Finally found what I've been looking for...

[R22tech]

Carreras aren't as slow as I thought! In my car search I've been reading up on various models of sports cars, including Porsches. I read that Car and Driver article on the 84 Carrera again just to keep a comparison in front of me. 0-60 in 5.3 seconds should "feel" quite fast IMO, but I figured C&D was off a little or just plain destroying the drivetrain to achieve that figure. Most of the mags. have the ///M Roadster in the 5.0-5.3 sec. to 60 range and I can say, YOU DO FEEL THE QUICKNESS OF THIS ///M CAR! So why does the Carrera feel so sluggish, for a 6 second car that is? I decided to test my car with a stopwatch, not the most accurate, but it should be fairly close. My car is consistently getting to 60 in the upper 7 second range, using a 3000 +/- rpm launch and very quick shifting at redline (my 915 shifts great since the coupler/bushings/swepco/linkage adjust). Something just wasn't right here. I have always thought my accelerator was not as responsive as i would like, even to the poit of adjusting the cruise control cable to hold the throttle ever-so-slightly open: this gave the car a great throttle response even though I am a bumbling idiot for doing that: I thought I was adjusting the throttle cable...duh ! Anyway, someone recently posted about adjusting the throttle linkage and described the process, so I decided to check it reluctantly. Oh, BTW, I also had adjusted the accelerator pedal from behind the pedal so it would go farther down to the floor in hopes of getting more power. Here's how the inspection went: I put the pedal to the floor and secured it there with a short pole, and checked the throttle position-it still had a good 3/8" to go before it hit the stop. Jacked it up and removed the cable end from the whatever you call it just in front of the clutch/tranny area. Loosened the lock nut and screwed the "ball socket" end in as far as it would let me. I checked again and the throttle was now touching the stop with the accelerator to the floor. Test drive revealed a significantly livelier car! I can't test the 0-60 now, but will report back when i do, just so I don't get too excited. If this adjustment ACTUALLY made a difference, not just in my head, I am going to reconsider the sale of my car. The fact is, a Porsche should feel fast, not just to me, but to my passengers as well. It's the King of the sportscars for christ's sake! It really hasn't performed up to my expectations since day one. Other 911 owners who have driven the car always said, "Yup, she's running great...just like mine!!" , but I always felt I had to be at 8/10ths to get my adrenelin pumping. So here is what's different now: the car requires less pedal to get it going in a spirited fashion, which means it "feels" fast when driving normal....yeah !!! If I floor it, it really screams in 2nd and 3rd at anything over 4000 rpm, even better than the ///M felt! I finally found what I've been looking for...A.D.R.E.N.E.L.I.N. in the form of a Porsche 911 that I can afford!!!! I hope I'm not just kidding myself and the stopwatch doesn't make a fool of me. You guys know I really want to keep this car, I have an emotional attachment to it.

[pwd72s]

Hey man, wanna drag?

[Doug Zielke]

Without actually *looking* at the throttle plate, how can one be sure it isn't opening fully *before* hitting the stop?
From this thread, and all the previous ones, it seems strange that almost everybody has a mal-adjusted throttle linkage, my SC included.

When I adjusted mine to take it to the stop, I found *no* extra acceleration. All I noticed was a slightly different geometry at the pedal.

This winter when I have the motor out, I will physically examine the throttle body to see what the plate is doing vs. the bellcrank position.

[MotoSook]

W/ the motor in the car you can remove the CIS boot and see that you have the throttle plate vertical for the least restriction.

[R22tech]

Supposedly there is some kind of full open throttle switch that changes fuel/air mixture in there. I've read that the throttle needs to hit this switch, which is at the stop, in order for this change to happen. Don't go by me, I know next to nothing about throttles and bellcranks and such, I just read that it needed to hit the stop to be fully open. I'm anxious to see what the stopwatch says.

Also, the picture shows where I adjusted in green. Is this right?
And in red, these sleeve bearings are brittle and worn...how important is replacing them and what are they exactly called?

[R22tech]

Here's the post that sparked my curiosity: 3.2 full throttle position

[cegerer]

The parts circled in red are your bellcrank bushings. They're plastic, but replacement bronze bushings are available. When I bought my car, it actually felt quite fast and I was happy with it. But while inspecting the engine one day I discovered my bellcrank bushings had disintegrated to the point that nothing was left! The throttle was not opening all the way. After replacement, a significant improvement in performance was noted. Hopefully, the same will happen on yours. -- Curt

[Steve W]

Glad to have helped. You might want to also check that the full throttle microswitch is also toggling on when the throttle is open all the way. You'll also be surprised at how many 3.2s are misadjusted here and do not have this closing. It sends the signal to the Motronic box telling it to go rich for max power. In fact, I just recently found mine wasn't engaging, though I had checked it six years ago - call it wear. You'll need a continuity tester or a multimeter, to check the contacts of the switch, which if I recall is the one on the right side of the throttle body.

[Adam]

This thread has inspired me to check my car's throttle linkages too. I had it checked on my 2.7 and there was a significant difference in performance afterward. Funny how I've not bothered with the 3.2...

Actually, the 3.2 has (so far) failed to deliver the punch I expected. Sure, it's got plenty of torque, but it doesn't shove you in the back the way my 2.7 (very eager) does. The Carrera is faster, I'm sure, but it doesn't feel much faster at all. In some cases, it actually feels slower! Hopefully, this will show an improvement. Thanks!

[Vipergrün]

Ahhh yes, I had the mal-adjusted linkage as well, about 3/4 of an inch. Did make a big difference! I don't know the specs of the Carrera, but I was able to adjust the advance on my SC which made another big difference thru the power band. Rather than setting at 5 degrees BTDC, I used my adjustable timing light to set the timing to the max at 6K RMP, which I believe was 30 degrees. This translated to 11-12 degrees at idle. I don't seem to have any problems with detonation with 91 octane. Perhaps something you can look into? Just know it works well on the SC, along with adjusting the CO and removing the O2 sensor. Again, don't know about this stuff on the 3.2

cheers
-Brad
80SC

[jluetjen]

BB80SC; I'm happy that advancing the time worked for you. From personal experience I'd be careful advancing the timing past the factory spec's without a dyno to test the results. Here's my story...

I had an ITB race car (Mazda 323 with essentially 0 engine wear after 120K of normal driving) that was rebuilt with .020 over pistons, CR bumped .5 by shaving the head and owner advanced ignition. I always ran the car on 91 octane and never heard any pinging. The part part throttle pick-up was greatly improved and I was loving life. Until -- one day a huge plume of smoke followed me down the main straight at NHIS and the motor went "off song".

The subsiquent teardown revealed 1 piston which looked like it had been pecked through by birds and another piston which had not been holed yet. The rings on the holed piston ended up scoring the block. I was able to buy a junk-yard engine and some new rings and pistons for about $1500 if my memory is correct, plus rebuild costs.

I've kept that holed piston since that time as a paperweight for my desk and as a reminder of what happens when you put too much advance into an engine.

[Vipergrün]

John, thanks for the heads up! What will the dyno be able to reveal with regards to too much advance? You've got me worrying now. I thought as long as I didn't exceed max advance at 6K RPM's I'd be fine. Do you think that higher octane fuel would have helped your situation? I plan on mixing in a few gallons of 100 octane each tank.

Thanks again for your reply, sorry to take the original thread off topic.

-Brad
80SC

[n8marx]

So, where is this "full throttle microswitch"? I checked my throttle linkage in hopes of finding more power after a new Altima smoked me from a stoplight ( I know, I know, it's not a drag car ) but there didn't seem to be much left in that. The throttle plate was about 1-2 mm from fully open so I didn't think I'd gain much if anything. Haven't adjusted it yet. My question is if I have 1-2 mm of travel left am I not tripping this switch?

[Steve W]

I checked this at lunch and there was a half inch of travel left before it hit the stop. I did the adjustment and now the car idles at 1500. Anyone else have this happen?
Mark

[jluetjen]

Do you have a manual or do you know what the timing should be? Both initially and at full advance? To be honest I don't know what the spec's are the for the SC. If you don't have it, you can most likely find it on the BBS or someone can share it with you.

My comment about the Dyno is because when you have a car on the dyno, depending on how it is instrumented, the operator can see if the car is detonating, even if you can't hear it. If you have a mappable ignition system, you would then back off the timing a little bit at that point on the map until the detonation stopped. Most distributors are pretty blunt instruments since you can only adjust the initial advance and by extension move the whole curve to the right or left. Changing the shape of the curve requires taking the distributor apart and cutting/welding or bending metal as well as playing with springs. Certainly not impossible for the home mechanic to do if they knew what they wanted for a curve. The trick is getting the right curve to maximize HP without melting a hole in a piston. At the end of the day, the factory has done a pretty good job unless you have changed one or more of the parameters (CR., Cam, Fuel, etc.).

- John

[R22tech]

I had someone PM me about this Mark. He also has a 79SC, so maybe it's different from the Carreras? I believe the DME gets a signal from a switch at full throttle and changes the fuel/air mixture for max. power. Maybe an SC guy can shed some light here for you guys because I have no idea how the 3.0 is set up.

[gr8fl4porsche]

Mark,
If you over adjusted the linkage by the bellcrank you can back it off a little with the adjustment at the throttle. I believe this is what I did to dial it in.

Thanks guys. I'll look over it again tonight. I wasn't able to check acceleration on the way back to work, but will give it a test run on a back road going home.

R22, Hope this convinces you to keep your car.

Mark

[gary-o]

Mark, I have a '79SC and adjusted the linkage as per R22tech's info. The linkage would meet the stop then (had been off by 3/8") but my idle went to 3,000 rpm. I moved the linkage back to it's original setting to get my revs back to normal.
It also seemed, when I had the linkage touching the stop, that the idle can be affected by a black cable that has an adjusting screw on it, it also is attached to the throttle linkage. I have Wayne's 101 projects as well as a Hayne's manual, but they don't tell me what the cable is for, so I'm not going to screw with it until I can find out from this BB. It ties into an accumulator of sorts on the left firewall. Is this how I can get my idle down if I tighten up my linkage?
- The timing spec on my '79SC is 5 degrees BTDC (plus or minus 2 1/2 degrees) @ 950~1000 rpm.

Regards,
Gary