knight Posted November 27, 2003 Share Posted November 27, 2003 I dunno if you speed crazed bunch of nutters are interested in this or not, but I picked this snippet of info off another site about 2 years ago - I have since done the simple mods to my engine and its now a flying machine! you can probably do the conversion with all the bits from a salvage yard for less than 100 bucks! the following parts you need for the conversion are from a carbed CBR600 F3 - which run ram-air as standard:- -Vacuum chamber vent filter (measeres about 2 by 4 inches) with inlet snorkel -Float chamber vent filter (measures about 1.5 by 1.5 inches) with inlet snorkel -Electric fuel pump - a point of note, this CBR600 F3 fuel pump is a very clever piece of kit! it has a small 4mm bore signal pipe that I connected to a 4 mm spigot on the float chamber vent filter (the 1.5 by 1.5 item) what this does is increase the fuel flow rate as the air box bressure rises to around 1 to 1.5 psi at full speed......it works a treat -You may want to block off any holes inside the air box with silicone bath sealant, such as the 2 water drains and breather, route the original breather pipe into a small catch tank. otherwise the air pressure will piss out of the holes! So here goes.........I have modified the instructions below slightly as his original instructions were a bit vague, if you follow this to the word it will work first time.......if its tested on a rolling road with simulated wind blowing to pressurise the air box, it should add around 5-6bhp..... Wone K. Yip, Canada My base mods are a Dynojet kit, K&N filter, Kerker Slip-ons. 143 rw hp 84 ft lb torque The Ram air quest begins with obtaining the left &right ram air snorkels, 2 stubby air box snorkels from your local Honda dealer. Various hosery, and 2 Honda inline filters for the carb pressurization hoses. (options: 99 oil cooler, shorter 99 oil lines, inner body work) 1.Remove the oil cooler, and oil cooler air duct. 2.Relocate oil cooler directly below triple clamp (either shorten lines or get 99 XX lines. 3.Re-position the horn by mounting it 180 degrees from it's original position. 4.You must pressurize the carb float bowls and vacuum chamber vents! Using the 2 float chamber overflow pipes, and the central big bore pipe for the vac slide vents. Route the 2 carb vent hoses into one hose, with a minimum of 13mm bore (use the CBR 600 stuff) and route it to one of the small snorkels. Then route a hose from the central vacuum slide vent hose (min of 13mm bore) into the other snorkel. I disconnected the pulsed air injection system , make sure if you do, that you run a little hose between the brass fitting and the little black one way valve on the side of # 4 carb, 98 models don't have it apparently. Install the CBR 600 F3 inline air filters in each line. The 2x4" item in the vac slide vent line and the 1.5 x 1.5 item in the single float chamber vent line......now place each snorkel INSIDE the ram duct and make sure its forward facing to the air flow..... possibly so you can see it at the front of the bike. 5.Install the ram ducts and position the fairing in place. Things slip in place fairly easily but keep an eye on how things go back in place. 6.The inner cowl panels must be trimmed a few inches to clear the underside of the ram ducts as you will discover. (If you want to do it really neat, buy the 99 inner cowl pieces, 99 oil cooler and lines and other associated bits. All it takes is more money! NOW... the big issue..... Since you are pressurizing the air box and the carbs above atmospheric pressure, it became apparent over 200 kph that it starved dramatically for gas. Logically, since the fuel is gravity fed at normal atmospheric pressure, higher than normal pressure in the bowls will overcome the flow of fuel to the point of preventing it from entering the bowls. SO.... a 2 psi electric fuel (supply) pump added to the system , has totally cured any starvation problems! I did end up dropping the needles one clip to compensate for a bit of richness/hard starting, on hot days. You must add a fuel pump... unless you like putting around mostly around under 120 mph!!! 7.Button up and recheck all re-connections..... Have fun! I can say that even the fresh air access to the air box in itself helps overall performance. 160 kph and above however, there is a very noticeable improvement in the roll-ons. I am consistently 2 tenths and 1-2 mph quicker in the 1/4 mile than before. Unfortunately, the ram air mods can't be demonstrated on the dyno but but it has been on the drag strip and the seat of the pants dyno! A stainless steel 4 into 1 exhaust is on order.. will keep ya'all posted I guess the quest for 150 hp at the rear wheel without internal motor work is on !! Quote Link to comment Share on other sites More sharing options...
knight Posted November 30, 2003 Author Share Posted November 30, 2003 so is anyone interested in this then? :mad: ....it took me a good 30 minutes to type all this lot..... and not a reply to be seen! - I'm assuming your all out raiding the breakers for CBR600 F3 parts?..... :grin: Quote Link to comment Share on other sites More sharing options...
Redbird Posted November 30, 2003 Share Posted November 30, 2003 Sorry, mine's injected. Thanks for the effort, though. Board has been slow the last few days, you may see more response after the holiday weekend is over, a lot of these guys are logging on from work. Quote Link to comment Share on other sites More sharing options...
pace Posted December 1, 2003 Share Posted December 1, 2003 Thanks for the groundwork. It looks interesting, but seems to involve a lot of work for just a ~5HP topend gain. I will probably take another look at it after the winter and see if it's something I'd like to tackle. Cheers! -Pace Quote Link to comment Share on other sites More sharing options...
typhoon186 Posted December 30, 2003 Share Posted December 30, 2003 And I believe tests have shown you have to be going well over 100 mph to get any advantage from ram effect. That's why Honda did not use it in the first place. The only reason it's on the newer model is because people like to hear it has ram air. What wast the top speed gain from the non-ram air bird to the ram-air bird? Quote Link to comment Share on other sites More sharing options...
MaXX Posted December 30, 2003 Share Posted December 30, 2003 I'm interested Knight, how is fuel economy afterwards? I try to spend as much time above 100 MPH as possible so I might try this. MaXX Quote Link to comment Share on other sites More sharing options...
erixx Posted December 31, 2003 Share Posted December 31, 2003 stupid question: wouldn't making the side air inlets of the carb'bird bigger convert it into a ram air? What wonders does a proper ram air do that the ordinary inlets don't? I understand your proposal is complex and clever, thanks for the brainpill! Quote Link to comment Share on other sites More sharing options...
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