Reciprocating weight tests ?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

David Redszus
Guru
Guru
Posts: 9633
Joined: Tue Nov 27, 2007 9:27 am
Location: Chicago
Contact:

Re: Reciprocating weight tests ?

Post by David Redszus »

Maximum lobe lift is only part of the story.

Consider the area under the lift curve which is quite different depending on lobe design.
The term commonly used is angle area, which is a function of valve diameter, valve lift,
and duration.
hoffman900
HotPass
HotPass
Posts: 3445
Joined: Sat Feb 23, 2013 5:42 pm
Location:

Re: Reciprocating weight tests ?

Post by hoffman900 »

In-Tech wrote: Thu Mar 16, 2023 3:33 pm The lobe can't be larger than the housing bore. The only way to increase valve lift is to take it off the base circle and then correct the geometry.
Here’s one solution: http://www.agap.se/Split-cam-2.html

And another: http://www.agap.se/Foersaeljningsdokume ... 11_eng.pdf
-Bob
User avatar
Stan Weiss
Vendor
Posts: 4801
Joined: Tue Feb 20, 2007 1:31 pm
Location: Philadelphia, PA
Contact:

Re: Reciprocating weight tests ?

Post by Stan Weiss »

hoffman900 wrote: Thu Mar 16, 2023 11:38 pm
In-Tech wrote: Thu Mar 16, 2023 3:33 pm The lobe can't be larger than the housing bore. The only way to increase valve lift is to take it off the base circle and then correct the geometry.
Here’s one solution: http://www.agap.se/Split-cam-2.html

And another: http://www.agap.se/Foersaeljningsdokume ... 11_eng.pdf
Bob,
I see that as having limited applications. Many high end cam in block engines run an enclosed cam tunnel.

Stan
Stan Weiss/World Wide Enterprises
Offering Performance Software Since 1987
http://www.magneticlynx.com/carfor/carfor.htm
David Vizard & Stan Weiss' IOP / Flow / Induction Optimization Software
http://www.magneticlynx.com/DV
hoffman900
HotPass
HotPass
Posts: 3445
Joined: Sat Feb 23, 2013 5:42 pm
Location:

Re: Reciprocating weight tests ?

Post by hoffman900 »

Stan Weiss wrote: Fri Mar 17, 2023 12:12 am
hoffman900 wrote: Thu Mar 16, 2023 11:38 pm
In-Tech wrote: Thu Mar 16, 2023 3:33 pm The lobe can't be larger than the housing bore. The only way to increase valve lift is to take it off the base circle and then correct the geometry.
Here’s one solution: http://www.agap.se/Split-cam-2.html

And another: http://www.agap.se/Foersaeljningsdokume ... 11_eng.pdf
Bob,
I see that as having limited applications. Many high end cam in block engines run an enclosed cam tunnel.

Stan
More meant for vintage OHC applications like the Fiat.

Most high end engine blocks are already set up for larger tunnels.
-Bob
David Redszus
Guru
Guru
Posts: 9633
Joined: Tue Nov 27, 2007 9:27 am
Location: Chicago
Contact:

Re: Reciprocating weight tests ?

Post by David Redszus »

As near as I can determine, camshafts are not reciprocating masses; which was the original thread topic. :D
User avatar
juuhanaa
HotPass
HotPass
Posts: 1193
Joined: Fri Oct 15, 2021 7:14 am
Location: Finland
Contact:

Re: Reciprocating weight tests ?

Post by juuhanaa »

And this is cast iron.

18.JPG


-juhana
You do not have the required permissions to view the files attached to this post.
A balanced person dares to stagger, and modify ports bigger
User avatar
Stan Weiss
Vendor
Posts: 4801
Joined: Tue Feb 20, 2007 1:31 pm
Location: Philadelphia, PA
Contact:

Re: Reciprocating weight tests ?

Post by Stan Weiss »

juuhanaa wrote: Sun Mar 19, 2023 11:30 am And this is cast iron.


18.JPG



-juhana
So just how many HP was that worth or what reduction in et did you see?

Stan
Stan Weiss/World Wide Enterprises
Offering Performance Software Since 1987
http://www.magneticlynx.com/carfor/carfor.htm
David Vizard & Stan Weiss' IOP / Flow / Induction Optimization Software
http://www.magneticlynx.com/DV
User avatar
juuhanaa
HotPass
HotPass
Posts: 1193
Joined: Fri Oct 15, 2021 7:14 am
Location: Finland
Contact:

Re: Reciprocating weight tests ?

Post by juuhanaa »

Stan Weiss wrote: Sun Mar 19, 2023 11:59 am
juuhanaa wrote: Sun Mar 19, 2023 11:30 am And this is cast iron.


18.JPG



-juhana
So just how many HP was that worth or what reduction in et did you see?

Stan
I dyno the car after winning a "circle track race". We had to stop the pulls because the car started smoking. Turned out the smoke was caused by shaky brakes.. I released the brakes and told the driver to take one more pull without touching the brake pedal when it made 20 more wheel hp. Funnily enough it won the dyno race too, but i dont know how much of that was down to weight. It was just a tow engine with limited rpm :?

Just one example about how dyno testing can go wrong. Steady state testing would be much better for evaluating engine performance or cylinder head flow characteristics.

And this story is true.

-juhana
A balanced person dares to stagger, and modify ports bigger
David Redszus
Guru
Guru
Posts: 9633
Joined: Tue Nov 27, 2007 9:27 am
Location: Chicago
Contact:

Re: Reciprocating weight tests ?

Post by David Redszus »

Just one example about how dyno testing can go wrong. Steady state testing would be much better for evaluating engine performance or cylinder head flow characteristics.
Dyno testing results are merely an estimation of track performnce.

Dyno testing conditions are almost never the same as track conditions.

Even if they were, the assumption is that nothing except engine power has changed
and that all other variables have remained the same. :D
User avatar
juuhanaa
HotPass
HotPass
Posts: 1193
Joined: Fri Oct 15, 2021 7:14 am
Location: Finland
Contact:

Re: Reciprocating weight tests ?

Post by juuhanaa »

Yeah. This stuff may need some tweaking after track testing.. :D

Btw that race 2 years ago, as a Neuville fanboy i had a hunch that something was going on, so after the race i went hunting and found one.

IMG_0291.JPG
IMG_0290.JPG


-juhana
You do not have the required permissions to view the files attached to this post.
A balanced person dares to stagger, and modify ports bigger
Post Reply