Pods Vs Air Box. Dyno and Road Testing

[koko64]

Having run and dyno tested an open air box on a carbed 900 Monster, I settled on a good set up with shortened velocity stacks which thickened the power and torque curves rather than gave any major top end power at the expense of mid range and bottom end. Tuning theory leaned towards the latter happening but it didn't. The inlet manifold are a mile long anyway..

The conlusion I reached because of this was that the velocity stacks were too close to the filter element making an inefficient air box even more so. Shortening the velocity stacks improved the available volume in the air box. The shorter stacks mitigated a shallow air box design to some extent. The location of the filter, available space between the filter and the stacks and the location of the carbs on the air box are all part of the equation. I'm no expert on this for sure but look at a modern air box on a GSXR and see the difference.

What about trying pods? The K&N RU 1750s have been shown to flow enough air to make over 100hp in worked carburetor desmodues. They also drop 1.5 kilos in weight and make servicing easier. I have a friends bike which runs very well with them, a 944 Superlight with FCR39s, a little porting, dialed cams, Dyna coils, Igniteck Ignition and Ti valves. This bike does 3rd gear wheelies down hill. It only required a change in needle position when changed from an open air box (#5 to #6). I did this mod on the bike as I owned it before by buddy. I painstakingly tuned this bike over six months.

I got my kids and Math teacher wife to help me calculate the filter area of the pair of pods compared to the K&N flat filter. The pair of pods had about 30% more filter area (roughly), I can't remember exactly. There was significantly more. Their shape concerned me and whether there is a good radius inside to give a velocity stack effect. If Jako and MBP have used them to good effect then I shouldn't worry too much. (Anyway Chris Kelley don't sell crap).

When I am well I will conduct road testing and then whack the old girl on the dyno. If I get 81-82 hp and no losses in the midrange or bottom end then I will keep them.

By the way she has JE high comps, advanced stock cams on Vee Two pulleys, Termis and some porting on the inlet side. There is also Kelley coils, Igniteck module, Vee Two/Barnett clutch (-1.9 kilos) and 1 kilo lightened stock flywheel. Going nuts with being ill with the flu at home, I got out of bed and carefully weighed all the stock components removed or replaced with lighter stuff and have dropped a whopping 16 kilos from the empty tank weight as weighed by Sportsrider in 1995-1996. From 186 to 170 all fluids sans gas. Pity I can't afford light wheels. As an aside, the sprung weight is low but the unsprung weight is heavy with the stock Brembo wheels, and I feel it in the handling as the unsprung weight is a bully to the chassis. The sprung and unsprung weight are out of balance to me.

With Pods servicing is easier and with a Shorai battery I have fitted the coils and ignition all into the battery box which I have seperated from the air box. Removing the ignition bracket removed another 200grams. That's 3 kilos off with the Shorai, 1.5 kilos off with the pods and 200 grams off with the ignition bracket.

I'm concerned about crankcase breathing which I will have to deal with (see the other thread)!

I'll get well and report soon.

Cheers. For medicinal purposes.

[the_Journeyman]

I have been toying with pods for my M750.  I haven't made the leap because of having to create a way to mount coils & battery AND all the tuning that goes into me setting up for the pods.  Currently, my crankcase has a tiny K&N style filter clamped in for crankcase venting.  Bike is running very good with the exception of an off-idle grumpiness.

JM

[Speeddog]

Get well soon! 

[rockaduc]

Who the hell gets the flu in July?

Feel better soon!

[ungeheuer]

Who the hell gets the flu in July?

Middle of winter Down Here mate...

Yup hope you're back on track soon Koko64 (looking forward to seeing how you go with this....) 

[koko64]

Thanks for the good wishes guys. Should be able to start testing in a week when I am well enough. It is snowing in the nearby hills...

Back to the sofa and granny blanket. Never thought I'd say this, but bring on global warming!

[rockaduc]

Middle of winter Down Here mate...

Yup hope you're back on track soon Koko64 (looking forward to seeing how you go with this....) 

Ah.  Got it.

[CDawg]

Good luck!  I'm curious at the results!

[koko64]

After three weeks of illness, I'm back on deck. Back to work tomorrow.

Will arrange for a dyno test next week as I can get it cheap including dyno diagnostics for A/F ratios at idle, 1/4, 1/2 3/4 and WOT for 80 bucks (which I don't have due to being off work). I'll see what deal can be arranged.

I will do the road testing first if it isn't raining (damn cold though). Haven't ridden the bike in nearly a month!

Based on doing this mod in the past I suspect no significant difference in power with the appropriate tuning. It's not like I have removed a really effective air box.

It's good to get off the couch..

[Dellikose]

I'm definitely keeping an eye on this thread 

[koko64]

First ride in a month! Had to richen idle mixture screw and will fiddle with the slow air jet. Pods seem to flow more air at idle and sub quarter throttle, I'm getting a lean spot off idle. Interesting.
Might have to increase slow fuel jet.
Bike is very responsive otherwise. Its running fine on the street. A lttle more responsive. Half to 3/4 throttle rich spot is resolved.
We will see what the dyno says.

[ducatiz]

probably a truckload less restriction for those pods

[koko64]

probably a truckload less restriction for those pods

I think thats correct from the seat of the pants. We will see with A/F ratios are on the dyno.

[Drunken Monkey]

One big issue the dyno isn't going to tell you about is that generally engines like to breathe from a large volume of relatively still air.

So pods on a dyno may work fine, but when exposed to a 60 MPH blast of air they'll make less power.

My local shop prefers the open airbox to pods on their race bikes.

Personally, I think pods look and sound great and I don't miss the few extra HP they may be costing me.

[koko64]

My view is that a correctly designed air box is the best way, eg ala Jako.