Dyno performance- actual readings

yea Red, i agree.  Fred never has a whinge. is always more than happy to help.

also, i agree with one of your earlier comments, a while ago in the Redax shed;
  "i reckon we keep Fred amused."

:D
 
ok blokes.  here's one for all the rivet-counters out there.

Miss J.  '81 Jota #8068.  that Maxene refers to as my, Miss 'just standard'.    :)
DynoRun-BSFOS-01.jpg

2011 at the BSFOS (Barry Sheene Festival of Speed) Eastern Creek, Sydney.  http://www.barrysheene.com.au/
i watched this bloke for a while and his equipment and procedure looked ok, so thought 'why bloody not ay?'

MissJ-20110402-98.jpg

the 85 HP at the back wheel was a bit unexpected.  but Miss J has always been good at the top end.  max torque > 57 ft-lb.
when it gets past 7,500 rpm the donk really spins up quick. so i guess it's breathing ok?
& i only wanted to take it to 8,000 rpm on that dyno.  'cause a bloke had to ride 1,000 k's to get back home.
happy days.

<note to self>  take Miss J down to Fred at Procycle for another run.  just as is.
has original factory Dellorto carbs and jetting.  only been cleaned and adjusted.  has done about 80,000 k's.
ok,  Redax did talk me into 'trying' an IIS ignition back in 2006.  i haven't given it back yet, but i'm tempted to go the next step with an Ignitech.  maybe after the dyno?
 
& here's a 120? crank.  Tim.C's RGA.
this was a 'mild' Redax rebuild?  if there is such a thing ??  :-\
i know it has the standard 75 mm bore, although new pistons would be oversize.  and it has Mikuni flat-slides.  and exhaust is 3-1-2 system (ex Wolfgang?)
Tim has had this cycle for many years and has always done an annual pilgrimage down to Phillip Island for the GP races.
Tim is a firm believer in "ya gotta luv ya Lav"
TimC-RGA-20130909-01.jpg

but i'm still pissed-off it's got 0.12 more farken HP at 7,500 rpm, compared to me Clyde!  :(
 
another graph ??

this is Tim.C's RGA and my 'standard' Jota and 'non-standard' Clyde ('78 1200).
dynoruncompare04.jpg

i'm guessing the Jota and RGA are 994 cc.  Clyde is 1130 cc.
all the individual dyno runs have been previously included.  see below (or above?)
 
Interesting results from the RGA Mark,

I will post mine up, just need to dig them out of a drawer in Brisvegas.

I am quite interested in seeing the various curve progressions, i'm curious to see what affect our revised inlet tracts are having, moreso when compared to 3:1:2 Moodified can Vs Standard can

Dynotopia is rather addictive

Peter
 
& i've nicked another off Robjota;  modified the exhaust.
http://www.laverdaforum.com/forum/index.php/topic,89999.msg279135.html#msg279135
& just for the benefit of our Dellortoman, i reckon blue is 2010 with the earlier 3-2, and red is 2011 with the modified downpipes, 3-1 collector, and only one of the previous tailpipes?
hence the '2 vs 1 can' tag?
Robjota-Exhaustgraph2vs1can2010-2011-r.jpg


83 ft-lb at 7,000 rpm.  yes please !!
 
& here's another earlier dyno run from Lothar, with a better link to what's going on;
http://www.laverdaforum.com/forum/index.php/topic,41318.msg61514.html#msg61514
& thanks again to Lothar, for sharing his experience.

SFC1000-L-cr.jpg

& i understand this is 'corrected' clutch power? 
so Lothar, how's yer SFC1000 clutch rods doing these days ??    :D  :D    (sorry, i just can't help meself ay.) 
 
Hi Mark,

yes, these are "clutch figures". Rear-wheel would be roughly 10% less I would say. BTW: on one of the videos at the very end, the operator did pull the clutch lever, too. Either just to downshift or to really measure the loss of the drive train - I don't know. If the 117HP of the one run are rear-wheel figures as I define them, that would mean the engine puts out well around 130HP. That would be one of the strongest Laverda engines (besides the V6) ever.

So - either our definitions of "rear-wheel horse power" are different or I really need to re-balance my assumptions about what is possible with a Laverda engine.  ;)

But the main thing is not the value itself, the main thing is that the power satisfies the owner and that it lasts a long time, which I assume is the case as Red's work seems to be exceptionally well done! 

BTW: the clutch rods are currently my least issue... The engine is currently being overhauled by OCT due to some minor issues... (burned valve on cylinder 3, a pulled exhaust stud etc. etc. )
 
Laverdalothar said:
BTW: the clutch rods are currently my least issue... The engine is currently being overhauled by OCT due to some minor issues... (burned valve on cylinder 3, a pulled exhaust stud etc. etc. )
Click to expand...
that's a bugga!  sorry to hear, Lothar.  excuse my earlier attempt of humour.

& i believe our definition of 'rear wheel' power would be the same?
Laverdalothar said:
So - either our definitions of "rear-wheel horse power" are different or I really need to re-balance my assumptions about what is possible with a Laverda engine.
Click to expand...
i.e.  the power available at the rear wheel, which is transmitted directly into the dyno.

Laverdalothar said:
But the main thing is not the value itself, the main thing is that the power satisfies the owner .............
Click to expand...
+1
the number is just a good benchmark for today's engine condition, and for tomorrow's future modifications.  if any.
i.e.  is it an improvement, or is it a backward step.
 
ok Cam,
Dellortoman said:
Any comment o header diameters & lengths? 
Click to expand...
it's about;
IMG_1485cr.jpg

header tubes, 38 mm OD straight, stepped up at exit to 44 mm,  about 520 mm long
collector tubes,  44 straight, stepped up at exit to 52, about 200 lg.
transition tube,  51 tapered to a 60 exit, about 450 lg.
tailpipe, 60 tapered to 102 for 450 lg, and tapered back to 65 for 50 lg, with 50 exit pipe.

now tiger,  don't go stressing yourself out over all yer calculations ay!
 
An interesting pipe...I've never liked "flat" pipe junctions, preferring them arranged in a circle or in this case a triangle arrangement. The stepup in pipe dia just before the junction is to get enough volume in the collector...which is why I don't like this arrangement.
Headers would seem a tad short....Personally, I'd try tapered headers,maybe 700 long, starting at 38OD and finishing at 44OD. triangular collector,Cosworth venturi on collector, plain parallel 52mmOD tailpipe with as much length before the silencer as possible...But that's just my opinion....
 
I like thinking about exhausts, don't know why, perhaps because it fries my brain a bit.

I see where Greg is going with the < dia header pipes. I too prefer the 'extractor' type collector hence creating a vacuum to withdraw the gasses, from each downtube exit (not the port or combustion chamber), a sort of pulsing effect.

If I had my ideal, I would consider 3 individual slash cut outlets, all within a sum-what oversized collector, each of a length dependant on firing order.

What happens after the collector is always a fry my brain issue.
Flow vs back pressure low enough to retain the vacuum effect .......... ouch, I won't sleep tonight.
 
ok. exhaust systems?  as always, an interesting topic.  & i really do no nothing!  ???  well,, bugga all.

i can remember reading one of Piet's comments a while back, so went a searching, again.
sfcpiet said:
...  Actually, we ended up with a ugly, awfull looking system that looked very similar to what Triumph fits to their "little" triple trailies these days.  Short primaries ending in front of the cylinders with a loooong collector branching into 2 silencers in the normal position.  Gave best results through the entire rev range, we felt the world wasn't ready for it yet!  piet 
Click to expand...
http://www.laverdaforum.com/forum/index.php/topic,89069.msg262677.html#msg262677

yes, i am more than a little interested in this concept.  so went looking for the Triumph mentioned.
triumph800-01.jpg


ok Piet, i can understand that you won't be throwing all of Moto Witt's development work out on the table for us, but can you add anything about this concept?
: was a single exit (3-1) tested?
: do you think it would perform similar with the 180? crank?
& i guess the outer tubes will have to wrap around the triple frame down-tubes.
maybe a bloke better go picking through some Triumph wrecking yards.  :-\

and i made note of this earlier comment, that others may also be interested in today.
sfcpiet said:
...  Did a lot of testing and experimenting with 120 systems on the Moto Witt dyno, always came back to the stock collector, and silencers!  Overall, a very efficient system, even with a fire breathing 1180cc  engine.  piet
Click to expand...
http://www.laverdaforum.com/forum/index.php/topic,89069.msg262569.html#msg262569

as always. comments are welcome.
but,,  dyno readings are better than any opinions ay?  8)  just saying.
 
Thanks for the dimensions Mark.

I'm on the wrong computer at present. I left the laptop with all my exhaust calcs at work (I'm at home at present). I'll have a look tomorrow, but off the top of my head, I think the diameter of the headers is about right, but the length may be a bit short unless you're chasing peak power around 9,000 RPM

I reckon 180s should have a different looking system anyway. The two outside cylinders should come together first, with the centre cylinder joining the collector further down the pipe. But that's just a guess. I'm as much in the dark as anybody.

Exhaust design for any particular engine comes down to trial and error, as Paul and his exhaust guy are finding out. The theory just gives an educated guess at the starting point for experimentation.

Cam

 
my bloke wanted all engine specs off red(bore/stroke-cam timing -head flow etc) and did his calcs off that
 
bevelman said:
my bloke wanted all engine specs off red(bore/stroke-cam timing -head flow etc) and did his calcs off that
Click to expand...

G'day Paul

Your bloke is probably using similar formulas as I am (from A Graham Bell's "Four-Stroke Performance Tuning"). Bore, stroke, and timing of exhaust valve opening are the basic parameters, then you factor in where you want the peak power and torque in the rev range.

For peak power at 7,800 RPM and torque at 7,000 on an 1130cc 120? engine running F1 cam timing, the number crunching tells me I need 38mm OD headers x 560mm long, going into a 50mm OD secondary. After that, it either doesn't matter too much or it's beyond the scope of simple arithmetic to figure it out. The system I bought from you has slightly longer headers than that, so it might move the power down the rev range a bit at the expense of top end. I haven't got as far as the dyno stage yet.

I suspect the uneven exhaust pressure pulses of a 180? might throw a spanner in the mathematical works, so your development work on the dyno is pretty much the only way of solving the puzzle. Must be costing you a heap in dyno runs and exhaust mods though.  ;)

Cam
 
uh yeah-am cool with it though-its a lot of fun-makes it easier for the next guy as well-was worth it last run when red had a good smile over the figures
 
You must log in or register to reply here.
Back
Top