ideas to make more significant horsepower.

[topcarbon]

I have a 1977S with a 2.7l motor. I have dual 40mm carbs instead of the cis injection.




How can I increase the horsepower on my car where I can notice significant changes?

Will a 46mm or 50 mm carb system do the trick, or am I asking for trouble?

I don't want to change out the engine, and want to work withwhat I have.

Am I asking the impossible?

Looking for ideas.

THanks

[topcarbon]

Originally Posted by JastionRock

How can I increase the horsepower on my car where I can notice significant changes.Will a 46mm or 50 mm carb system do the trick, or am I asking for trouble..

so, is this the answer? Or are you playing with a novice 911 owner?

[Wil Ferch]

JastionRock:
This is the second post (see also S-hose thread).... I see where you simply copy and repeat something said in a previous response within that thread.....what's goin' on friend???

[IROC]

One idea that most people don't consider is leaving the engine alone (and that is a beautiful engine) and changing the gearing in the transmission. A 7:31 ring and pinion (or simply installing an entire gearbox from a '72 to '74 911 would effectively add horsepower for far less $$ than tearing into the engine.

[andyt11]

I assume JastionRock is not a real person, but a computer that posts randomly in an attempt to sell his Chinese wares.

Anyway, back to the OP's question.....

[Geronimo '74]

Originally Posted by Wil Ferch

JastionRock:
This is the second post (see also S-hose thread).... I see where you simply copy and repeat something said in a previous response within that thread.....what's goin' on friend???

SPAM, only want his hyperlinks posted

(reported to mods)

[BK911]

Originally Posted by IROC

One idea that most people don't consider is leaving the engine alone (and that is a beautiful engine) and changing the gearing in the transmission. A 7:31 ring and pinion (or simply installing an entire gearbox from a '72 to '74 911 would effectively add horsepower for far less $$ than tearing into the engine.

Or get a lower profile tire.
Or do both!

[winders]

Is it just me or do those wing nuts look out of place in there?

Scott

[Wil Ferch]

Or lose some weight on the car....or simply noodle on some serious suspension mods. Quickens the over-the-road sensations w/o doing engine mods.

[tobluforu]

Wing nuts or not, that is one hell of a clean engine and bay-looks like it's never driven.

[911pcars]

A large bank account helps. In fact, for significant power increase, the bank account is essential.

There is no easy solution without significant modifications. Increasing the engine displacement has been known to provide good results.

Sherwood

[Zeke]

You have the wrong pistons and cams in that engine to do much. Bigger carbs will get you nowhere. To work with what you have, put the CIS back on and get a turbo kit. There are a few reliable ones built by members here.

[Tom '74 911]

Originally Posted by topcarbon

How can I increase the horsepower on my car where I can notice significant changes?

Looking for ideas.

I have a '74 911. I am replacing the engine, which was a strong running 2.7L CIS motor, with a 3.6L engine for more HP. I did quite a bit of research and while I would have loved to stay with my 2.7L motor, there aren't really any "bolt on" type things you can do to significantly increase the HP. Even w/Carbs, you really need to do P&Cs and cams to realize a big difference. Once you start digging into an engine, especially a mag cased 2.7L, it's hard not to spend A LOT of money when your primary goal is more HP.

If you're looking for significant HP change, either swap a larger disp. engine in or expect to spend big $$ on upgrading the internals of your 2.7L.

Alternative courses could include gearing and weight loss - both of which would most likely be more affordable than engine work.

Nice looking engine bay BTW!

All the above is just my opinion of course - but I've been exactly where you are and asked the exact same questions!

Tom

[tobluforu]

^^^ What he said, sell that motor which looks like a piece of art, take money add to it, buy a 3.6 and put that in it.

[Trackrash]

As long as you don't have to worry about smog checks there are a couple of things that can be done for modest gains.
Back dating the exhaust to the pre-74 type system should help.
Those zenith carbs may need bigger venturis as well.
Otherwise pistons and cams will be needed to see any real gains in hp.

[James Brown]

3.6 should do it

[911pcars]

Originally Posted by James Brown

3.6 should do it

3.2 and 3.0 too.

If you DIY on your engine (RS P/C, more aggressive cams, head work, etc.), should be worth an extra 40-50 HP for <$6K. YMMV. Remove some extraneous weight and it should be pretty responsive.

Sherwood

[MysticLlama]

On my 3.0L, at the same time on mine I did a shortened gearbox (stock 1st, short 2,3,4,5), SSIs / Sport muffler, and slightly shorter tires all at the same time.

Made a big difference, and less expensive than the rebuild route probably.

The gearbox and tires will work just fine if I do the 3.6L later too, where messing with the current engine would be higher lost value.

And weight makes a huge diff too, though looking at that engine compartment, a lot of stuff is already lighter there (no sound pad, etc.), so the rest of the car may already be...

[topcarbon]

thanks for all the help. Ive driven the car one weekend, for the first time last weekend. Before, it sat waiting for me to return to the States. I will be driving it more. I have lots of suspension mods already, so maybe lightening will be the way to go.

Or, I could always leave it.

[JeremyD]

Sell the car and buy a turbo.

Or change the transmission for an earlier car with a 7.3 to on gearing. I can't imagine a 2.7 with the later 8.31...