Home
Don't have an account? Create one now! It's always free!


Forgot Password
Ed's Auto Parts - Mention MOTORGEN for a Discount!
Motorgen Sponsor: McLeod Racing
Motorgen Sponsor: American Muscle - Add style and performance to your Stang
Motorgen Sponsor: Hall Fabrication & Racing
Motorgen Sponsor: Injectors Plus - Performance Fuel Delivery Systems
View Poll Results: Is back pressure a good thing?
No way Jose. 3 30.00%
Some, but with qualifications. 7 70.00%
Voters: 10. You may not vote on this poll

Reply
Page 5 of 5 « First < 34 5
 
Thread Tools
Old 09-21-2009, 05:19 PM   #41
VettezukiVettezuki is offline
I, Vettezuki
 
Vettezuki's Avatar
 
Join Date: Feb 2006
Posts: 14,754
Default
Quote:
Originally Posted by BRUTAL64 View Post
The only ones I've ever seen is the 180 degree exhaust systems. But I think that was to due to having to run header tubes all over and under the engine.

As in they actually mechanically change length over the rpm range. For instance longer to shorter on intake.
__________________
Motorgen on
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

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

Motorgen Project Car
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(active)
Motorgen Project Car
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(back burner)
  Reply With Quote
Old 09-21-2009, 05:21 PM   #42
Throttle CrazyThrottle Crazy is offline
Senior Member
 
Join Date: Sep 2008
Posts: 187
Default
Quote:
Originally Posted by Vettezuki View Post
Crazy ass tangent.

We know that some (super fancy race) engines utilize variable length intake runners. Most modern super bikes use this technology. Has there ever been an engine with variable length exhaust?
I do not know about variable length, but I do know of late model ferrari and the corvette z06 have computer controled exhaust flaps to tune the velosity
at different rpms and load conditions.
  Reply With Quote
Old 09-21-2009, 05:22 PM   #43
BRUTAL64BRUTAL64 is offline
Neanderthal
 
BRUTAL64's Avatar
 
Join Date: Mar 2008
Posts: 5,320
Default
Quote:
Originally Posted by Vettezuki View Post
As in they actually mechanically change length over the rpm range. For instance longer to shorter on intake.
No, haven't seen anything like that. There might be something to that. Instead of variable timing, variable exhaust length.
__________________
64 Vette Roadster 400 ci
1990 F150 351 ci SuperCharged
48 Harley Pan Head 76 ci
2016 Nissan Altma
  Reply With Quote
Old 09-21-2009, 05:25 PM   #44
BRUTAL64BRUTAL64 is offline
Neanderthal
 
BRUTAL64's Avatar
 
Join Date: Mar 2008
Posts: 5,320
Default
Quote:
Originally Posted by Throttle Crazy View Post
I do not know about variable length, but I do know of late model ferrari and the corvette z06 have computer controled exhaust flaps to tune the velosity
at different rpms and load conditions.
That makes sense. Actually "resistance to flow" could be adjusted that way.
__________________
64 Vette Roadster 400 ci
1990 F150 351 ci SuperCharged
48 Harley Pan Head 76 ci
2016 Nissan Altma
  Reply With Quote
Old 09-21-2009, 05:28 PM   #45
94cobra69ss39694cobra69ss396 is offline
Fast & Filthy
 
94cobra69ss396's Avatar
 
Join Date: Jun 2008
Posts: 3,840
Default
Quote:
Originally Posted by Throttle Crazy View Post
I do not know about variable length, but I do know of late model ferrari and the corvette z06 have computer controled exhaust flaps to tune the velosity
at different rpms and load conditions.
Yah, on the Z06 it's worth 6HP. On a side note I don't think that OEM's take into account performance when they design an exhaust for new cars. I think it is more a factor of what will fit and emissions. That's why you can gain so much HP by upgrading the exhaust on some cars such as the 03/04 Cobras.
  Reply With Quote
Old 09-21-2009, 06:22 PM   #46
VettezukiVettezuki is offline
I, Vettezuki
 
Vettezuki's Avatar
 
Join Date: Feb 2006
Posts: 14,754
Default
Quote:
Originally Posted by 94cobra69ss396 View Post
Yah, on the Z06 it's worth 6HP. On a side note I don't think that OEM's take into account performance when they design an exhaust for new cars. I think it is more a factor of what will fit and emissions. That's why you can gain so much HP by upgrading the exhaust on some cars such as the 03/04 Cobras.
I'm goddmaned curious what my "BP" is now. . .

I know my exact motor with headers, but with a much less high flowing intake (LS1, I have an LS6) was making 432WHP in a C5 on an aggressive tune. I'm making 391 with stock headers and a very conservative tune (18 degrees total as I recall) in my C3.
__________________
Motorgen on
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

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

Motorgen Project Car
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(active)
Motorgen Project Car
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(back burner)
  Reply With Quote
Old 09-21-2009, 06:35 PM   #47
Throttle CrazyThrottle Crazy is offline
Senior Member
 
Join Date: Sep 2008
Posts: 187
Default
Quote:
Originally Posted by Vettezuki View Post
I'm goddmaned curious what my "BP" is now. . .

I know my exact motor with headers, but with a much less high flowing intake (LS1, I have an LS6) was making 432WHP in a C5 on an aggressive tune. I'm making 391 with stock headers and a very conservative tune (18 degrees total as I recall) in my C3.
I have a back pressure tester if you would like to borrow it.
  Reply With Quote
Old 09-21-2009, 06:44 PM   #48
VettezukiVettezuki is offline
I, Vettezuki
 
Vettezuki's Avatar
 
Join Date: Feb 2006
Posts: 14,754
Default
Quote:
Originally Posted by Throttle Crazy View Post
I have a back pressure tester if you would like to borrow it.
Please and thank you. Do you live close to your brother? Maybe I can just come out and use it on the spot?
__________________
Motorgen on
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

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

Motorgen Project Car
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(active)
Motorgen Project Car
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(back burner)
  Reply With Quote
Old 09-21-2009, 06:52 PM   #49
Throttle CrazyThrottle Crazy is offline
Senior Member
 
Join Date: Sep 2008
Posts: 187
Default
Quote:
Originally Posted by Vettezuki View Post
Please and thank you. Do you live close to your brother? Maybe I can just come out and use it on the spot?
Yes, within 5 miles. I can just leave it with my brother.
  Reply With Quote
Reply
Page 5 of 5 « First < 34 5

« Previous Thread | Next Thread »


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
vB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -7. The time now is 04:00 AM.

Contact Us - Home - Archive - Top