Suspension swap, Swap 911/930 front suspension to my 914 Options

[pnewman]

Hey Eric!

I pressed in your hubs. They are ready to be put in as soon as the tub is ready that is. I got new koni reds for the back too. I also just ordered 140 lbs rear coils the other day per your advise. All should be assembled this summer.

thanks for the good work w/ the odd studs and all.

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) Oh and yes! i AGREE!

BOLT IT ON AND GOOOOOOOO!

[Eric_Shea]

Glad everything is working out... (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

(IMG:http://www.914world.com/bbs2/html/emoticons/thisthreadisworthlesswithoutpics.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[rickyhgarcia]

When I bought my car back in 1989, the common wisdom to 914 suspension upgrades was to bolt on a 911 front suspension. So I bought a 911SC front suspension and bolted it to my car. The car was OK...not great, but OK.

A couple of years back, I met Rich Johnson and he provided a completely different wisdom about 914 front suspension. Rich indicated that the 911 front struts are not the best option for a 914 because you can only install inserts that are designed for 911 chassis dynamics. For example, a 911SC or late Carrera weight about 3000 pounds and has a very heavy rear end. True, for an additional cost, both Bilstein and Koni provide custom valving on their inserts to make it workable. Using these struts, however, you cannot buy off-the-shelf inserts that would be ideal for the 914 chassis dynamics.

The solution is therefore to use 914 OE struts and modify them with 3.5" spacing ears for the bigger brakes and install the necessary hardware to convert to 5 bolts wheels and 911 vented rotors. Using such modified struts you can therefore take advantage of the bigger and vented 911 brakes, use 5-bolt wheels and use off-the-shelf inserts (i.e. Bilstein or Koni) designed specifically for the 914 chassis dynamics.

Additionally, it is most likely that if these upgrades are performed on the front suspension, the rear suspension will also be modified. The performance rear suspension shocks available (i.e. Bilstein or Koni) are also designed to work in conjunction with the off-the-shelf inserts for the 914. That is, using front 911 inserts with rear 914 shocks results in a mismatch of suspension components. However, using 914 front inserts with 914 rear shocks you get components that were designed to work together in the 914 chassis.

Rich´s suspension wisdom made a lot of sense to me. Therefore, I traded my 911SC front struts for a set of modified 914 struts. The modifications inlude 3.5" spacing ears, and a raised (by 15mm from stock) spindler to lower the car. By the way, 15mm is the maximum allowable displacement on the spindler so the suspension fit perfectly inside my 15" five bolts Fuchs...you can do 17mm if using 16" wheels. I transferred all the hardware from my 911SC struts to the modified struts. These parts provided the five bolts conversion and the ability to install crossdrilled/slotted/vented 911 rotors. The 3.5" spacing ears on the struts allowed me to install 911S alloy calipers for a reduction of weight. Finally, I installed 914 adjustable yellow Konis on all four corners.

The car is no longer OK...it is great.

Did I make the right choice? I believe I did...

Which wisdom is the correct one? Do not use parts that were specifically designed to improve the handling of a 911 on your 914...

[Dr. Roger]

it's true. my new 911 front suspension is way stiffer than my old 914 suspension. it' didn't need to be any stiffer..... it was just right before. now i'm kinda worried.... time on the road will tell...

[Andyrew]

Rogger, you need some stiff rear suspension.. What are you going to use?

I needed 225lbs just to get by with a stock sway bar.. I got 275 a big bar up front, and I like control over oversteer without using my right foot.

[shoguneagle]

This is a good thread and it is nice to read about Rich Johnson's knowledge regarding the 914 front end. When I build my 914-8, I used both the 914 front and the 911 front. The 914 front had 22mm torsion bars and 22mm Weltmeister sway bar; rear 180-200# Koni adjustable Gas with adjustable perch and no sway bar. Thus, I converted the entire front end to 911 with 19mm torsion bars and the 22mm Weltmeister sway bar. Through the body sway bar is the only way to go whether street or race; none in the rear if you do not have a posi- or locked rear.

Which was better? I kinda liked the 914 modified front, especially Rich Johnson's dropped front spindle and 3.5 conversion. The changes I went through above probably proved either is go for the street; racing I do not know since I do not race.

I am currently building a 914-6GT/916 Replica and I will use the 911 front end for a short time to get the entire car put together and running. Once I start tearing it apart for painting and modifications, I will probably go with Rich Johnson's mods to the 914 front. Somehow I like 22mm torsion bars since I seem to get a better feel for the road while driving the curves.

Thread has been most informative making sure I am thinking right.

Thanks
Steve Hurt

[michel richard]

Brant,

Final front end suspension.

1988 struts

New pads, bearings, seals, and flex hoses

New Zimmerman cross drilled rotors. I am painting the rotor hats red.

1988 calipers rebuilt and painted red

. . .

Pete

Did'nt the 1988 911 use servo brakes ? Are you changng your maste cylinder ?

[rickyhgarcia]

Elephant racing has a great tool in their website to help set up the suspension. They provide different combinations of front/rear sway bars, torsion bars and rear springs for set ups ranging from street use to full racetrack cars.

Just check:

914 suspension setups...

These configurations, however, assume that you are using the correct damping (i.e. shocks) system in your car since the shocks they provide are the 914 units from Bilstein (Konis would be OK too). On a 914, it is easier to accomplish this by using OE struts.

[Dr. Roger]

Rogger, you need some stiff rear suspension.. What are you going to use?

I needed 225lbs just to get by with a stock sway bar.. I got 275 a big bar up front, and I like control over oversteer without using my right foot.

i'm starting off with some 140lb coils, colemans, koni's on stiff, and no rear sway bar.

i'm also starting with no sway in front.

then i'm installing the front sway bar and testing...

i just want to get a good feel for what's over and understeer in this car.

it's a new relationship afterall....... going slow.... LOL (IMG:style_emoticons/default/wub.gif)

[rickyhgarcia]

Can also check in here:

Struts spindler mods...

[Dr. Roger]

andyrew,

did u notice on elephants website that they suggest 140# rear coils for street/track 1, and 180# coils for street/track II?
and for their full race the don't suggest going over the 180#ers...

i guess we should be bumping it up a bit for the added weight?

[rickyhgarcia]

225lbs...275lbs rear springs? On a lightweight car as the 914...isn´t that overkill?

Besides, I´ve always thought that rear springs and front torsion bars should go hand in hand for the suspension to work OK. I have always seen the combination of 23mm torsions to 180lbs springs. So for these bigger springs, what torsion is required? I´ve never seen torsions bigger than 23mm...

[Mueller]

225lbs...275lbs rear springs? On a lightweight car as the 914...isn´t that overkill?

Besides, I´ve always thought that rear springs and front torsion bars should go hand in hand for the suspension to work OK. I have always seen the combination of 23mm torsions to 180lbs springs. So for these bigger springs, what torsion is required? I´ve never seen torsions bigger than 23mm...

he has a V8 and wider rear tires...he's using the stiffer rear springs to get the rear of the car "upset" so that it is easier to swing around

[Andyrew]

What mike said.

Rogger, For about 300lbs more /2000lb car

on a stock car about 120lbs in the back feels about neutral.. i do believe. little calculation says 140's should feel the same...

but the center of gravity is higher, and gives it a bigger upset... Also your fat tires on the back and 225's on the front will make quick steering, but understeering... I then would assume you would need about 2-5lbs more per 10mm of tire.. just a guess though.. that given, 225-295 is 70/5 is 14-40.. so 165 progressives might give a nice ride for no sway bar up front? 180's with a sway bar, and up...

I guess we'll see, wont we.

As far as my car, 180's were not cutting it with 22mm T bars and a stock front (on the track, it was quite neutral, but I was too scared of the car to push it)
I have a freeking huge sway bar with adustability for the front, and 275's in the back with 285 tires in the back and 255 tires up front... I think it just might work.

Andrew

[blabla914]

Good thread.

Did the 911 strut housing itself change at some point?

I agree with the idea that a 911 valved front strut is not going to work well on the front of a 914. first there is the obvious weight bias difference and then there is a weight difference which varies with the year of the 911 in question.

However, I was able to put my 914 Koni yellow struts directly into '71 911T Boge front struts without a problem. Since the early 911 front struts also have 3" spacing on the caliper mounts the struts appear to be identical except for the spindle itself.

What am I missing?

Kelly

[Eric_Shea]

QUOTE

What am I missing?

Nothing. You're spot on.

It's simple, use the 914 inserts... the only issue is when you go to 3.5" Koni or Bilstein struts. Even then, I'd say the 914 valved insert would be less expensive than a 914 strut with the 3" to 3.5 Mods or brackets (because you're only going to 3.5 to use an A/S-Caliper or larger).

I'm not buying the modified 914 strut thingy... what about the spindle? Ricky, you're saying on Rich's car he's using 914 struts? Did he weld a 911 spindle on there as well? Or... is he using adapters or drilled 914 rotors...? I don't think so. A 914 strut with a 911 spindle welded to it is a 911 strut. There's too much to be changed vs. simply installing a 914 insert or a 914 valved insert in a 911 strut.

A 914-6 used a 911 strut. I owned one. The ride isn't harsh. It's exactly like a stock 914. For that strut you can get stock 914-6 Boges, 914 Konis or 914 Bilsteins...

Please explain... (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[rickyhgarcia]

Koni Inserts P/N

914/914-6 8641-1077
911 75-89 (Boge strut) 8641-1039
911 75-89 (Koni strut) 86-1942
911 65-68 (Koni strut) 86-1308
911 65-68 (Boge strut) 86-1394
911 69-74 (Koni strut) 86-1638
911 69-74 Boge strut) 86-1647

The sport version is only available for 914´s and 911´s 75-89 w/Boge strut. P/N is the same as above with an "S" at the end.

No 911 inserts share the same P/N as the 914 insert. Maybe they are the same physically, and the differences are in the valving. Any ideas?

Furthermore, 914 inserts have the exact same price as 911 75-89 (Boge struts) inserts. Both in sports and HD versions.

These numbers I got from Paragon Products website.

[Eric_Shea]

QUOTE

Therefore, I traded my 911SC front struts for a set of modified 914 struts. The modifications inlude 3.5" spacing ears, and a raised (by 15mm from stock) spindler to lower the car. By the way, 15mm is the maximum allowable displacement on the spindler so the suspension fit perfectly inside my 15" five bolts Fuchs...you can do 17mm if using 16" wheels.

Again, something's missing here. I 'think' you have modified 911 'Boge' struts. The 911 spindle being the key. You would need the much thicker 911 spindle to put the 5-lug goodies on this strut. Otherwise... too much effort to simply make the equivalent of a 911 'Boge' strut.

(18mm is the highest you can go with 15" wheels BTW... both cars are sitting in the garage with the wheels on them)

Maybe you could have Rich clarify... I don't want to mislead people.

[Eric_Shea]

QUOTE

914/914-6 8641-1077

Well... there ya go. You successfully found an 'off the shelf' 914 Koni insert that will fit a 911 strut. Not a 911 Koni strut or a 911 Bilstein strut but this will fit the most common 911 strut, the Boge.

[rickyhgarcia]

QUOTE

I'm not buying the modified 914 strut thingy... what about the spindle? Ricky, you're saying on Rich's car he's using 914 struts? Did he weld a 911 spindle on there as well? Or... is he using adapters or drilled 914 rotors...? I don't think so. A 914 strut with a 911 spindle welded to it is a 911 strut. There's too much to be changed vs. simply installing a 914 insert or a 914 valved insert in a 911 strut.

Eric,

I have a 914 Boge strut with 3.5" ears, with a 15mm raised spindler. Installed on my struts are all the pieces from my previous 911SC front suspension. These include 911SC vented rotors that I bought from performancerotors.com. These are not drilled rotors...and no adapters were used. I bought Koni´s P/N 8641-1077S which is the correct P/N for 914/914-6.

If you say that the 914-6 strut is identical to the 911 (any year?) strut, and, according to Koni´s P/N, 914-6 and 914 use the same insert, then the 914 insert should fit the 911 (any year?) strut. Right??