Airbox dyno runs 2014

[tony.mon]

I got a baseline run today with my modified (gutted) airbox, GLSR stacks, modified snorkel and lid spacer:


Chain's knackered, cans are leaking/falling apart, but all I needed was a baseline for comparison with the enlarged airbox which will be fitted this weekend.
Just sussed how to route the choke cables in through the airbox wall, and it will poke out on one side under the little tank cutout, just about accessible using gloves, so all good. The cutout on the other side will have the access hole/bung for the Flo Commander.

Lots of smoke on the overrun after hitting the rev limiter, so I hope the bore's ok, as I already have the std size high comp pistons and rings to go in after the airbox swap has been measured...
Ah well, if not I'll have to learn to change gear before the rev limiter.

I'm using the same dyno for the h u g e airbox once I've stuck it on and sealed it up, and will post results, then I plan to fit the ram air, but will have to use HM Racing's dyno as they have the 100mph fans I'll need for evaluation purposes. I'll have to re-jet first, I would have thought.

ps- the 116 Bhp and 119 torque figures are not to be trusted on the through-the-gears runs as the tyre was spinning up on the roller- they didn't bother strapping it down....for comparison purposes the 101 and 64 torque will be the figures I compare with the larger airbox.

[lloydie]

Nice base line to work from tho the jetting could be better but as your just using it as a base line no point playing till the changes have been made

[tony.mon]

Nice base line to work from tho the jetting could be better but as your just using it as a base line no point playing till the changes have been made

It's just the main jets (180 rear, 172 front) that are set about right at the moment- no point worrying about needles (2nd clip down from top, Factory Pro needles)and pilots (45's both) for now. Fuel screws both out 2 turns, but I got bored fiddling so went with these settings for the dyno run.

With the mains I wanted to see how small I could go and still have good enough performance.

These bikes run well when set up rich, a few more top end Bhp, but you lose the snappy throttle response and quick pickup.

[Duffy1964]

That engine ran a 104.8 BHP on the dyno at Brands last year Tony IIRC

Did you do a burn out to warm the rear tyre before the run

[tony.mon]

No burnout, but mine has an exhaust that's falling apart and the chain and sprockets are a few years old, so that probably accounts for the difference- plus I've been fiddling with the carbs

[tony.mon]

Well, finally got the fibreglass airbox to the point of being able to dyno it. without changing anything else.
Well, apart from fitting the Flo-Commander, which is a very impressive bit of kit- the dyno operators hadn't seen one before, and were amazed that I could alter the fulling between runs so easily.
But that doesn't really affect power, any more than fitting the correct jets would.
The seat-of-the pants impression was that it would be up on power, but not by a dramatic amount, and so it proved, really.



Compared to the previous run, fuelling seemed to be further form ideal stoichiometric values, but a lot smoother in transition- the Flo-Commander doing it's stuff, I guess.
It ran rich in the high three's, as the throttle was wrenched fully open in top, then getting to a weak mixture at 6000, richening off again as it heads for the red.
These engines like to run rich, I've found, anywhere from 11.5 to 12:1 seems to get the best feel, but you get poorer fuel economy, compared to 13-13.5.

Headline numbers: Baseline run was 101.3Bhp, big airbox gave 105.5.
But interestingly torque was also up quite a bit, from 64.7 to 68.

So all good, really, +4 Bhp and +3 ft/lbs of torque for nothing, really, and with more to come as I dial the carbs in better, seal the carb rubbers, (I think the rear one is allowing air to seep in) and ad the ram air tubes.

Now I've done the back-to-back comparison I can get on with rebuilding the leaking cans- I didn't want to do anything between runs, as it would stop me being able to draw a direct comparison between airboxes.

Please note that the first run wasn't a standard airbox, far from it, and so the difference between a standard airbox and the huge one would have been greater- I'd guess at +5 Bhp and +5ft/lbs of torque, over standard.

Lastly, these aren't impressive numbers, due for the most part to the knackered chain and sprockets, but I haven't done anything to this engine- I merely wanted to leave it as I bought it and run the two airboxes back-to-back, that way I don't have other factors to correct for. It had Mark GLSR intake stack fitted for both sets of runs.

I might treat it to a new set of chain and sprockets when I fit the high compression pistons and cams in a couple or three weeks.

[lloydie]

Good return for the cost and happy modding

[Jamoi]

Nice results there dude

Surely worth the time & effort!

[AMCQ46]

I like the idea of the flow commander, does it work only on the range normally covered by the main jets or is it effecting the needle settings too?

[Jscobey]

good work mate

its nice to have someone take the time to do work and post up results for others in the future. now is this an airbox you made? moriwaki?

and are the GLSR stacks the mori style (one short and one even shorter) or the HPower style (2 med length)

[mik_str]

Not sure how relevant this is, but one chap on the Speedzilla forum who has supposedly dynoed many SPs noted that max hp is produced at 12.6:1 air-fuel ratio.

Nice project, keep us posted

[bigtwinthing]

Tony your certainly dedicated and that has to be admired. Good luck with the rest.

[tony.mon]

I like the idea of the flow commander, does it work only on the range normally covered by the main jets or is it effecting the needle settings too?

It effectively covers both, roughly duplicating the effects of going down three sizes of main weaker or a half size richer. Have a look at their website:
http://www.flo-commander.com/index.htm
The main benefit for me is being able to put in some jets, then get a clear idea of which way to go, richer or weaker, and roughly how much.
That saves time swapping jets over and over again. Once you're near enough, you can then fine tune with the FC rather than keep doing it. i have the advantage of having the lambda display, which isolates each cylinder's fuel air ratio so that I can tune each carb separately.
It overlaps with the needle settings as well- it actually can't affect needle heights, but seems to duplicate the effects.

[tony.mon]

good work mate

its nice to have someone take the time to do work and post up results for others in the future. now is this an airbox you made? moriwaki?

and are the GLSR stacks the mori style (one short and one even shorter) or the HPower style (2 med length)

I've made the airbox from glass fibre- I have a dummy rolling chassis and empty engine case/heads, and merely made a cardboard lining and glassed over it, then grafted the top of a standard airbox onto it. Remember to allow for hoses! (that caught me out....)

The moriwaki ones seal against the underside of the tank, and would be bigger, but I could not get a good seal, hence the grafted on lid.

I'm running one long one short, same specs as Moriwaki, and similar to Dr Honda's.

[sirch345]

Nice work there Tony good effort, and good results

Chris.