ESE's works engine tuner

**Yow Ling** · 28th May 2012, 06:30

Originally Posted by Frits Overmars

You might wanna take a look here: http://kreidler.nl/forum/viewtopic.php?f=5&t=38866 . Don't be put off by the writing; that is what Dutch looks like.
Never mind, all pictures are in English and so is the video ( http://www.youtube.com/watch?v=tMDJcSqpImM ).

In the video the piston-controlled carb is set for a high idle and the second carb is opened much too early but nevertheless you can hear it is contributing to the revs.
Getting the carburation spot-on may become a nightmare though. Closing the first carb while the second one opens, will not make much difference so you may as well leave the first one open. But clean carburation is essential for lap times. That is why I want injection (is that allowed in bucketracing?)

The above example with a piston-controlled inlet plus a permanently open inlet is one of the options I considered over the years. But I think he simplest solution is my present approach with just one inlet, just one carburetter (until the injection becomes available) and a simple reed that is swung out of the way (can be done by the powervalve-servomotor).

Hi Frits, Dutch is fine, my parents used to use it all the time. Fuel injection is fine for buckets, just too hard on wallet and you kinda need to like electronics. I have it on my old Fiat 500. I thought by separating the functions of the carbs would help to make it tunable. with injection directly into the crankcase I guess that would solve all those problems, maybe create some new ones.

**Bert** · 28th May 2012, 07:39

Originally Posted by Yow Ling

...... Fuel injection is fine for buckets, just too hard on wallet and you kinda need to like electronics. .......

The following could be an option (about the same $$ as a FCR carb and spares; Damm the exchange rate) and offers a programmable ignition as well:
http://www.mbe-motorsports.com/catal...h1kh1lp0dlbdl3

In the MBE forum they talk about a two stroke kit (but it has gone from the website) using two injectors (theory was: one very small-bottom end, normal size-rest of the range, both together at the topend). largest throttle body looks to be 28mm.
and if you look hard enough there is a turbo kit as well...

But it would still take some work to get it functioning with a two stroke.
I'm guessing the best starting point would be to log a map sensor on a standard carb to get an idea of air flow rates vs. RPM.
then start building a fuel map around the ideal A/F ratios.

**dmcca** · 28th May 2012, 09:24

Originally Posted by Bert

In the MBE forum they talk about a two stroke kit (but it has gone from the website) using two injectors .

These guys have already been mentioned here before but seem to have updated their kits recently... This is their 2 injector kit...
http://www.ecotrons.com/2_Stroke_Sma...e_EFI_kit.html

**bucketracer** · 28th May 2012, 09:39

Originally Posted by bucketracer

Attachment 264158

TeeZee's idea of a plenum was to get around the restriction of a 24mm carb by allowing the motor to draw through an increased inlet diameter from a plenum full of fuel mixture.

Attachment 264157 Attachment 264159

Changing the length and diameter of the inlet runner is easyish.

I think TeeZee has plans to re visit this idea so he can increase the crankcase volume. Fuel dropout and guarantied lubrication were problems encountered with the initial efforts with the plenum.

Originally Posted by dmcca

These guys have already been mentioned here before but seem to have updated their kits recently... This is their 2 injector kit...
http://www.ecotrons.com/2_Stroke_Sma...e_EFI_kit.html

To get around fuel dropout in the plenum, maybe a 24mm throttle body on the inlet to the plenum in place of the carb and fuel injectors inside firing into the secondary intake tract.

**twotempi** · 28th May 2012, 19:27

May I come and watch the first run of this setup - preferably from a safe distance.

**husaberg** · 29th May 2012, 23:53

Frits and Wob

if you were to design a 100-125 2 stroke from scratch what would it look like?

IE would the architecture follow the layout of a Rotax based single.

**Frits Overmars** · 30th May 2012, 00:18

Originally Posted by husaberg

Frits and Wob, if you were to design a 100-125 2 stroke from scratch what would it look like? IE would the architecture follow the layout of a Rotax based single.

For me: FOS symmetrical schavenging, 24/7 inlet system, continuously variable transmission; not even remotely related to a Rotax based single.

**dinamik2t** · 30th May 2012, 04:42

Speaking of the dual pipe FOS, Frits, is it possible to make a dual-to-single 2T pipe to match the performance of two singles? E.g. two seperate headers going into one diffuser or two headers-diffusers going into one belly? Have you ever tried anything like that?
On a two cylinder engine, I imagine it won't be easy, as with the two seperate pipes you can have control over temperatures and cooling with minor changes between the two pipes' dimensions. With the single cylinder symmetric system, would it be easier?

**Frits Overmars** · 30th May 2012, 05:27

It would be nice if I could join both headers of my FOS cylinder into a single diffuser for package reasons, but it is impossible because as the picture below shows, those headers are much too short, due to the high rpm this cylinder layout permits.
Joining the headers of a twin cylinder engine is possible but you will not get the power of two separate exhausts.
In theory you can get massive power if you use the blowdown pulse of one cylinder to supercharge its neighbour, because that blowdown pulse is much, much stronger than any reflected pulse. But in order to make that work both exhaust ducts have to face each other so there can be a very short connection, plus you'll need an exhaust timing of well over 200°.

**koba** · 30th May 2012, 20:53

Originally Posted by Frits Overmars

It would be nice if I could join both headers of my FOS cylinder into a single diffuser for package reasons, but it is impossible because as the picture below shows, those headers are much too short, due to the high rpm this cylinder layout permits.

So, how is your FOS project going?

I fully appreciate if you can only release limited information but it sure sounds interesting.

**Frits Overmars** · 30th May 2012, 22:36

Originally Posted by koba

So, how is your FOS project going? I fully appreciate if you can only release limited information but it sure sounds interesting.

It is slowly moving forward, Koba. If I would win the lottery (the chance is rather small because I'm not playing) things would move a whole lot quicker.
As it is, with two-stroke GP-racing killed by Dorna, funding is hard to find and I am relying on friends. They are enthousiastic which is heartwarming, but they have their own obligations so everything takes time.

**F5 Dave** · 30th May 2012, 23:21

Originally Posted by Frits Overmars

. .. If I would win the lottery (the chance is rather small because I'm not playing) . . .

If you look at the maths your chances don't increase appreciably. I say if you're going to get lucky you might as well push the boat out & expect luck to overcome that insignificant obstacle.

As luck would have it, I got an email the other day. . .

**F5 Dave** · 30th May 2012, 23:32

Just been thinking about trying to make a new manifold for a reedblock, so that's simple enough, a mikuni type spigot bolted to a block of ally that bolts to the reedblock.

But I'm trying to think of a clever way to make a few different stuffers to try out. I'm using a TZR250 1KT 6 petal block & trying to get a block of acetal to fit tight in there & then bore & port it sounds like a wind up. . .

. . . .. Actually I think I'm answering my own question. I have a perished block as well & could cut that in half which at least would mean I could see what I was doing.

I'm dubious of all these wings & stuff, but just want to fill in the corners so the velocity doesn't stall, esp when using the 32mm carb leaves a heap of space (the 36 won't be such an issue).

Bit like the pic on the right, but without the cut outs.

Any other ideas for fabrication?

**husaberg** · 31st May 2012, 00:28

Originally Posted by Frits Overmars

For me: FOS symmetrical schavenging, 24/7 inlet system, continuously variable transmission; not even remotely related to a Rotax based single.

Sorry the Rotax remark was alluding to the right side power output and left side clutch (kind of like a real Husaberg.)

But as it not disk i guess, it maters not.

**Frits Overmars** · 31st May 2012, 01:49

Originally Posted by F5 Dave

Just been thinking about trying to make a new manifold for a reedblock, so that's simple enough, a mikuni type spigot bolted to a block of ally that bolts to the reedblock.

Try to keep the length down, Dave. That is especially important if you are using a small-diameter carb.

I'm using a TZR250 1KT 6 petal block & trying to get a block of acetal to fit tight in there & then bore & port it sounds like a wind up. . .I'm dubious of all these wings & stuff, but just want to fill in the corners so the velocity doesn't stall, esp when using the 32mm carb leaves a heap of space (the 36 won't be such an issue).

Good approach.

Any other ideas for fabrication?

I used to use the rubbery stuff that is used to fit car windows. You can model it with a wet finger and it stays somewhat elastic.