150MPH Speedo

[Janusz1]

I have 1978 930 with original 150MPH speedo. The car is modified with lots of power. After the speedo is maxed car still accelerates strongly and I wonder if the speedo can be damaged from it.

Also, is this speedometer mechanical or electronic?

[356911930]

I do not think that the 150mph speedometer is original. All 930s, to my knowledge, had 180 mph speedometers. They are all electronic.

Speeds over 150mph on a 150mph speedometer damage? Not sure on that issue. Call North Hollywood Speedometer.

Rahl

[porche]

Originally Posted by 356911930

I do not think that the 150mph speedometer is original. All 930s, to my knowledge, had 180 mph speedometers. They are all electronic.
Speeds over 150mph on a 150mph speedometer damage? Not sure on that issue. Call North Hollywood Speedometer.
Rahl

The North American Build 1978 and Early North American Build 1979 930's all had 150 MPH electric speedometers. It is interesting that the 3.0 930's had higher MPH speedometers, but the reduction to 150 may likely have been a way for Porsche to tone down the 930's performance in the eyes of the Department of Transportation in the late '70's.

Note; 1979 Model Year North American 1980 Build 930's started using 85 MPH speedometers. All other 1980 Model Year North American Porsche cars (911, 924. 928) also received the 85 MPH style speedometer. There were big differences between listed and actual top speed on these.

Never heard of an issue with either the 150 or 85 speedos but it would be interesting to hear what someone like NH would have to say.
.

[Janusz1]

Speedo in my car is original.

I've checked with GPS and 100 mph indicated gives me true speed of exactly 150 km/h (I am Canadian and understand metric units better) which is 93.2 mph. I use 275/40/17 tires with the diameter of 25.4 as compared to stock tire with diameter of 24.9.

Still wondering if driving at higher speed then speedo can handle will affect the gauge in any way; anybody who knows please chime in.

But, tripmeters are mechanical are they not? I am getting confused here...

[JFairman]

No, it won't hurt anything. The older mechanical speedo's won't be hurt either. Take one apart sometime and you'll see how they work.

[TheRedSlantnose]

The only actual issue with your speedometer going past 150 mph is not being able to read the speed accurately. It'll go past 150 even with a stock '78 930 since the 3.3 models without the 330 hp option have a top speed of about 160 mph. You can have a look at North Hollywood Speedometers so they can possibly modify yours to read up to a higher speed. The highest I've seen their speedometers go up to is 220 mph, so you got quite a few options if you decide to send yours to them.

All 930 speedometers read up to 150 or 170, but there is also the rare occurrence of a 930 with an 85 mph speedometer, in which case it would have to pass the maximum reading.

Out of curiosity, exactly how much power is your 930 making?

[Hams930T]

My '86 reads 160.

[TheRedSlantnose]

Originally Posted by Hams930T

My '86 reads 160.

The last mark below the 160 is the 170 mark. It's just the numbers that only go up to 160.

[356911930]

1976 930 speedometers show 180mph and I think the 1977 930 does too.

Rahl

[Janusz1]

Originally Posted by TheRedSlantnose

Out of curiosity, exactly how much power is your 930 making?

I don't know, but more then enough. Here is the list of mechanical mods:

•Complete Engine Rebuild- Matching #’s case
•3.4 Liter RUF Mahle P&C’s 7.5-1 Compression
•ARP Head Studs
•AASCO High Performance Valve job with springs and titanium retainers
•Ollies Machine Shop- Balance, rebuild rods, Crankshaft magnafluxed polished and heat treated
•911SC Cams
•Kokeln Ball Bearing Turbo
•Kokeln Intercooler
•Tial 46mm wastegate (1 bar)
•Nology Wires
•B&B Polished headers w/heat
•B&B Polished Exhaust
•Fuel Distributor recurved
•Rennline Polished Alternator Strap
•New ERP copper oil cooler lines and thermostat
•New engine chains and rails, CDI box, Fuel Accumulator
•Billet Valve Covers and aluminum sump plate
•WEVO Engine Mounts

Transmission-
•915 5-speed conversion
•Full Transmission Rebuild
•RSR 6lb lightweight flywheel
•RSR Carbon Kevlar Clutch
•Limited Slip
•WEVO Shifter
•WEVO transmission mounts

Suspension-
•Smart racing 23mm front and rear swaybars with reinforced mounts
•Hollow 22mm front and 29mm rear torsion bars
•ERP Bump Steer Kit
•Custom Valved Bilsteins w/reinforced spindles with front camber adjustability
•Rear mono-ball bushings
•New plastic front, rear and spring plate bushings
•Hawk Performance Brake pads

Back to speedo.
If it is electronic then the odometer part, with total miles driven and daytrip meter must be mechanical since there are rotating drums with digits. So, does it mean that a speed gauge is electric and the trip/mileage meter is mechanical?

Never mind, just an idle curiosity.

[onboost]

Originally Posted by porche

The North American Build 1978 and Early North American Build 1979 930's all had 150 MPH electric speedometers. Never heard of an issue with either the 150 or 85 speedos but it would be interesting to hear what someone like NH would have to say.

That would be correct, my early 78 had 150mph, but was changed to an Andial 180mph by NH speedo service during one of its visits prior to my ownership

Originally Posted by Janusz1

I don't know, but more then enough. Here is the list of mechanical mods:

•Complete Engine Rebuild- Matching #’s case
•3.4 Liter RUF Mahle P&C’s 7.5-1 Compression
•ARP Head Studs
•AASCO High Performance Valve job with springs and titanium retainers
•Ollies Machine Shop- Balance, rebuild rods, Crankshaft magnafluxed polished and heat treated
•911SC Cams
•Kokeln Ball Bearing Turbo
•Kokeln Intercooler
•Tial 46mm wastegate (1 bar)
•Nology Wires
•B&B Polished headers w/heat
•B&B Polished Exhaust
•Fuel Distributor recurved
•Rennline Polished Alternator Strap
•New ERP copper oil cooler lines and thermostat
•New engine chains and rails, CDI box, Fuel Accumulator
•Billet Valve Covers and aluminum sump plate
•WEVO Engine Mounts

Transmission-
•915 5-speed conversion
•Full Transmission Rebuild
•RSR 6lb lightweight flywheel
•RSR Carbon Kevlar Clutch
•Limited Slip
•WEVO Shifter
•WEVO transmission mounts

Suspension-
•Smart racing 23mm front and rear swaybars with reinforced mounts
•Hollow 22mm front and 29mm rear torsion bars
•ERP Bump Steer Kit
•Custom Valved Bilsteins w/reinforced spindles with front camber adjustability
•Rear mono-ball bushings
•New plastic front, rear and spring plate bushings
•Hawk Performance Brake pads

Is your car a factory 930, or 930 conversion?

I only ask because of the trans details...

"•915 5-speed conversion"?? Not a normal conversion on an actual 930.

Would typically see a G50 or Ruf 5spd conversion as opposed to going to a 915, especially in a 78 or later and with the additional power modifications you have.

Sounds like you have some goodies on that car and it should be making good power Mid 400s?

Any pics to share?

[shlobeck]

Hmm a few discrepancies on stock 930 speedos: Early '76 speedos were 180mph and changed to 150mph in the middle of the production year. '77-'79 are all 150 mph. Late '79s, vin 800 and higher, usually corresponds to a built date of August '79 or later and will have a 85mph speedos. 86-89 930 are equipped with 160mph speedos. Different years have different speedos.

[quattrorunner]

About that 915.....how long has it been run with that power?

[Janusz1]

Originally Posted by onboost

Is your car a factory 930, or 930 conversion?

I only ask because of the trans details...

"•915 5-speed conversion"?? Not a normal conversion on an actual 930.

Would typically see a G50 or Ruf 5spd conversion as opposed to going to a 915, especially in a 78 or later and with the additional power modifications you have.

Sounds like you have some goodies on that car and it should be making good power Mid 400s?

Any pics to share?

My car is a real 930 and also significant since it is the very last made for 1978; VIN # 9308800461.

I bought it in 2012 and it was with original 27xxx miles with almost zero miles after engine rebuild/ all mods done. I was breaking in the engine.

The PO installed 1979 SC 915 transmission with LSD which he bought from California Motorsports as rebuilt but it was junk and the only thing not perfect on the car. I had it properly rebuilt and strengthened with billet side plate, larger bearings etc. The final drive 8:31 and 5th gear 38/30. It cost me a lot and also I overpaid for the whole car at the time but now, in the middle of this insane price increases, all seems good.

I've driven almost 13k miles since then and everything works perfectly and the whole car seems to continue to improve. I am never impressed with and never do drag races/take offs so I am confident that this tranny will last for a while.

Even if not, this 5 speed is perfect for this car and transforms it from fast cruiser into almost a racer.

The car drives and performs way better then stock and the suspension is set in a way to constantly impress and amaze. I won race with two 1000cc sportsbikes on a local fast mountain road.

[onboost]

Originally Posted by Janusz1

My car is a real 930 and also significant since it is the very last made for 1978; VIN # 9308800461.

I bought it in 2012 and it was with original 27xxx miles with almost zero miles after engine rebuild/ all mods done. I was breaking in the engine.

The PO installed 1979 SC 915 transmission with LSD which he bought from California Motorsports as rebuilt but it was junk and the only thing not perfect on the car. I had it properly rebuilt and strengthened with billet side plate, larger bearings etc. The final drive 8:31 and 5th gear 38/30. for a while.

Even if not, this 5 speed is perfect for this car and transforms it from fast cruiser into almost a racer.

Janusz1 .. yes I remember you/your car now.. I believe we spoke on another thread somewhere with regard to you having the last 78 produced, and mine being as close to the 1st one as possible at #2 produced. Still have heard anything of where #1 is currently, or if its still around at all.

I think your car looks great, and although many of the purist may cringe about the modifications, with those specs, its nice to hear that you're enjoying it and putting in some miles. Sounds like the SC box is pretty well built. Did you change any of the gearing at all?