ORIGINAL: nitrorevo
Very nice and clean build Brent. I looks well thought out. With the carbon fibre chassis and no rear bulk heads, on the surface it looks a bit lighter than the Walbern, even with the slightly heavier side pipe. You weight them both yet? I'm sure you have the matched pipe for your engine which IMO is better than the Macs as who knows the perfect length to cut those for max power, the sweet spot is small, and every engine is different. That along with the more efficient transmission and the very short header to get on the pipe quicker and for more top end, could prove to be a great combination.
If you don't get any rear chassis flex, this is gonna be one of your best projects, and you gonna run some great times to prove it.
I am taking the same route with the matching engine pipe combo. I have seen and read enough now to convince me that faster spool up and rpm with the right amount of torque, not over powered, but a good power to weight ratio yields the best results. Keep me posted on the test runs, and also let me know how the dual head button tests come out. As you know Rick is already doing my RB V15 and I have spoken to him about getting a kangaroo done later this month. I may do the head button as well, if the tests prove to make more power without impacting tuning.
Good luck man..
Well the new car is actually heavier. It comes in at 49 oz. whereas the Walbern is 44 oz. Both have fuel in them and servos. The reason the new car is heavier is that the rear chassis plate is much longer BUT I never made cut-outs in the chassis like the Walbern is. I know that if I traced the Walbern buts and did it so to mine that I could shave off 4-5 oz. The 1/10th scale transmission with the .08 gears rolls soooooo smoothly on the floor plus it is 22 grams lighter than the 1/8th scale Mugen trans in the Walbern car so less rotational mass is a good thing.
The pipe deal is definately going to be a side pipe this time. This 'roo on this car has already been tested with the pipe which is an 086 OFNA and ran GREAT. In my CD3 and 'roo, I got some 2.0's and the car was not stable the entire runs. It was making power and spinning the tires so 1.9's are there and this was with my 086 pipe and in a street car that weighs 4 lbs. minimum. There's a guy in Australia that run nothing but boat pipes and he ran a 1.604@85 MPH[X(] with a Novarossi 9886 side pipe and the reasons for the side pipe he said was the inconsisten boat pipe tuning and boy do I know what he means. I do have the boat pipe for now on the one car and will leave it there for now.
The dual plug heads do work but I will warn you that you need to know all you can about shimming the motor correctly or else bye-bye piston. The bore of the button is deeper than a standard button and sits lower in your sleeve which makes more compression than needed plus if not shimmed right, your piston will hit the button ever so slightly and wear the rod out on the big end.......ask me how I know.[
] The tune up can be finicky as well because of two plugs and so far though, my single button that came with the engine has produced my best times because of consistency. The dual stuff is still out in deliberation as at the track it is really hard to test it when you are also at a race. I do know that it can make more power, it is just more tuning involved with the pipe, header, head shimming, nitro content, gearing, traction compound, carb inserts and all because of the dual button[:@]. Imma try and get it all together though and let you know.
Hopefully you get your Rody V-15 back and whoop some azzes around there. If you get a 'roo from Rick, you will have an instant low 1.7 engine and with more tuning, etc. you can run 1.6's as there are several of Rick's 'roos around here that run 1.65 to 1.78 ranges. It's just getting the rest of your car tuned and dialed in to make the engine do what it is capable of doing. Keep me posted on your stuff too man.