Scooterotica

Shhhhhhhh, I mentioned the war once but I think I got away with it.

corrado wrote:Shhhhhhhh, I mentioned the war once but I think I got away with it.

No you didnt....

Giankx your graph and gearing (4.25) shows that peak power is produced at about 69 ish mph in 3rd, 93 ish mph in top (around 7,700 rpm) and it starts making power at 55 ish mph in 3rd, 72 ish mph in top (around 6,000 rpm). Not a stump puller like a GT kit.

Sounds overgeared to me if the dyno readout is accurate. 16/46 would be better theoretically, but if you ever ride 2 up std 15/46 would give you a theoretical top speed of about 78 mph and a chance of reaching it on a semi regular basis.

Only about 1,700 power band there.

BTW what is the bhp figure?

Special X wrote:Giankx your graph and gearing (4.25) shows that peak power is produced at over 10,000 rpm, and it starts making power at over 6,000 rpm. With the gearing you have quoted peak power would be produced at around 190 kph and it would pull (in a fashion) from 120 kph in top.

Sounds radically overgeared to me if the dyno readout is accurate. Power should peak at about 7,000 rpm to give your quoted max speed with that gearing.

Box pipe making peak power at over 10,000 rpm? all the group 4 guys need one of those

Not quite sure about that, bottom scale of graph appears to be kph not RPM?

victor wrote:
I'm sure the GT kit is absolutely fine, but the RT seems to have a little more oomph at the same time being completely untried which adds excitement - will it work or blow up the engine?

I wouldn't be so sure about that; GT's are no slouch. As a bolt together they easily achieve 20bhp and I really do not put a huge amount of effort into getting 20BHP (I'm no tuner), the first two are newly built engines not run in, the third I didn't build. What can be achieved with a bit more time and effort is evident with the 20.2BHP reading which was done with a PHBL25 through the airbox (Darrell's work as I understand).

All of these engines make 20BHP, all from off the shelf parts, all on small block casings and no welding. The description on the pictures give you the setup information on each.

You're right Minority . . . crap screen res at work

I've corrected the post but it then shows to be overgeared and would be better with a 16/47 set up (solo). Very peaky for a box pipe with power only starting to build at 6,000 rpm and gone at just under 7,700 rpm. Not a stump puller.

Can't get a handle on how much power is being made.

eden wrote:

giankx wrote:My rt240 has just clocked 5000 km. No problems so far, also under really hot temperatures (40 degrees this summer in south Italy).
Pulls like a train with my Mito reverse pipe and VHSH 30mm (sx200 17x46 , final ratio 4,25). At cruising speed it is also really cheap on fuel (24km/l) and i've clocked a top speed of 136km/h.

These are some dyno sheets, the lowest figures is with a gori 50mm pipe, the other with a Mito reverse pipe.

Is this enough?

Looking at that graph on my phone it looks like its less than 20bhp.
Not great for an expensive 240 if thats all it produces.

Sent from my GT-I9000 using Tapatalk 2

Very narrow power band too. Needs a JL4 to make use of the cylinders toppy nature. (IMHO)

giankx wrote:My rt240 has just clocked 5000 km. No problems so far, also under really hot temperatures (40 degrees this summer in south Italy).
Pulls like a train with my Mito reverse pipe and VHSH 30mm (sx200 17x46 , final ratio 4,25). At cruising speed it is also really cheap on fuel (24km/l) and i've clocked a top speed of 136km/h.

These are some dyno sheets, the lowest figures is with a gori 50mm pipe, the other with a Mito reverse pipe.

Is this enough?

Interesting - did you bolt it on as was or did you need any porting and matching done?

Thats impressive Richard over 20hp from a small block with a 25PHBL.
Would these barrels have had some more tuning work or is it the pipe alone making the big jump in BHP.
I've not had mine dynoed yet but would guess its nearer 14HP with a 25PHBL and and Ancillotti clubman.
Who's Darrel? , would be nice to squeeze some more horses out of it!

Special X wrote:You're right Minority . . . crap screen res at work

I've corrected the post but it then shows to be overgeared and would be better with a 16/47 set up (solo). Very peaky for a box pipe with power only starting to build at 6,000 rpm and gone at just under 7,700 rpm. Not a stump puller.

Can't get a handle on how much power is being made.

The horizontal line on the graph is km/h not rpm.

When i installed the kit i just matched the transfers on the casing. The pipe is really torquey and as you can see on the graph (down-right, sorry for the crap res), max torque is at just 4954 rpm with 24nm. The engine starts pulling at about 55 km/h in 3rd that means about 3.700 rpm (sx 200 17x46) and you feel the loss in torque at 95 km/h at 6.500 rpm as shown in the graph.

So i don't think the pipe, neither the kit is peaky.

20 hp could not be enough from a 240ccm3 kit with a box pipe, but the spread of torque is really considerable when riding on open road.

Next step is to try another pipe. A modified Innocenti box with expansion cones inside.