zx7r ram air ducts

[tmc]

Hey guys,

i was just wondering if anyone has played around with the ram air ducts on the 7.

my bike currently has been tuned with jetting/ k&n filter and pipe and i was thinking of making some carbon ram air tubes to replace the factory stuff.

as everyone with a 7 should know they have all the resonator?? guff in the pipes which maked them not really direct 'ram air' to the air box...

this arvo i took the stock tubes out and using strong sticky cloth tape, i have taped up the whole bottom of the tubes, blocking the massive hole in the bottom of the tubes, creating a direct ram air environment.

I just took the bike out for a spin and first off, there is a huge difference in idle induction noise. IT IS LOUD

Once riding the induction noise to me doesnt seem that loud but i guess if you were oncomming to me you'd hear the roar! , but the exhaust sounds different AND the power seems down!

When riding hard though the gears when i let the clutch out or change gears with out the clutch there seems a brief loss in power, not a lot but before doing this when you changed gear it used to really boot if u know what i mean...

My bike i due for a service anyways so i was thinking of leaving this as is and getting it tuned to suit the taped up tubes and hopefully overcoming the issues now and overall maybe it should gaining something???

So i guess im after any opinions and or experience that anyones had...

Should i get it tuned to suit then make the carbon replacements or will this be a big waste??

I guess the only reason i ask i cos all the race bikes run direct ram air... but i guess they have custom air boxes etc.... so maybe it isnt worth it??? any thoughs???

Travis

[MadKaw]

I did exactly what you did on my 7, than I got my hands on some carbon fibre air ducts... They are the ducks guts and look great.
You won't need to tune your bike for the mod either.
The biggest improvement I noticed, apart from the induction noise, was increase in throttle response... and tossing all that crap from the standard setup has gotta be a weight saving too..

I also found the K&N filter didn't perform as good as the stock filter with the mesh removed. I had it checked on a dyno and the std filter with no mesh gave the best HP... My $180 K&N then sat on the shelf....

[tmc]

Thanks for the info...

While i think of it, another thing i think i noticed was that the engine braking was different!

When i took it out i tried everything... 0-220ish 1,2,3,4gears to about 10K etc... roll on's and so on.

I was very dissapionted.

Back on the engine braking thing... usually above say 6k when i jump off the gas the braking is quite obvious, now it seems very subtle.

I dont know how this could be related to what i did... but im thinking i might just get take the tape out...

Travis

[mrmina]

with carbon fibre things mattyv can make them and he also has a 7r which is a real convience for us 7r owners.

i know hes really busy with study and work but sould have a few pieces soon (i think).

[tmc]

Hey again,

what i saw on matts bike on the arthers seat ride,

so far he has only made the covers for the ram air tubes.

and i cannot believe... i just read a post in another section from him say he has done the exact same thing with tape... and is happy with the results...

makes me think his bike wasnt tuned right b4 he taped them up

will have to wait till he posts.

when i get a good walm weekend im going to do some carbon tubes for sure! when i took the covers off, i recon it will look mad with the carbon tubes only! the duct covers ... cover all the good stuff!

IMO i looks so tough with the free floating tubes going from the front into the frame!

Travis

[Neka79]

I also found the K&N filter didn't perform as good as the stock filter with the mesh removed. I had it checked on a dyno and the std filter with no mesh gave the best HP... My $180 K&N then sat on the shelf....

funny u say that dave...i told sum1 that once & they laughed at me & told me i was nuts...but when i got my cbr staintune had dyno'd it, and found with a full system, the best power & torque figures & curves were with the standard filter, over a K&N,UNI and sum other one they found..
neka

[mattyv74]

Hey Trav, can't remember if I wrote this in the forums or by pm t o a couple of guys.
What I found with the ram tubes was slightly different to Dave. I found that around town at about 60-80km and under 6k rpm the bike wasn't quite as responsive as when I used stock tubes. However, from about 180km up all the way to revlimiter in 6th there was a noticeable difference.
We are only talking about 2-5hp improvement here which is not like finding another gear. Consider that the stock 123bhp will pull 265km, 5hp more won't get you a massive improvement in speed. 10 extra at 250km/h will cost 4 times as much hp as a 10km improvement at 100km.

The point of all those chambers and baffles is to maximise preassure in the airbox at slow speeds and to reduce any pulsating in the air charge. At high speeds, the airbox volume isn't as critical as the velocity at which the air is travelling. This seems to be consistant with the results found.
For every day riding, I'm not sure that it's the way to go, but on the open road at a high clip it certtainly is crisper and sharper. It now runs with Scotts 9r right up untill it runs out of rpm.

As for the tunning, I've got fresh plugs that I gapped only obout 1000k
ago, valve shims are all done, and I've balanced the carbies have been several times.

There is no single massive fix for making extra hp. This is just one tiny little step in making these oldish things haul arse. There heaps of little mods that can be done, but they all come at cost, usually of usability at lower revs and speed.
KHI's R&D is aimed at a usable bike for the masses.