Revisiting Horspower gains for a '79 911 sc

[FinallyGotOne]

I've searched a lot of the forum's previous posts and have found the follwing seems to apply.

The 0-60 speed is stock at 6.0 seconds.
Lightening the car as much as possible will DEFINITELY help the quickness. even 100 pounds lighter makes a .01 second difference 0-60? is this correct?

Does having 17 inch wheels help in the 0-60 times?

and review the following summarized info and discuss please.

1) You cannot chip a 79 to help out here with a Swoog or anything
2) It has no O2 sensors
3) Changing to a SSI will NOT help quickness at lower end, only mid range.
4) Changing the gearing WILL SIGNIFICANTLY help quickness and lower end the most-but you drop top end to 125MPH and get worse Fuel economy
5) Changing to a test pipe will really not help.
6) Gutting a Cat Converter is useless
7) Changing to different mufflers is a waste since the OEM muffler is a great piece of quality and equipment
8) Deleting the air pump and belt will help quickness
9) 3.2 Pistons make a big difference in HP
10) Shifting beyond about 5500 RPM'S is USELESS as there is no more power gained
11) Dropping weight on the bumpers and whale tails to go fiberglas helps the quickness as it lightens the car.

So far with my 911 we have done the following
17 inch wheels
removed and replaced front bumper and bump shocks with fiberglas
rear bumper and bump shocks to fiberglas
Removed air pump
replaced whale tail with fiberglas
Has short shift kit
Removed rockers replaced with fiberglas

For quicker 0-60 time I am now debating what is best option to do.

For those of you with an O2 sensor, I've heard you can pull the plug to increase power? worse fuel economy tho

[quattrorunner]

You don't have O2 as you stated already. I doubt unpluging o2 will help, probably hurt.
Add turbo and see many things improve.

[dd74]

First, you should know any 911s strong suit isn't 0-60 times. I'd be afraid of damaging the transmission if too much emphasis is put on fast take offs to 60. Here's why:

My suggestion is to get hold of a 7.31 r/p and put that in the transmission. It'll effectively lower the gears, and make your SC very quick in acceleration. Also, get a high-end lwt. Sachs clutch, which will give additional snap. But beware, in lieu of not building a custom gearbox, your transmission with a 7.31 r/p will not be able to handle a lot of 0-60 abuse. The car will be faster, but the transmission more fragile.

Continue to lighten as much as possible. I've seen some SCs which still had all stock body panels come in under 2300 pounds. With all the f/g you're putting on the car, you're probably there already.

Exhaust/engine mods I have found to be a waste of time and money, unless you go all out and tear apart your engine. Even then, the money spent may not equal the increase in power that you'll receive. Of course if you find a good deal on a newly-built motor or a good used motor, you should jump on it. Otherwise, I'd avoid messing with the engine and exhaust and run what the good Doctor gave you.

With gearbox and weight work alone, you'll have a very fast car that will also continue to pass smog.

Good luck.

[Won]

SSIs may or may not improve lower end but you don't just drag race under 2k RPM, do you? In other words, any improvement in the system will help, to a certain degree (as dd74 pointed out, may not be the best bang-for-the-buck).

Shifting above 5500RPM means you'll be right around the power peak when you go into the next gear, I imagine that helps too.

A lighter aftermarket muffler will, well, make your car lighter.

A test pipe or a gutted cat is better than a clogged cat.

The diameter of the wheel is irrelevant; the overall diameter including the tire wall height will determine the effect on the final gearing. However, a 17" wheel with shortest sidewall tire will still be taller than a 15" wheel with equally short tire.

[FinallyGotOne]

Thanks ! Well I just went thru a tranny overhaul and don't neccessarrily want a more fragile tranny, I think I'll keep lightening it if I can. Though it is not a track car. I would like to take it to a track. Maybe with the PCA I can go track it sometime. A turbo may be a cool add on- That will get me moving, but I wonder how much costs in the end it will be, and what amount of work it will be. The car looks a bit like a 964 RSR now (I think that was what I was told) so I want to make sure the performance is atleast pretty good. I'm not one to drive around in a car that just looks aggressive, i want it to be aggressive.

And i dpon't have to worry about emissions in Colorado as it is a Collector vehicle. I just pay to register every 5 years!

[Drago]

Take it to the track and you'll soon forget about having the quickest car on the street from stop light to stop light.

If the feeling persists I would recommend a different car as you will inevitably start breaking things that are not cheap to fix.

[joetiii]

Originally posted by dd74
First, you should know any 911s strong suit isn't 0-60 times. I'd be afraid of damaging the transmission if too much emphasis is put on fast take offs to 60. Here's why:

My suggestion is to get hold of a 7.31 r/p and put that in the transmission. It'll effectively lower the gears, and make your SC very quick in acceleration. Also, get a high-end lwt. Sachs clutch, which will give additional snap. But beware, in lieu of not building a custom gearbox, your transmission with a 7.31 r/p will not be able to handle a lot of 0-60 abuse. The car will be faster, but the transmission more fragile.

Continue to lighten as much as possible. I've seen some SCs which still had all stock body panels come in under 2300 pounds. With all the f/g you're putting on the car, you're probably there already.

Exhaust/engine mods I have found to be a waste of time and money, unless you go all out and tear apart your engine. Even then, the money spent may not equal the increase in power that you'll receive. Of course if you find a good deal on a newly-built motor or a good used motor, you should jump on it. Otherwise, I'd avoid messing with the engine and exhaust and run what the good Doctor gave you.

With gearbox and weight work alone, you'll have a very fast car that will also continue to pass smog.

Good luck.

.02+

I lightened my rear end with an M&K muffler. That would be about the only other add on I could recommend w/o getting into engine work. Another trick is to reduce your overall tire diameter which has the similar affect as the 7.3:1 R&P, though you appear to be heading in the other direction w 17s.

I've got 15s w/50 series tires and an overall 23.1 tire diameter. Add a 901 trans w/7.3:1 ratio and a 2300 lb car just scoots. I'm gentle w/ first gear and don't care much for 0-60 times. But 2nd through 5th pulls strong all the way up to 125 MPH. And that my friend is what puts a smile on my face.

[JP911]

Trying to find out how fast you can get your 911 to hit 60 from a stop is a great way to trash the transmission (no matter the R&P). Take your car on a track and your concerns about 0-60 will go out the window. You will, however, become obsessed with more track time, and this will lead to suspension modifications, lightening the car, roll bar, carbs, headers, sticky tires, etc. It's a slippery slope, but damn it's a fun ride!