Comments on: Why 2-Stroke Direct Injection is a Big Deal

By: Ryen Miller

Ryen Miller — Sat, 06 Nov 2010 06:11:04 +0000

@rm500

my highly modified superkart engine cr250 already makes that kind of power

By: rodcr500

rodcr500 — Fri, 22 Oct 2010 18:56:14 +0000

Yo can make a fuel injection for an Cr 500 ????

By: 2STROKEREVOLUTION

2STROKEREVOLUTION — Thu, 03 Jun 2010 01:15:04 +0000

DI 2-strokes would still have expansion chambers. The DI will give the 2-stroke a linear powerband and the pipe will be used to tune the powerband. Right now the KTM 300XC has a linear powerband. Expect a DI 250 to have the same powerband and peak power as that bike. Maybe even better.
KTM makes 49hp in the 250SX and Maico makes 54hp in their 250. I figure a DI 2-stroke with increased compression could easily make 54hp+ with much more low end power.

I wonder what the comparrison of E-Tec direct injection( High Pressure) vs Orbital’s air assisted Direct Injection. Especially for small engine sizes. Aprilia has an Orbital DI 2-stroke, 50cc scooter. The smallest high pressure DI right now is the E-Tec 600 Ski-Doo. (Evinrude has a 25hp 578cc outboard also)

By: RM500

RM500 — Fri, 28 May 2010 18:44:42 +0000

I like to give much for a onecylinder version of that e-tec 600 on a dirtbike bottom end and gearbox. Mounted in a KTM chassie… Can we have 55-60 hp from 300cc?

By: RM500

RM500 — Fri, 28 May 2010 18:40:35 +0000

@ 2STROKEREVOLUTION

Well DI snowmobiles still have expansionchambers and a ripping powerband.

By: 2STROKEREVOLUTION

2STROKEREVOLUTION — Wed, 26 May 2010 03:13:22 +0000

@RM500

The flat curve has nothing to do with the pipe. The Direct Injection is able to provide the precise fuel/air mixture at any rpm. A carb can only do so at about 4 different rpm’s. Adding direct injection will not increase your peak horsepower. But since DI cools the engine slightly and is injected after the compression the compression ratio is able to be increased slightly yielding more horsepower.

By: 2STROKEREVOLUTION

2STROKEREVOLUTION — Wed, 26 May 2010 03:01:34 +0000

@nick1881

Only some people ride 2-strokes for the powerband. Most people in the world prefer a wide powerband, part of the reason 4-strokes took over. The main reason for riding a 2-stroke is not the powerband but the huge amounts of power that come with a very light weight bike. DI2T bikes retain the “on the pipe” characteristics of huge fun power, they just add tons of power to the bottom end. If you ride a bike on the pipe you are not experiencing the power hit and you can ride a DI2T the same way. It will still try to rip your arms out, it just won’t bog down in the wrong gear leaving you helpless up a hill or jump face.
Most people are on the constant search to add bottom end power to their 2-stroke. One of my favorite bikes is the KTM 300XC because it has a wide powerband. I am trying to jet my 380SX to give it more low end.
With DI you don’t have to compromise the on the pipe power for low end. With the 300XC I can ride all day in the mid range and at any time I can get on the pipe and rip up anything in my path. DI would improve the top end of that bike. It is just more options without compromise.

By: 2STROKEREVOLUTION

2STROKEREVOLUTION — Wed, 26 May 2010 03:01:09 +0000

@Sachsgs250

Exactly. There is drag in the cams, valves, and cam chain that the 2-stroke doesn’t have which is one of the reasons DI2t bikes get better gas mileage. The other is the less weight. I may have heard a 5% drag from the cams and such, but I may be wrong.

By: RM500

RM500 — Fri, 30 Apr 2010 20:56:47 +0000

Nick1881
I cant see why a DI 2t would have a flat power curve. The expansion chamber should work the same way and charge the cylinder as today. Just more power and less smoke…

By: nick1881

nick1881 — Thu, 29 Apr 2010 03:45:32 +0000

The cleaner emmisions and better economy are definately good things. However, dont we ride 2 strokes because of how fun the powerband is and how simple the engine is. I can do a top end in an hour, and its so cheap relatively. And the biggest reason i ride a two stroke is because of the sensation i get when it comes on the pipe and tries to rip my arms out. Why would we want the two stroke to mimic the four stroke. Just seems like less fun and alot more complications.