Scooterotica

I think i'm another "most people"

I'm trying to explain this away as a Tractor versus a saloon car.....the tractor has more HP but the saloon is faster......is this a correct analogy (on a very basic level) ?

tony wrote:Ok. You still don't get the inertia dyno thing v step dyno thing.
No one seems to understand what's happening regarding heat. You are all so blinded by these inertia dynos.
Let me try again. A standing start mile takes how long on a tuned lambretta? A minute ? Maybe 50 seconds. Ok
The bike is under full load , wind resistance too. Lots of heat in the pipe and motor.
Now.., inertia dyno to plot a graph . Third gear run. Maybe 10 seconds , no wind resistance, just a roller to turn. A roller that's too light on the mjp dyno as shown by the fact that not one of the Pt bikes made the correct egt values.
So.. It's not a real interpretation of real power. And therefore you can jet lower as I showed by not switching on my powerjet.. That's some -25% off my main jet and it STILL wouldnt achieve its correct egt values. Can you not see what's happening ? So. I could jet even lower on an inertia dyno to raise my egt and show great power and I would be a hero. Pub talk would be rife.
Put that bike in the track and it would seize. I say again -- seize .

I would say Jimmy's made 27/28 on step test on Charlie's dyno and it's this motor that did 105 over the mile on tall gearing.
After all my ce tuned 153cc Vespa did 106.6 in HALF MILE with a similar power output

This, i personally think has a lot to do with it. Remember all the PT scoots including the supermonza could not reach the EGT temps they normally run when put on an inertia dyno as they were all set up on a step dyno.
It makes perfect sense to me but everyone is entitled to their own opinions.

Thread tidied up. Please keep on track and refrain from personal insults, threats and other crap.


Moving on.......

Its an interesting thread, and there are some interesting questions.....so I had hoped this could have been approached via a technical route rather than a personal/argumentative one. I am on good terms with both Tony and Darrell and hope they can find some reasonable answers to some, if not all of their questions......as those questions/answers may benefit them AND others.

So, maybe we can re-examine the basics: As far as i can see there are a few things going on here.....

1) Starting on dyno day at our garage Jimmys CE built SM225 hit circa 30bhp on my dyno and the TT RB252 of Eric Cope hit circa 41bhp

2) Moving on, both bikes are neck-a-neck on various 1/8th and 1/4 mile standing start sprints - with the SM having the edge by a fraction of a second, but with the RB going through with faster times on one of the distances.

3) The 'top speed' event is run and on day 1 both bikes seem closely matched, but on day 2 the SM225 hits circa 105mph.

4) Speculation occurs as to whether or not there was a fault with timing equipment, Trev from Straightliners confirms the 105.6mph time and also the 104mph time.

5) Speculation occurs as to the correlation between SM 30bhp on dyno day and any difference at the track, as to whether 30bhp can pull 105.6mph

6) This thread starts and its all goes Pete Tong......


Given the level of interest and debate in this thread, i shall try and bring it back on track with some thoughts as to some popular questions which have cropped up.....these are not my questions, and i certainly have no answers:

Questions:

1) How does a bike with 30bhp manage 105.6mph and a bike with 41bhp run close but not quite as fast?

2) Did the SM really only have 30bhp when it did 105.6mph, or had it been tweaked to give more?

3) If it had been tweaked, by how much BHP do we estimate the tweaks increased power?

4) Does the SM manage heat better than a tuned RB, and the RB suffer power fade? Thus the SM putting down more effective power?

5) EGT temps could not be reached on dyno day, if they had been....what difference would this have made to peak power?

6) Has something else gone on that we are not aware of, or do not understand?

There have been other questions......how much does this cost, what tweaking was done track-side, can A&B be compared to Y&Z, and we have 'supporters' from both sides getting more involved than the original posters and parties concerned.........which is not needed. Given that both guys are valued members on here, i would hope that they can (if they wish) along with anyone else who has something intelligent to add, make some technical/fact based posts/questions/answers without the thread going 'off track' too much again.

Thanks.

Maybe it was tweaked with those cough cough special bits he used on his race bike or maybe it was a detuned 40 hp engine maybe with the ignition remapped then for the sprint put back to the original setting. ....

drunkmunkey6969 wrote:
1) How does a bike with 30bhp manage 105.6mph and a bike with 41bhp run close but not quite as fast?


3) If it had been tweaked, by how much BHP do we estimate the tweaks increased power?

.

1)I'm guessing it was up geared to do so which I'm sure I read it a few pages back.
3)according to your post/advert in the dealer innovations page (which has now been removed) up to 9hp with a mapped ign.system plus whatever for a larger carb.

soosh wrote: 3)according to your post/advert in the dealer innovations page (which has now been removed) up to 9hp with a mapped ign.system plus whatever for a larger carb.

I have neither made nor removed a post from the dealer section regarding this?


Do you mean this thread? viewtopic.php?f=7&t=28488

That's the one! Was it moved or am I pissed?

Well it wasnt moved......lol

soosh wrote:That's the one! Was it moved or am I pissed?

Just a tiny amount..

Muttley McLadd wrote:

soosh wrote:That's the one! Was it moved or am I pissed?

Just a tiny amount..

Lol