Pods Vs Air Box. Dyno and Road Testing

[ducatiz]

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.

I wonder what you'd get if you kept the bottom of the airbox with no filter and modified the horns to take the pods... 

[koko64]

I have considered an air box mod like that, but if MBP and Jako can run pods and make over 100 hp, then I thought why bother? My next rebuild will be incorporating some of those tuning mods. Mind you Jako has a carbon air box that gives about 110 hp.

[Ddan]

How much of that 110 is due to the airbox?

[koko64]

Pods were at 102SAE and carbon air box toward the 110SAE mark. Jako normally uses ps hp so you take a couple off.
Check out the site its interesting. I know you speak French (smooth move), the Jako site is in German. I winged it and found some dyno graphs. The air box appeared to work well but would be pricey.  I would be happy with the Jako 100 hp kit!

[Drunken Monkey]

I have considered an air box mod like that, but if MBP and Jako can run pods and make over 100 hp, then I thought why bother? My next rebuild will be incorporating some of those tuning mods. Mind you Jako has a carbon air box that gives about 110 hp.

Now that's an interesting idea! So are they basically using some kind of "shield" to protect the pods from the airstream?

Off to check out their site (and brush up on my German)

[koko64]

I saw one air box that had pods in it with possible ram air and another that looked like it was custom made for split FCRs. Jv might chime in, he told me about the site and had been looking at the carbon air boxes.  Jako have been using Del'Ortos and seem to have alot of experience with them.
Unfortunately my German is limited to what I learned from Hogan's Heros.  

[CDawg]

Are you thinking about this one?
http://www.riding-house.com/products/ducati/fiber_parts/dfm020.html

[koko64]

Very nice. There is so much more available for the S4R/S4RS.
Have you seen the Jako air boxes? Jako cater for carb desmodues.

[koko64]

It's my day off and I have been doing overtime (gotta claw it back)!

We have a break in the weather, a sunny but cold 15-16 deg C. Any lean spots in the fueling will show up today!

Will test slow air screw settings for 1/8-1/4 throttle operation and general road testing for responsiveness, etc.

Will post my impressions.

EDIT.

I went for a two hour ride thru the local hills. The response up to half throttle and 3/4 was impressive.
There is a little dip in the power at 1/4 throttle (on the lean side, well feels like a lean dip) and then an improvement at 1/2 throttle from before where it was on the rich side.

The climb out of the dip has the front wheel lifting easier than before in second and this occured with a gradual rolling on of the throttle climbing a hill. This surprised me as I was overtaking a car on a switchback corner in the overtaking lane, the road was greasy and I was leaning the bike!

My take is that a couple of slightly rich spots (1/2 and 3/4 throttle) have evened out nicely and I believe I now I have a lean spot at 1/4 throttle. I will continue the bottom end tuning with the slow air screw as it overlaps at 1/4 throttle with the needle pos-n, needle diameter and slow fuel jet. When I tune out that lean spot it won't feel as rippy but will actually be faster.

Rolling on hard to WOT from 3500-4000 rpm and 50mph (80kph) was a little cleaner and more immediate. Nice.

We will see what the dyno says as to any measurable change in power. I wouldn't be surprised if a lost a pony or two in some places and gained a pony or two in others. I couldn't hazard a guess for peak power.
Main thing is that there are no ill effects. I reckon "much of a muchness."

Like any intake mod, it's just a matter of tuning.

[Dellikose]

I'm sure it's from years of experience...but, how are you determining the difference between lean, rich, and normal spots in your throttle?

[koko64]

I'm sure it's from years of experience...but, how are you determining the difference between lean, rich, and normal spots in your throttle?

You know we could have a separate Tuning tips/Tuning Principles thread dealing with that question.

Thanks for your interest.
It's so much easier (or less difficult) responding to a specific tuning issue or set of symptoms. There are a number of very qualified and experienced people on this forum who could contribute to such a thread. Some related threads already exist. Try the search function and enter the inputs relating to your bike.

Before we go there how about checking out the following sites?
Brad Black's "Bike Boy".org site and his articles on Dyno Tuning and Carbed Monsters/SS,
Factory Pro's Tuning guide on their site,
Patrick Burns Keihin FCR Tuning site (you can also get to it via Chris Kelley's Ducati Tech site,
Dynojet's site.
Keihin's site for tuning it's range of carbs.
Doug Lofgrens Motorcycle Performance Services site.
You could even Google Motorcycle Carburetor Tuning (I'll have to try that).

I would read up on these and then consider a separate thread on general tuning tips and Principles. If your bike is displaying specific symptoms put a querie in the Tech section.

[Dellikose]

Wow... I hope I didn't bite off more than I can chew 

I don't have anything wrong with my bike, I was just curious to what specifics you were using to diagnose your situation.

I would love a thread dedicated to tuning, it would help a lot. For now, I'll start digging through the links that you posted, thanks for the info.

[ducatiz]

Wow... I hope I didn't bite off more than I can chew 

I don't have anything wrong with my bike, I was just curious to what specifics you were using to diagnose your situation.

I would love a thread dedicated to tuning, it would help a lot. For now, I'll start digging through the links that you posted, thanks for the info.

start here:
http://www.bikeboy.org/performance.html

[koko64]

Still dealing with a lean spot at 1/4 throttle.
The needle won't fix it without buggering up the 1/2 and 3/4 throttle fueling. Could change needles but will look at the overlap of the slow circuit before I consider a needle with a smaller root diameter or less aggressive taper (depending which way I would want to go). Another tuner who deals with dirt racers that use these carbs suggested some tuning of the accelerator pump. He feels a common problem is a lack of fuel from the a/p with a leaner/smooth/cruise setting.
Those adjustable accelerator pumps are am option also.

It's a matter what angle to attack from without buggering another fuel range.
By the way, the pods are loud. I swear the engine/intake note from the seat has changed, it's a little harsher with a more strident edge to it.

I richened the slow air screw/jet and the lean transition to 1/4 throttle is solved. The bike was running on the rich side, but not hurting it at 1/2 and 3/4 throttle (12 and 12.5 a/f ratio). I figure if the pods flow more air this will be leaned out a little closer towards the theoretical optimum for power. Maybe raising a/f ratio half a point which would be fine. We will see.


Will do a couple of customer jobs and then i'll dyno it. The sun has finally emerged.

[junior varsity]

fun catching up on reading this after being away for awhile; that riding house ram-air lid is bfa! One day I will master fiberglassing/carbon-fiber'ing and make some type of gonzo airbox for my 900