Or Winter Project II

So first let me say…… to the DR FI pioneers….wildwestsydney and msiddalingaiah..... And to Mkane160 for pointing out the fuel injected  LT-A700 Suzuki ATV as a possible parts doner.

In setting up the FCR-MX I was dead set against (and proved it in my dyno sheets) that a big bore FCR was not the way to go for the DR650’s torque based powerband. The reason was velocity issues on a larger carb at lower engine speeds. This is an issue with any carb. Too big and your low speed atomization goes to heck in a hand basket. The 39 proved that out when comparing it to the 42mm FCR that I have built up. With FI the fuel is always atomized properly, even better than what a carb can do at any velocity, so there is no performance loss due to unatomized fuel. The second motivation was the dyno sheet after doing the HC piston, Web cam and porting. The slight gain that the 42mm carb showed way up in the over-run RPM on the stock engine now moved to a bigger gain much lower in the powerband and would now actually be useful. So with a larger FI TB I'm expecting better power/torque everywhere.

I’ve received the first piece of the puzzle.  A 43mm Suzuki LT-A700 TB. It looks to be just what I need. With its injector already sized very close for the big DR I’m hoping it will eliminate one of the things to figure out in the process. The unit is tiny compared to the FCR-MX so room will not be an issue. It measures 95mm long and has a smaller intake horn, 52mm OD, than the FCR does so making a step-up adapter the correct length to attach the air boot is a no brainer. The intake side is too large for the stock DR intake manifold but not by a large margin. For those of you with an FCR on your bike you know that the FCR was bigger on the manifold side than the BST and is a bit of a challenge to get into the manifold. So going even bigger is not an option. I have a stock LTA manifold coming…. we’ll see how the bolt pattern and port size matches up to the DR’s head.

Pictures!







Isn’t it a beautiful thing? The TB has TPS and IAC on board. It also has a MAP port that is restricted to reduce the MAP signal oscillation that reaches the sensor. I’ve been reading how this is an issue with the manifold pressure pulses of a thumper using the Megasquit’s on board MAP sensor or the standard GM sensor. Since I’m going with a Microsquirt, which does not have on-board MAP, it just seemed logical to me to use the Suzuki LTA remote MAP sensor and even the same hose and length. The big LT-A700 is certainly a thumper.  I haven’t tried it yet but I wouldn’t be surprised if the stock DR throttle cable will work as well.
  
The next issue I’ve been reading about is component electrical connection concerns…. Soldered pin terminals, unsealed connectors…. I just can’t have that on my bike the way I use it. This was also a motivating fact in going with the more costly Microsquirt as it is credit card small and totally weather proof including the plug…… but what about all the connectors on the TB and remote MAP sensor?  Ebay to the rescue! I scored the entire wiring harness (cheap) off a LTA700 so I have every sealed connector I need. The additional benefit will be having the LTA700 wiring diagram and wire color codes so I can figure out what did what on the ATV. I’m sure this is going to help in proper connection to the Microsquirt. I have paid keen attention to those that have posted on the FI sites about miss wiring and allowing all the smoke to escape their ECU.

Enough for now...

Edited by mx_rob, 16 December 2009 - 12:28 PM.

I'm getting in line now for the FI kit. Can't wait to see how it turns out.

Maybe we can get together in the spring and dyno our bikes with the FCR-MX 39mm and with the FI throttle body (my 725cc kit was broken in before the snow flew here). Just for comparison with stock bore vs big bore. Of course all the extras like cams, porting, and exhaust are already done.

very interested I will be following this thread closely

Is it just the camera angle or is the interior of the TB not round?

IT's not! Being a betting man, I'd say it's matched to the intake port on the LT700 head.
If I'm not just rememberin wrong, the ITB setup I drooled over on a Toyota 4-AG was severly ovaled to give a bigger throat size while not sacrificing throttle body to throttle body clearance. Might have been a Corolla that engine was stuffed in, but man was it cool! (Google AE86 for pics of the same style).

This is all pretty cool to see, I converted my AMC I6 to EFI, but I had the cheating point of a stock engine out of a 4.0L Jeep (which also had parts donated to other areas)
I didn't program the F.A.S.T. system, but I did map out the table in 3D as my grade 12 auto project. EFI makes my head hurt, so I salute you, wildwestsydney and msiddalingaiah for taking this on! Wish I'd have found the Megasquirt before I dropped six months pay on the F.A.S.T. ECU and tuning!

You are right... it is not round. The air horn side is round and taper bored. I will continue the same taper in the airboot adapter that I machine. Very cool stuff. I'm really wishing it wasn't 14 degrees in my shop right now. But I have a lot of bench work to do before I tear into the DR anyway. I'm working on the fuel pump right now...... next progress posting will have more info.

I thought I'd mention for 700 TBs , a lot of those guys were upgrading theirs to an m109 (i think thats the model) when upgrading the ecm for more fuel , you might find a deal on a stocker by posting to a suzuki atv forum.

good luck with the project!

Paving the way as usual Rob, so us klutzes can follow.  

I have a suggestion that would solve the fuel supply problem: Just put on the tank from a KTM 690 Supermoto / Duke 3. Comes with internal fuel pump and regulator, and fits the frame really well. And when you are done, please send me some kinf of a bolt-on bracket so I don't have to come up with something.

LukasM said:

Wow! That's a tank all right... I could see my bike coming to a sudden stop hooking one of those wings on a tree... Michigan has some pretty tight trails.

Hey, since we see posts of 65mpg on stock DR650's here all the time I should have no problem getting 80 MPG, or more, with FI right? Who needs a huge tank with that kind of mileage?

Awesome!!!  Another kick ass project Rob!  Can't wait to see what you come up with.

mx_rob said:

It's not too bad really, holds 3.6 gallons. It is also nicely tapered towards the back so your knees are not spread out at all. If you ever get a chance I can highly recommend that you take a Duke 690 for a spin. Probably not the right time in Michigan right now, through.

Sweet, the DR 650 FI project is officially on!  That TB you have looks very similar to a twin mikuni TB set up that I bought off ebay for a vstrom(I think) for cheap, I ended up using the injector, the butterfly, shaft, and spring return so the price was still fine plus I have a spare injector.  

Great thread!  You will do a great job and I think you will love the tuning process, key strokes instead of turning wrenches.  Not that turning wrenchs is not fun but when the lap top is hooked up an you are tuning it is so sweet to see and feel results in seconds.

Also I ended up getting one of the new style netbook lap tops for my tuning, it is great and very affordable, around $300.  

Sam

The older Palm PDAs with a serial connection can also be used to tune(and datalog) with a MegaSquirt. It's a bit more cumbersome, but it does make it a lot easier to datalog the engine under load without a dyno because it can fit in a pocket while you ride instead of stuffing a laptop in a backpack. Just needs the PalmTune software instead of MegaTune.

Thanks guys... I know I will enjoy the tuning process and I'm sure there will be some frustrations involved. I have a smaller Thinkpad and my son has a couple of different older PDA's. I'm sure I'll be able rig something up that will net me some curious questioning from onlookers. I've spent a ton of money and burned up lots of time on the FCR looking for that perfect needle. What I settled on is good but can't hold a candle to an FI map. At least now all of the hours I put into the tuning process will produce results, however incremental they may be, instead of repeated disappointments. It's going to be nice to install the TB and likely never need to remove it again.... except maybe to install one of Procycle's 725cc kits....

http://www.rockinhor...vice_manual.htm

Here is a link to that info we talked about.

Yet another great DR mod by Rob, nice pics as usual with easy to understand write up`s    

Popcorn at the ready.

Mezo.

That's a very cool TB. Do you have any idea about the injector flow rate? Is it high impedance? It sounds like EFI interest is building, which is great!

This is quite an ambitious project!
I would love to see a plug & play F.I. kit for the DR650!
I think you'd sell a lot of them if kept simple and not too expensive.
But would you have to use the donor ATV's ECM to be able to control the F.I. ? Or does the "squirt" device do all that? ... and how does it interface with the stock ECM? Sounds like a challenge! Good luck with it!

I love my DR for it's cheap cheerfulness, it's "do-it-all" abilities and bullet proof nature. But when Suzuki come out with an upgraded DR650 with F.I., I'll be first in line.

When will this happen? Who knows? Maybe never. Keep at it Rob!

54321 said:

The MegaSquirt/MicroSquirt ECUs are "standalone" in that they control everything. The stock ECU is out of the picture completely.

What are you going to use to trigger the injector to fire with Engine RPM?