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I sent in a request to have the Porsche 911S classified last fall. Each month I get a notice that it has been "Tabled". How long can this go on? What does the ITAC need before this car gets classified? I've got the engine parts but just need to know how many barbells to buy.....
:shrug:
Chuck
We are really really close now, but we need to gather the spec line details. One of the ITAC members volunteered to do a VTS the other night but if you want to put one together for us (with copies of shop manual pages that corroborate the data), then please do!
If we can get this done this week, we still have a small window to get it in the June Fastrack. July for sure.
Chuck it has been hard on our end to find accurate stock hp numbers for the car for the requested years, and to determine if the hp figures we do have are gross or net.
Anything you can give us in that regard will help move this along.
Thanks.
Jeff
Jeff, Ed has a early 911S and is a storehouse of knowledge about them. Been futzing with them for 20 years, at least.
Well I've been futzing with them since 1973 and the max HP for the 2.0 Liter, 2.2Liter or 2.4 Liter 911S was 185 at the crank from the factory. The 69S 2.0 was the epitome with MFI, lightened flywheel & PP and higher compression. The later years used displacement to make up for different flywheel and reduced compression. All years came with factory headers and mechanical distributor.
1967S Carbs and smaller valves 170 HP
1969S - 73S MFI, 36mm intake ports in heads, MFI pump matched to S cams, various compression ratios, various displacements - same HP.
1973 CIS later in year.
Twenty five percent IT build improvement isn't doable with a half point compression bump and MFI enrichment. The headers are already there and the port matching from the factory is great. Mechanical advance timing is already optimum with factory setting.
Regards,
Chuck
We see numbers ranging from 190 to as high as 210 for the 73s on the web and other places....are we bad off?
can you tell me where you get those numbers, and are they gross or net?
Thanks Chuck.
We went over this on the con call moths ago, I thought. Those numbers are way high Jeff,
Bruce Andersons book has all the specs. Top power was 185. 165 for the E in 73. All the ratings are consistent back to the 60s, and it's crank, gross.
If you're going to class it at 185 x 1.25, don't even bother, it will be a dog.
With all due respect to both Jake and Chuck, I can find numbers as high as 210 published for the 2.4L 911S. And that one is in a real service manual published by Porsche. But it just says "SAE", not "SAE Net" or "SAE Gross". My guess is that it's gross, although by 1973, lots of manufacturers were using SAE Net.
The problem is that the process is based on the assumption that all manufacturers measure HP the same way, which is what the SAE Net standard is all about (designed to be comparable across manufacturers with the engine as installed in the car). In my opinion, it's very very risky to use anything other than an SAE Net number as the basis for the process.
On this car, pretty much anywhere you look you find a different published number, and none of them are clearly SAE Net, and pretty much nothing (including what both Chuck and Jake just posted) are attributable directly to Porsche.
This is why it's still tabled. Plus we don't have a VTS or shop manual pages that describe the other details needed for a spec line. Frankly I think we have the most accurate numbers yet (because they come from an actual Porsche manual), and they are higher than what either of you have posted. Again, unknown if they are SAE Net.
But if you want to help, stop just posting numbers and show us OFFICIAL numbers. Bruce Anderson's book, although a bible of sorts, mine is around here somewhere, isn't official, and it disagrees with a lot of other sources.
BTW, are you saying the 2.2L is 185 Jake, or the 2.4L? Both? And Chuck why does your post say both 170 and 185?
Copies of official documentation, please.
He's saying that the 1967S, which came with carbs made 170.
I don't know the early versions well, and I was working from my memory of Andersons listings, the bible, as you say. Chuck is saying that the 69 through 73S made 185, which is the number I'm familiar with for the 72 -73 2.4 engine.
OK, let me ask around, see what else I come up with.
Josh,
I'm on a trip right now but will copy some numbers from my Porsche spec books when I get home. I'm quoting from memory but Jake and I went around and around about these specs several years ago.
BTW the 210 HP you are referring to is for the '73 RS which is a 2.7 liter motor that Porsche did for their racing efforts.
Regards,
Chuck
Well, check it out when you get home. I think you're looking at DIN numbers, not SAE.Quote:
Originally Posted by callard
I'm looking at a photocopy right now.
It says for the 2.4 911S: 190 DIN/210 SAE
And for the 2.7 911RS: 210 DIN/230 SAE
For those of you spectating at home, take note: Include copies of official manufacturer's documentation when submitting a request to the ITAC. I don't care which ITAC, when, or with what members, leaving it to them to find source documentation is going to slow down your request a LOT.
K
That 210 is for the Carrera RS? That is what I thought too last night. It is not the S right?
I've seen 190 for the S though, not 185.
Listen guys, posting what everyone thinks they know from memory doesn't do anyone any good and doesn't get us any closer to publishing a spec line. And numbers from non-Porsche sources don't work as well as Porsche sources as far as I'm concerned. I'm attaching the document we have.Quote:
Originally Posted by JeffYoung
As I posted a couple of posts back, according to this document, it's 190 DIN (German spec) for the 2.4L 911S, but 210 SAE. The 2.7L is even more. I too have seen other numbers on various websites, but data source is unknown.
I have learned a lot about horsepower in the last few days. It's tough when you have cars that weren't specified with SAE Net (on which the process is based.)
DIN horsepower and SAE Net horsepower have the same testing protocols, just different underlying units. That means they can be converted. There are 1.0139 DIN hp for every SAE Net hp. In other words, according to this doc which shows the 2.4 911S at 190 DIN, that's 187 SAE Net.
Unless you've got something to refute that ...
And BTW, the 911SC is already in ITR, it had 180 hp (SAE Net).
And we still need a VTS and copies of the service manual pages for all of the other spec line info. One of the ITAC members is planning to put that together when he gets back from vacation, but Chuck, if you want to get that to us first, that would be good too.
That matches the info I've gotten overnight exactly.
Heres a factory manual scan for the 67S, which shows 160DIN.
http://forums.pelicanparts.com/uploa...1274920301.jpg
Josh, whatever happened to the "IT friendly" VTS sheet that we (the ITAC) were going to do? The VTS has, for those who have never seen one, some pretty arcane info requests. For example, it asks for the windshield layback angle. In IT, thats not a consideration.
Everybody thought it was a good idea....as I recall.
Josh,
I'm home again and you and I have the same spec book. So after the conversion, I agree that the 2.4 S is 187 HP SAE Net.
Where can I get a blank VTS sheet? I have the factory workshop manuals for the 2.4 and should be able to dig up the info and pages requested.
Regards,
Chuck
There is a link right at crbscca.com, or go to scca.com, to "Club Racing", then "Cars & Rules."
Chuck, any progress? Our meeting is a week away.Quote:
Originally Posted by callard