ESE's works engine tuner

[dmcca]

We dont race buckets here in Australia we race scooters. Well some people may race buckets but scooters as well

Hi Wax, nice scooter pics... Where are you in OZ? I wouldn't mind checking out the scooter race scene over here

Dave.

[wax]

Thanks
Im on the gold coast, the racing is in brisbane an hour up the road.
The 24 hour is held on the gold coast ( bikini central)

[Bren_chch]

The 24 hour is held on the gold coast ( bikini central)

On my way!!

[husaberg]

On my way!!

Take that guy. Bikini girls seem to Worship him.

[SwePatrick]

A little question for anyone interested:

when altering rodlength in the same setup, are there any gains or losses due to altered time the full areas are open in cylinder(spool and exhaust)

We all know that longer rod is having slower pistonspeeds at tdc and bottom tdc.

Rgds.
Patrick

[dinamik2t]

In a 54.5 stroke engine, with a given port distance from TDC, increasing the rod** C2C length 5mm, would decrease total timing by 0.6 degrees.

Starting at 26mm from TDC (200 deg total) and 105 rod:
> 110 rod = 199.4 total timing
> 115 rod = 198.8 >> >>
> 120 rod = 198.2 >> >>

So, you would have to reset the timings. That's port wise, the rest you could look them up in the forum


**for usual "125ish" rod length 105~120mm. e.g. at 100 rod length, same case as above, duration would be 200.8 (+0.8deg/5mm)

[husaberg]

Anyone out there have a RS125 NF4 radiator they can measure up for

Height
Height of finned area
Width
Thickness

Pretty please there could be a Chocolate fish in it.....

[bucketracer]

... why not take that approach and look at the advantages of a rideable, torquey, smooth engine.

Rideable and torquey its what TeeZee and Thomas have been advocating for ages and have posted how Team ESE have achieved that with 26-28 HP and a best run of 18NM with a 4K power spread.

This is the sort of engine that Chambers prepaired for Av and she used it at Tokoroa to totally blits the field.

If anyone wants to build a similar motor, my links post on page 500 points to the essential information.

... My opinion is that a 28PS 25NM air cooled two stroke 125 would currently clean up in NZ buckets.

Its the 25NM that might be the problem.



It sure might clean up but first lets use BMEP calcs to see if a F4 legal 28PS 25NM air cooled 125 two stroke is possible.

Converting metric to imperial:-

28PS = 27.6BHP (1PS = 0.987BHP)

25NM = 18.4Ft/Lbs (1NM = 0.737Ft/Lb)

Finding the RPM that 28PS 25NM relates to from the formula for HP.

HP = (RPM*Torque)/5252

transposing for RPM gives :-

RPM = (HP*5252)/Torque
RPM = (27.6*5252)/18.4
RPM = 144,955.2/18.4
RPM = 7,878

Now to find the BMEP needed for a 125 2-Stroke to make 25PS at 7,878RPM

BMEP = (HP*6500)/(L*RPM)
BMEP = (27.6*6500)/(0.125*7878)
BMEP = 179,400/984.75
BMEP = 182.2 PSI

Converting PSI to Bar. 1PSI = 0.06895Bar

182.2 PSI = 12.6 Bar

That's a higher BMEP than Wobblys water cooled F3 400 or the Honda 500 V Twin GP bike.

My opinion is that a 28PS 25 NM air cooled two stroke 125 would currently clean up in NZ buckets. It might even get some points just by virtue of finishing a race. (or starting)

Unless someone knows more than Wob and Honda I am not sure they could make a 28PS 25NM 125 F4 legal 125 air cooled 2-Stroke let alone finish a race or even start one.



I think the idea of a high 25NMs of torque and 28PS from a 125 aircooled is ... Busted

[koba]

As I am obviously full of shit and know nothing about twostrokes, I will refrain from helping people on this site with posts, until ESE BULLSHIT
contributes something of tangible use.

Ignore the stupid, shit-stirring fool.

[Frits Overmars]

....We all know that longer rod is having slower pistonspeeds at tdc and bottom tdc.

I didn't know that. Patrick. I always thought that piston speed at tdc and at bdc was zero, irrespective of rod length .

[bucketracer]

Anyone out there have a RS125 NF4 radiator they can measure up
Pretty please there could be a Chocolate fish in it.....

I like chocolate fish, so is that the pre 95 RS? as we have one of those.

[husaberg]

I like chocolate fish, so is that the pre 95 RS? as we have one of those.

Yes it is the pre 95 (NF4). the 95 and later is the NX4 is very conventional looking But they are all Hondalishish the later ones just more so

PS that would be great if you could.

i am assuming,Maybe guessing (i don't think i am clever enough to make assumptions) that as i will be aiming for approx 4/5 of the HP and 4/5 of the engine size i can predict i will need 4/5 of the cooling capacity?Yeah i know it wont be that simple as the tank sizes construction etc will vary heaps but i am an optimist.
Is there any rules of thumbs regarding radiator sizes?

I see in my attachments the 95 on NX4 is 19% larger area.but i guess over-cooled a lot of the time in the NZ climate?

[cotswold]

I see in my attachments the 95 on NX4 is 19% larger area.but i guess over-cooled a lot of the time in the NZ climate?[/QUOTE]

Not just the NZ climate, used a lot of tape in cold old UK as well.

[Brian d marge]

I did some work on Enfield engine cooling if its any help

Stephen

[husaberg]

I did some work on Enfield engine cooling if its any help

Stephen

Was it?