Not today, but yesterday I was trying to finish off the ZX2R drag bike for the upcoming Gunnedah meeting. The bike didn't want to start, but after pulling the plugs and seeing how fowled they were, a quick clean and she fired up rough, but eventually cleared. I had put the bike on a diet, but I haven't had the time to finalise fitting everything properly. Plus, not being able to run the bike down a drag strip gives me little chance to check for issues. Victoria is back in lockdown, so the wife and I are in Tassie today and will stay here until it's 'safe' to return. This is how I left the bike yesterday. The one-piece, single seat rear section needs to be braced and fitted properly, so I will put the old rear back on when (and if) I get back.
This week it’s been taking daily records I’ve learnt when someone else try’s to fiddle with the bike thinking they can get something out of it doesn’t end well been looking at it and going for a walk asking about spark plugs battery cables and a petcock still no luck although a friend around the neighborhood says he has battery cables that’s good news tho and added spray starter fluid to things got the petcock that’s sealed from the inside on what I presume is res.
So... as I do, I managed to make one good move with one bad one. I got a good measurement for my intake runners- they flow perfectly to the head. Unfortunately the wall of the mandrels are too thin to get good clamping force on them! Lesson learned, you gotta look at both dimensions. Bead rolled the runners and the bead in the gasket is damned near right on the bead so I’m still fettling that. At least I popped one off the head and saw how heat baked the intake gasket was though. Now I have two problems to solve- getting 4 new intake rubbers and getting the runners to hold tight. Cut my plenum tonight, will draft up velocity stacks for the end of the runners tomorrow. I’m gonna end up with damn near 7” of runner, injectors on a straight shot and 5x the displacement in plenum volume. Closer than expected to what I wanted.
@maelstrom might be worth talking to, I believe he was doing some work with silicone rubber parts; better temperature resistance
I'm lost (again) I thought @DamnitLaverty was doing an EFI but obviously it is a turbo EFI. I am printing manifold stubs from nylon and then using rubber spigots to mount the carbs. This is because for some bikes, like my FZR400 you cannot buy inlet manifold rubbers anymore. Even if you could they would be Chinesium and only last 12 months. I do plan to make mini versions soon to suit 28mm carbs in the future. Silicone for coolant systems & Fluorosilicone for fuel systems - two different animals. Silicone will swell like a balloon if it gets near fuel.
The plan is turbo EFI, but not until I have spares... and I can't get spares until other countries let me in. I'm building it NA EFI for now, but everything I'd do for the turbo except maybe the throttle body location will hold up NA as well as turbo. I'm buying a spare set of carbs to do throttle body injection if I have to... but I'd like to build a manifold once and use it both times... gaining runner length can only help torque- and building the manifold now gets me my wiring length/location for the injectors. The ZXR 250 boots are still available, about 25USD/each. I'm just ordering them since mine are hardened and the o-ring at the bottom is done for on the one I popped off.
Not significantly, but it will set your tuning rpm, more than anything else. If the length is long, the resonant frequency is low. Your length mightn't be that different, depends what you want to achieve, but you might have to match the exhaust, too.
Also need to ensure there is enough velocity in the each runner....dual inlet tract systems have been used for a long time to gain torque by the use of high velocity (in the longer but smaller inlet tracts) and then at higher inlet speeds the shorter tracts allow the higher air flow required... exhaust need to be designed to effectively scavenge the combustion chambers by having a higher flow capability than the incoming charge... it isnt a simple science... Race engine designers spend millions of hours all round the world looking for ways to improve combustion efficiency and gain those 10's of seconds that can make the difference..
Fair. I was oversimplifying to the end of the earth there- and I'm learning as I go/making it up on the fly. I ran some basic calculators online for runner length, and for the peak numbers of the ZXR as published@RPM, it advocated for about 7" runners. You get 3" from the valve to the flange for free, I've got about another 3 on the far side of a 45* bend into the manifold, I'm printing velocity stacks for the end of the runner tonight. Manifold, I just went as big as I could, a 250x75 tube gave me ~1.1liters- once I add a little to locate the throttle body, I should end up around 1.25l of volume, less whatever the runners take up in the manifold.
Is that still the case in a forced induction system? I'm just wondering if the pressurised incoming charge doesn't just push everything out until the exhaust valves closes?
Forced induction is an entirely different kettle of fish @Frankster.... it is still the case to have a large low restriction exhaust and good scavenging (dependant on cam grinds etc) for Turbo and Surpercharged engines.. they need to sized to get rid of the incoming charge (lots more than NA engines)... its all about Airflow... the more you push through at pressure the more power you make.. as long as you can get the fuel in and ignite it. In very simple terms anyway... I like simple
Lost the timing plug. Searched my garage for something with the same threads. Found one, now I have 2x power on my DRZ!
Ever felt like choosing a 250cc only gets you craving a worthy 1000cc or more contester? Sent from my iPhone using Tapatalk
Stick a dummy coil plug and lead on it for many laughs when you tell people it's got a 2 stroke assist motor
Today I watched some videos on bike suspension setup and adjusted my suspension. Previous settings were Max preload, Minimum Rebound and Minimum compression. Now I have 3 clicks of preload, 3 clicks out compression and 2 rebound. Feels like a different bike.
That sounds dangerously close to what the standard setup recommendation is for normal riding with a 75kg rider.
Getting there... Spent today making manifold stuff! Gave the 3d printer a workout, as well as the abrasive saw, drill press and welder.