V-twin vs Inline 4 - Sportbike Forum: Sportbike Motorcycle Forums
 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 08-13-2002, 07:34 AM Thread Starter
Registered User
 
NSteveA's Avatar
 
Join Date: Jul 2002
Location: Northern Jersey
Posts: 90
V-twin vs Inline 4

I've posted this in one or two other locations with little response so please forgive me if your reading this twice. Is there any good information available, or can someone explain, how/why similar displacement V-twins and Inline 4s produce power differently? Surely the Ducatisti know?!
NSteveA is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 10-04-2002, 12:43 AM
Registered User
 
748L_rider's Avatar
 
Join Date: May 2002
Location: San Jose, CA
Posts: 6
Inline 4 vs V twins

Take a look at this thread on Google:
Honda goes back to a V4 for WSB


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
748L_rider is offline  
post #3 of 7 (permalink) Old 10-04-2002, 01:03 AM
Registered User
 
748L_rider's Avatar
 
Join Date: May 2002
Location: San Jose, CA
Posts: 6
Inline 4 vs V twins

Take a look at this thread on Google:
Honda goes back to a V4 for WSB


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
748L_rider is offline  
 
post #4 of 7 (permalink) Old 10-04-2002, 02:17 AM
Registered User
 
funksouljon's Avatar
 
Join Date: Sep 2000
Location: Austell, GA 30106
Posts: 2,166
If that doesn't explain it to ya........

www.ftb-racing.com
funksouljon is offline  
post #5 of 7 (permalink) Old 10-04-2002, 02:39 AM Thread Starter
Registered User
 
NSteveA's Avatar
 
Join Date: Jul 2002
Location: Northern Jersey
Posts: 90
Thanks!
NSteveA is offline  
post #6 of 7 (permalink) Old 10-05-2002, 08:50 AM
Registered User
 
BamBam's Avatar
 
Join Date: Aug 2001
Location: Bolivar, Ohio USA 44612
Posts: 148
Send a message via AIM to BamBam Send a message via Yahoo to BamBam
Wow... that thread is certainly interesting but some of it went over my head!!

Particularly:

"The liter inline fours (GSXR-1K, R1 & 929) have become increasingly less 'over square', whereas the 'opposite' trend has become prevalent in the liter twins (998, TL, RC-51 & Prillers). This trend attempts to make the four's more like twins and twins more like fours, in terms of bore vs effective valve area."

Anyone got any idea what this means?

And does moving intertia of the larger piston mass have no effect - is it just the valve/exhaust area issue?

Cheers, Bill (BamBam)


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
-
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
-
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

I live in fear of not being misunderstood. ~ Oscar Wilde
BamBam is offline  
post #7 of 7 (permalink) Old 10-05-2002, 10:22 AM
Registered User
 
748L_rider's Avatar
 
Join Date: May 2002
Location: San Jose, CA
Posts: 6
It means that the bore to stroke ratio of v-twins are increasing (bore is increasing while stroke decreases) in order to rev higher to get more horse power.

While on the inline fours, the ratio is decreasing (smaller bores with longer stroke) so that the engines can breathe better at slow speed, this making more torque at lower rpms.

Case in point, the new Ducati 998/999 testastretta engine has bore and stroke of 100x63.5xmm compared to 98x66mm from the 996. And the 2002 Yamaha R1 is 74x58mm compared to old YZF1000 at 75.5x56mm. The mighty Suzuki GSXR1000 has an even smaller ratio at 73x59mm (the GSXR1000 shares the same head as the GSXR750).

Advances in material sciences and manufacturing methods have lead to stronger and lighter parts that are up to the task. It's fascinating stuff. Check out the references below.

The New Testastretta
YZF-R1 Engine Article


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
748L_rider is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Sportbike Forum: Sportbike Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome