Relative Peformance of a '77 911S with a 3.2

[JTO]

The local PCA chapter got together for a spring drive through the local country side. Some of you may know that I have had some running issues that were traced back to a broken air box. My 911 is running really well now after completing some fuel system/ CIS maintenance.

A friend just finished putting a 3.2 Carrera motor in his 77 911S. He has done a few things to lighten the car. The rest of the cars on the drive were SCs and one 993 C4S (beautiful Yellow coupe). So as we leave enhabited areas we pick up the pace. Impromptu drag races from stops up to red line in third (lets say around 90 MPH) the guy with the 3.2 in his 77 is shrinking in my mirror. At a stop he says, "your car is a rocket!" I said yea, its pretty light, port and polish, higher CR, blah blah. I asked him if he was rodding on his car, he said yes, redline shifts, etc. What gives? Seriously, I'm not looking to have the fastest car or have people tell me, "wow, you have a fast car". I want to know why this 3.2 powered '77 wasn't faster? Anybody have any insight? I have considered seriously getting an 87-89 Carrera for my daily driver, and letting the '75 go further toward the track car. If my car is faster than a Carrera (which I am assuming based on how this lighter-than-Carrera-'77 performed with the same motor as a Carrera), I don't think I'd like the performance trade-off.

Comments? Thanks,
Troy

[Jim Richards]

Ask Pelican marcesq. His car is fast.

[Jim Sims]

Given the relative weights and likely horsepower I will venture to guess that the cars are within a lb per horsepower of each other.
With this small of a difference, state of tune, gearing, and the driver's performance and actions can readily determine the difference. Absolute horsepower and torque aren't everything; it's also when you have it and how you use it. Also, other things being equal (tires, etc.), additional horsepower offsets weight only as long as you're going in a straight line. Cheers, Jim

[JTO]

I suppose your'e right Jim. I guess I'll have to drive a well-maintained Carrera and judge its performance.

Are 3.2s "peekier" engines than a massaged 2.7 (still with CIS)? This friend who did the 3.2 install says the motor doesn't really feel very strong until you break 4000 RPM.

Troy

[JeremyD]

Look on Steve Wong's website 911chips.com according to him (and from the several 3.2's I test drove) over 1/2 of them have poorly adjusted thottle linkages and the WOT switch does not engage.

[fintstone]

I agree with Jeremy. Must be something wrong with the 3.2. The only thing that makes Carrera's slow is their weight, gearing, and exhaust (cat). Most, if not all, would probably be fixed in a swap.

[JTO]

OK. So, you guys are saying that a properly maintained Carrera, with a function WOT switch, SSIs and a sport muffler, will have enough power to overcome the several hundred pound weight penalty? In addition, Steve W's chip only helps performance, right? That's encouraging. Thanks,
Troy

[ChrisBennet]

I wonder if he's getting full throttle? It's not too uncommon to see misadjusted throttle linkage keep the throttle from fully opening.
-Chris

[JeremyD]

A guy I had been communicating with over the Internet came to look at a car in my neighborhood - same model 1987 Cabriolet. He asked (ok begged) if he could drive my car to compare. After a short drive commented that he could not believe the difference in power and asked if I had a bigger engine in there...

[IROC]

I recently installed a nice 3.2 (245hp or so) into my '76 that used to have a fully decent 2.7 in it. No doubt the 3.2 is much quicker. There's no way my car with the 2.7 could come close to keeping up with my car with the 3.2.

Having said that, I still maintain that the 3.2 and the 2.7 are about equal below 4k rpms. Above 4k rpms, the 3.2 is a rocket. Pulls waaay harder than my 2.7 ever did.

Anyway, if you were able to best him with your 2.7 (even a nice 2.7) there was something wrong with his 3.2.

Mike

[vash]

maybe he was holding back?

[JTO]

Oh Cliff, stop bursting my bubble! Just kidding. Yea, maybe he was holding back. But, as I said on my original post, he claims he was shifting at red line, etc. Not important. What I really wanted to know was whether my car is faster than a stock Carrera. I was planning on buying one but found myself questioning that decision after seeing how a lighter car performed with that 3.2. I sounds like from the group that my friends 3.2 is not performing up to snuff. I'll talk to him about it today.
Thanks guys,
Troy

[JeremyD]

Originally posted by unfixed
maybe he was holding back?

Yeah, waiting for money to be put on the table...

[fintstone]

One might expect your car to be very close to a stock carrera, but not a 3.2 in a '77 that weighs about the same unless something is amiss.

[304065]

77 911S 2425#, 167HP = 14.52 lb/hp (engine weighs 386#)

84 Carrera 2756#, 200HP = 13.78 lb/hp (engine weighs 482#)

Hybrid: 2425# + 96# extra engine wt = 2521#, 200 HP 12.60 lb/hp

915 gearbox should have same R/P and gear ratios.

[JTO]

Finstone,
Yep. I agree. I sure like the sounds of Mike's (IROC) motor. That would be a nice powerplant in a Carrera or a mid-year car.

Troy

[fintstone]

John
I agree on your "lbs per hp" comparison, but add the additional hp that Troy gets from the SSI and GHL, the fact that his is a fresh engine, and of course the weight loss from removing the thermal reactors and the 40 lbs of rust that all of our midyear cars have lost (sorta like acid dipping)...evens it up a bit with the stock Carrera.

[IROC]

Originally posted by JTO
Finstone,
Yep. I agree. I sure like the sounds of Mike's (IROC) motor. That would be a nice powerplant in a Carrera or a mid-year car.

Troy

Yeah...works especially nice since my car only weighed about 2350lbs with the 2.7, so I'm figuring add 100 lbs or so for the 3.2 and that puts me up around 2450lbs and with a 245hp 3.2 (10.3:1 pistons, SSIs, etc.) then I should be around a 10:1 weight/hp ratio.

Mike

[JTO]

I think John put together a nice comparison. Finstone, I can't claim the rust induced weight reduction (car never had thermal reactors-OR car all its life) but I can claim 2650 lbs fully gased and me sitting in it on our certified truck scale at work (I weight 220 lb and 20 gallons of gas at circa 7 lb/gal = a dry car weight of 2290 lb). I removed the factory seats and put in SRDs, I have no AC, no sunroof, no power anything. I did add a Carrera oil cooler, thermostate and Elephant's hard lines. I removed the stock lead anchor battery and put in a gel-cell. If the estimates of 200 HP from the motor are accurate (this is an estimate based on the combination of mods that were done to the motor from experienced P-car mechanics) then I have a P/W of 11.45 pounds/hp. I wonder if that could be true. I need to dyno the car, don't I?

Thanks guys. Its fun to talk about.
troy

[Bill Verburg]

I see no mention of gearing any where above