Injectors and heat

Alan R Pratt · Post by **Alan R Pratt** » Sat Nov 26, 2005 4:34 am

I am working on a plan for injecting a Harley panhead and would like some feed back on injector placement.
For reference this is a 93 ci 3 5/8 bore 4 5/8 stroke running 11-1 compression.
I will be running a dual throat manifold and would like to place the injectors as close to the valve as possible. Due to the limited space this would best be done by placing it in the head.
So my question is, would there be an injector the would stand up to the heat? And, would this be the best placement in a low RPM (3500) motor?
Thanks in advance, Alan

Alan R Pratt · Post by **Alan R Pratt** » Mon Nov 28, 2005 6:24 pm

I'm afraid it will get too hot also. I will have the engine running with a carb first and I'll get a better idea of head temp. With the compression I'm running I was hoping to use the injector to cool the valves.
This will be about a year project as I will need to fab up an intake adaptor, 2 into 1 pipes and the sheet metal to hide and protect the MS unit.
Anyone with any thoughts are more than welcome to throw them my way. .
Alan

spmullen · Post by **spmullen** » Mon Jan 02, 2006 12:06 pm

The heat on the injectors is not going to be a problem on your Pan. I'm running Bosch injectors on my 120+HP EVO engine (97CID 11.5:1 compression). You can see pictures of the throttle body/injectors at http://www.nightrider.com/caferacer/ . There is also a video on the bike that shows all the all the components. In the pictures on the WEB I have the SDS ECU mounted, but the MS mounts the same way.

I mounted the ECU on the right side of my bike over the electrical panel. While a little more open to the elements, there aren't any heat issues. You could use the MiniMS for an underseat area mount.

spmullen · Post by **spmullen** » Mon Jan 02, 2006 12:16 pm

As a second note, I don't think you need to worry about placing the injectors right in the heads. Because the MS runs in "batch" mode and you are trying to run a highly modifed engine, you aren't going to be injecting past an open valve directly into the cylinder. The best I've done is use the odd-fire code, take the tach signal for MS input and have the injectors fire on every ignition event. This works good for small injectors at low RPMs, but at higher RPMs the opening time of the two events can overlap. Using a throttle body similar to the older HD MM unit might work. But from a simplicity standpoint, the old standby of the common plenum manifold is easiest to work with. Trying to get individual runners on a 45 degree V-twin end up putting too many restriction on the intake design unless you go to a "two front head" design ala XR-750.

I am the original HD MS'er.

Alan R Pratt · Post by **Alan R Pratt** » Mon Jan 02, 2006 12:56 pm

Since I posted this I decided to go with an S&S single manifold with a jenvey throttle body. Since we're running close to the same specs I may bother you for a baseline to start with.
People say I'm crazy for wanting to inject a pan but I never really cared what people said anyway.

spmullen · Post by **spmullen** » Mon Jan 02, 2006 2:23 pm

There is still a significant portion of HD riders that swear they will never buy an EFI bike. Those are probably the same riders that would rather have a set of points on their engine over an electronic ignition. I started working on an EFI design for my engine before HD had introduced the M/M EFI. It took me a couple of years to put everything together. There was little to nothing in the way of DIY EFI help at the time. Interesting thing about the whole experience is that it wasn't really that hard to get the engine running once everything came together.
http://www.nightrider.com/biketech/efi_project_01.htm
shows my "test" setup. Despite the rough looks, the bike went from carb to EFI over 2 weekends. I did spend about 3-4 weeks running the electronics while the carb was still on the bike. This is a technique I'd recommend for anyone installing a home brew EFI system on a vehicle. Because I started with the SDS unit, I was able to use their programmer to monitor ECU operations while riding. Getting the MS to work was quite easy after my EFI first experience. You can install the MS ECU, connect up the sensor and watch everything through MegaTune. I was able to test multiple versions of the MS code and MS boards. I have a pretty good idea what will work and what is going to cause problems with the HD engine.
My propensity for constant experimentation is what gets me into trouble. Never satisfied with an engine build, major components always change.

Good luck with your setup. The basic components should be sound. I'll help you all I can. Always glad to see another HD up an running with a home brew EFI system.

Alan R Pratt · Post by **Alan R Pratt** » Mon Jan 02, 2006 2:51 pm

Thanks for the info Steve. I look at your video and you have one impressive ride. I'm going for more of a spartan look with pretty much everthing blacked out but a small amount of chrome. I'm running STD dual plug heads with a mallory electronic ignition. Once I figure out a few things on my engine I may have a new cam ground.
I know about tinkering. In 85 I went suicide shift and built me a hydraulic clutch from an old master cylinder and a junkyard slave cylinder. I'm still running hydralic but upgraded to a kicker cover with the slave built in. As far as I know I had the first hyd suicide.
Here is what I am building. Still collecting and fabricating parts. Changes being made daily.
I'll keep you posted on progress.
Alan

spmullen · Post by **spmullen** » Mon Jan 02, 2006 3:12 pm

I like the bobber style. Minimalist, but makes a great statement. The EFI should be a very interesting discussion point on the bike. With the heads you've choosen, you actually have a pretty good power potential. A nice set of 3-step drags would give the look, sound and not sacrifice the power you get.

Keep in touch. You can also e-mail me through the nightrider motorcycle performance guide web site.

Uncle Bob · Post by **Uncle Bob** » Mon Jan 09, 2006 1:10 am

spmullen wrote:There is still a significant portion of HD riders that swear they will never buy an EFI bike. Those are probably the same riders that would rather have a set of points on their engine over an electronic ignition.

its too bad too, the newer HD's with EFI are actually pretty good systems too.

spmullen · Post by **spmullen** » Mon Jan 09, 2006 5:44 am

The Delphi system used on HD's is probably the most sophisticated EFI available on any motorcycle right now.

Uncle Bob · Post by **Uncle Bob** » Mon Jan 09, 2006 11:39 am

spmullen wrote:The Delphi system used on HD's is probably the most sophisticated EFI available on any motorcycle right now.

I don't know if I'd go that far....it has some pretty cool engine cool down features that you won't see on other bikes, but no closed loop.

spmullen · Post by **spmullen** » Mon Jan 09, 2006 12:28 pm

You are probably correct. The very recent advent of the dual throttle body engines and some of the exhaust controlled bikes probably do exceede the capabilities of the Delphi, but it is still an excellent ECU.

Uncle Bob · Post by **Uncle Bob** » Mon Jan 09, 2006 12:31 pm

wasn't putting it down, most bikes are open loop, but you are starting to see the closed loop systems pop up here and there. I know some BMW's, Truimphs and Honda's have closed loop....but I don't keep up on it as much as I used to.

spmullen · Post by **spmullen** » Mon Jan 09, 2006 1:17 pm

Some of the new HD's are using WBO2 closed loop. This is model specific right now, but for 2007 is probably going to be universal in Harley's lineup. I'm surprized they have put EFI on the Sportster line since they have EFI experience from Buell's using the same engine.

I see motorcycle EFI in the same position that automobiles were in the early 90's. Technology is pretty much there, but acceptance by theperformance enthusiast is just coming around. The aftermarket industry and independent repair shops are just beginning tap the EFI market potential.

Alan R Pratt · Post by **Alan R Pratt** » Tue Jan 17, 2006 5:52 pm

. A nice set of 3-step drags would give the look, sound and not sacrifice the power you get.

Steve, I have heard all kinds of theories on how to set up an exhaust. Drags are best for WOT, 2 into 1 best for mid and top, keep each pipe lenghth divisible by seven, etc. Unfortunatly I have never had the time, equipment or money to test all this to sort out the bullshit. It sounds like you have more background on this than I do.
What I am looking for is a good everyday rider with pipes that won't create undo attention. I am not familiar with the three step. I was looking at building a 2 into 1 with a supertrapp on the end.
I have a lot of questions on your injection setup if you have time
Thanks, Alan

spmullen · Post by **spmullen** » Tue Jan 17, 2006 7:59 pm

I have a distinct preference for 2-1 pipes on the street. They typically provide the best power in the street RPM range. But I also want to point out from dyno testing that I did that a good 2-2 will provide almost identical average power. I don't believe that a straight pipe provides any benefit unless you have a very narrow band you plan on running the engine. By going to a 3 step drag pipe, you improve the scavenging and thus improve power. A step pipe is one that changes diameter (usually by a telescoping pipe) about .250" for each step. The change in pipe diameter is enought to add scavenging waves to the exhaust. Where the steps are has a big impact on the power band.

You can see a heads up test of a good 2-1 and 2-2 at
http://www.nightrider.com/biketech/exhaust_test_03.htm

I created an online calculator that estimates exhaust lenghts and the location of steps should you decide to try them.
http://www.nightrider.com/biketech/calc ... length.htm
The calculator is only an estimate, but the interesting thing is that the lenghts it calculated happen to match the lenghts of my SuperTrapp 2-1.

In short, there isn't one "best" pipe. I happen to like exhaust systems that have a lot of noise reduction capabilities and my two favorite exhaust systems both meet this need; SuperTrapp 2-1 and Khrome Werks AR exhaust system or mufflers on OEM headers. These exhaust systems are hard to beat, although many will match.