tiddy1 Posted June 26, 2013 Share Posted June 26, 2013 I have a honda s800 race car and am looking to put a blackbird/ fireblade engine in, in place of teh std honda 800cc engine, now the problem is that the s800 has a drop down gear on the end of the gearbox which reverses the prop shaft direction so you can not justtake the honda box out and stick a nova reverse box in (or similar) unless you could run the nova boz backwards. ie in reverse for car going forward. I assume that the nova box is direct drive for forwards and step down for reverse so would not be happy running in reverse? The diff also runs 'backwards' so there are no different crown wheel and pinions available. anyone with good/ bad experiances with the nova box or similar Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 26, 2013 Share Posted June 26, 2013 Nova box is straight-through as standard, with a chain drive to an idler shaft for reverse. Wouldn't recommend running that all the time! How about putting the engine in the boot with a chain drive to the rear axle a la Z-Cars? Is there any class capacity limit you need to comply with? The Blackbird is actually 1137cc, which frequently puts it in with the big boy Hayabusa brigade. The latest CBR1000RR engine is 999cc and 178bhp so quite a handy lump! (Previous Blades are 893, 918, 929 or 954 cc depending on year.) Link to comment Share on other sites More sharing options...
Molecular--Bob Posted June 26, 2013 Share Posted June 26, 2013 Check the rotation direction of the engine and the prop. Honda engines (at least the FWD ones) used to rotate in the reverse direction to a conventional engine. You may be lucky and find that you are ok if the drop gear was there to change prop rotation to allow a conventional axle to be used? Link to comment Share on other sites More sharing options...
charlie_pank Posted June 26, 2013 Share Posted June 26, 2013 R1: 995cc, 180hp Link to comment Share on other sites More sharing options...
NoLimits Posted June 26, 2013 Share Posted June 26, 2013 Give me a call. I am just about to remove my Elite reverse box which is about 80 miles old and is direct drive forward and reverse dog to dog. Can run in either direction. Link to comment Share on other sites More sharing options...
Alan Reeves Posted June 26, 2013 Share Posted June 26, 2013 I cant believe that you would change from the original gem like engine...the ending of the Sprites Link to comment Share on other sites More sharing options...
tiddy1 Posted June 27, 2013 Author Share Posted June 27, 2013 Alan we have origional engines in the coupe and convertable but this is a pure mod sport car we want more power for playing, still going to keep it honda engine, and the origional one can just slot back in if needed. Rebuilding a race honda s800 engine can be pricey and the bits are getting rather hard to find. Link to comment Share on other sites More sharing options...
Alan Reeves Posted June 27, 2013 Share Posted June 27, 2013 I hear what you say. You have three, very nice. Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 27, 2013 Share Posted June 27, 2013 Quoting charlie_pank: R1: 995cc, 180hp That would be a *Yamaha* R1, wouldn't it? Link to comment Share on other sites More sharing options...
tiddy1 Posted June 27, 2013 Author Share Posted June 27, 2013 Alan to be honest none of them are actually mine, they all belong to a friend, I just get to play with them and help with the engineering challanges. The coupe is running on throttle body fuel injection taken form a honda motobike, which was an interesting conversion as we are still running the motobike ecu. Link to comment Share on other sites More sharing options...
NoLimits Posted June 27, 2013 Share Posted June 27, 2013 Simon - sorry busy on the other line when you called. Free now. Link to comment Share on other sites More sharing options...
charlie_pank Posted June 27, 2013 Share Posted June 27, 2013 Quoting Fred Gassit: Quoting charlie_pank: R1: 995cc, 180hp That would be a *Yamaha* R1, wouldn't it? Is there something wrong with that? You're not going to use the original engine, so why get picky about manufacturers? The hard work to get a bike engine in a car isn't down to manufacturer choice. If you wanted to swap my R1 for a blackbird, you'd have to make sure the input and output of the cooling system were the right diameters, do some fiddling with the loom and fabricate some engine mounts to make it fit. Oh and maybe make up throttle and clutch cables. Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 27, 2013 Share Posted June 27, 2013 The "Super 7" guys over in Canada use a chain drive adaptor for their LHD Hayabusa Se7en. You can just see it on this pic: http://proxy.baremetal.com/super7cars.com/images/006_Engine_RS.JPG I think it basically moves the engine over to clear the steering column, but I guess something similar could help you with getting the prop alignment right and spinning the correct way, plus maybe incorporating reverse? One off engineering though! (=$$$ 😳) Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 27, 2013 Share Posted June 27, 2013 Quoting charlie_pank: Quoting Fred Gassit: Quoting charlie_pank: R1: 995cc, 180hp That would be a *Yamaha* R1, wouldn't it? Is there something wrong with that? Yes, it's not a Honda... (And it's a bit weedy! ) Link to comment Share on other sites More sharing options...
charlie_pank Posted June 27, 2013 Share Posted June 27, 2013 Quoting Fred Gassit: (And it's a bit weedy! ) I think you might be confusing a gearing issue with a power issue Link to comment Share on other sites More sharing options...
charlie_pank Posted June 27, 2013 Share Posted June 27, 2013 Quoting Fred Gassit: The "Super 7" guys over in Canada use a chain drive adaptor for their LHD Hayabusa Se7en. You can just see it on this pic: http://proxy.baremetal.com/super7cars.com/images/006_Engine_RS.JPG I think it basically moves the engine over to clear the steering column, but I guess something similar could help you with getting the prop alignment right and spinning the correct way, plus maybe incorporating reverse? One off engineering though! (=$$$ 😳) There must be some other reason for that, surely a more sensible solution would be to put a linkage in the steering column, rather than the transmission? Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 27, 2013 Share Posted June 27, 2013 Quoting charlie_pank: Quoting Fred Gassit: (And it's a bit weedy! ) I think you might be confusing a gearing issue with a power issue R1 (2006): 78.6 lb ft Hayabusa (2009): 102.3 lb ft Ain't no substitute for cubes, Bubba! We are still waiting for some quantitative evidence that your R1 is as fast as you keep claiming... Get a move on man! 😬 Link to comment Share on other sites More sharing options...
elie boone Posted June 27, 2013 Share Posted June 27, 2013 They modifyed Hayabusa's to go into single seaters and use a Hewland, It would be a big challenge but maybe you could modify a blackbird to fit to a coventional gearbox, it would solve all your issues at once. Link to comment Share on other sites More sharing options...
tiddy1 Posted June 27, 2013 Author Share Posted June 27, 2013 Ok after a lot of head scratching and prop shaft twiddling I find that the honda engine spins clockwise viewed from front pully propshaft then spins anticlockwise (viewed from the front) so if we keep the drop down part of the honda geadbox then the blackbird engine will be spinning the right way the proble is the gear ratio, the diff is about 5.7:1 and there are no alternatives, (this is also going to limit us to 140 bhp max) The fireblade primary ratio drops the revs by 1.52:1 and with a 1.19:1 6th gear we are only going to get about 90 mph (hence why caterhams drop from 3.92 diffs to 3.14) as to engine choice the best for us would be a yamaha GSXR 750 as thi is the one we used for the fuel injection mod and so know all the wiring etc Link to comment Share on other sites More sharing options...
charlie_pank Posted June 27, 2013 Share Posted June 27, 2013 Good luck finding a Yamaha GSXR! Ain't no substitute for cubes, Bubba! 'Aint no replacement for displacement' is the old saying that gets wheeled out when people start bragging about muscle cars. My assumption is that it harks from an age when titanium valves were a dream and nothing revved over 5k. What you need to bear in mind is that: a) It is the power of an engine which determines how fast it can accelerate a mass. (Provided you have the right gearing). b) The power output is directly proportional to the rate of fuel burned. Therefore there are 3 replacements for displacement which immediately spring to mind: 1. Assuming the same filling rate (which isn't true, of course), then if you spin a an engine of half the CC at twice the speed, you'll make the same HP 2. If you compress the air before it goes in, then there's more fuel and air to burn per CC 3. If you reduce the mass you have to move, then you don't need so much power for the same acceleration. We are still waiting for some quantitative evidence that your R1 is as fast as you keep claiming... Get a move on man! My heart is beating to a different rhythm at the moment, you'll just have to wait. Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 27, 2013 Share Posted June 27, 2013 Quoting charlie_pank: My heart is beating to a different rhythm at the moment, you'll just have to wait. Ha-ha. Well, I say you're a weedy pigeon, and you can call me `Susan' if it isn't so. 😬 Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 27, 2013 Share Posted June 27, 2013 As a long term BEC owner, I have had the "bike engines have no torque" argument a lot of times. I always cite the statement that low(er) torque at high(er) rpm means you can take advantage of gearing. However... (Back on the cubes thing...) If you take a dyno curve for something like a R300 (175bhp), factor in the gearing, and then plot a "road speed vs. torque at the wheels" graph, and then compare the with the same plot for your R1, you will see a much greater "area under the curve" for the bigger cc engine. Edited by - Fred Gassit on 27 Jun 2013 19:29:17 Link to comment Share on other sites More sharing options...
charlie_pank Posted June 28, 2013 Share Posted June 28, 2013 The force is the expansion of the gasses in the cylinder pushing the piston down. The mass is the car. The resultant acceleration *per cycle* is lower with lower cc, but there are many more cycles per unit of time. Your equation of course also ignores any frictional or air resistance. Without them you'd be able to just keep accelerating forever... On a speed against time graph, the area under the graph shows distance travelled (speed x time). What does the area under a speed against torque graph show, I genuinely don't know. If you convert both to SI units you get m/s and nm. Multiplying them gives nm^2/s, what's that a measure of? Link to comment Share on other sites More sharing options...
charlie_pank Posted June 28, 2013 Share Posted June 28, 2013 Looking at it another way, why is my 675cc (69nm) motorbike faster over the quarter mile than my diesel estate (340nm)? When the former is roughly 1/5 the mass of the latter? Edited by - charlie_pank on 28 Jun 2013 07:17:27 Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 28, 2013 Share Posted June 28, 2013 It's all about Q-factor,isn't it. The torque-at-the-wheels curves allow you to make a genuine apples-for-apples comparison between the two types of engine. The larger capacity engine has a the same peak torque at the wheels, but it is spread over a much greater road speed range. That's the BEC trade-off. You get lighter weight (10 or 15%?) but you have to keep the engine buzzing in a narrower region to extract the same performance. Kinda like an old fashioned 2 stroke bike. Link to comment Share on other sites More sharing options...
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