Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: 30 / 31 cc zen pipe length  (Read 3203 times)

Brigadair

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 215
  • Race to enjoy; winning is a bonus!
  • Location: Lincolnshire
30 / 31 cc zen pipe length
« on: September 14, 2014, 07:52:09 PM »

Hi all


Just wondered what people thought of the best prop and pipe length for a surface drive cat or mono  with a pmc competition pipe (or one of the good Chinese ones).


Reason I ask is that I ran a boat recently with a 29.5-30cm length (from manifold flange to max dia of pipe cone).


This I was advised (and agree) was too short.




Ran  both octura 2 bladed props x470 and x670.
Thanks


Garry
Logged
Best regards
Garry Dickson (BMPRS Committee member and Webmaster)

MPM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 55
  • Model Boat Mayhem is Great!
  • Location: Blackpool
    • MillPond Models
Re: 30 / 31 cc zen pipe length
« Reply #1 on: September 14, 2014, 09:47:27 PM »

I run 34cm on my 30cc.... Seems to give good HP and plenty of RPM to go along with it.
We tried a short Pipe on the Dyno plenty of RPMs but not as much Hp and torque...
Go longer than 34cm and it produced lots of Hp but the curve was along longer so the RPM build up was alot slower

Its all Trial and Error.

I still think your two short for a 31...

F1 madness

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 416
  • Location: Staffordshire
Re: 30 / 31 cc zen pipe length
« Reply #2 on: September 15, 2014, 08:02:47 AM »

Hi garry
does sound to short
My K30 29.5cc likes pipe length around 12 3/4" or just over 32cm and im using the chinese pipe which it seems to run well on
Also make sure you not got too much excess manifold pipe in the pipe itself hehe
Logged

black magic racing

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 342
  • when winning is all . it stops being a hobby
  • Location: stockport,manchester
Re: 30 / 31 cc zen pipe length
« Reply #3 on: September 15, 2014, 06:10:48 PM »

i run my own tuned 29.5 conquest cat with a very short bonzi pipe and short header,i use a 6717 3 blade prop and to be fair it runs pretty good on this combination.try a different prop,as most of us who have been running cats for years have found out that a good smaller 3 blade works alot better than a larger 2 blade,cats love a bit of lift which is what a 3 blade will give it,,,,just my opinion    %)
Logged
FAST is never FAST enough
Black Magic Racing with BMPRS    Telford Model Boat Club
Birkenhead Model Power Boat club Vice Commodore

black magic racing

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 342
  • when winning is all . it stops being a hobby
  • Location: stockport,manchester
Re: 30 / 31 cc zen pipe length
« Reply #4 on: September 15, 2014, 06:17:07 PM »

another thing to consider is a cat is not pushing a deep v through the water.RPMs is what you want,loading the engine up with a big prop is no good,you want a prop that will let the engine rev out.once the cat is going and set up right it should fly  :-))
Logged
FAST is never FAST enough
Black Magic Racing with BMPRS    Telford Model Boat Club
Birkenhead Model Power Boat club Vice Commodore

Brigadair

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 215
  • Race to enjoy; winning is a bonus!
  • Location: Lincolnshire
Re: 30 / 31 cc zen pipe length
« Reply #5 on: September 16, 2014, 08:21:22 PM »

Many thanks Kurt, Daz and Jack, very much appreciated,




I ran Saturn testing las pt sat with the longer pipe length.


It ran very well.


Whilst I like to test boats a good bit, I won't this time so I'll gamble on on running Saturn at Leicester this Sunday,


Cheers for now guys.


Garry
Logged
Best regards
Garry Dickson (BMPRS Committee member and Webmaster)

Brigadair

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 215
  • Race to enjoy; winning is a bonus!
  • Location: Lincolnshire
Re: 30 / 31 cc zen pipe length
« Reply #6 on: September 26, 2014, 09:20:53 PM »

Thanks all for pipe length advice! It cured my teething probs with Saturn and created a few more!!! Lol!!




Time for more testing!!


Briggy.
Logged
Best regards
Garry Dickson (BMPRS Committee member and Webmaster)

craig dickson

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 335
  • Location: Brigg North Lincolnshire United Kingdom
Re: 30 / 31 cc zen pipe length
« Reply #7 on: September 26, 2014, 10:14:08 PM »

Hi Garry


That longer pipe length paid dividends, I reckon you should be in for a shout next race ..... <*<
Logged
Forget all insults, always remember compliments.

tmbc

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 257
  • Location: south manchester trafford model boat club
    • www.tmbc.org.uk
Re: 30 / 31 cc zen pipe length
« Reply #8 on: September 27, 2014, 08:31:56 AM »

Hi Garry


That longer pipe length paid dividends, I reckon you should be in for a shout next race ..... <*<


FIGHTING TALK THERE I WILL HAVE TO KEEP MY BEADY OOD EYE'S ON YOU PAIR  %% %%
Logged
BMPRS  Health and Safety Co-Ordinator

Brigadair

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 215
  • Race to enjoy; winning is a bonus!
  • Location: Lincolnshire
Re: 30 / 31 cc zen pipe length
« Reply #9 on: October 01, 2014, 09:02:24 PM »

Hi all.


Checked three setups with same engines, same pipes (but diff hulls).


Concluded with your good advice, my Saturn pipe length was definitely too short,


Have lengthened it from - approx 29.5 cm to 33cm. My quickest boat is a massive 39cm on a tuned 31cc zen.


Food for thought......




Thank you all for your advice. Much appreciated.
Logged
Best regards
Garry Dickson (BMPRS Committee member and Webmaster)

Brigadair

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 215
  • Race to enjoy; winning is a bonus!
  • Location: Lincolnshire
Re: 30 / 31 cc zen pipe length
« Reply #10 on: October 01, 2014, 09:13:02 PM »

Kurt


Are you racing on Sunday?

Logged
Best regards
Garry Dickson (BMPRS Committee member and Webmaster)

black magic racing

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 342
  • when winning is all . it stops being a hobby
  • Location: stockport,manchester
Re: 30 / 31 cc zen pipe length
« Reply #11 on: October 01, 2014, 09:21:29 PM »

we are hoping to be there this sunday :-)) :-)) just trying to sort out boats ,looking forward to it :-))
Logged
FAST is never FAST enough
Black Magic Racing with BMPRS    Telford Model Boat Club
Birkenhead Model Power Boat club Vice Commodore

Brigadair

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 215
  • Race to enjoy; winning is a bonus!
  • Location: Lincolnshire
Re: 30 / 31 cc zen pipe length
« Reply #12 on: October 01, 2014, 09:23:23 PM »

Ffffaaaaannnntttttaaaassssttttiiiiicccc!
Logged
Best regards
Garry Dickson (BMPRS Committee member and Webmaster)

craig dickson

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 335
  • Location: Brigg North Lincolnshire United Kingdom
Re: 30 / 31 cc zen pipe length
« Reply #13 on: October 01, 2014, 09:47:34 PM »

we are hoping to be there this sunday :-)) :-)) just trying to sort out boats ,looking forward to it :-))


It will be great to see you with us mate :-))


Craig
Logged
Forget all insults, always remember compliments.

F1 madness

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 416
  • Location: Staffordshire
Re: 30 / 31 cc zen pipe length
« Reply #14 on: October 01, 2014, 09:49:17 PM »

Be good to see ya bud
I know some1 who be glad aswell to see his unc kurt lol
Logged

MPM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 55
  • Model Boat Mayhem is Great!
  • Location: Blackpool
    • MillPond Models
Re: 30 / 31 cc zen pipe length
« Reply #15 on: October 01, 2014, 09:53:28 PM »

The longer pipe will create more HP.... But having a shorter pipe might create a less hp but will have much more usable rpm with hp.
Pages: [1]   Go Up