"16volt" (thecrashingdoor)
08/25/2014 at 19:48 • Filed to: Porsche 911, Porsche 911 Turbo, No love for hose
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"16volt" (thecrashingdoor)
08/25/2014 at 19:48 • Filed to: Porsche 911, Porsche 911 Turbo, No love for hose | 4
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My name is Shannon, I am used part hoarder. I throw away nothing when it comes to crusty used car parts. The more complex and consequently unlikely to be reusable, all the better in my book. A very long time ago I used a battery tie down bolt to replace a missing brake caliper bolt on a road trip in the Scirocco. Now I stuff everything in a drawer labeled 'Just In Case'. Truthfully there are many drawers, used electronics drawer, used coolant hose drawer, used hose clamp and fastener drawer. My God, the used fasteners.
I can count on one hand just how many times I have actually re-used any of this detritus on a car. More often is the case that I end up "fixing" something around the house with car parts. For instance, as I type this my pricey Ergotron dual monitor stand is affixed to my desk with a collection of Audi Allroad spare parts, purchased from a wrecking yard via eBay. A 25lb box of greasy Allroad nuts, bolts and brackets for $40 bucks shipped? Done.
When we last spoke I had attempted to delete the decel valve on the 930, unfortunately I succeeded only in disabling the BOV. Stand back folks, I am a professional. The 930 uses an interesting slide piston arraignment to re-circulate boost into the lower manifold below the throttle body. Close the throttle and a spring assisted piston slides forward, allowing boost pressure to route directly to the intake after the throttle-body. Normally the decel valve sits in the middle of this system and providing a buffer, in theory to keep the throttle from slamming shut thus slowing the revs from falling between shifts. Some folks also believe it exists for a mysterious emissions purpose…at the end of the day it's un-needed and makes removal/install of the upper intake manifold a pain. The source of that pain and subject of this post is a hose which runs under and around the lower intake manifold.
Looks innocuous enough right? Well when trying to remove it I discovered it to be very stiff and really froze on. I then committed a cardinal sin in car repair. I justified it was going in the bin anyway, so I decided to cut it off. I never, ever, ever do this. It goes against my keep/reuse everything ethos and this is why, upon trying to cut it I found that this was no simple run of the mill cloth wrapped rubber hose. It had a metal winding imbedded in the rubber. Dammit. If I didn't know it before, I knew it then. I made a mistake. I moved forward, in too deep to go back. I then proceeded to cap off what I thought to be the right ports and went off on the ill-fated test drive we spoke of last time. You guessed it folks that line needs to be retained to provide a path for bleed boost to route behind the TB. /sigh
That brings us to replacing the hose. There are four basic categories of 930 replacement parts:
No Longer Available (NLA) = $$$$$$$ Used, likely broken exactly like yours.
New Old Stock = $$$$ Box covered in rare Porsche warehouse dust.
New Expensive = $$$ Has a Porsche logo on the box, made in China.
Cheap = $ Made in China, likely to last just short of the return policy.
I had the shop call around and they could not readily locate a replacement. I didn't really have time to scour the internet to find the part number for the hose as I needed to have the car back up and running by Monday to make a service appointment.
So into my (and the shops) used hose bin I went. This is where I discovered the reasoning behind that internal metal winding. Its purpose is to keep the hose from collapsing on itself as it makes a few ridiculously small complex radius turns under the lower intake manifold. I have never had any other car with such a hose so there is nothing that special in my bin but there was a used heater core hose from MK1 Cabriolet which looked like it would fit perfectly.
There was also a A4 coolant hose which looked like a strong candidate. I grabbed a few more and some new bulk hose with the same ID as the factory hose and set to work test fitting.
After trying a few hoses it was painfully clear that the metal winding was crucial in making this work. Hoses that fit well all ended up kinking at the bends, those that didn't kink were too thick to fit under the manifold. Dammit. I then tried the Cabriolet hose…..perfect. The molded bends were in just the right places. The only problem? It's a used coolant hose….filled with crudy coolant scale, rust etc. I did my best to clean it out but decided that it was foolish to use. I then checked the A4 line which was very, very close but ultimately came too close to kinking.
I had spent nearly the entire day at this point test fitting hoses. It was time for a hail mary, I grabbed the Cabriolet hose and headed to the auto-parts store, hat in hand. While driving in the car I made an even more desperate attempt to fix my stupidity with money. I called the Porsche dealership. I am sure that their parts dept will return my call, any day now. Still waiting Barrier Porsche lol.
Its times like these where I miss the good old days when you could go to NAPA and they had pretty much everything on hand. Or the days when every car used pretty much 10 different hoses….but then I wouldn't have a 930 I suppose.
There's no need to relate in great detail the frustration of trying to explain to the counter guy what I had and what I was trying to do. The counter person was first road blocked when I told him I didn't know the specific year of cabriolet, then was blocked again by not being able to look the hose up by its part number. At which point he was so frustrated that he asked "just what is it that you are trying to do", so I told him. "Im trying to use this VW heater core hose as a boost recirculation hose on a 911 Turbo". That apparently was the correct password to be escorted behind the counter to the hose section. We just had to both agree that neither of us knew what we were doing without saying as much. Cooperation in its purest form.
Once behind the counter I was amazed/disappointed to find a collection much smaller than that of which I had at home. I digress. After about 10mins of browsing I selected the most complicated hose they had in stock, the venerable Gates 18830 for those in the know. Twelve bucks later (I also picked up a neat preformed steel spring device made to slip over hoses and provide rigidity to keep coolant lines kinking at bends) I was on my way.
A quick test fit and slight trim later we were in business. YES! I took back all the asshole comments I made about O'Reilly auto parts. So for those still reading, you can use a coolant hose from a 1992 Ford Bronco to replace your super rare and likely expensive 930 diverter valve hose. The fit is absolutely spot on. At this point I can re-assemble all the intake plumbing on a 930 in about 4mins. I rolled the car back out of the garage, adjusted the idle and told the dog to stand by for a phone call in case the car left me stranded again. Before setting off though I got the feeling I was forgetting something……..ahhh, YES! Rain coat.
Taking it nice and easy the car felt ok, still running very rich but not as bad as before. I did about 10 slow laps around the neighborhood to get some heat into the motor. My neighbors really love the 930 which is clear from the amount of stares I get from slightly parted curtains. Once warm I headed out to the longest deserted stretch of road close by. After bringing the revs up in first and a quick check for dog walkers I let the 930 off leash. The wind up and the pitch…boom, full boost. Rear end fully squatting the 930 did something it's never done before, it tried to come around on me. A quick stab of clutch and grab of second and here we go again. Still on tilt the power is immediate and again the rear tries to sidestep. By now reason began to take over and I lifted off (slowly) only to be greeted with some pretty hairy chested overrun burble, pop and crackles. Yeah, that decel valve is never going back on.
Figuring that's all I needed to know and without an AFR gauge I settled on just the one run and headed back home, 930 purring and gurgling all the way there. Two days later after taking the car back to Walker for a timing and mixture check she is back in beast mode, the bark a little closer to the bite.
I then put about 350 miles on it and I can report that the cruise surging and boost cutout issues are all gone. It's not all roses however, during its visit with Walker he found that the timing advance side of the vacuum pot on the distributer is not working. Thankfully the boost retard side is (not sure how that could be). For reference, the vacuum pot…NLA. In our next installment….well hopefully it will be something more entertaining that hose replacement. Thanks for reading.
B_dol
> 16volt
12/01/2014 at 14:31 |
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This picture! All the reason I want an 80s Turbo. NSFW!
gergey - Wishes vette was Datsun
> 16volt
12/02/2014 at 00:16 |
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Fantastic read
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gergey - Wishes vette was Datsun
> gergey - Wishes vette was Datsun
12/02/2014 at 00:17 |
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WTF, I have authorship, why am I grey???
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16volt
> gergey - Wishes vette was Datsun
12/02/2014 at 11:35 |
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And a better question is who can approve them?
Nice job Kinja.