-
Weber Tuning
(
http://www.clubcobra.com/forums/weber-tuning/)
| Gaz64 |
04-11-2019 05:28 PM |
Quote:
Originally Posted by blykins
(Post 1460451)
That camshaft, even with changing the LSA to 112, still has 73° of overlap.
Just randomly changing a cam to a wider LSA doesn't make it "friendly".
|
Yes, that's correct.
Reducing the overlap by widening the LSA delays the inlet closing point, all else being equal.
So the late closing inlet will still have reversion out the stacks on an IR intake.
One camshaft grind that sticks in my head is for the Cosworth DFV 3.0 V8. 68/86 for the inlet, 86/68 for the exhaust. 136 degrees of overlap. LSA 99. IR intake, Lucas mechanical injection.
Extreme example, I know.
Gary |
Quote:
Originally Posted by CSX 4133
(Post 1460473)
It was a hard choice between SAAC 44 and the Pitt Vintage Race, but time constraints dictated my attending only SAAC 44 this year. But at least I'll get to do the track days.
|
Steve,
I will be doing the test day and possibly some SAAC sessions as well, as I have never been on the Pitt Race track before. So I should see you there. Look for the red #10 car. What does your's look like?
Jim |
| CSX 4133 |
04-11-2019 06:03 PM |
Quote:
Originally Posted by 1795
(Post 1460485)
Steve,
I will be doing the test day and possibly some SAAC sessions as well, as I have never been on the Pitt Race track before. So I should see you there. Look for the red #10 car. What does your's look like?
Jim
|
Jim,
Your basic '66 Shelby B/P GT350 (#74) in Sapphire Blue w/wht.stripes. I anticipate there being a large contingent of vintage Shelby & Cobra track cars using the track days as a test & tune opportunity for the following weekends race. Like you I've never driven this circuit, should be a fun time. |
| moar_carbz |
04-16-2019 10:37 PM |
Quote:
Originally Posted by Gaz64
(Post 1460484)
Yes, that's correct.
Reducing the overlap by widening the LSA delays the inlet closing point, all else being equal.
So the late closing inlet will still have reversion out the stacks on an IR intake.
One camshaft grind that sticks in my head is for the Cosworth DFV 3.0 V8. 68/86 for the inlet, 86/68 for the exhaust. 136 degrees of overlap. LSA 99. IR intake, Lucas mechanical injection.
Extreme example, I know.
Gary
|
Wow. The intake closed at 86? What was the reversion like? |
| moar_carbz |
04-16-2019 10:39 PM |
Quote:
Originally Posted by 1795
(Post 1460300)
|
The idle seems surprisingly smooth for a 250@50 cam... but the idle speed does seem high. What's that idle set at? |
Quote:
Originally Posted by moar_carbz
(Post 1460672)
The idle seems surprisingly smooth for a 250@50 cam... but the idle speed does seem high. What's that idle set at?
|
I cannot recall what the idle speed was set at right now. After I ge the engine backing the car and start her up I will let you know. Race engines usually have a high idle speed, as they do not like low idle situations. Most of the time when you are on the grid you are feathering the engine to warm it up before hitting the track.
Jim |
| Gaz64 |
04-17-2019 04:12 AM |
Quote:
Originally Posted by moar_carbz
(Post 1460671)
Wow. The intake closed at 86? What was the reversion like?
|
I'll assume it was evident, but that is a racing F1 engine peaking at around 11000 rpm.
Quote:
Originally Posted by moar_carbz
(Post 1460672)
The idle seems surprisingly smooth for a 250@50 cam... but the idle speed does seem high. What's that idle set at?
|
The engine is solid in a framework, so no rocking as such, and no tachometer.
Also exhaust system fitted while on the stand would affect idle quality.
Gary |
| moar_carbz |
04-18-2019 08:27 PM |
Quote:
Originally Posted by Gaz64
(Post 1460684)
The engine is solid in a framework, so no rocking as such, and no tachometer.
Also exhaust system fitted while on the stand would affect idle quality.
Gary
|
Yeah... not really a noticeable lope though either. If it's idling at 1600 or something I'll attribute some of the smoothness to that. |
| All times are GMT -7. The time now is 06:22 PM. |
|
Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link:
