Would there be any interest in a DIY fully programmable, stand alone EFI set up for the DS? I just bought the stuff for the EFI unit, and i already have the Throttle bodies, injectors and fuel rails. I have it about 75% figured out in my head(no comments, please[img]i/expressions/face-icon-small-wink.gif[/img]). I would not be selling this, just passing along most of the How-to info to anyone interested.

I'll be using dual throttlebodies(easier for me to do) with built in injectors and fuel rails. This efi computer has a built-in Map sensor good for 18psi. You can put a 3 bar that is good to 30psi or so. This would be easy to use with a turbo. It uses air temp sensor, coolant temp sensor and can use narrow band OR wide band 02's. You can fire up to 12 injectors(don't think that will be needed!). They can be fired simultaniously or alternatly. The neat thing about firing them alternatily is that you can use one at lower power levels and then at bigger power levels they actually overlap! This would be great for good response down low and still be able to support good hp. In theary it'll work great, we shall see....

All componants are redily available and cheap through motorcycle salvage yards(or Ebay). You put together the EFI computer yourself(yes, you solder the parts together). There are a few people that'll put one together for a small fee. The EFI unit is nothing new and has been tested by NUMEROUS people on different vehicles(Turbo subaru's, Porsche's, turbo bikes, Big Block Camaros, etc). It is tunable with a laptop and very compact. I wondered about how well it would hold up on an ATV and a fella told me he has had one mounted on the roof of his sand rail for over a year. It'll prolly hold up ok...

I should be able to have it up and running for less than $800(actually quite a bit less), but some one should be able to duplicate it for around that.

I don't know how long it'll be before i get it up and running(i still have to actually get my DS back together and running with carbs before i try this out!!!). I don't wanna give out too much info just incase i do run into a snag and can't complete it. It'll have to be a BIG snag though...

 

That sounds like a great project, I can't wait to hear how it turns out. The hardest part may be dailing it in and comparing it to a carbureted bikes performance.

 

Dialing it in is the fun part! Using an 02 would make it easier. I dunno if i'm gonna use one or not. I just finished piecing together the throttle bodies, injectors and fuel rail. It worked like i was hoping it would. I use a set of T-bodies from a 01 GSXR750. The suzuki's(others may as well, i dunno) bolt their t-bodies together. I needed the throttle linkage from one outside TB, and i also need the TPS sensor which is mounted to the other outer TB. I pulled them all apart and was able to bolt the two outers together. The fuel rail pieces together as well, so i was able to do the same thing and now i have a set of dual TB's complete with TPS, injectors, rail and linkage. Took me a little over 30 minutes to do. I'll find out for sure on the spacing when i get my dual intake, but it should'nt need much tweaking(if any) to make work.I may have to use a twist grip set-up from a bike, at least at first.
As for comparrison to carbs, i fully intend to do that. I'm switching to dual carbs(along with porting, cams, piston). Once the EFI is complete, i will be able to remove the TB's and slap the carbs back on. Should'nt take more than a few minutes. The computer controls the EFI only, so the factory ignition(well, the Vortex ignition) will work both. The only thing i'll need is a T in the fuel line feeding the fuel pump. That way i can uncap one end, turn off the fuel pump and it'll work for the carbs. Cap the T, and turn on the fuel pump and it'll be ready to inject...

 

I found out that the Busa injectors flow 270cc/min. Not sure what duty cycle that was at. Given that info(assuming 85% duty cycle), two should support around 88hp(.50BSFC).

I think this will be ok for my project. I should make between 55-65 hp at the wheels. I'm guessing that would be around 59-70hp at the crank(6% drive train loss)

One injector would support right at 44hp(again assuming 85% duty and .50BSFC), which is just under what the Rotax motor makes stk.

The Busa injectors are low impedance injectors. Which should help some with the low rpm response(IE:not running too rich with big injectors) since they react quicker which allows better control of very short pulse widths.,