FOXHAT RB 260 DYNO RESULTS

[amazombi]

Wenn man sich das bei SE so durchliest, ist doch ein nicht ganz unerheblicher Aufwand getrieben worden um die zur Diskussion stehenden Kurven auf ein Blatt zu drucken.

Das unsere angelsächsischen Freunde schnelle Moppeds bauen können sieht man z.B. am Barlow Harry seinem Renngerät oder dem Edmonds Charlie seinem.

Ich gehen also mal grundsätzlich davon aus, das eine RB mit 260 cc durchaus Qualm haben kann, wie das jetzt mit den Papieren da in Einklang gebracht werden kann verstehe ich aber auch nicht.

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Also den Verweis auf Herrn Barlows (ein ganz Netter übrigens) Karren verstehe ich jetzt nicht ganz. Das ist ja doch, mehrfach nachgewiesen, guter 80er Jahre Standard. Mehr aber auch nicht. Herrn Edmonds Gerät ist dagegen schon im 21 Jhdt. angekommen, ist aber halt auch eine grundsätzlich andere Entwicklungsrichtung als das, was für uns hier rennmäßig interessant ist. Ansonsten fällt mir, außer Nostalgiekram und meintwegen Zylinderrohmaterial, jetzt nix ein, was tuningmäßig direkt einen Habenwill-Reflex auslöst.

[amazombi]

@Muttonjeff:

Would you care to share some more information about the engine's spec? It's a Lectron carb, right? What size? Why did your mate go for such a comparatively exotic device? Do you have and idea what the port times are? Is it meant as a road tourer? I'd really love to learn about these details. If I understand the guys reactions correctly they consider the result to be slightly dissappointing, considering the spec sheet of the engine that is.

[muttonjeff]

Hi

This Engine Was Commissioned To Run On Sunaco E85 + E85 Locally Sourced Ethanol. Due To Circumstances Beyond Our Control, Ethanol No Longer Available In UK At The Fore Court.

No Option But To Change Set Up, Lectron/ Ignition/ Cylinder Head.

What We Posted Is The Result. We Will Convert Back TO E85 As Soon As The UK Starts To Resell Ethanol At Pump.

No Where To Fuel Up On Route.

Art

[muttonjeff]

This Is The Bullet Exhaust On The TS1 260. Straight On, No Adjustments. This Is The Results.

I Will Post 4th Gear Run When Its Obtained.

Art

[amazombi]

The port timing of this setup is not as it should be, I'd say. I bet it's 28ish blowdowm, with transfers high in the 120ies. At a guess I'd say you're loosing 3-4 Bhp on max power, and probably 500-800rmpm width of band. If the timing is as I wrote you (or the owner) would be well advised to work on it. I know this is the traditional setup of those who started with castiron conversions, but it's not very god once you go modern with the pipe. It's a bit like trying to use a Porsche cylinder head while insisting to run the engine on diesel. If you get the gun out you need to have it loaded, and you got to be prepared to actually fire it. In plain English that's: do it right, or don't do it at all. You've got everything to turn this one into a firebreathing monster. Just raise the exhaust to something well over 190 with over 30° blowdown, and the thing will start to fly.

[praktikant]

I also think, there could be some problems with the port timings.

Bearbeitet 25. Dezember 2010 von praktikant

[Truls221]

Hi Arthur

All respect for the work of this engine and too you!

I have to agree that the results does not live up to a 260 cc engine though.

On the similar dyno as you did your run, there have been several vespas and lambrettas, and which

have put out similar horsepower within -+ few percent on an Amerschläger P4.

It is worth to notice though that the calibration settings for the dyno could provide results +-5% in power easily.

Still seeing graphs from "drunkmunkey" on the same dyno he has over 30 bhp on a TS1, and seeing the graphs from John B, he has over 35bhp on a RB258, and over 30 hp on several engines, despite another dyno. It is always hard to compare absolute numbers of power.

The next thing that makes me wonder is that you mention E85? We have a lot of experience with this in sweden and on two-stroke, allthough I have not run my engine on it yet. But if we convert from RON98 to E85 we normally see that the EGT drop by more than 100 degrees, even if we are running near to stoichiometric or even slightly lean.

As I am sure you know, we need 40% more fuel to run stoichometric for E85 compared to RON95.

On a mikuni jet this is apprx the jet size * 1.4. on a "metric" jet, it is the dia * 1.18

It would be interesting to hear your experience regarding the re-jetting from gasoline to E85.

For constant full load at max power the EGT should be around 475-550 deg C on the EGT, which is an AFR around 10

hope to hear your comments Arthur, and thanks for sharing the results!

cheers

Truls

[Schniedel]

moin!

beside my good english,i only understand trainstation...

mfg,schniedel!