simplistic approach or fail, 6 conversion mount and pressure regulator Options

[nditiz1]

Welder is setup and I'm practicing - check
Under the car and started to clean the metal for the mad dog mount - check
Proportioning valve Pressure regulator is in my way to weld in the mount - (IMG:style_emoticons/default/headbang.gif)

I like removing things from the car that are not needed no longer needed i.e. -4 engine mounts, relay board mounts. I read another post from 2009 that some members remove and put a T fitting in it's place. Is this a poor move? The car has an SC front end so the brakes have been upgraded, I assume (IMG:style_emoticons/default/rolleyes.gif)

I can't believe the factory would have the audacity to place it right in my way knowing full well that this 74 914 would one day turn into a 6 (IMG:style_emoticons/default/dry.gif)

So what are my best options here - relocate further towards the driver side and elongate the main line running down the center tunnel - (IMG:style_emoticons/default/bs.gif) and replacing the passenger rear with a longer line? Maybe there is just enough main line to get it out of the way. Looks like passenger rear has already been replaced once.

I just want to be where @930cabman is right now (IMG:style_emoticons/default/beerchug.gif)

Also, thanks Metric AutoHaus for patching that small hole with a lap weld possibly causing this bracket to not sit flush (IMG:style_emoticons/default/mad.gif)

(IMG:http://www.914world.com/bbs2/uploads_offsite/live.staticflickr.com-18763-1619202501.1.jpg)

[Root_Werks]

Installed a few variations of this mount and don't recall ever moving the proportioning valve. I thought the factory mounted them more to the left side?

There's other mount options, could always use a quick six bar. Some don't like them, but if you don't have a 200+ hp engine, they're fine.

[PanelBilly]

I relocated the stock valve and changed the lines to fit.

[Justinp71]

I took out the proportioning valve. You don't really need it in a 914. Also depends on how you've upgraded your brakes. My front brakes are stronger than the rear, so I want as much flow to the back as I can get. I still lock up the fronts first (IMG:style_emoticons/default/smile.gif).

[Root_Werks]

I relocated the stock valve and changed the lines to fit.

Ah, so it does need to be relocated. Probably my bad memory.

[Steve]

I have a 75 and installed a T back in 1987 when I installed my first six in my car. Multiple auto crosses and emergency situations where i locked up the fronts and so far no problems. I have had many brake setups with no problems. I am currently running boxster brakes front and back.

[nditiz1]

Ok, I like what I am hearing. Time to "T" it up..."foooouuurrrrrrrrr" oh wait "sssiiiiixxxxxxx"

[Steve]

Ok, I like what I am hearing. Time to "T" it up..."foooouuurrrrrrrrr" oh wait "sssiiiiixxxxxxx"

(IMG:style_emoticons/default/hide.gif)
Now i'm in trouble..... Eric Shea is a huuuuge proponent of that valve. PMB rebuilds them and if it wasn't needed Porsche wouldn't have put it in there. Under conditions where the rear tires lose traction in a braking situation, they could lock up. Maybe the rear tires in water, snow, etc. could cause them to lock up first. In my over 40 years of 914 ownership, I have never run into that situation. A lot of track cars use a T, but its a controlled track situation versus street.

[Superhawk996]

Ok, I like what I am hearing. Time to "T" it up..."foooouuurrrrrrrrr" oh wait "sssiiiiixxxxxxx"

(IMG:style_emoticons/default/hide.gif)
Now i'm in trouble..... Eric Shea is a huuuuge proponent of that valve. PMB rebuilds them and if it wasn't needed Porsche wouldn't have put it in there. Under conditions where the rear tires lose traction in a braking situation, they could lock up. Maybe the rear tires in water, snow, etc. could cause them to lock up first. In my over 40 years of 914 ownership, I have never run into that situation. A lot of track cars use a T, but its a controlled track situation versus street.

(IMG:style_emoticons/default/agree.gif)

You will never find a production car without a proportioning valve. It's not becuase the OEM's felt like giving away money for hardware that wasn't needed.

I won't write the dissertation on proper brake system design. This has been covered elsewhere endlessly.

The proportioning valve covers all sorts of load scenarios you're not thinking of. God bless those happy with a T but there are too many variables in play for me to do it on a street car.

FYI - my car is 73' and the valve is further to the left. I belive they moved to your postion for 75' & 76' but will leave it to others that better know the exact date.

If it were me, I'd relocate the valve to the early position, and extend the feed from the tunnel to the proportioning valve.

[Chris914n6]

Simple version... it increases front bias at higher pedal efforts. So the rear is less likely to lockup in corners on not dry streets.
But so many factors have changed in the past 50 years that it is not really the safety switch it was designed to be.

[Retroracer]

Just to add to the various approaches: I'd suggest removing the factory proportioning valve (big, heavy, designed for a different braking system than the one you have, etc) and add an aftermarket, adjustable proportioning valve and T-piece. That way, you have all bases covered - adjustable if you want, otherwise set and forget.

I mounted to so it can be adjusted from underneath the car - I seem to have hit a good compromise setting as I don't find myself tweaking it at all.

Yes, that patch on the bottom of the panel will need some attention! Also, careful of weld heat near the loom - melted insulation at that choke point can cause all manner of amusing intermittent electrical problems in your future....

FWIW,

- Tony

[mlindner]

I did the same, any thing not needed is gone. I had a T for 20 years of hard driving and stayed with it.

[bbrock]

From the brake guru himself: https://www.pmbperformance.com/914-brakes/L..._Regulator.html

Repeat after me, "Pressure Regulator" -- "Pressure Regulator"

That's right, this little beast is a pressure regulator, "NOT" a proportioning valve. It proportions "NADA". It is the first anti-lock brake device ever to be installed on a Porsche. Here's the story:

The 914 is a mid-engine automobile. As such, it has amazing handling characteristics... to a point. Once that point is reached, it can bite you like a rabid dog. It's a physics principle called "Polar Moment Inertia". We're all familiar with the childs play toy the "top". Here it is straight out of Mr. Elford's mouth: http://www.amazon.com/Porsche-High-Perform...d/dp/0760327548

Porsche knew the issues with rear and mid-engined automobiles so, they installed this pressure regulator in the system to prevent the rear wheels from ever locking up. You see, if you lock your rear wheels in a rear or mid-engine car and your front wheels are anything but straight, you can be that "top" we were talking about and, that's not a fun toy at that time. This pressure regulator senses a panic stop (which it is set and locked at 525psi). Once it sees that pressure on the system, the valve body slides over and activates a microswitch which shuts off pressure to the rear wheels. This is a panic stop mind you, this device flows fluid like a "T" fitting until you need it. That's why we insist that it proportions "Nothing". Once the pressure equalizes in the chamber, it brings the rear calipers back into the circuit. This is "split second" stuff gang, not a leisurely event.

So, yeah, the internet guru's steered you in the wrong direction. You "never" want to replace this regulator in a street car and, you want to make sure it's operating properly otherwise, your rear calipers aren't even working and, that's 30% of your braking power.

Here's what we do; We will completely disassemble the regulator. We will zinc plate the spring housing and the valve housing. We will clean and reseal the valve body using new EPDM seals throughout. We will repaint the freshly plated spring housing and the valve housing. We will zinc plate the mount and the fasteners. We will then reassemble the regulator and reset the pressure switch to 525psi. We will then epoxy the lock nut just like the factory and send you back a perfectly operating pressure regulator that not only makes sure you and your passengers are safe but, it give you back your full braking potential so your 914 stops as good as it did when it was new (and that's still damn good my friends).

If you don't see your model listed here please send us an e-mail at sales@pmbperformance.com or call (855) STOP-101 (855-786-7101). We can usually get what you need within 1-2 business days.

[nditiz1]

Ah Jeeze - I guess I will think about relocating. I trust Eric when it comes to 914 braking.

Good news is I can continue to clean the metal.

(IMG:http://www.914world.com/bbs2/uploads_offsite/live.staticflickr.com-18763-1619210755.1.jpg)

[seanpaulmc]

My rear brake pressure regulator is mounted more to the left (driver's side) than what yours shows to be.



I have all the original rust, and then some. I do not believe it has been moved.

[mlindner]

Brent thanks for that information. And Eric's top shelf service to our hobby.
Butt, this is only my observation. My 74 1.8 with big bore with cams and webers at many Road America, Blackhawk track days, over 100 autocross, has had a T when I started. A street car, driven to Porland Main PCA Parade, driven to Colorado Spings PCA event...driven all over, PAC events in the Mid-West. All the bad weather, high speed events and never had the back end come around. I would follow PMB but just wanted to give some my experience . Thanks, Mark

[mepstein]

My rear brake pressure regulator is mounted more to the left (driver's side) than what yours shows to be.



I have all the original rust, and then some. I do not believe it has been moved.

(IMG:style_emoticons/default/agree.gif) Yours looks stock. Nick's looks modded.
I was wondering why it looked strange to me. It's missing the right angle fitting and the ~8" piece to the regulator.

[930cabman]

Sounds as though the consensus is: relocate the valve

Our /6 conversion has been moved to the back burner for a few months. I had a complex (3 hernias and a diastasis repair mid March), still recovering. I would recommend to make sure the base metal is clean/clean/clean and your welding skills are in order prior to securing the Mad Dog mount. Ours fit like a glove and I am sure it will never come loose.

Best of luck

[Superhawk996]

My rear brake pressure regulator is mounted more to the left (driver's side) than what yours shows to be.



I have all the original rust, and then some. I do not believe it has been moved.

(IMG:style_emoticons/default/agree.gif) Yours looks stock. Nick's looks modded.
I was wondering why it looked strange to me. It's missing the right angle fitting and the ~8" piece to the regulator.

There is a difference in hard lines and routing between early and late. I'm sure of it because when I ordered SS brake lines, I recevied the wrong ones. PMB made it right and sent me the proper lines. Great company!

@Nditiz1 if you want measurement of where to locate the valve to match 73 location, I'll be happy to send you dimensions. Then you can use PMB lines. 4 lines will be affected. The bulkhead pass though, a L shaped estension and 90 fitting to the valve, and the two sides. However and I think you'll need a different banjo. Eric would be able to tell you for sure or if the actual valve housing changed. Betting that Eric would exhange early for late valve if needed and you did a rebuild ((IMG:style_emoticons/default/poke.gif)) to get you all set up.

[brant]

I adjust my bias valve on the -6 race car nearly every weekend
Depending on grip and weather

I once tracked with the T and no bias valve on a 4.
Went off the track backwards at the end of a straight

Your putting a lot of weight in the rear (150 lbs) with a -6
Changing you balance
I’d want the stock valve on the street