power commanders, but has anyone tried using an actual stand alone EFI system with these motors? AFAIK, the power commander is unable to control ignition timing on the VFR, and thats usually a good way to increase power on most engines. I'm sure thats part of why the RC45 makes more power. Of course our engines are designed to run on 87 octane, but if you take that out of the equation... Yeah, just like on any other engine, adjusting ignition timing (advancing at high RPM's, I'd imagine) and running a higher octane fuel is theoretically good for some ponies. I think Power Commander II's can adjust ignition timing, anyone tried this, and someone said the rapidfire module can, anyone tried this? Link to comment Share on other sites More sharing options...
Member Contributer fastrc46 Posted August 14, 2009 Member Contributer Share Posted August 14, 2009 A stock RC45 actually makes less power than a 5th gen stock. To make more power on an RC45 you need to install all the race kit parts from HRC. You can't for example just switch the cams. The valve timing is different between the 360 deg. RC45 and the 180 deg. VFR motor. And I don't believe any of the race kit stuff will even fit a VFR motor, if you could even get it. The best thing you can do is buy the toro-charger and supercharge it. It would actually be cheaper. Link to comment Share on other sites More sharing options...
Member Contributer kostritzer Posted August 14, 2009 Author Member Contributer Share Posted August 14, 2009 A stock RC46 actually makes less power than a 5th gen stock. To make more power on an RC45 you need to install all the race kit parts from HRC. You can't for example just switch the cams. The valve timing is different between the 360 deg. RC45 and the 180 deg. VFR motor. And I don't believe any of the race kit stuff will even fit a VFR motor, if you could even get it. The best thing you can do is buy the toro-charger and supercharge it. It would actually be cheaper. I'm not considering installing any RC45 specific parts on an RC46. I know most won't fit and I'm sure they're pretty much unobtanium anyway. I know the cams won't work because the valve timing is different, but it might be possible to have some RC46 cams ground to RC45 specs for lift and duration. If I had a set of RC45 cams I could put them on a cam doctor and see what the specs are, anyone have a set they want to let me borrow? :blink: The toro-charger is awesome, probably the nicest supercharger kit I've ever seen for ANY engine. The quality of the hardware and machined pieces if beautiful. I've always been a fan of naturally aspirated engines however, and am just curious to see what the potential of this engine is without forced induction. Link to comment Share on other sites More sharing options...
Member Contributer BusyLittleShop Posted August 16, 2009 Member Contributer Share Posted August 16, 2009 Any thoughts? Larry? My thoughts are this even if you up the power on the VFR the suspension and chassis won't give you the confidence to go much quicker... what makes the RC45 special is all parts gel into a totally user friendly package... Kevin Raymond explains... HRC design goals for the RC45... What an RC45 makes on the dyno after Rob Lindeman's home made titanium exhaust... Quote Performance Bikes on engine characteristics "The RC45 motor feels like a VFR except with more of everything-acres of torque and smooth power delivery. Basically the RC45 gives you it all- bottom end plod, midrange drive and top end rush. after all the RC45 was inspired by the RVF-a hand built Formula One missle." Stock versus HRC kitted RC45... HRC even provides a blue print of extra port work an owner can invest in... Link to comment Share on other sites More sharing options...
Member Contributer kostritzer Posted August 16, 2009 Author Member Contributer Share Posted August 16, 2009 My thoughts are this even if you up the power on the VFR the suspension and chassis won't give you the confidence to go much quicker... what makes the RC45 special is all parts gel into a totally user friendly package... Kevin Raymond explains... I definitely would not argue that. The RC45 is an amazing motorcycle no doubt about it, and its obviously the complete package. Unfortunately not everyone can own this little piece of Honda brilliance, there weren't that many made, and they're a bit pricey when you do find one for sale. There are still plenty of VFR owners who would like a little extra power, and don't want to sell their unique V4 to have to get it. Suspension can be upgraded pretty easily, and while it probably won't make the bike handle anywhere near as good as an RC45 or most of the current road racers, it would likely be more than most of us would ever need on a sport-touring bike. My original question was about the motors themselves, and what the differences are, regardless of what chassis they're utilized in. And I'm well aware of the different crankshafts and firing orders which I believe is mostly irrelevant in regards to power output. I'm not trying to take anything away from the RVF by comparing it to a 5th gen, but a machine is a machine, and when the parts are this similar (interchangeable heads!) there has got to be some potential for more power with the VFR. Thanks for posting up the Honda info that shows the differences between the standard and HRC kitted RC45. It looks like compression is higher, ignition timing is more aggressive, and the cam timing is completely different which is to be expected. The rev limit is also higher, so obviously the cams are designed to increase power up top(probably everywhere as the torque is higher as well). Basically all the typical tricks to making a normally aspirated engine more powerful are implemented on the HRC bike. Do you know what the throttle body, and intake and exhaust valve diameter is on the RC45 Larry? Link to comment Share on other sites More sharing options...
Member Contributer BusyLittleShop Posted August 16, 2009 Member Contributer Share Posted August 16, 2009 And I'm well aware of the different crankshafts and firing orders which I believe is mostly irrelevant in regards to power output. VFR riders that have been lucky enough to sample Mr.RC45 swear it produces more torque than their VFR but it doesn't... it just feels like more on the seat of your pants courtesy of the 360º Big Bang engine... that's why Honda only raced the 360º... it's a shame the VFR got slapped with the 180º back in 86... because prior to that year all Honda's V4 were 360º Big Bang... it was marketing who discovered that the buying public didn't like the drone of the Big Bang and Honda could sell more V4s if they phased the crank 180º... but I hope that the sounds of MotoGp Big Bangs may shift the buying publics preference back in favor of the 360º over the 180º... For part compatibility check your VFR parts code... any part with an MW4 is an RC45 part... any part with an MR7 is an RC30 part... your 5th gen VFR code is MBG... http://fiche.ronayers.com/ Example VFR part number for the valve springs is 14751-MW4-003... the MW4 code means this part was specifically designed for the RC45 but it is also cleared by engineering to fit the VFR... Do you know what the throttle body, and intake and exhaust valve diameter is on the RC45 Larry? 46mm throttle bodies... Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted July 26, 2012 Member Contributer Share Posted July 26, 2012 Well based on this & other research, I have had a set of cams reground based on RC45 cam timing & here are the results. This matches exactly the performance level for a standard RC45 with Slip on can, but as expected with the extra 32cc & slightly higher compression ratio, it makes more torque & power everywhere compared to a standard RC45 in the same state of tune. & as I have reduced the wet weight to 208Kg which is less than a standard RC45, it looks like a match in engine performance terms. Stock VFR = 95rwhp VFR mods1 + map = 102rwhp (+7hp) VFR mods1 + cams + map = 107rwhp (+5hp) Total = + 12hp or 12.6% power increase. Check here for the full SP - Enjoy Link to comment Share on other sites More sharing options...
AB-Oz Posted July 26, 2012 Share Posted July 26, 2012 now that's what I call a thread update!! Wow. Link to comment Share on other sites More sharing options...
Member Contributer vfrcapn Posted July 27, 2012 Member Contributer Share Posted July 27, 2012 it's a shame the VFR got slapped with the 180º back in 86... because prior to that year all Honda's V4 were 360º Big Bang... Picking up on an old comment, does this include the 1000's, or were you referring only to the 750's? Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted July 27, 2012 Member Contributer Share Posted July 27, 2012 it's a shame the VFR got slapped with the 180º back in 86... because prior to that year all Honda's V4 were 360º Big Bang... Picking up on an old comment, does this include the 1000's, or were you referring only to the 750's? IIRC it was for anything with the prefix of VFR...since the 1000 was a VF1000R I believe that the crank was not yet changed from the VF1000F Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted July 27, 2012 Member Contributer Share Posted July 27, 2012 Nice write up on the other site, but brrrr.... adds popping up everywhere.... Me liky add-free VFRD! Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted July 27, 2012 Member Contributer Share Posted July 27, 2012 Added it to VFRD now, sorry about adds on PIC site, its free so such is life. It never used to do that. Don't have time right now to sort pic on VFRD upload, but will attempt it next week. Link to comment Share on other sites More sharing options...
Voided76 Posted August 16, 2014 Share Posted August 16, 2014 What I wanna know is: What diameter are the RC45's throttle bodies as compared to the VFR800? especially in race trim? the VFR800's TB's look like peep holes. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted August 16, 2014 Member Contributer Share Posted August 16, 2014 Vfr800 has 36mm TB's. RC45 Std & Race have 46mm TB's, but that is because WSB rules say you can't change them or did at the time. So Honda cheated & added 40mm restrictors in the Velocity stacks so the street bike would run properly, but once you add the race kit you ditch the velocity stacks for the race versions & get the full breathing version. Larry machined up a set for his bike & lost power with the big velocity stacks as the standard bike can't breath properly with them. The BioBlade makes, 124rwhp & uses standard 800 TB's & airbox. Just added some cams & a one off Akrapovic exhaust, plus a power commander & some fine tuning. Link to comment Share on other sites More sharing options...
Member Contributer gmtech94 Posted August 16, 2014 Member Contributer Share Posted August 16, 2014 I rode #001 for a while during the break-in and some after that I did not find it to be all that much more pwerful or fun to ride then the Rc30 bikes . Those bikes were tiny and handled so well out of the box .Cost for the 45 was astronmical here in Canada so caution was the name of te game when riding public roads , Mosport was another story. Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 17, 2014 Member Contributer Share Posted August 17, 2014 What I wanna know is: What diameter are the RC45's throttle bodies as compared to the VFR800? especially in race trim? the VFR800's TB's look like peep holes. Dude... you dig up and old thread (which, BTW... I'm glad you did... lots of good info), but then you ask a question that is answered right in the thread like 6 - 7 posts earlier... BLS shares lots of great RC45 info... you should read what he has to say... Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted September 11, 2014 Share Posted September 11, 2014 Guess where my throttle bodies are about to go to.... http://maxbore.com/ Then sending the injectors of to: http://www.witchhunter.com/ and replacing the plugs for good measure before installing the Rapid Bike Racing. I am thinking we're gonna see some really good numbers, and the engine hasn't even been opened up, yet Link to comment Share on other sites More sharing options...
Member Contributer trjerm Posted September 11, 2014 Member Contributer Share Posted September 11, 2014 On my 4th gen, they had the stock cams welded and reground to the HRC RC30 race specs, than rejetted so that it'd work w/the new cams, and it made a huge difference in the performance(along w/ porting, lightnining,shot peened and balancing crank and adding short skirted slipper pistons, non cush drive spocket carrier, etc etc etc)So possibly if you could get the HRC RC 45 cam race spec's and have your cams welded and reground to those specs or possibly somewhat less and than used a power commander and a race exhaust , I'd think that you'd wake the engine up Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted September 11, 2014 Share Posted September 11, 2014 Yup we have the HRC RC45 cam specs and a few guys are in the process of throwing CBR929 pistons in right now. I already have a full two brothers racing exhaust on my bike now and Rapid Bike Racing computer on the way. I am going to have to wait on pulling the engine for the cams/porting/pistons, but I am sure that I will see great gains with the full exhaust/throttle bodies/ignition advance/fueling corrections alone. Link to comment Share on other sites More sharing options...
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