Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 914 & 914-6 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jun 2008
Posts: 323
torsion bars

I am changing the front end of my 1974 porsche 914 to 911 parts as I needed the wider bolt spacing for the larger brakes. My question is should I use the same torsion bars from the 914 are should I use the bars from the 911. The front end came from a 911S and I got all the parts from the front end .
Thanks

Old 01-03-2020, 09:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Administrator
 
Dave at Pelican Parts's Avatar
 
Join Date: Dec 1969
Location: Silly-Con Valley
Posts: 14,224
Garage
Send a message via AIM to Dave at Pelican Parts Send a message via Yahoo to Dave at Pelican Parts
The torsion bars should match the A-arms. As should the adjusters at the rear of the torsion bars. The 911 and 914 have different splines on the ends of the torsion bars, and the splines that they mate with in the front of the A arm and in the ride height adjusters need to match those.

--DD
__________________
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling
Old 01-04-2020, 11:38 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Oct 2008
Location: Catalunya, Spain, Europe
Posts: 30
Garage
When I converted to 911 front wheel suspension, at first I left out the torion bar. (My 914 did not have one.) Later I placed the 911 22mm torsion bar and my feeling is that its cornering stability has become fabulous.
Old 01-10-2020, 01:22 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Emo993's Avatar
 
Join Date: May 2008
Location: Merrimac,WI
Posts: 666
Dave is correct....but are we talking torsion bars or sway bars. Mark
__________________
1974, 914-6 GT Tribute
2007 Cayman S
1998 993 Carrera S, speed yellow (Yellow Bird) gone but not forgotten.
2017 Golf Sportwagon 4motion
Old 01-10-2020, 08:44 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Administrator
 
Dave at Pelican Parts's Avatar
 
Join Date: Dec 1969
Location: Silly-Con Valley
Posts: 14,224
Garage
Send a message via AIM to Dave at Pelican Parts Send a message via Yahoo to Dave at Pelican Parts
ggraaf, I think you mean the sway bar. Or anti-roll bar. The torsion bars are the springs for the front suspension; leave them out and the front of the car will basically sit on the ground.

--DD
__________________
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling
Old 01-10-2020, 08:21 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Jun 2008
Posts: 323
torsion bars

Which should I use. I have both 912 control arm with the bars and also the control arms for a 911 with its torsion bars. I can put either on the car. My question is which will improve the car as for as handling , ride etc.I all so have the sway bar which fits the 911 arms . I am replacing the complete shock strut with 3.5 brake spacing for the bigger brakes.
Thanks guys
Old 01-12-2020, 07:48 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Join Date: Jun 2008
Posts: 323
torsion bars

in the last question I made a mistake I said I had control arms for a 912 I have control arms for a 914 and 911
Old 01-12-2020, 07:51 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Administrator
 
Dave at Pelican Parts's Avatar
 
Join Date: Dec 1969
Location: Silly-Con Valley
Posts: 14,224
Garage
Send a message via AIM to Dave at Pelican Parts Send a message via Yahoo to Dave at Pelican Parts
There are several ways to answer this question.

First, in an older car like the 914 handling and ride comfort are usually inversely related. Especially when it comes to spring rates. In general, going with a higher spring rate (a thicker torsion bar) provides better handling and worse comfort, and a lower spring rate does the opposite.

Second, handling is partly about balance. A stiffer front end will usually make the back of the car grip better, changing the balance of the car. That's great if you want less oversteer or more understeer, not so great if you don't. So part of your decision needs to take into account whatever you are going to do with the rear of the car as well.

Now for a bit of research, and a bit of math.

Stock torsion bars for the 914 (and the 914-6!) are 17.9mm in diameter. Stock torsion bars for most or all of the torsion-bar 911s are 19mm in front. The effective spring rate for a torsion bar goes up with the fourth power of the diameter, so the 19mm ones are about 25% higher rate than the 17.9mm ones.

Adding a front sway bar to a 914 that doesn't have one will effectively increase the roll resistance on that end of the car as well. The math for this is more involved and depends on what type of bar you add, but suffice it to say the front roll resistance will be even higher.

If you like the balance of the 914 as-is, then doing both of those things is not going to help unless you beef up the rear spring rate by a good amount. Stock rear springs are on the order of 60 lb/in, though, so you don't have to use super high-rate springs to go up a good amount in proportion. But remember that will make the ride harder...

Also note that ride height, tire size, alignment, and driver preference all mix into this as well!!!

So, my recommendation for you is to follow a well-known recipe. If possible, get a ride in a car equipped with similar spring rates and sway bar sizes to what you want to use. That will give you an idea of ride comfort and some idea of handling if the owner is willing to throw the car around.

I would use 914 A-arms and torsion bars, and a through-body type sway bar, and either stock rear springs or 100 lb/in rear springs. If you use an adjustable sway bar and adjustable rear spring perches, you can fine tune the handling and ride height to get things where you want them.

Please note: If you're going racing, ignore all of the above and start out by carefully reading through the rules for all of the series/organizations you want to run with! Those will have a major effect on what you can and cannot use and in combination with what.

--DD
__________________
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling
Old 01-12-2020, 12:30 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
Join Date: Jun 2008
Posts: 323
torsion bars

Thanks Dave that was what I wanted to hear, Very good information
Thanks

Old 01-12-2020, 08:57 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 05:38 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2020 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.