Exhaust, pod filter, IAT probe mod: performance results

This thread will eventually contain all the info of the various stages I've gone through while 'tweaking' my Swing. I will edit this original post to keep all updated info in one place.

So far I have a dyno baseline for a stock 5,000 mile engine with 22gram Dr Pulleys.

I have since fitted:
Step 1) A Delkevic 320mm stainless exhaust. It is significantly light and narrower than the stock item. I also removed the snorkel from the airbox.
Step 2) Fitted a new sensor to replace the IAT probe to trick the engine in to thinking it was 20 degrees C colder than actual. This should richen things up during acceleration by around 6%.
Step 3) Replaced entire airbox with large (6" long, 3.5" dia) K&N pod filter mounted to the plenum chamber. Details to follow. Kept the -20deg C probe at this point.
Step 4) Fitted a -25C probe and removed the luggage/grab rail. That shaves off a fair few more pounds, and only take circa 60s to replace if I plan to take the wife out.

I did a set of acceleration tests at 'Step 3'. As before, two way averages were done on a relatively still day, with so-called 'drag' starts where I hold the revs just before clutch bite.

Test type:----- Stock 28g rollers: -------- 22g Dr Pulleys: -------- Step 3 tune:

40-80mph----------------8.60s--------------------8.77s ----------------7.24s

00-50mph----------------5.15s--------------------4.93s----------------4.15s
....-60mph--------------6.93s----------------------6.78s---------------5.62s
....-70mph--------------9.44s--------------------9.03s---------------- 7.79s
....-80mph--------------12.22s-------------------12.13s----------------10.10s
....-90mph--------------15.79s-------------------17.57s----------------14.09s

I will add dyno results once I've got them for each stage. I will also post all pictures & links of the various bits.

Suffice to say I'm please so far - sub 6s!

Crucially performance 2-up is now much better, although the wench still bugger up the handling!

Very nice. Huge improvement in acceleration times. 0-80 is most impressive over 2 seconds.

Looks like more fuel and better breathing from air box made huge difference. Does KN filter fit under side cover? The filter box is huge. KN makes many different filters lengths, sizes. Sounds like you are having fun testing and moding SW.

Yeah, it feels better, but even I was surprised how much faster it actually was. There's a big dip around 50mph when the Dr Pulleys transition from their acceleration profile to their cruising profile. This causes the revs to dip down below 5,000rpm. Peak power is probably north of 6,000 still on this motor - stock was 6,250rpm. Once the engine's finished I'll then sort the transmission to match. Will probably want a stiffer contra-spring to more the target rpm to just over 6,250rpm. The will hopefully shift that dip until after 60mph, i.e. after you've finished acceleration most of the way.

The K&N filter fits neatly under the cover, loads of free space. The problem is more one of getting the airbox off in the first place. Honda fitted the clamp with the screw head facing into the bike, so you have to remove the entire back of the bike to get to it (grab rails, both side panels, rear panels, battery & box, luggage compartment!). Once remove, just face the head outwards, and you can get to it by poking a screwdriver through the gap between the luggage compartment and the engine cover. Not the best decision by Honda me-thinks.

Filter is an RB-0720.
https://www.knfilters.co.uk/search/product.aspx?prod=RB-0720

Good information. I really want to make mine accelerate quicker and this seems to be a good way to do that. Do you have any pictures to share?

Do you have any pics of the pod filter mounted?

Did you lose the airbox entirely?

Thanks!

Sorry for the slow replies. Work blocked the forum, and then it went offline for a bit (cough), and then I kept forgetting to check when at home!

I don't have pictures handy, will try to get some at some point.

I lost the filter box entirely (the one behind the side panel), but kept the 'plenum chamber' (with the air temp sensor, the one under the seat in front of the luggage box. The pod filter mounts to the spigot on this latter box.

I would like to put on a slip on to lose a few lbs. but I do not want to annoy anyone with an objectionably loud scooter. I've been looking at a few Delkevic models online. How would you rate the noise?

I can only comment on the one I have (pictured), and it's not too obnoxious. No worse than a typical sports bike, and certainly not as bad as anything with a straight through pipe. Passed a road inspection (MOT) here no problems.

I mean, I don't worry about warming up the scooter on my driveway (a very closely packed housing area. Think 6m wide plots!) at 6am. I just have to do it on the drive. I tried doing it in the garage with the pipe pointing out the door, and the wife ran downstairs to tell me off because it was acting like a fog horn!

gavinfdavies wrote:

I can only comment on the one I have (pictured), and it's not too obnoxious. No worse than a typical sports bike, and certainly not as bad as anything with a straight through pipe. Passed a road inspection (MOT) here no problems.

I mean, I don't worry about warming up the scooter on my driveway (a very closely packed housing area. Think 6m wide plots!) at 6am. I just have to do it on the drive. I tried doing it in the garage with the pipe pointing out the door, and the wife ran downstairs to tell me off because it was acting like a fog horn!

Thanks for the info.

Any updates on this?
Any pics of the airbox and filter mods?
Thanks.