ZR-1 Net Registry Forums  

Go Back   ZR-1 Net Registry Forums > C4 ZR-1 > C4 ZR-1 Technical Postings

Reply
 
Thread Tools Display Modes
Old 04-06-2010   #31
tpepmeie
 
Join Date: Aug 2005
Location: Fishers, IN
Posts: 815
Default Re: Camshafts almost done

Quote:
Originally Posted by XfireZ51 View Post
How will that affect your final cam profile if not looking for that last 10cfm?
It'll be .020 less lift

Maybe 5-10 hp at most. He might be able to use a little more max valve acceleration to get more lift sooner with the .500 max lift. Although from the seat to .050 lift, it is already pretty aggressive at only 40 degrees. It's an endurance motor, though. Can't be eating up springs every 500 miles.
tpepmeie is offline   Reply With Quote
Old 04-06-2010   #32
rkreigh
 
Join Date: Jan 2004
Location: Alex VA
Posts: 1,089
Default Re: Camshafts almost done

great stuff

congrats todd, I saw your heads at the local shop early in the project and those cams look great.

cam development takes so much hard work and I love the idea of using the ford mod motor as a "similar" model, but head flow, velocity, displacement, compression, chamber, all those cool variables and lobe shape lift duration separation all take lots of research and knowing how to maximize "area under the curve" and streetablility concerns

I'll trade 5-10 hp any day for a car that's a pleasure to drive you'll be making so much that hooking it up is the hard part, not worry about 600 or 650, it will be "ample" either way

look at the article on heads in the chevy perform magazine, the are doing a really cool series about head flow "quality, velocity, ect.." which is the basis for cam selection along with gearing, car weight and all those other factors that make selecting the perfect cam such a chore

I have the stg III on my 390, which are pretty "streetable" and I think are only at about 234 deg 435 or somthing like that lift

I know Bill played around with huge cams on his 415s, but they were a bit too rowdy and only gained just a bit way up top, the trade off wasn't a good one as the engines got very "peaky"

graham would be very good to talk to on this subject, seek ye him at BG
__________________
95 390 LPE ZR1 (505 rwhp)
LSV = Lingenfelter Super Vette
Twin Turbo 2003 Z06 (800 RWHP)
rkreigh is offline   Reply With Quote
Old 04-06-2010   #33
Locobob
 
Join Date: Jan 2004
Location: Portland, OR
Posts: 1,057
Default Re: Camshafts almost done

Quote:
Originally Posted by rkreigh View Post
graham would be very good to talk to on this subject, seek ye him at BG
That sounds like an excellent idea. I'm still interested in doing something with my cams - hopefully Todds project will lead to renewed interest in new production of performance camshafts.
__________________
Robert

ZR-1 Net Registry Oregon State Director

91 ZR-1 #431 Black/Black LPE 368
Locobob is offline   Reply With Quote
Old 04-25-2010   #34
tpepmeie
 
Join Date: Aug 2005
Location: Fishers, IN
Posts: 815
Default Re: Camshafts almost done

Update... finding springs for the monster cams has been almost impossible. Most of the springs I had identified were from imports (Honda/Audi/VW), and thus had a very high natural frequency, suitable to 9000+ rpms. The guy doing my cams is a bit of a professor when it comes to dynamic valvetrain design, so he was not happy with such heavy springs and associated wire stress.

We're leaning toward a single spring setup, with a rate similar to the stock spring, but able to handle the bigger lift. His lobe design is spring friendly, such that we dont need extremely high pressures. And the rev limiter will be set at 7500, so a low frequency environment.

The downside... looks like custom titanium retainers will be needed. I was hoping to use some off-the-shelf ti retainers, but the springs we picked don't match anything exactly. 7mm valve stems add to the problem.

By the time this thing is done, I could write a book about what works/fits and what doesn't. The parts list is definitely unlike any other LT5 out there, that's for sure.

BTW... we're doing the bigger intake lift.

Todd
tpepmeie is offline   Reply With Quote
Old 04-25-2010   #35
A26B
 
A26B's Avatar
 
Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,395
Default Re: Camshafts almost done

Quote:
Originally Posted by tpepmeie View Post
........By the time this thing is done, I could write a book about what works/fits and what doesn't..........Todd
Please Do!!
__________________
Jerry Downey
JERRYS LT5 GASKETS & PARTS
http://www.jerrysgaskets.com
1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc.
2016 Black-Red, 3LT-Z51 Auto 8-speed.
A26B is offline   Reply With Quote
Old 04-25-2010   #36
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,710
Default Re: Camshafts almost done

Quote:
Originally Posted by tpepmeie View Post
Update... finding springs for the monster cams has been almost impossible. Most of the springs I had identified were from imports (Honda/Audi/VW), and thus had a very high natural frequency, suitable to 9000+ rpms. The guy doing my cams is a bit of a professor when it comes to dynamic valvetrain design, so he was not happy with such heavy springs and associated wire stress.

We're leaning toward a single spring setup, with a rate similar to the stock spring, but able to handle the bigger lift. His lobe design is spring friendly, such that we dont need extremely high pressures. And the rev limiter will be set at 7500, so a low frequency environment.

The downside... looks like custom titanium retainers will be needed. I was hoping to use some off-the-shelf ti retainers, but the springs we picked don't match anything exactly. 7mm valve stems add to the problem.

By the time this thing is done, I could write a book about what works/fits and what doesn't. The parts list is definitely unlike any other LT5 out there, that's for sure.

BTW... we're doing the bigger intake lift.

Todd

"To go beyond where no man has gone before"!
XfireZ51 is offline   Reply With Quote
Old 04-25-2010   #37
FU
 
FU's Avatar
 
Join Date: Mar 2004
Location: Found Member
Posts: 4,346
Default Re: Camshafts almost done

Do it Todd ...........Be da Terminator !

FU is offline   Reply With Quote
Old 05-02-2010   #38
tpepmeie
 
Join Date: Aug 2005
Location: Fishers, IN
Posts: 815
Default Re: Camshafts almost done

Cams are being ground to final dimensions early this week. What a sweet design... requiring very little spring force to control. With only 60 lbs on the seat, and 170 lbs open, my valves remained in control to 8600 rpm! Here's what he had to say about the stock cams.
The stock cams are over-sprung because they have really bad cam designs (high jerk and bad harmonics) so they need a lot more spring force to try to control that.
The same can be said of the usual aftermarket cams. My lobes have less than half (!) the acceleration peaks compare to the old ".470" Jeal cams, yet more than 6.5% higher opening velocity.

These are more than 7% bigger lobe area than the Jeals, and around 15% bigger than Stage II cams. Don't know what Stage III's typically measure, but probably somewhere in between.

Now have to wait 6 weeks for the custom retainers.

Todd
tpepmeie is offline   Reply With Quote
Old 05-02-2010   #39
wdo-mkr
 
Join Date: Sep 2005
Posts: 45
Default Re: Camshafts almost done

Quote:
Originally Posted by tpepmeie View Post
Now have to wait 6 weeks for the custom retainers.

Todd
Your welcome. Did you order valves too?
wdo-mkr is offline   Reply With Quote
Old 05-02-2010   #40
tpepmeie
 
Join Date: Aug 2005
Location: Fishers, IN
Posts: 815
Default Re: Camshafts almost done

Quote:
Originally Posted by wdo-mkr View Post
Your welcome. Did you order valves too?
?????
tpepmeie is offline   Reply With Quote
Reply


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


All times are GMT -4. The time now is 09:16 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ZR-1 Net Registry 2020