Has anybody tried there Hi flow air filter set up that mounts where the top of your airbox connects? Wondering if it is better than just a clamp on filter at the carb. It is a lot of money for a clamp on and a piece of billet alluminum. Any info is appreciated.

 

I seen that setup on Rath site. (In coming soon) give him a call.
later

 

Is that just the air box mod or a clamp on system?

 

The Hot Seat unit has you remove the toolkit from the bottom of the seat. You can leave the airbox bottom on, or take it off...depending on mud/splash protection requirements. It does flow some air. [img]i/expressions/face-icon-small-happy.gif[/img]

 

Has anyone tried it and do you feel it is better than the clamp on right on the carb? 149.00 is a lot of money for it.

 

I've been wondering about this too. I actually emailed them a while back asking for some dyno numbers or flowbench numbers, but they did not tell me anything in their reply. Seems weird to not advertise the gains, unless there really aren't any. I got into a long discussion with some folks including gary on the esuperbike shop site a while back, arguing it really isn't any different than cutting huge gaping holes in your airbox such as the airforce kit does, so it should provide similar if not better results. I think it was jsyi who tried a filter on the intake tube without the box, and claimed to have good results except for the thing flopping around. It would be nice if someone impartial and not defending their particular product could try them all out: 1. stock air box with k&n 2. clamp on k&n right to carb 3. clamp on k&n with intake tube (such as hotseat's) 4. Air box with holes cut in it, k&n. All would need to be tried on the same bike, so as to not have mismatched pipes and what not.

 

In all fairness to HSP, they've been busting their butts on the 600 kit....which I believe is ready to go.

 

2MINS, these test have been done on the same bike, (except for the K&N on factory intake tube.) Superbike dynoed it, and so did Edelbrock. The HSP kit or Rath's new kit will outperform a clamp on in the low to mid and be about the same at the top of the RPM's. All of the aftermarket filters produce similar numbers at the top of the Rpm's, the difference is in the low to mid range torque. Rath got 3HP on the top end with a similar set up to HSP. Maintaining the stock intake should produce a better low to mid range. (Velocity)

 

That's about what I would expect...K&N with intake tube a little better in low end than just straight clamp on, however without actually trying it, its all speculation. Also, would that setup outperform the airforce kit concept, ie large holes in the airbox? If you remember the thread from the superbike shop, we had a discussion about this that I never really agreed with. I think the HSP/Rath setup will do better until the holes in the airbox get big enough to have negligible pressure loss through them. At that time the airforce kit concept is essentially identical to the HSP setup, if filter surface areas are the same. (I guess I don't buy into the whole resonance thing with the airbox after you cut it all up and completely change the flow characteristics.) I will be very interested to see the curve that Rath gets, 3 HP on top and hopefully 6-7 somewhere in the middle (would be very similar to Airforce kit then with out the after-filter inlet on top of the airbox, and would also give evidence that the airbox does nothing essential after big holes are in it). Whaddaya think? [img]i/expressions/face-icon-small-smile.gif[/img]

 

I think the Airbox does play a role in the Airforce systems large gains in the low and mid range. The perfect airbox would be closer to the carb and be larger in volume than the stock unit. Engineers at polaris spent alot of time trying to get the best they could with what room they had available. If I remember that thread correctly this is where the disagreement in theory occured, the box breathes as the piston stroke occurs. (similar to lung swelling out then exhaling). The stock box volume is smaller than desired, thats where the top Airforce plate came from. The location of that plate created the effect of a larger volume box. Yes it would have been better to put that plate under the filter, but it's location was critical to the performance of the Airforce system. They tried bigger holes under the filter but the results never improved beyond a certain point. Without the top plate the kit would make 4 to 5 HP in the low to mid and 2 to 3 on top. With some engineering help a top plate was added and 8hp in the low to mid and 3 on top. I would guess the filter at the end of the pipe will perform close to what a hole in the airbox did without the top plate. Your are not going to get the breathing effect of the box. we are only talking 2 to 3 hp difference, most bikes will not be jetted well enough to ever notice a difference.