follow ft86club on our blog, twitter or facebook.
FT86CLUB
Ft86Club
FT86 Motorsports
Register Garage Members List Calendar Search Today's Posts Mark Forums Read

Go Back   Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB > Scion FR-S / Toyota 86 > Scion FR-S / Toyota 86 GT86 General Forum

Scion FR-S / Toyota 86 GT86 General Forum The place to start for the Scion FR-S / Toyota 86 | GT86


User Tag List

Reply
 
Thread Tools Search this Thread
Old 08-31-2011, 05:15 PM   #141
madfast
Senior Member
 
Join Date: May 2011
Drives: 2010 Evo X MR-T
Location: NY
Posts: 942
Thanks: 0
Thanked 21 Times in 11 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Type[R]+ View Post
Are you aware that sports bikes are short stroke for better performance?
thats because, like F1, they use super high rpm to make power with their limited displacement. sportbikes are much closer to their racing counterparts than cars. as such they are designed with racing classes in mind. for example the death of the 750cc bikes due to the increased displacement allowed in racing.
madfast is offline   Reply With Quote
Old 08-31-2011, 05:21 PM   #142
Random_Art
professional smartass
 
Random_Art's Avatar
 
Join Date: Apr 2010
Drives: 16 speed mountain bike...
Location: Georgia
Posts: 659
Thanks: 0
Thanked 2 Times in 2 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by RRnold View Post
Who said sportbikes!?!
Now we know what your Scooby Snacks are
__________________

Goodbye Celica, you served me well.

http://artsofrandomness.blogspot.com/
Random_Art is offline   Reply With Quote
Old 08-31-2011, 05:28 PM   #143
RRnold
2 wheel member
 
RRnold's Avatar
 
Join Date: Feb 2010
Drives: JZA80, 997.1, Taco
Location: SoCal->NorCal
Posts: 4,308
Thanks: 1,292
Thanked 920 Times in 466 Posts
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Random_Art View Post
Now we know what your Scooby Snacks are
Someone said the magic word! My favorite!!



Quote:
Originally Posted by madfast View Post
thats because, like F1, they use super high rpm to make power with their limited displacement. sportbikes are much closer to their racing counterparts than cars. as such they are designed with racing classes in mind. for example the death of the 750cc bikes due to the increased displacement allowed in racing.
+1

Using the current gen R6 for example, it wasn't a street oriented bike since it's power was from 8K to 14,200K. Anything below 8K felt like it was undergeared. Most of the smaller displacement I4 bikes are torqueless wonders yet only weight 410 lbs wet.
__________________
RRnold is offline   Reply With Quote
Old 08-31-2011, 05:32 PM   #144
82mm 4g63
4G63 & Rotary
 
82mm 4g63's Avatar
 
Join Date: Jun 2011
Drives: 92TalonAWD, 93RX7, 11F150EcoBoost
Location: Florida
Posts: 627
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Send a message via AIM to 82mm 4g63
Quote:
Originally Posted by Type[R]+ View Post
Im just suprised you can say that so adamantly?

Are you aware of less piston speeds, less piston loads, higher engine efficiencies with short stroke ect?

Are you aware that sports bikes are short stroke for better performance?
Why are you surprised?

Yes, I am aware of lower piston speeds and less piston load. Are you aware of the general rule of thumb that is a 90% bore stroke ratio? That means that the stroke should be 90% of the bore. This combination gives a reasonable amount of piston travel per degrees of rotation without being excessive.

Are you aware that a short stoke motor requires a high dome to obtain a high compression ratio which comes with its own set of problems? Are you aware that sometimes the dome is so high that flame travel in the cylinder suffers? The piston does not move away from TDC as far (travels a shorter distance per degrees of rotation) so it may be plagued with valve to piston clearance problems that will be difficult (but surmountable) at best.

Are you aware that it will have to operate at higher RPM (see motorcycle engines) to obtain the same HP because it will be smaller in cubic inches than say the 90% motor? RPM is expensive. Valves, valve springs, cams, retainers, pushrods etc etc must be of the very best (read expensive) quality to survive this.

If the engine is only making the same HP as the larger one can at a lower RPM, then all one has accomplished is to build a difficult, expensive, high maintenance "grenade".

However, the same problem exists at the other end of the scale. If the stroke is too long then the cylinder heads cannot keep up with the sheer volume of air being pumped . Often a stroker will produce the same power but at a lower RPM, because the cylinder heads have reached their peak at a lower RPM than would have happened on a stock stroke engine.

So again, all modifications being equal, more displacement = more power.
82mm 4g63 is offline   Reply With Quote
Old 08-31-2011, 05:41 PM   #145
Dimman
Kuruma Otaku
 
Dimman's Avatar
 
Join Date: Dec 2009
Drives: Mk3 Supra with Semi-built 7MGTE
Location: Greater Vancouver (New West)
Posts: 6,854
Thanks: 2,396
Thanked 2,264 Times in 1,234 Posts
Mentioned: 78 Post(s)
Tagged: 2 Thread(s)
Garage
Quote:
Originally Posted by 82mm 4g63 View Post
Why are you surprised?

Yes, I am aware of lower piston speeds and less piston load. Are you aware of the general rule of thumb that is a 90% bore stroke ratio? That means that the stroke should be 90% of the bore. This combination gives a reasonable amount of piston travel per degrees of rotation without being excessive.

Are you aware that a short stoke motor requires a high dome to obtain a high compression ratio which comes with its own set of problems? Are you aware that sometimes the dome is so high that flame travel in the cylinder suffers? The piston does not move away from TDC as far (travels a shorter distance per degrees of rotation) so it may be plagued with valve to piston clearance problems that will be difficult (but surmountable) at best.

Are you aware that it will have to operate at higher RPM (see motorcycle engines) to obtain the same HP because it will be smaller in cubic inches than say the 90% motor? RPM is expensive. Valves, valve springs, cams, retainers, pushrods etc etc must be of the very best (read expensive) quality to survive this.

If the engine is only making the same HP as the larger one can at a lower RPM, then all one has accomplished is to build a difficult, expensive, high maintenance "grenade".

However, the same problem exists at the other end of the scale. If the stroke is too long then the cylinder heads cannot keep up with the sheer volume of air being pumped . Often a stroker will produce the same power but at a lower RPM, because the cylinder heads have reached their peak at a lower RPM than would have happened on a stock stroke engine.

So again, all modifications being equal, more displacement = more power.
What? Are you talking about de-stroking a longer stroke motor?
__________________


Because titanium.
Dimman is offline   Reply With Quote
Old 08-31-2011, 05:57 PM   #146
82mm 4g63
4G63 & Rotary
 
82mm 4g63's Avatar
 
Join Date: Jun 2011
Drives: 92TalonAWD, 93RX7, 11F150EcoBoost
Location: Florida
Posts: 627
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Send a message via AIM to 82mm 4g63
Quote:
Originally Posted by Dimman View Post
What? Are you talking about de-stroking a longer stroke motor?
If by longer stroke motor you mean motors with strokes longer than their bores are wide? Yes, the majority of 2.0L 4-cylinder engines typically have a >100% stroke bore ratio.
82mm 4g63 is offline   Reply With Quote
Old 08-31-2011, 05:58 PM   #147
Type[R]+
Senior Member
 
Type[R]+'s Avatar
 
Join Date: Aug 2011
Drives: Lexus IS-F
Location: Australia
Posts: 528
Thanks: 26
Thanked 16 Times in 11 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Exage View Post
And we go round the circle again with the "no" usable low-midrange power, low torque nonsense again.

Honestly, there's really no point trying to argue or persuade. He wants engine Tq and doesn't like engine Hp streetwise. Fair enough...

But for the record, torque-less 2ZZ and I get along quite famously in both the low and high rpm ranges.
I just don't think he's woken up to the fact that a short stroke motors handle more boost, rev higher and make more power.....

Torque comes from capacity, not from stroke.
Type[R]+ is offline   Reply With Quote
Old 08-31-2011, 06:06 PM   #148
Dimman
Kuruma Otaku
 
Dimman's Avatar
 
Join Date: Dec 2009
Drives: Mk3 Supra with Semi-built 7MGTE
Location: Greater Vancouver (New West)
Posts: 6,854
Thanks: 2,396
Thanked 2,264 Times in 1,234 Posts
Mentioned: 78 Post(s)
Tagged: 2 Thread(s)
Garage
Quote:
Originally Posted by 82mm 4g63 View Post
If by longer stroke motor you mean motors with strokes longer than their bores are wide? Yes, the majority of 2.0L 4-cylinder engines typically have a >100% stroke bore ratio.
I mean the difference between taking the FB20 with its 84 X 90 BXS and de-stroking it with a custom crank/rods, and designing one from scratch.

I don't see the piston dome problem on a dedicated short-stroke motor. Example my old 1JZGTE was 86mm X 71.5mm, vs the 86mm X 86mm 2JZGTE. No piston issues with the 1JZ.
__________________


Because titanium.
Dimman is offline   Reply With Quote
Old 08-31-2011, 06:12 PM   #149
82mm 4g63
4G63 & Rotary
 
82mm 4g63's Avatar
 
Join Date: Jun 2011
Drives: 92TalonAWD, 93RX7, 11F150EcoBoost
Location: Florida
Posts: 627
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Send a message via AIM to 82mm 4g63
Quote:
Originally Posted by Dimman View Post
I mean the difference between taking the FB20 with its 84 X 90 BXS and de-stroking it with a custom crank/rods, and designing one from scratch.

I don't see the piston dome problem on a dedicated short-stroke motor. Example my old 1JZGTE was 86mm X 71.5mm, vs the 86mm X 86mm 2JZGTE. No piston issues with the 1JZ.
Oh, I wasn't referring to shortening the stroke at the factory, totally talking about aftermarket. I would hope a dedicated short stroke engine would have those issues worked out before it went into production.
82mm 4g63 is offline   Reply With Quote
Old 08-31-2011, 06:14 PM   #150
Dimman
Kuruma Otaku
 
Dimman's Avatar
 
Join Date: Dec 2009
Drives: Mk3 Supra with Semi-built 7MGTE
Location: Greater Vancouver (New West)
Posts: 6,854
Thanks: 2,396
Thanked 2,264 Times in 1,234 Posts
Mentioned: 78 Post(s)
Tagged: 2 Thread(s)
Garage
Quote:
Originally Posted by 82mm 4g63 View Post
Oh, I wasn't referring to shortening the stroke at the factory, totally talking about aftermarket. I would hope a dedicated short stroke engine would have those issues worked out before it went into production.
On factory ones there are no issues to work out. Aftermarket de-stroking leads to a mis-match between stroke and intended deck-height.
__________________


Because titanium.
Dimman is offline   Reply With Quote
Old 08-31-2011, 06:50 PM   #151
Type[R]+
Senior Member
 
Type[R]+'s Avatar
 
Join Date: Aug 2011
Drives: Lexus IS-F
Location: Australia
Posts: 528
Thanks: 26
Thanked 16 Times in 11 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Dimman View Post
On factory ones there are no issues to work out. Aftermarket de-stroking leads to a mis-match between stroke and intended deck-height.
shorter stroke, longer rods, same deck height?
Type[R]+ is offline   Reply With Quote
Old 08-31-2011, 06:55 PM   #152
82mm 4g63
4G63 & Rotary
 
82mm 4g63's Avatar
 
Join Date: Jun 2011
Drives: 92TalonAWD, 93RX7, 11F150EcoBoost
Location: Florida
Posts: 627
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Send a message via AIM to 82mm 4g63
Quote:
Originally Posted by Type[R]+ View Post
I just don't think he's woken up to the fact that a short stroke motors handle more boost, rev higher and make more power.....
That statement is entirely too general and I partially disagree with the boost handling part.

What do you consider to be short stroke? 100mm bore x 80mm stroke? I prefer a "square" engines powerband characteristics, which is why I never stroked my 4g63, or swapped in a destroked 4g64. I have adequate power in the lowend and more than enough power in the high end. The 2.3 stroker version of my 63 gives up too much high end, the 2.1 destroked 4g64 gives up too much low end.

Yes, a shorter stroke = higher revs. Yes, higher revs = more top end power. On the other hand... longer stroke = more low end torque = smoother transition from pre-boost to boost. Longer stroke/shorter stroke, unless taken to the extreme, doesn't make a car handle more/less boost. [Edit] Look at the 2JZ GTE, perfectly square 86mm x 86mm and it handles gobs of boost before needing to be rebuilt with beefier internals.

Quote:
Originally Posted by Type[R]+ View Post
Torque comes from capacity, not from stroke.
Then you agree with my original statement "TLDR: Larger displacement = more robust and forgiving torque curve." :happy0180:
82mm 4g63 is offline   Reply With Quote
Old 08-31-2011, 07:08 PM   #153
82mm 4g63
4G63 & Rotary
 
82mm 4g63's Avatar
 
Join Date: Jun 2011
Drives: 92TalonAWD, 93RX7, 11F150EcoBoost
Location: Florida
Posts: 627
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Send a message via AIM to 82mm 4g63
Quote:
Originally Posted by Dimman View Post
Aftermarket de-stroking leads to a mis-match between stroke and intended deck-height.
Right. Longer rods, taller pistons, or shortened deck height. I've never destroked a motor so I'm not sure exactly which is more cost effective.
82mm 4g63 is offline   Reply With Quote
Old 08-31-2011, 07:21 PM   #154
blur
ლ(ಠ益ಠ)ლ
 
blur's Avatar
 
Join Date: Apr 2010
Drives: E36 5.7 V8
Location: Bronx, NYC
Posts: 1,573
Thanks: 194
Thanked 198 Times in 112 Posts
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Ford 1.6l Ecoboost

Max power 150 (110) / 182 (134) at 5700 rpm
Max torque
240 (270 with transient overboost) at 1600-4000 rpm (1900-3500 rpm for overboost)

What are we arguing again?
__________________
I wish I was cool enough to have an FR-S
blur is offline   Reply With Quote
 
Reply

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Initial D cyde01 Off-Topic Lounge 122 11-21-2012 02:05 AM
Panda FT-86 Initial D style andyroo Photos, Videos, Wallpapers, Gallery Forum 28 03-13-2011 02:38 AM
Rumor of the day Kids Heart Scion FR-S / Toyota 86 GT86 General Forum 12 01-18-2011 10:09 AM
Ae86 roll cage in initial d? CyberFormula Off-Topic Lounge 8 03-14-2010 12:23 AM


All times are GMT -4. The time now is 07:11 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Garage vBulletin Plugins by Drive Thru Online, Inc.