To STROKE or not to STROKE: 100th Topic (in ENGINE) - Mustang Evolution

Go Back   Mustang Evolution > 4 Cylinder | V6 | Classic Mustangs || Tech and Talk > Pre-2005 V6 Mustang



Reply
 
Thread Tools Search this Thread
Please support our sponsors and let them know you heard about them here!
Old 12-05-2003, 05:37 AM   #1
RGR
Registered Member
Regular
 
Join Date: May 2003
Region: Indiana
Posts: 1,065
Send a message via AIM to RGR
BLAST FOM THE PAST: 100th Topic in ENGINE, STROKERS

One of the main tools I use are dyno sims. The best
use they have is setting RPM range for componentry
like cams and airflow and porting. I recently ran a
very long sim and the main result tested was STROKE.

It seems that for maximum HP (all-out RPM)
the V6 really likes about what a stock 3.8 has
in terms of stroke. Right around 3.39" stroke...
It also seems that for maximum torque, the
truck crank of 3.74" is darn close to what the
computer liked for torque, 3.80" stroke.
1 result even had a 3.74" stroke making
nearly identical torque, just with different
other aspects changed just a bit.

Seems like Ford knew what they were doing!

Anybody have any ideas as to why they chose these stroke sizes ???
I mean theoretical, mathematical ideas, not just "cuz it works best"

COMMENTS GUYS? You are all much smarter now, so hit it!
__________________
Originally Posted by Flex:
You are the true cam master dude...
RGR is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-08-2003, 10:43 AM   #2
Registered Member
Regular
 
tire's Avatar
 
Join Date: Jul 2003
Posts: 941
Send a message via AIM to tire
Anything to do with the fact is was copied from Buick? Maybe the answer lies in the Buick engineers?
tire is offline   Reply With Quote
Old 12-08-2003, 11:47 AM   #3
RGR
Registered Member
Regular
 
Join Date: May 2003
Region: Indiana
Posts: 1,065
Send a message via AIM to RGR
Quote:
Originally Posted by V6PowerStang
Anything to do with the fact is was copied from Buick? Maybe the answer lies in the Buick engineers?
nope, but perhaps buick used the same rationale too...

It's because of piston speed in the bore for a given stroke,
strokers have to travel more distance in the same RPM range
so they have higher piston speeds. That limits RPM range
and increases frictional losses, so strokers generally have a
lower RPM range. A huge stroke may only want to rev to 6500
but makes much better torque than the smaller motor below this
range. For streetable motors it's best to use the biggest stroke
and matching components to get the power in by the RPM limit.
A 4.5 may not rev as high as a 3.8 but makes better torque
under the rev limit. This is highly simplified but generally true.
__________________
Originally Posted by Flex:
You are the true cam master dude...
RGR is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-19-2003, 10:18 AM   #4
RGR
Registered Member
Regular
 
Join Date: May 2003
Region: Indiana
Posts: 1,065
Send a message via AIM to RGR
Overall, a stroker will run circles around a stock stroke V6,
under a given rev limit. Under ~6500 RPM I like the extra torque
these babies make. Even more so under 5500, in streetable RPM ranges.
But head and itnake flow is critical, as is camming.
__________________
Originally Posted by Flex:
You are the true cam master dude...
RGR is offline   Reply With Quote
Old 02-09-2005, 02:55 PM   #5
RGR
Registered Member
Regular
 
Join Date: May 2003
Region: Indiana
Posts: 1,065
Send a message via AIM to RGR
TOP, good topic, from the past
__________________
Originally Posted by Flex:
You are the true cam master dude...
RGR is offline   Reply With Quote
Old 02-09-2005, 06:17 PM   #6
I liek gramer
Legacy
 
WhiteStang99's Avatar
 
Join Date: Jan 2004
Region: Florida
Posts: 8,537
Send a message via AIM to WhiteStang99
wow, I missed all these topics back in the day...
WhiteStang99 is offline   Reply With Quote
Old 02-10-2005, 07:38 AM   #7
Legacy Member
Legacy
 
dark's Avatar
 
Join Date: Jul 2003
Region: Tennessee
Posts: 1,389
Send a message via AIM to dark Send a message via Yahoo to dark
word. can i get a layman's definition of "stroking" robert?
__________________
I don't own a mustang at the moment
dark is offline   Reply With Quote
Old 02-10-2005, 11:13 AM   #8
RGR
Registered Member
Regular
 
Join Date: May 2003
Region: Indiana
Posts: 1,065
Send a message via AIM to RGR
Quote:
Originally Posted by dark
word. can i get a layman's definition of "stroking" ROBERT?
The stock 3.8 has a 3.39" stroke on the crank, and a 4.2 has a 3.74"
so using a 4.2 crank in a 3.8 is "stroking " it or increasing cubes through
using a bigger stroke crank. Then you can also offset grind a 4.2 crank,
that offsets the rod journals further from center, giving even more stroke.
It determines how far the pistons move, and that "swept volume" is the
engine's displacement, or cubic inch size.

I adjusted your quote above,
__________________
Originally Posted by Flex:
You are the true cam master dude...
RGR is offline   Reply With Quote
Old 02-13-2005, 10:06 PM   #9
Legacy Member
Legacy
 
Join Date: Oct 2004
Region: Florida
Posts: 595
Send a message via AIM to tedness
stroke it good.

the v6 will love you for it. also consider blower
__________________
tedness is offline   Reply With Quote
Old 02-14-2005, 09:34 AM   #10
Legacy Member
Legacy
 
dark's Avatar
 
Join Date: Jul 2003
Region: Tennessee
Posts: 1,389
Send a message via AIM to dark Send a message via Yahoo to dark
Quote:
Originally Posted by RGR
The stock 3.8 has a 3.39" stroke on the crank, and a 4.2 has a 3.74"
so using a 4.2 crank in a 3.8 is "stroking " it or increasing cubes through
using a bigger stroke crank. Then you can also offset grind a 4.2 crank,
that offsets the rod journals further from center, giving even more stroke.
It determines how far the pistons move, and that "swept volume" is the
engine's displacement, or cubic inch size.

I adjusted your quote above,
first off, sorry about the name error, i fixed it

second, thanks for that definition, but my question is, can i stroke my 3.8 up to 4.2, or do i have to get the 4.2 block?
__________________
I don't own a mustang at the moment
dark is offline   Reply With Quote
Old 02-14-2005, 10:17 AM   #11
RGR
Registered Member
Regular
 
Join Date: May 2003
Region: Indiana
Posts: 1,065
Send a message via AIM to RGR
Quote:
Originally Posted by dark
first off, sorry about the name error, i fixed it
No Problem

second, thanks for that definition, but my question is, can i stroke my 3.8 up to 4.2, or do i have to get the 4.2 block?
YES, you can use your block. Everything fits.
See Pete's 4.2 post at the top of this board, it explains everything!

BTW, i have a 4.2 crank and pistons for sale, waiting to get a buyer!
__________________
Originally Posted by Flex:
You are the true cam master dude...
RGR is offline   Reply With Quote
Reply

Lower Navigation
Go Back   Mustang Evolution > 4 Cylinder | V6 | Classic Mustangs || Tech and Talk > Pre-2005 V6 Mustang

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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 Off
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Next topic back from iraq 1996-2004 Mustang GT 1 06-02-2008 07:56 AM
give me a stroke o3mustangGTafs 1996-2004 Mustang GT 9 07-23-2006 08:17 PM
can you stroke your 3.8 cjd10 Pre-2005 V6 Mustang 11 01-11-2005 05:04 PM
100th Timeslip stangin99 The Bar 0 10-31-2004 10:09 PM
100th post!! n8r The Bar 18 06-07-2004 10:52 PM

» Like Us On Facebook



02:11 PM


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0

MustangEvolution.com is in no way associated with or endorsed by Ford Motor Company.