ESE's works engine tuner

[husaberg]

Freddie doing the double
Quite a few intersting bits in it.

I will fix it later A3 wasn't a great idea
click three times

[peewee]

I've been racing model boats a long time. In 3.5 to 15cc glow ignition engines we run 50 to 60% nitro with around 20% synthetic oil. Castor oil doesn't mix with high nitro, but castor/synthetic blends are also used. The oil is more for sealing the ringless pistons than for lubrication. Record setting engines often run up to 80% nitro. Other exotic chemicals like propylene oxide have been added in small amounts in the past. Raising the nitro % requires different head volume and some pipe length adjustment. It doesn't increase the rpm, but the boats can run bigger props at the same rpm. As was pointed out before, the nitro increases MEP and therefore torque.

In 26 to 36cc spark ignition, gasoline engines it was found that doubling the recommended oil mix increased power. Again, I suspect most comes from improved sealing of the single ring piston. By the way, it was common with older style 2 ring pistons to remove the bottom ring for more power.

We did a series of dyno tests on a 26cc engine with various fuels. See below. We found that it was hard to beat the standard pump gasolines even with added nitro and/or ethanol and methanol. Nitro mixes very well with ethanol containing "gasoline". Even Coleman fuel at 50 octane ran well. The reason was we didn't/couldn't change the combustion chamber volume, pipe, or ignition timing. All we did was richen the needle settings for peak power. Methanol and nitro fuels have a lot lower exhaust temperatures and need a different pipe. Nitro burns slower and probably could use more advance. The compression ratio of these industrial engines with one piece head and cylinder designs already have too low compression ratios. Head button engines have more power out of the box. We ran some nitro/methanol fuels in a head button engine briefly. The engine ran fine on 15% nitro, but burned off the plug electrodes on 40% nitro. Again we didn't try to optimize the engine for the different fuel since the race rules specify "gasoline". We did run VP's U-2 for record setting. That fuel was pretty far from pump gasoline.

Lohring Miller

Attachment 337601

do you know of any tests to see what affect a high oil content has on combustion in a spark engine ? since so much liquid is put in the cyl, likely only a small amount is vapor. some of the liquid will eventually vaporize but I wonder if high oil content has any influence on this, one way or the other. the other thing I was thinking, nitro is adding alot of internal load on parts, im wondering if alot of oil can act as a cushion in a spark engine with typical roller or ball bearings. also I think methanol and nitro might be strong solvents trying to wash down everything they contact, so maybe alot of oil helps in this regard also. I was considering lowering my oil content a bit (16% currently) but im having second thoughts whether that's a good idea or not. not to mention if a viscous mix helps a glow engine piston seal better , then maybe it can help a ringed piston seal better also

[TZ350]

do you know of any tests to see what affect a high oil content has on combustion in a spark engine ?

Looks like more oil = more power.

Ok, not a test as such, but by using the Google "Site:" Search option. oil power site:https://www.kiwibiker.co.nz/forums/s...-engine-tuner?

I got these results.

[lohring]

We actually did a few tests on oil mixes over the years. Mostly we relied on others experiences, though. One test on a 35 cc disk valve race engine is posted below. I believe that's the most oil we ever tried. Normally we ran between 8 and 10 oz per US gallon. It looks like in this engine more oil helped the power a little except at the very top end. It's only one test on one engine, though. I feel the main effect is better sealing, even with ringed pistons. Synthetic oils seem to mostly burn up because the exhaust is fairly clean.

Lohring Miller

[lohring]

Has anyone tried to put a thin divider into the A-port as per the attached second picture? Let say out of 0,5 mm aluminium. I was thinking that it might help to decrease the short circuit of fresh mix into the exhaust by straightening and force more of the flow in the port angle direction? Could it make a performance difference? (More or less flow will also go straight at the section with the curved arrows).

Model engines try similar things. Often I think the fancy porting is more for advertising than real power. We actually tested one of these modifications and did find more power on a 35 cc engine. Below is a picture of a Novarossi piston and sleeve from a 3.5 cc engine.



Below is a series of liners we tested for a 35 cc engine. The second sleeve from the left produced the most power. I think the small cuts encouraged the flow at the front of the transfer to aim more upward over the exhaust. The tops of the transfers were otherwise flat and the transfer passages were poorly shaped, not tea cupped.



Lohring Miller

[katinas]

Freddie doing the double
Quite a few intersting bits in it.

I will fix it later A3 wasn't a great idea
click three times

No problems with A3, as it very interesting.
I found only one photo from 1985 Le Man race with Spencer's NSR 500, and not sure , but exhaust looks in strange position, not like on std. But difficult to say, as bike angle in photo is not very informative.
Other photo from 1985 tests in Japan with 180 firing NSR 500, but cant say about crank.

[tdc211]

Has anyone tried to put a thin divider into the A-port as per the attached second picture? Let say out of 0,5 mm aluminium. I was thinking that it might help to decrease the short circuit of fresh mix into the exhaust by straightening and force more of the flow in the port angle direction? Could it make a performance difference? (More or less flow will also go straight at the section with the curved arrows).

Just use epoxy. Prep it well. I use a green marine epoxy.
I cure cylinder in oven at 150. Never has come out. Grind A angle any thing you want after cured. Keep epoxy away from piston about. .15mm .i use very fine grinding wheels here.
Only time it has come out ,is when the cylinder needs a plate after lots of hrs,and the platers grind it out.

You prep it right.
It will stay . It helped my curve every where. Bottom to top.

[husaberg]

No problems with A3, as it very interesting.
I found only one photo from 1985 Le Man race with Spencer's NSR 500, and not sure , but exhaust looks in strange position, not like on std. But difficult to say, as bike angle in photo is not very informative.
Other photo from 1985 tests in Japan with 180 firing NSR 500, but cant say about crank.

Most of it is translated

[husaberg]

It does weird things in press reader with text?
Oguma

[husaberg]

As above....

[husaberg]

Doohan
I missed the original mag.

[katinas]

Info from NSR 500 90'-94' specifications, it coud be interesting.

For vertical cylinders (1 and 3) exhaust - Titanium 0.8 mm header, 0.6 mm other.
Lower cylinders (2 and 4) exhaust - Steel 0.7mm header, 0.6mm other
Maybe because of dfferent material thermal properieties or still avoided cracking on more complex lower pair.

And different squash (I'm not sure): on 93'-94' vertical -0.56mm, lower-1.25mm. Maybe different cylinders pair position or crank-firing-load route or teperature difference and vertical cylinders higher elongations , interesting.

[Frits Overmars]

Info from NSR 500 90'-94' specifications, it coud be interesting. For vertical cylinders (1 and 3) exhaust - Titanium 0.8 mm header, 0.6 mm other. Lower cylinders (2 and 4) exhaust - Steel 0.7mm header, 0.6mm other
Maybe because of dfferent material thermal properieties or still avoided cracking on more complex lower pair.

The main reason for using different materials for the upper and lower pipes was not the thermal properties of those materials, but the shapes of the pipes.
The lower pipes required some twisting and turning in order to get them past the rear tire and preserve some cornering clearance. Using stamped segments was the easiest way to build them. But you cannot stamp titanium, it's too stubborn, so steel was used for those lower pipes.
The only curved sections in the upper pipes were the headers, which were produced as separate castings, so the remainder of the pipes could be dead straight.
This enabled Honda to build those upper pipes out of rolled titanium segments.

[Dutch Fisher]

And different squash (I'm not sure): on 93'-94' vertical -0.56mm, lower-1.25mm. Maybe different cylinders pair position or crank-firing-load route or teperature difference and vertical cylinders higher elongations , interesting.

Squish?? err nope チャンバ means chamber, that #1 to#4 is the weight of the bare expansion chambers per cyl number
The two rows above are サイレンサ means sliencer, so material and weight of the silencers.

[koenich]

But you cannot stamp titanium, it's too stubborn, so steel was used for those lower pipes.

Nope, totally possible to deep draw titanium.