MUSSBERGER

Sean-
You have to be really push the brake limits to do that. Hello bus stop!

When will spring be here?

Ed Hughes

I don't think he was talking about top speeds at a track. Street top end is what he's after, and it came about by him wondering why it had an 85mph speedo.

I've never gone more than 130 on a track either, and that was coming out of #4 @ TMS on the ALMS course. But, while I don't make a habit of it, I've exceeded that speed on the highway a time or two.

Sean F

I guess my point is I don't see how anyone is getting a top speed on the street higher than what I've seen on the track. Without sounding like an @ss, there isn't a better prepped stock SC out there than mine and in ideal conditions with a hoosiers and a light car with no exhaust, I can't break 130.

Jessterlh

Ahh but what about an SC with a 3.2 like mine?

DARISC

At the risk of pushing this thread in a Smothers brothersian "OH YEAH?! direction, and having no idea how old you are ( not at all meant as a sarcastic comment ), if you talk to SC guys who, "back in the day" were the equivalent of today's Rennlisters/Pelicanites, you'll find that photos of one's speedo registering 145 mph (before Photoshop) were the thing to have for bragging rights. And, if you happen to see one of those old photos where knuckles on steering wheel are at all visible they will probably be quite white (and I ain't talkin' racial here ) according to several guys who laughingly reflected on their younger days. To deny that these cars, stock, can get a bit floaty in the front end at that speed is a losing arguement.

Granted, an indicated 145 isn't an actual 145, but the accuracy of the Porsche speedo isn't so far off as to be an actual 130.

Of course, all the above is anecdotal (as is your input) without official timing slips.

However, Porsche has always, if I'm correct, been a bit conservative in their advertising claims and what they published in their owner's manuals was, as I posted:

From the factory manual that came with my '82 SC RoW (204 hp):
Max. speed = 235 km/h (146 m/h).

And, OH YEAH? Well Uncle Ferdy liked MY car best!

autobonrun

Sean, have you confirmed your throttle linkage in the engine compartment is full open when the pedal is to the floor? Mine had about 1/4" adjustment left. After I corrected this problem, the top end improved. Without doubting your figures, I can only speak for myself. I've shifted out of 4th to 5th gear around 120mph and it continued to pull well past 130mph, and I was drafting no one. The rpms and speeds fairly well tracked the graph in the owners manual. Again not doubting your numbers but my car was registering about 145 full out in 5th on a long open stretch of interstate. In checking my speedo against radar, its typically been registering high by about 3 mph and this figure has been fairly consistent whether I'm registering 30mph or 60 mph which makes me think the error is a percent of full scale rather than a percent of reading. One thing to consider is no track that I know of has a straight longer than a 5 mile stretch of interstate . I'm curious were you redlined in 5th when you were at 130 mph or did you just run out of straight? I've also been speed limited on a track because I just flat ran out of space before the next curve.

Lastly, the weight of the car or the Hoosiers don't really affect the top end speed as I'm sure you know. Top end is about HP and Cd, drag coefficient; acceleration is a function of weight and torque. The hoosiers will help with initial acceleration out of the hole and grip through the curves but I don't think loss of grip will be a problem once you're moving 100mph+. I should be so lucky to have enough HP to break my tires loose at this speed.

flatsics

Sean,
Most tracks do not have long enough straights to get up to top speed. With my SC at Road America I hit around 135-137 mph and it is still accelerating when I have to brake It is very easy to top out a car outside of the track if you have a nice clear stretch of road. Where i live, after the fields are cleared and visibility is great there are many country roads where reaching top speed is fairly easy.

Sean F

I guess we'll have to agree to disagree, especially since my car has been dyno'd and I know I'm well above stock (170 at the wheels). Doug, I don't know about you, but I redline at WG coming into the bustop. I brush the brakes for T11 then trailbrake the cr@p out of T1 but still take it North of 70mph and I'm flat footed from prior to the apex of T1 to the 300 brake marker for the bustop.

My point about the Hoosiers and weight is that I will get to top speed faster than a heavier stock car on street tires. And yes they help in the turns which is why I can get a top speed on the back straight and don't need 10 miles of highway.

MUSSBERGER

Sean

Thats textbook for the Glen in an SC. I finally got it on my last two days there.

Ed Hughes

Well, we probably need to start talking about gears and such. Somewhere along the way, something may have been changed in your tranny? Having said that, I don't know if SC's had lower 5th gears for some reason from the factory than the Carreras.

I'm not trying to one-up anyone, but my weight isn't far off from yours, I was at about 2700 too with my lead rollbar, and I was dynoing at 205-207 @ the wheels. So a bit higher power to weight ratio, but not immensely. My guess is it's all in the gearing. I can 'easily' (with a long straight) push high 140's; 130 is a piece of cake, so to speak. Your car shouldn't struggle hitting 130, unless it's geared lower, IMO.

flatsixnut

Are you dreaming? A stock 944 Turbo S can in no way come even close to 180mph. To say you hit 180 at the top of 4th has BS written all over it. Yes I like 944's, and yes I know they have a higher top speed than stock 911's....but to say you can hit 180 is pretty funny. The 944 Turbo S's are rated somewhere around 160.....just being fair here.


In all honesty, I am too afraid to find out what the top speed of my 911 is. It gets floaty enough at 130mph.

autobonrun

I agree, a gear change by a PO would be the next thing I'd look at. Sean, how well does your 1st,2nd,3rd, and 4th gear speeds align to the factory quoted 30,60,90,120 mph figures? I know on my C4S, my top end is down from the stock 993 because my 3rd, 4th, and 5th gears have been swapped out, and what was 5th gear is now my 6th. Since you have a rebuilt race engine, there's a very good chance that they did not match the factory gear ratios; which would explain the top end differences. In fact, you probably have a better shifting car if they did not return to the stock ratios.

333pg333

No I didn't say that they hitting 180mph in 4th, I said that at 135mph where the SC is topping out that is about where we are in 4th and then change into top gear on to a variety of top speeds depending on mods and the country of origin. I've read road tests back in the day from UK and European mags that showed them hitting over the 170mph figure. Of course we have to also allow for speedo error and that's in all our cars. The stock 250hp one will hit into the 170's given the right road. Modified ones such as DFASTESTS have hit over 190mph and that's with a stock gearbox. He is looking at changing his final drive to increase his top end to over 200mph. Don't forget these cars are still a very slippery shape and have a low CD factor.
I am still a fan of the old air cooled 911's too and would love to have one some time in the future. Very involving cars.

Jay Laifman

Anyone with an idea what 911 came with a 180 mph speedo? I have one, but don't know what it's from.

racer

That straight is all uphill too! My SC hit an indicated 200-210km (125-130) at WG too. Fastest I saw at the track was Pocono.. Running clockwise.. thru the bowl and down the front straight.. saw just over 220km (137).. 15" rims.. 225/50 rears. stock gears.