ESE's works engine tuner

[adegnes]

Wait!
If I just wrote off the oil, did my nitro to methanol ratio just go up, and I must take that into consideration?

[adegnes]

No not sure about the exact Octane rating, it was a long time ago. Tried to check the net, found nothing substantive, but from memory I am confident that Acetone has a rating as good as or higher than Methanol.

SeattleSmitty who posted a bit on here about his hydroplane racing experiences with 2T engines on nitro. He said they found there was a nitro limit, maybe only 10-15% from memory before sever heat issues with the expansion chambers. Again not sure about the exact numbers but his posts would be worth a read if you can find them.

Hmm wonder what afr works for acetone? It has about the same energy content as ethanol.
Thanks, I'll see if I can find his posts!

[Ocean1]

Direct injection?

No, more or less standard throttle body mounted directly onto case reed induction.

[wobbly]

OK, so I have deleted all the " nasty " posts except for the " good " bit where I suggested that Luc maybe wasnt an incompetent idiot.
This now means I have a life, and I ( we ) would also be really,really friendly if the " hard proof " was posted here - a World Exclusive, as the media would say.
Your turn Luc.

[malcy25]

The only simple position guide I can give is to say about 3 X Bore down the header from the port face.
You are trying to get out of the unburnt air/fuel zone that sits in the header - but not so far down as to see the gradual temp drop from wall heat radiation.
As far as depth into the header, do what ever you can to get it as close to the middle as possible.
The short,capped end 5mm probes some suppliers sell are useless for reliable use as a tuning tool.
This makes a HUGE difference , believe it or not.

In a 125 kart engine at the Nationals, I got completely lost for 2 days practice trying to get it tuned.
The egt said it was on the limit at 660*C, but the piston and plug were nowhere near,and we were 3/10 sec off the pace.
Luckily on the morning of the final I noticed from the outside that the probe seemed to be pushed in along way.
It was a long exposed tip Stinger type from EGT Industries ( the best and only guaranteed probe you can buy ) with a 90* bend just above the ferule and locknut.
And sure enough, it was 10mm too far in ,past center-line.
I pulled it back up to on center and in the warmup, what was 660*, now read as 610*.
At least an easy 2 jet sizes too rich.
We won, having been second all thru qualifying and the heat races.

As you are running a 10.4 cc head, you will be on Avgas, so in F you are looking for a minimum of 1220 and a max close to 1280.
Start rich, and go down a jet at at a time,you should see around 30 to 40* F increase in temp each change.
If you go down a jet and only see a 20*F increase ,or even worse it stays the same ,or real BAD it drops - then Mr Deto is in the house - go back one, or two in size.
Just remember that ignition timing affects the reading as well,+2* will drop the temp around 2 jet sizes in a RS125 - so then the delta temp change rule becomes even more important.

Wob. Interesting. When I get a chance I'll check my probe depth (again!) on the 350. I'm six inches roughly from the mid point of the exh port(64x 3 is c190, so possibly a bit close?), but always end up with way high temps showing (1375 F on green avgas), but relatively soft on jetting and are not showing any signs of distress on the plug. Prior experiments of advancing up have not changed much in reality and even changing to a different ignition system made no real impact!

[F5 Dave]

Stinger size?

[peewee]

SeattleSmitty who posted a bit on here about his hydroplane racing experiences with 2T engines on nitro. He said they found there was a nitro limit, maybe only 10-15% from memory before sever heat issues with the expansion chambers. .

i wondered why very high percentages can be used in 4t but ive never heard of it being sucessful in 2t. maybe has something to do with the expansion chamber ?

[TZ350]

i wondered why very high percentages can be used in 4t but ive never heard of it being sucessful in 2t. maybe has something to do with the expansion chamber ?

It might be that Nitro is slow burning and is still burning going down a 2T pipe.

There may be an answer, Hydrazine hurry's Nitro up, but now that is really getting into dangerous territory. As a very very small amount makes Nitro burn faster and not much more makes Nitro explosive.



In the 70's Nitro with a splash of Hydrazine chaser was all the go. Eventually "Tipping the Can" was banned after spectators started being injured and even killed by flying shrapnel.

[Grumph]

I'd have thought there's a good chance of a crankcase explosion too with Nitro.

Back when we could use it in roadrace engines here a local sidecar outfit used 11%...I asked why 11% ? The answer was because that's all this engine will take...I noticed the crankcase breather (sorry, it was a 4T) had it's end up by the steering head so asked why....The answer was that if the pilot saw a blue flame at the hose end, he was to switch off, take it out of gear and brake - then reach over, tap the passenger on the shoulder and they'd both roll off the bike...Then walk to the nearest marshals point for a broom to sweep up the bits from the crankcase explosion.

They went through a few motors before arriving at this happy place - it was fast though....

[peewee]

im quit sure i could configure my lectron to use nitro. maybe a needle change and a third powerjet. its already set pretty close for straight methanol so I would just have to add nitro until it melts the plug or piston then reduce the percentage a tad . adegnes you have any idea how much extra power 10% would give ? I was always scared of a explosion hazard with nitro so I never tried it

[husaberg]

Itohs bike was the fastest in a straight line but Doohan still wiped the floor with him.

True but that wasn't the point i was offering. That said.
Wayne Raineys bikes were often slower than the pre big bang and two up honda.
Wayne kicked a lot of arse with bikes that were easier to ride and had more linear power delivery.

No, more or less standard throttle body mounted directly onto case reed induction.

Interesting i will have a look

[adegnes]

It might be that Nitro is slow burning and is still burning going down a 2T pipe.

There may be an answer, Hydrazine hurry's Nitro up, but now that is really getting into dangerous territory. As a very very small amount makes Nitro burn faster and not much more makes Nitro explosive.

And even if you don't get blown up, it's got lots of other ways to kill you.

im quit sure i could configure my lectron to use nitro. maybe a needle change and a third powerjet. its already set pretty close for straight methanol so I would just have to add nitro until it melts the plug or piston then reduce the percentage a tad . adegnes you have any idea how much extra power 10% would give ? I was always scared of a explosion hazard with nitro so I never tried it

Theoretically you could just add it's btu on top of your methanol.

Methanol btu ~ 9.5
Nitro btu ~ 5

(1x9.5)+(0.1x5) = 10 = 5% gain

What's special is you can just keep on adding nitro without removing methanol.

50% added
9.5+(0.5x5) = 12 = 25% gain

100% added (50/50 mix)
9.5+5 = 14.5 = 50% gain

200%
9.5+(2x5) = 19.5 = 100% gain

This might all be wrong...

[peewee]

adegnes did you find out if the comp ratio can remain the same as with methanol or would it need to be lower or higher, would the percentage factor into this ? what about the spark lead ?

[adegnes]

adegnes did you find out if the comp ratio can remain the same as with methanol or would it need to be lower or higher, would the percentage factor into this ? what about the spark lead ?

Best ask someone else, my only experience with it(other than in rc cars) is what you saw in the video. I've been told that you need less comp compared to methanol alone, probably because with high nitro ratios there's so much liquid in the chamber.

[teriks]

i wondered why very high percentages can be used in 4t but ive never heard of it being sucessful in 2t. maybe has something to do with the expansion chamber ?

Different scales, but in the eighties my Dad were into RC hydroplanes. His fuel with "only" 40% nitromethane was in no way the highest nitro content, so for sure two-strokes for sure can burn such fuels. If that's applicable on all sizes, who knows..