Re: Puch Gila theoretical max RPM

Matt Mahloch -- MBM Customs /
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JBOT - none of those questions have anything to do with the ability of transfer flow, but I'm happy to answer. HPI inner rotor, 2.1mm BTDC. MLM BK100. 17x42. 2 rings on stock piston, so 1 dykes, 1 regular. I have ported the cylinder slightly and feel the transfers are "pushed back" as far as possible w/o welding the cased, I'm already getting into the bolts deeper in so anything more at the deck would just bell out at the top. I'll list the port numbers later.

Adam Smith - not talking max RPM before the engine scatters, talking about the ability of transfers to flow air.

Chöschi21 - I wonder what their porting looks like.

To add a little more to this here are the area numbers I came up with for certain things, I assume these would all be listed as millimeters squared

Carb and Intake manifold 452

Intake port 510

Transfers 491

Exhaust port 600

I'm pretty simple minded when it comes to some of this but when you have a smaller port like the transfers the port velocity is higher than a larger port so depending on the size of the port vs port velocity you could have larger or smaller ports at different velocities that flow the same.

Port durations in degrees

Exhaust 192

Main transfers 130

Auxiliary transfer 118

Intake 152

Blowdown 31

Squish is at 1mm.

This is the same cylinder that hit 77.6mph in 2014 that has been massaged a bit. At that time I was only spinning it to 10,700 relying on the torque to pull the gear. Now I'm trying to get it to breath better in hopes of getting in the 80's. I'm kinda working against myself here because I have gotten more RPM out of it since before but haven't put a load on it with more gear to verify it pulls the gear to a higher RPM. I should do that to see if it breaks 80. But, for street use and everyday practicality it would be nice to spin 14k to have a wide power band/speed range. With 17x42 its in the low/mid 60's but 70 would be ideal. Still has great takeoff at that gearing.

This is getting long winded. I think I need to gear up and see how fast this thing goes then mess with RPM. I'm convinced the transfers are the issue but still appreciate any input. Talking gets the ideas flowing.

I'll post a picture of the transfer to cylinder from my phone, can't figure it out on the computer.

Matt

This single post is part of a larger thread. Start from the top or view this post in context.
Subject Written By Posted
  Puch Gila theoretical max RPMTopic by: Matt Mahloch -- MBM Customs Matt Mahloch -- MBM Customs 05/30/19 01:09PM
  Re: Puch Gila theoretical max RPMRe: JBOT Admin JBOT Admin 05/30/19 01:42PM
  Re: Puch Gila theoretical max RPMRe: JBOT Admin JBOT Admin 05/30/19 01:44PM
  Re: Puch Gila theoretical max RPMRe: Adam Smith Adam Smith 05/30/19 02:21PM
  Re: Puch Gila theoretical max RPMRe: Chöschi21 C.K. Chöschi21 C.K. 05/30/19 02:45PM
  Re: Puch Gila theoretical max RPMRe: Matt Mahloch -- MBM Customs Matt Mahloch -- MBM Customs 05/30/19 07:26PM
  Re: Puch Gila theoretical max RPMRe: Dirty30 Dillon Dirty30 Dillon 05/31/19 06:28AM
  Re: Puch Gila theoretical max RPMRe: Baron Von Moped Baron Von Moped 05/31/19 09:09AM
  Re: Puch Gila theoretical max RPMRe: Matt Mahloch -- MBM Customs Matt Mahloch -- MBM Customs 05/30/19 07:28PM
  Re: Puch Gila theoretical max RPMRe: Matt Mahloch -- MBM Customs Matt Mahloch -- MBM Customs 05/30/19 07:46PM
  Re: Puch Gila theoretical max RPMRe: jordan * jordan * 05/30/19 08:07PM
  Re: Puch Gila theoretical max RPMRe: Daniel '' Daniel '' 05/30/19 08:20PM
  Re: Puch Gila theoretical max RPMRe: JBOT Admin JBOT Admin 05/30/19 10:42PM
  Re: Puch Gila theoretical max RPMRe: Matt Mahloch -- MBM Customs Matt Mahloch -- MBM Customs 05/30/19 11:40PM
  Re: Puch Gila theoretical max RPMRe: JBOT Admin JBOT Admin 05/31/19 12:23AM
  Re: Puch Gila theoretical max RPMRe: Daniel '' Daniel '' 05/31/19 12:24PM
  Re: Puch Gila theoretical max RPMRe: Toledo Riot Toledo Riot 06/06/19 01:55PM
  Re: Puch Gila theoretical max RPMRe: Daniel '' Daniel '' 06/07/19 11:27AM
  Re: Puch Gila theoretical max RPMRe: Toledo Riot Toledo Riot 06/08/19 03:08PM
  Re: Puch Gila theoretical max RPMRe: Jake P Jake P 05/31/19 10:46AM
  Re: Puch Gila theoretical max RPMRe: Dirty30 Dillon Dirty30 Dillon 05/31/19 11:06AM
  Re: Puch Gila theoretical max RPMRe: Graham Motzing Graham Motzing 05/31/19 11:19AM
  Re: Puch Gila theoretical max RPMRe: Baron Von Moped Baron Von Moped 05/31/19 12:34PM
  Re: Puch Gila theoretical max RPMRe: Overpriced Parts Overpriced Parts 05/31/19 01:51PM
  Re: Puch Gila theoretical max RPMRe: Derek Stahl Derek Stahl 05/31/19 02:28PM
  Re: Puch Gila theoretical max RPMRe: Baron Von Moped Baron Von Moped 05/31/19 03:48PM
  Re: Puch Gila theoretical max RPMRe: not a Baron Asshole not a Baron Asshole 06/05/19 09:40AM
  Re: Puch Gila theoretical max RPMRe: will warn will warn 06/08/19 09:59PM
  Re: Puch Gila theoretical max RPMRe: will warn will warn 06/08/19 10:05PM
  Re: Puch Gila theoretical max RPMRe: Matt Mahloch -- MBM Customs Matt Mahloch -- MBM Customs 06/09/19 06:31PM

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