How fast will your SC go???

rdane · rdane's Garage

Who can give me actual numbers from their *stock* SC 1978/79 (any SC would be good but I think the 80/83 cars are a bit faster IIRC) on MPH and each gear at redline?

The 1980 C&D review gave 37 mph in 1st, 65/2nd, 94/3rd, 118/4th all at 6300rpm and 130mph @ 5650rpm.

I just had a tune up and oil change on my '79. Here is what I got this morning @ 6300rpm 37, 66, 97, 122, and then hit 132 @ around 5600 but I was a little busy and running out of road to push it further. But at least the car was still pulling now and willing to give me more when I shut down. Before the tune up 130mph only came in a tailwind and a 5 mile straight

129 was the actual top end and it would not pull 5600rpm.

Adding SSIs and a Danske d/t sport muffler next. Any feed back on what this will do over all.

Eric Mckenna · 12-21-2002, 04:10 PM

The speeds you listed for your run this afternoon sound just about right.. I do not know about fellas taking (stock) SC's and running 145 and so on.. sound like they need to caliberate the SPEEDO! cuz thats FAST for a SC.. I think your about right on with your speeds.

Eric

emcon5 · emcon5's Garage

Here are the charts from the manual:

The top speed is limited by drag/power rather than gearing. The gearing is good for ~150 at rev limiter in 5th, but I doubt you would get there.

Neither my speedo nor my tach are accurate.

Tom

rdane · rdane's Garage

Thanks Eric. I read another thread where most were saying 130 was way to light for an SC. So I just had to check for myself. I figure I'll be doing good to top 140 as is and suspect it won't make it.

Thanks Tom for the charts. Any one done 140 or better in their stock SC??

RarlyL8 · RarlyL8's Garage

My '78 had SSIs, rest stock sans normal upgrades.
This car, in widebody form, ran 140mph every time I took it out. The speedo was dead nuts on due to the tire hieght. I had both the speedo and the tach calibrated.

My gearing must not be the same as yours. Do you have a 7:31 ratio? Mine is the stock 8:31. This gave 44mph @ 6000rpm in first. The car had no problem pulling a tick over 140mph @ 6300 rpm in fifth gear.

rdane · rdane's Garage

Best I have done in 1st is 40mph wound tight at 63/6400rpm. Just shy of that is a little more honest I think for my car.

My gearing is the stock 8:31 via my original owners manual. Sounds like the SSIs aren't hurting you. I'll know the difference soon on that point I guess. Love to hear what anyone else is getting. Looks like there is hope for 140+. Thanks guys!

fred cook · fred cook's Garage

Not sure about the intermediate gears, but about 110 in 4th gear
just slightly below redline. Just checked the spedo/odometer. The spedo seems to be right on and the odo is about 1/10 of a mile fast in 10 miles.

'80 911SC coupe
Fred Cook

Superman · 12-21-2002, 07:25 PM

There has never been a question in my mind that my car will achieve its mathematical top speed. It will not run out of power now, nor would it have before I installed the cams. At 125 mph, it still pulls strong, always has. My rev limiter kicks in at an indicated 7000 rpm, so I'm guessing 150 mph is thinkable. I'm certain of being able to get into the 140's. I've heard 137 for top speed on these things and I've heard 145. I've heard people report running out of power in an SC, but I think folks whose engines are tuned properly seem to have no trouble.

N11Porsche · N11Porsche's Garage

I had my 1979 SC up to 130 and it was still pulling. I ran out of clear freeway and was way out of my comfort zone. The car felt very secure at that speed. I've read that the Porsche speedo's read, very much, on the high side

Moses · 12-21-2002, 09:04 PM

Right now my SC will not go very fast. In fact I don't believe there is a slower SC anywhere in the world.

That should change very shortly.

Kevin Stewart · 12-21-2002, 09:20 PM

Moses our cars have the same rear view, nota in the compartment, but boy are they gonna get something, Kevin
sc trying to be a 964

rdane · rdane's Garage

Easy enough to check the speedos with a stopwatch.
120mph is a mile in 30 sec

US '78 and '79 SCs have 8.5:1 compression, '80s 9.3:1, late Euro cars are doing 9.8:1 compression and a added 24 hp. That is gonna make a difference 130+ mph.

But no question the state of tune does make a big difference. Ceratainly did in my car. Finding a place to run a SC out, even on the track (you need a couple miles of straight with my car) is hard to do.

RazorRacer · 12-22-2002, 06:55 AM

I haven't had the chance to run higher than 120mph, but I do notice a vibration above 80mph. Is this normal? Is an increase in vibration normal at higher speeds? It feels like wheel balance vibration. So do you notice any increase in vibration at the steering wheel as you go faster than 80, 100, 120 mph?

RarlyL8 · RarlyL8's Garage

Rock solid ride. No vibration ever.

One good point - my engine was a Euro. There is always argument of how much power that little word added. I can tell you that every mechanic that drove the car commented on how strong it ran. She now has a new home in the bay of a '77 911 in New York.

rdane · rdane's Garage

"Is an increase in vibration normal at higher speeds?"

Nope....as the man said, "rock solid"...enough so that it begs to be driven faster

plain fan · 12-22-2002, 08:41 AM

Well when my 78 wasn't in pieces (restoration time baby!) it pulled very hard to redline. I had it over 130 mph and it was still pulling, my dad had it over 140 and it was still pulling so....

Of course at 70 things start to get smooth, over 80 everything get evens out and over 90 the wind noise dies down, the road becomes smoother, bumps disappear and I swear the car smiles....

sammyg2 · 12-22-2002, 08:48 AM

I figure mine will do 140, unless I go off track onto the grass, then it will speed up to 150

Jbabic · Jbabic's Garage

Highway patrol man here....I am giving all of you tickets!!!!!

ok, kidding, but could you imagine if they could!!!

beepbeep · 02:05 PM

Opps...wasn't me! It's fake!

That's roughly...errr...'lemme dig out my aicraft engine books...178mph...and electrical supercharger was running all the way ;-)

(If you wonder if car was taking a bend or something the answer is no...pic is taken after they changed front strut, so steering wheel was out of whack)

P.S. I don't recomend doing this...front end feels light and steering is very nervous indeed.

ErVikingo · 03-12-2003, 01:53 PM

I got clocked (and ticketed by Florida's finest) at 156 with the 3.2. I could pull 6300 with the 3.0. According to a friend who drives a Henessey Viper, he stayed with me up to approx 145 and then pulled away.

I don't really trust neither Dodge's speedos or Police radar but, there you have my 2 cents (actually it was much more and a visit to the county court....)