2 short stack/bellmouth questions

[VTRDark]

I see where the confusion lies now. Not sure if HPower sells them as a mix or not so basically then there would be an option of 2 long, 2 short or 1 long and 1 short. It's a shame Dr Honda doesn't do the short version and sell stacks individually. God...this is fluid dynamics all over again.

(:-})

[Jscobey]

I see where the confusion lies now. Not sure if HPower sells them as a mix or not so basically then there would be an option of 2 long, 2 short or 1 long and 1 short. It's a shame Dr Honda doesn't do the short version and sell stacks individually. God...this is fluid dynamics all over again.

(:-})

the first thing i asked Bill was about short stacks and here was his replys in 2 separate emails as we were talking about short vs long stacks and the benefits of each.

"The short stacks showing on the web sight require a larger under carburettor air box with ram air. To get the ram air in the fuel tank requires major modifications and this cost a lot of money and as a result of this cost these items are no longer available."

"The short stacks that I used to make gave less power than STD under 4000 RPM but more power upper midrange and top end. To get this, the conversion for the air box and tank cost about $1800,00, so I only sold 3 kits. The carburettors also required major modifications internally to make this package work, again most people did not want to do this."


Carl, i dont think he ever mix-an-matched kits. from what i gathered you could by either the short stack kit (which is now discontinued) or the long stack kit. i think he's basically saying unless your going to do all the engine work to make the most of the 2 short stacks then its not worth it, there's not much top end to gain by slapping 2 shorts on and re-jetting. however with the oh-so-expensive camshafts, pistons, valves & springs, ram-air, etc... only THEN would the 2 short stacks make sense. and seeing as how he didnt have alot of customers doing that sort of work on the VTR, he stopped production of the shorts.

contrary to the short stacks, from what he told me, there is considerable gains(2-3+bhp) through the low to upper mid range with the long stacks he still currently sells when jetted correctly, without any loss of top end power, which is why he still produces them.

[VTRDark]

Thanks for that Interesting info on the short stacks requiring ram air etc. Happy I have my long ones now.

(:-})

[mik_str]

A performance shop here in Québec (Dynamohumm, no longer in business) ordred a set of the short stacks and dynoed them (stock engine) and he lost power everywhere, including on top-end (IIRC, lost 2.5 hp on top). The Web page with teh result is no longer up, but I do recall reading about it..... For anything but an all-out racebike, I think the two long HPower/Dr H stacks are the way to go.....

[Jscobey]

A performance shop here in Québec (Dynamohumm, no longer in business) ordred a set of the short stacks and dynoed them (stock engine) and he lost power everywhere, including on top-end (IIRC, lost 2.5 hp on top). The Web page with teh result is no longer up, but I do recall reading about it..... For anything but an all-out racebike, I think the two long HPower/Dr H stacks are the way to go.....

thats what i did. makes much more sense. plus i think a ram air kit is unobtanium

[Max]

Maybe I'll try 2 long again, I did prefer how the bike felt with 2 short but it was a while ago.