ESE's works engine tuner

[TZ350]

Does the oil pump have any way of stopping the flow? Centrifugal force is going to suck oil through that passage once the revs come up, whether the pump is running or not

It can only deliver what is pumped through due to the way it works. it basically has a built in non return valve. Also you can monitor oil flow and slow down the speed of the motor to suit the required delivery, as you can control the speed of the pump precisely.

Yes, a peristaltic pump has a natural stop valve at the squeeze point. At normal pressures you cant suck or blow fluid back through a peristaltic pump.

[lohring]

Anyone know about how much power gain is typical when switching from gas to methanol ? 10-15% more power if the exhaust pipe is not changed, just fuel flow and timing ? 15-20% if the exhaust pipe is corrected too ?

We did a series of fuel tests on a 26 cc race engine. It is a piston ported industrial weedeater style engine with a tuned pipe. We wanted to see if our race organization needed fuel testing. The bottom line was adding methanol and/or nitromethane didn't help power when all you could change was the needle setting. See below for a test summary. We did find in other testing that serious race fuels like VP's U1 did help performance, especially in higher compression, head button, engines.

Lohring Miller

[F5 Dave]

Well, yeah you need like 2.3x the gas, so not such a broad scope test.

[TZ350]

.
On Methanol you can have a two stroke running so rich that raw liquid fuel dribbles out of the silencer. Been there done that.

On my Kawasaki F81M look alike air cooled 250cc single cylinder Classic racer I am going to blend in enough Methanol to keep the engine about 70 deg. When the temperature goes above that then a temperature controller is going to switch in an auxiliary jet to add more cooling fuel.

For me, the Methanol will be all about cooling and temperature stability in an air cooled motor. It is all about fuel blending to get the engine temperature I want. 70 deg C helps the Nitro do its job.

[pete376403]

Speedway bikes (four stroke, sorry) ran methanol because it would allow much higher compression without detonation (iirc the JAP was about 14:1, the 2v Jawa was 12 or 13:1). Both of the 2v designs had a hemispherical cylinder head and a high dome piston and ran a lot of ignition (magneto) advance. The higher comp gave better acceleration. At one time in the UK there were test with petrol powered bikes, obviously they had to lower the compression, petrol reportedly gave better power but the bikes didnt accelerate as well (speedway is all about acceleration rather than top speed)

[lohring]

Our fuel testing was done to show that there's no magic in fuel for our industrial engine based engine classes where the engine was setup to run on gasoline. Open class engines are a different animal. We are currently considering adapting one of those to run on E85. We believe more power should be possible with the right head button, Powerspark ignition, a larger carb, and the right pipe. We just need to get a ruling that it's considered "pump gasoline" as specified in our rules.

Lohring Miller

[andreas]

The 250 DEA kart cylinder or Rotax dito, are there any portmaps, measures, photos, pipe drawings or other useful information circulating?

[SwePatrick]

The huge knowledge in this forum might have the answer to my question below..

A complete without carbs and exhaust TDR250 engine (1kt) , how many kg´s is it?
Need to know for a shipping project.

Rgds
Patrick

[dgee]

The huge knowledge in this forum might have the answer to my question below..

A complete without carbs and exhaust TDR250 engine (1kt) , how many kg´s is it?
Need to know for a shipping project.

Rgds
Patrick

Just under 30kg according to my cheapo scales.

[SwePatrick]

Nice,, thanks =)

[F5 Dave]

From RGV forum. That's quite some reed stuffer. Not sure I'm really convinced, but perhaps if, like in the CPI example Wob gave before, the Reed area is too large, maybe this sort of stuffer would be beneficial?

[speedpro]

I wouldn't be surprised if that worked. It is surprisingly similar to one I made ages back right down to the centre splitter with the curved leading edge which I also had a nice radius on. My idea was to keep the cross-sectional area as constant as possible from the carb right up to the petals. It went OK and was distinctly different sounding to all other stuffers I tried

[Grumph]

.
On Methanol you can have a two stroke running so rich that raw liquid fuel dribbles out of the silencer. Been there done that.

On my Kawasaki F81M look alike air cooled 250cc single cylinder Classic racer I am going to blend in enough Methanol to keep the engine about 70 deg. When the temperature goes above that then a temperature controller is going to switch in an auxiliary jet to add more cooling fuel.

For me, the Methanol will be all about cooling and temperature stability in an air cooled motor. It is all about fuel blending to get the engine temperature I want. 70 deg C helps the Nitro do its job.

Don't think you can do it, Rob. The fuel regs as they stand only recognise "petrol" - matching a set of standards in the book with an allowable oil content.
And "methanol" - again matching a spec in the book, again with an allowable oil and solvent content.
Blends are apparently non-compliant. I've asked the MNZ tech steward and he's in agreement, the book makes no provision for blends.

Personally, it pisses me off as the Post Classic regs are supposed to reflect what was in force at the relevant period. Nitro was in common use as were meth based blends.

[TZ350]

.
Hi Grumph. Good point I had not thought of that. Totally unexpected interpenetration of the Methanol fuel rule.

With Meth I was basically just heading down the same path that I did back in the 70's. Fuel blending to get the air cooled engines to run at the right temperature was a must. Interesting that some official would through absolute technical ignorance resort to a literal interpenetration. Not ignorant I guess, just interpenetrating the rules as written. No surprise I suppose, You and I have seen enough out of touch bureaucratic bull shit in our time.

It won't stop me though as a water test for an acetone methanol blend will come up the same as 100% methanol. Acetone and methanol have similar reactions to water. A hygrometer much the same. I ran my air cooled racers on a 50/50 mix of acetone and methanol back in the day.

Acetone has a higher octane rating than Methanol and cooling property's about half way between Av gas and Methanol. Acetone is a great fuel in itself. If I have to, I can blend in some Nitro to bring the specific gravity of the fuel up to spec. This whole thing brings back happy memories of cat and mouse tussles with tec inspectors back in the day. Love it.

[Grumph]

I'd still advise caution. As I see it, your problem is that you won't be dealing with MNZ officials - the current guys are experienced and reasonable to deal with - but Classic Register officials....I seem to remember a register member being banned for using a "rocket fuel" drum to carry his 100 octane.
No proof of use of the illegal fuel, just the drum. No appeal.

The other thing likely to happen is meth being banned as a fuel for 2 strokes again - as it was in the aftermath of the Cal Rayborn fatality.