[mick968]

My wife and I are going to take the 968 on a little cruise(St.Louis to Vail-13 plus hrs).Stopping in Denver 1st to see concert(Live) and then heading into the mountains for 3 or 4 days.My question is will(should) I worry about the altitude and the effect it may have on the performance of the car.Will the brains automatically compensate with the difference in air/fuel.I've had the car for a few months but this will be the first real extended drive that I will have taken and I'm really looking forward to it.

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[TheMirror]

It will be fine, albeit noticably slower once you get up in the mountains!







[quote name='mick968' date='Apr 24 2006, 01:54 PM']My wife and I are going to take the 968 on a little cruise(St.Louis to Vail-13 plus hrs).Stopping in Denver 1st to see concert(Live) and then heading into the mountains for 3 or 4 days.My question is will(should) I worry about the altitude and the effect it may have on the performance of the car.Will the brains automatically compensate with the difference in air/fuel.I've had the car for a few months but this will be the first real extended drive that I will have taken and I'm really looking forward to it.

[right][post="19719"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[ether_joe]

have fun man <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



make sure you have a spare DME relay and the compressor for your spare. Might want to swap the HCV valve if you still have the original plastic one - mine just blew out on me a week ago.

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[flash]

assuming it is stock, it will run fine - according to math chris came up with, it will be lacking about 50hp, but it will run - if you have a chip or other such mods, it won't run as well - i did it last august, and got away with it just fine - this year though, i am going to play with the mixture a bit to compensate

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[bob blackwell]

Mine has lived above 5,000 feet for the last few years and there are no problems running at this altitude. It is true that the power will be lower than at sea level, but so will other cars, so just do not challenge any turbo or super charged cars to races and expect to win, good luck, Bob Blackwell.

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[mick968]

Whats the problem with the DME relay?Its about the 3rd or 4th time someone has suggested carrying a spare.If I do get a spare,what does it do and where does it go?I don't want to appear mechanically ignorant but I had 4 different 944's and don't recall that problem.My car came with a performance chip(not installed) and I'm glad I didn't have it done (I think).No problem with not racing turbos(going to play golf not race).Thanks for the feedback and need help with the DME thing.

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[flash]

they fail regularly - not really sure why - mine did on the way home to los angeles from clevelend - at least a dozen we know of in the last year have as well



when istalled, it lives in the fuse box - the chart on the lid will show you where - pretty simple - 25 bucks and you're safe

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[bob blackwell]

Mick, the DME Relay controls the fuel pump on your 968 among other things. When it fails the pump does not work and the engine will not run. They are common problem items for 944 as well as 968 Porsches. They are inexpensive and simple to pull out and replace by merely pushing back into the slots of the Fuse/Relay box under the hood on the driver side of the car back near the windshield. Last time I bought one it was around $20. Good luck, Bob Blackwell.

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[mick968]

Alright,I just happened to have my car in the shop for an oil change so I called and had them get another DME relay but is the HVC valve and what does it do and what is the problem with its failure?

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[TheMirror]

Ah yes, the dreaded Heater Control Valve. Its a glued together, two piece plastic part of the cooling system that sits far too close to the exhaust header....with predictable results. To paraphrase, its a two piece part that likes to separate....and dump coolant all over the place including under your car and onto your rear tires. Very bad in a track situation.

Here's the thread with all you need to know.



If you are unsure of the age and provenance of the one in your car, replace it.



http://www.968forums.com/index.php?showtop...r+control+valve



Cheers!



-Mirror







[quote name='mick968' date='Apr 27 2006, 01:05 PM']Alright,I just happened to have my car in the shop for an oil change so I called and had them get another DME relay but is the HVC valve and what does it do and what is the problem with its failure?

[right][post="19935"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

it's over by the distributor - it tells the water when to go throught the heater core - unfortunately, it is located in the hottest part of the engine bay, and is made of plastic



i'm going to try to work out an alternate fix for that this weekend - seems to me that just relocating it farther from the header, or inserting a heat shield, is a better solution

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[bob blackwell]

The metal part from Audi is a fine replacement. I have had no problems since exchanging the plastic piece for the Metal Audi part and recommend it as a simple solution at a reasonable cost. Good luck, Bob Blackwell.

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[flash]

yeah - not bad - i'm not too thrilled with the vacuum connection though, and still it's closer to the header than i'd like - it's a bit like an aspirin for a headache, when what you really need is to stop banging your head with a hammer



what i'd really like to do is stop the heat from damaging it - the hall sensor is the same way - i think a heat shield down there would do wonders for both



the metal unit may be the only viable solution though



film at 11

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[TheMirror]

My car has the metal version (thanks, Josh!), and as long as it doesn't melt the hoses (no stories of that I've seen), all is well.



Putting some of that high temp blanket material in an appropriate place does seem like another good solution though.

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[flash]

i'm just as worried about the diaphram in there as i am the plastic - after all, that's the part that fails and leaks (at least on mine) - i'm not really convinced that the metal one is any better in that respect, and it may well be that they are just too new to fail - only time will tell on that one, but as i said, i'm really after solving the cause



anyway, back to altitude issues - i have found that there appears to be a mixture issue even between philidelphia and los angeles - in talking with pete when i was setting my car up, he related something that i had completely forgotten (it's ben way too long since i was setting something up for travel) - as a result, and at his suggestion, i bumped my pressure up just a touch and got better results running like that than he saw with the same pressure there - in philly, he got the best results at stock pressure, but like when he was racing out here, it seems that we need to run a bit richer down here at the ocean



as a result of that, i plan to lean the car out when i get to denver - on the hunt now for the right gauge

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[TheMirror]

Interesting, so it was the diaphram that failed on yours? Did it do "the big spew", or did it just start leaking? Curious.

All in all, I'll take metal over plastic any day of the week when it comes to absorbing heat. That being said, I do agree that getting the heat reduced in that area would be a proper solution.....ala this item from 9xauto.



Flexible heat shield will cover exhaust manifolds & protect components from heat. Made individually by 9xauto for all 924S/944 cars, heat shield’s two-ply material is composed of an aluminum layer as well as thermal-carbon woven. The heat shield is riveted into the aluminum bar, which in turn, mounts into the existing holes on the antifreeze rail above the header. (See Picture) This shield will also wrap around the header, creating a barrier between the header and the oil cooler. Installation requires no drilling, and two mounting screws are supplied.



This shield is an important addition for the cars with an internal air intake.



[quote name='flash' date='Apr 27 2006, 04:04 PM']i'm just as worried about the diaphram in there as i am the plastic - after all, that's the part that fails and leaks (at least on mine) - i'm not really convinced that the metal one is any better in that respect, and it may well be that they are just too new to fail - only time will tell on that one, but as i said, i'm really after solving the cause





[right][post="19954"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

yes, it just started a small weep - not exacly sure what was going on, but it wasn't sealing anymore - no visible cracks in plastic - i think i still have the part, and will pressurize it if i do, and find out where it leaked

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[flash]

ok - dug it up - vacuum diapghram fine - the leak is the seal between the white half and the black half - if the metal unit is all one piece, that problem should not exist



the other problem though, that of the vacuum diaphram failing, which has been happening on a few cars lately, would not change



i'm looking at a shield very much like the one at 9X

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[TheMirror]

Ah indeed. That sounds like other failures I'm aware of.



Lots of racing teams use that heat shield fabric stuff, its all over the headers of Champ Cars and others. Shouldn't be a big problem to fashion a piece of it to protect the HCV. A project for the back burner maybe.



Anyway, Summit sells piles of the stuff.

http://store.summitracing.com/egnsearch.as...+115+4294845359







[quote name='flash' date='Apr 28 2006, 10:31 AM']ok - dug it up - vacuum diapghram fine - the leak is the seal between the white half and the black half - if the metal unit is all one piece, that problem should not exist



the other problem though, that of the vacuum diaphram failing, which has been happening on a few cars lately, would not change



i'm looking at a shield very much like the one at 9X

[right][post="20008"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

yeah - it's been almost a year and a half since i changed it, and when i saw a leak, since i had a brand new one, i just yanked and swapped, with no further investigation - my bad



ooh - huge thanks - that saved me some research time for sure - i'm doing it this week, along with some other similar sheetmetal work

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