Trying to figure out if I should use my complete 911 front suspension or keep the 914 a arms and tbars and just use the 911 struts.

Based on a brief search I can't find any reasoning one way or the other and looking at different vendors it looks like the same size bars can be had in either 914 or 911 spline counts for the same price.

What would be the prefered choice of components? 914 arms with 911 struts or all 911?

you would be better off with all 911 components. Yes the splines are different, but also the diameter of the torsion bar is thicker, for a slight upgrade. Get the 3.5" bolt spacing on the struts allows the S aluminum calipers or the SC or Carrera calipers to be used. The late model 911 front ends have an aluminum crossmember that weighs much less than the steel one 914/6 one. jim

All true, but consider this:
-- The 911 torsion bars were intended for a heavier car and are thus too stiff for the 914.
-- The aluminum crossbar will bolt up to the 914, but you can no longer install the 914 suspension pan. Some people won't care, but I prefer to have the rack and tie-rod ends protected from road debris.

I say use the 911 struts and brakes. Keep the the 914 arms, bars, and crossbeam.

I was asking generally incase someone else ever needed this information.

In my case, I have 911 bilstein struts with the 3.5" caliper spacing and 930 brakes.

The point that the 911 bars where intended for a heavier car seems moot since most people upgrade the thickness of the bar regardless of 914 or 911 orgin.

Keep it coming though! and thanks for the replies.

Well... if this truly is for the edification of others, I'll "keep it coming"

I don't agree. It's hardly moot... until the newer GT3 knocked it off the top spot, the 1973 911RS with it's stock 19mm torsion bars was heralded as the best 911 of all times. Handling and all.

I don't think most people are doing it or should be doing it. In fact, I'd only really recommend it in very serious road course racing and some of the serious autocrossers (the ones that trailer their cars to events).

There are torsion bar calculators out there and there's a thread here somewhere where I did the math using one... that seemingly slight change will give you a health dose of spring over the stock.

The factory thought so too... they installed the entire 911 front suspension to the 914-6 and then went to the effort to have a special set of torsion bars made with the 911 spline count just for the 914-6.

I have a 911 front suspension (complete) in my GT project and I have a pair of 914-6 torsion bars on the shelf just in case I can't get it to balance out. I also have original GT rear shocks and springs so it will probably mate up well with the 19mm front bars. But... just in case.

Bottom line and back to the original question; for 99.9% of all street and Sunday autocross cars would do well with Mr. Sprinkle's suggestions. Keep the stock A-Arms and torsion bars and use the 911 struts.

I'm not a huge fan of the AL crossbar either... if there's any place in a 914 or 911 I'd want weight, it's up front and down low.

Not a huge fan of the heaviest caliper ever put on a 911 either (the aforementioned A-Caliper), especially on a 914.

Keep'em nimble guys... get some great shocks, killer tires and a great adjustable sway bar. Add some monster brake pads and begin driving.

Eric said it better, but...

No good reason to swap out the cross member or the A-arms. Don't bother.

So to boil it all down. There is no reason to choose the 911 a arms over 914.

Another quick question. You mention 19mm bars but later say keep stock bars. I thought stock 914 bars were something along the lines of 17mm?

Your not giving them the whole equation, 3.6, flares , big fat Kinesis wheels, 930struts/brakes.

I would use the 911 Arms /18.8 and steel crossmember.

I have 1979, 930* Bilstein struts with 914 a-arms on my flared, 3.6L 914 with no worries. A note/question however, on the crossmember and master cylinder fit is in order.

I use a 23mm (Mercedes) master cylinder to actuate big aluminum brakes all around. That ms is longer than the original and butts right up to the round, steel 914 crossmember. In fact, I had to grind a few mm's off of the end of the cylinder to get it to fit. Perhaps the aluminum 911 I-beam crossmember would make more room?

Question: Who here has that 23mm master cylinder / aluminum crossmember combination and can report?



* I think there was no difference in the 930 and 911 Bilstein struts... haven't checked part numbers in Pet on that.

This is true for me, what I had been initially searching for was information as to which arm would be best for the 914 application, not which t bar size. Obviously arm type will dicatate which bars you can use but if the same sizes are available for both for the same price why choose one over the other?

Also, I need to get a hold of you soon. Im going to the eastside this weekend and want to make sure I can drop off your linkage on my way back home!

It won't matter if
- both 914 and 911 splined bars are available
- it doesn't matter if the splash plate is usable (in the case of the 911 c-member)

and since it's a track car...
- it doesn't matter if the car is a little lighter when the front should be a little heavier

I moved my fuel cell as far forward as possible and the battery to the front just to get a better weight distribution. Over the duration of the build (years in my case) it makes a difference how well a car changes direction.

The closer to 50-50 I am the easier it is to make over/understeer changes with small adjustments like tire pressures and sway-bar adjustments once I've found my spring rate "sweet spot".

As far as I can tell, there isn't any compelling reason to go with one or the other. Frankly, the main practical difference that I can think of is that some 914 A-arms have the brackets for the sway-bar drop-links.

True, some 911 A-arms have the brackets for the under-body sway bar, but I don't like that style of bar.

And, of course, there are bolt-on and weld-on brackets for drop-links that are in some ways better than the stock parts.


So, what other considerations are there? If you're ordering parts, you'll have to keep track of what car the original suspension came from. I think the ball joints go with the struts, so those are 911 ones no matter what if you swap. The torsion bars go with the A-arms, so those could be either 914 or 911; but torsion bar replacement is pretty rare, it is not exactly a maintenance item.

I can't really think of any compelling reason to go with the 914 parts, or to go with the 911 parts.

Oh, and the stock torsion bars for the 914 and the 914-6 were all the same diameter, something like 17.9mm. But aftermarket bars are available in just about any size in either 911 or 914 spline count.

And the effective spring rate of a torsion bar goes up with the FOURTH POWER of the diameter, so doubling the diameter of the bar gives you SIXTEEN TIMES the spring rate.

--DD

The only reason I went with the 911 arms is because my passenger side 914 arm was bent. I got the 911 arms with the front end I bought. The A-arms are exactly the same with the exception of the spline count. I did have to cut off the under body sway bar mounts on the 911 arms and weld on the U tabs. Took about 20 min and now I have two straight arms for the cost of some U tabs.

The fact that a 17mm t-bar is "basically" unavailable for the 911 spline count. It's called a rare 914-6 t-bar. I don't know of anyone making one.



That depends on bar length and lever (t-bar center to ball joint) length but, sounds accurate.



URO makes a 23mm MC that is the same dimensionally as the 17/19mm unit. Not sure if I trust them yet but... they're out there.



I think we're referring to the fact that you mentioned:



I was just referrencing that the 911 uses a 19mm stock (18.8 actually, these are in inches I believe with that being 3/4") and the 914 uses a 17mm stock. I like stock spring rates for "both" cars respectively and an adjustable sway bar for street applications. Again, that said, my car is sitting on the 19's right now as Jeff recommends. We'll see...

The advantage of the 914 arms is, you get to run the stock spring rate. You can also get some other spring rates but, I believe the 911 spring rates are more prevailent.

Advantage of the 911 stuff is, as above, the 911 spring rates are probably more vast and available.

Are all of the ATE 23mm master cylinders gone? I've never tried the URO stuff.

Smallest 911 torsion bars are 18.8mm
Smallest 914 torsion bars are 17.9mm

The difference will give you a 20% stiffer suspension.

I'm with Dave. (I've had it both ways) The one with the SC front suspension rode like a truck. Never tracked the car, so can't judge how it differ on the track.

No... fairly common on Mercedes sedans and other makes but, they're longer as you know.

Well, the length of the bar and the length of the lever are the same lengths on the 911 and the 914, so it is pretty accurate.




From reading other threads on URO parts, you probably want to keep it that way.

--DD

I'm running the Ate 23mm mc in my 911 with the steel rack. It's tight but works real nice.