3.2 vs 3.6 question
 

Wondering what the approximate horsepower gain would be on a 3.2 if the stock catalytic converter is removed.
There's no place near me that I can get my 3.2 on a machine to measure its' HP.

Second, would a 1988 3.2 with Fabspeed exhaust, no catalytic converter, and Steve Wong chip, out accelerate a stock 964 with 3.6?
Just opinions...

It depends. Weight would be key in this situation. I have the same basic exhaust and chip setup in my '84 and it's been lightened down to 2500 pounds, so it has noticeably better acceleration than a stock Carrera (I've driven quite a few stock cars). Considering that I am (barely) able to match pace with my friend's 2000 996 Cabriolet up to about 100ish, I'd say that the setup you mention should at least match a stock 964, which is a pretty heavy car compared to the earlier cars. A stock 964 puts out 250 HP, but your chipped, no-catalyst, aftermarket muffler Carrera should put out in the vicinity of 235 or so. Considering the weight difference, at the very least I'd say you'd be even with a stock 964.

I have just finished modifying my 1986 and Im very pleased with the outcome.

My car is a european spec car which is already 236 BHP. I dont have a clue what kind of BHP Ive got now. All I can say I can feel the it. Revs better across the range and now revs to 6800 RPM. Now when I gun it from the lights etc, it wheel spins in second which, it never did before. Wow!

Here are the mods are did:

Steve Wong chip, cut the face of my air-box cover and fitted a BMC Race filter, changed the spark plugs to NGK Race plugs and SSI stainless steel heat exchangers with a M&K 2 into 1 Muffler. The car is also a little lighter. This in my opinion is the best bang for your dollar, without messing with the motor.

All the best, Rob.

you might gain 15HP by mods to the engine, including a chip, if setup for your exhaust config. By losing 300 lbs, you would be also gaining power to weight ratio. With your mods this might look like 225HP / 2500 lbs ~ 1 / 11.1 . This would feel the same as 252HP / 2800 ~ 1 / 11.1, which would cost about $12k if you added a 964 or 993 engine to your Carrera.

Stock 964 is 250 / 2900 lbs. ~ 1 / 11.6
At those very close power to weight ratios, gearing, tires, etc. would also matter. Lose some weight on the car first. Those mods are free. From there, you can make the other changes.

The 964 has a more capable suspension, better brakes and if stripped out would out perform the earlier car. But, there is always a quicker car.

Doug

I have never driving a 964 on the track, let a lone one that's prepped for the track. Is a well prepped early chassis really giving up anything to a 964 prepped chassis? Assume the early chassis has coil overs all around with double adjustable shocks with appropriate spring rates.

I have a friend with a $10,000 Moton set up on his 964. I've never actually had my car setup to the point that I'd considered challenging his pace at the tracj....but $10,000 would be me a hell of a suspension setup for my early chassis.

Just to throw this out - IIRC acceleration is more a function of torque than horsepower and a 3.6 (by virtue of it's larger displacement) has more torque than a 3.2 will generally have regardless of the hp numbers. In other words, I don't think hp numbers tell the whole story.

If you want to out-accelerate a 3.6, I would imagine it would be cheaper to re-gear the transmission more favorably than to try to add torque to the 3.2 engine.

F=MA, where F is related to applied torque to the ground and M=Mass and A = accelleration. So you are correct, but if revs and gearing were not a factor HP would be useless and torque would rule.

However, if you can use a greater torque multiplier for a given speed (by combining lower gearing and an engine optimized for higher revs) then higher HP with higher revving engines rule. Though extremely expensive, F1 engines are an example with their revs to 20k rpm-ish. Ever seen their torque numbers?

But living in a comparably modest budget, we have to balance streetability, torque across a wider (more useable) rpm band, and HP.

Bottom line, as has been pointed out, the cheapest way to have a quicker car is to reduce weight. $800 to $1k for the proposed bypase and muffler is worth about 5 to 10 HP.

Doug

My thoughts exactly. I'm thinking the torque of the 3.6 would outperform a 3.2 in most situations. For example, low rpm situations where you can't get the engine high in the powerband where they like to be.

In a straight drag race, i'd give the nod to his 3.2 if he's willing to do more than a cat bypass. Because a 3.2 is fairly easy to make lighter. Plus, I bet the curb weight of a 964 is over 3000 lbs with a driver. My 911 was put on a pretty good diet (no A/C, no cat., no audio system) before I did the fiberglass, and it still weighed 2900 lbs with me in it. Now it weighs 2650 w/me and 5/8 tank of gas. Now it's just under 2500 w/out me in it. Have no clue how fast it is acceleration-wise.

Agreed the bypass is not a huge bang for the buck. But it can be done cheap. Get a used steel bypass pipe and a Dynomax/Flowmaster/Magnaflow 1-in, single or dual-out and you can spend only around $200-$300 bucks tops and end up with the same results. Or you could be a complete nut and do no muffler. Our friend Elbow does this and it's ridiculously loud/obnoxious and hilarious. :D

"I have never driving a 964 on the track..."

- but poster has not stated his intended use -- is it for track?

Thanks for all the replies guys! You sure know what you're talking about!
My question was meant for road driving, and not track.
I guess I'll have to actually drive my buddies 964 to see if there is a difference between our cars. I just figured his would be a tad slower due to increased weight. Also...I did calculate power to weight ratio, but didn't figure torque into the equation.


Happy 911'ing!

Here's my take from owning both.

I had a 964 Targa that was basically stock

I have a 1987 Carrera that is anything but stock.

I think that if you remove a ton of weight from a 3.2 carrera that you could make it an interesting race - with that said - the 964 Targa that I had was quick. The 3.6 has so much more usable torque I really think it would be tough to beat.

Just my opinion.