Collectibility question: 1974 2.7 Carrera
03-23-2011, 03:58 PM
#31
I haddah Google dat
Rennlist Member
Rennlist Member
Thread Starter
I also want to add that my friend is the same guy who owns the 928S4, the 930 Targa Slantnose, 993TT, various BMWs, etc etc. He's not a broker or dealer, just a Porsche and car nut like us....but with more $$ than most.
03-23-2011, 03:58 PM
#32
Race Car
Lots of little things. The 73S was the fastest 911 in the US until the late 80s in terms of whole numbers.
Eventually the 911 started recouping it's power, but also tacked on weight. Looking back, the 2.4S was the dominant torsion bar car in the US from a performance view.
The 74s were actually right nice little cars. The 2.7 has nice charectaristics, but a 74 - 77 is a fun plug and play with a 3.0 sc motor. I'm loving the market on the mid year cars, may find me one yet.
Eventually the 911 started recouping it's power, but also tacked on weight. Looking back, the 2.4S was the dominant torsion bar car in the US from a performance view.
The 74s were actually right nice little cars. The 2.7 has nice charectaristics, but a 74 - 77 is a fun plug and play with a 3.0 sc motor. I'm loving the market on the mid year cars, may find me one yet.
03-23-2011, 04:01 PM
#34
Rennlist Member
It seems as though the special cars were the 2.4 911S, which had 210 bhp at 6,500 rpm. But there is one 2.7 variant that produced the same 210 bhp at 6,300 rpm with the same valve size, port diameter, valve timing (cams) as the S. Torque was increased 18% over the S due to the larger displacement.
The Euro models did not have the thermal reactors. What I don't know is if the U.S. models were de-tuned in terms of compression, valve timing, etc. compared to ROW. It sounds as if they might have been detuned from 1975 on but not in 1974. Therefore, the 1974 US 2.7 is a defacto ROW Carrera. Is this true?
All 1974- models had the higher impact bumpers, and the 2.7 "Carrera" had larger flares and the duck tail.
The K-Jetronic produced better fuel economy and more torque, necessitating a heavier clutch (915). The omega spring was introduced. Gearing was raised.
It seems the 2.7 model year to avoid would be the 1975- US models, which had air injection pumps, and detuned K-Jetronic. Even worse were the California models with egr systems.
Euro 2.7s might have produced 210 hp, but I see a quoted hp of 175 elsewhere. Which 2.7 had this lower hp figure? It seems that 1975- US models all dropped to 165 bhp due to smog emissions, and the Calif 2.7s were even lower. *
* "Porsche 911 Story", 7th ed. by Paul Frere (edit: I'm paraphrasing, not quoting directly)
Can someone proof check this for me, or even give me their impressions from memory? Thanks. I will call my friend later today. It also seems that the highest anyone has given in terms of value to date has been $30K, not the $40K the seller wants.
The Euro models did not have the thermal reactors. What I don't know is if the U.S. models were de-tuned in terms of compression, valve timing, etc. compared to ROW. It sounds as if they might have been detuned from 1975 on but not in 1974. Therefore, the 1974 US 2.7 is a defacto ROW Carrera. Is this true?
All 1974- models had the higher impact bumpers, and the 2.7 "Carrera" had larger flares and the duck tail.
The K-Jetronic produced better fuel economy and more torque, necessitating a heavier clutch (915). The omega spring was introduced. Gearing was raised.
It seems the 2.7 model year to avoid would be the 1975- US models, which had air injection pumps, and detuned K-Jetronic. Even worse were the California models with egr systems.
Euro 2.7s might have produced 210 hp, but I see a quoted hp of 175 elsewhere. Which 2.7 had this lower hp figure? It seems that 1975- US models all dropped to 165 bhp due to smog emissions, and the Calif 2.7s were even lower. *
* "Porsche 911 Story", 7th ed. by Paul Frere (edit: I'm paraphrasing, not quoting directly)
Can someone proof check this for me, or even give me their impressions from memory? Thanks. I will call my friend later today. It also seems that the highest anyone has given in terms of value to date has been $30K, not the $40K the seller wants.
The 911/83 (aka RS) which was a 2.4S MFI engine with 90mm pistons. Same nominal 8.5:1 compression, same "S" cams, same valves/intake/exhaust. Came in the '73 RS + '74 and '75 ROW Carrera.
The 1974 2.7L S is the 175HP CIS variant. 8.5:1, 35mm intake ports, still had the good exhaust carried over from Day One. Come 1975, what we now call the SC/3.2L Carrera exhaust appeared on ROW cars and 49 state US cars. That dropped the power output, but the compression/cams/intake were the same. Further restricted were the thermal reactor cars of '75-6 CA and '77 US. (EGR in and of itself really isn't going to drop the power output. Yeah, the EGR nozzles are disruptive to the exhaust airflow, but to what extent on a street engine. And the drag of the air pump? Sure, a bit.)
Then there was a mild, 8.0:1, 32mm intake port, timid cam'd non-S that was sold in '74-5. Not sure how the power output differed from from '74 to '75 with the exhaust change. And I'm blanking out whether a thermal reactor/air pump/EGR version was even sold in CA in '75.
I don't have a gear chart in front of me, but the '74 had a 7:31 R&P, changed to 8:31 in '75. 5th gear cruising was pretty much the same, right? It's just that the lower gears became taller with the final drive change.
Not sure what the comment on the clutch is. The 915 was introduced in '72 with the 2.4L. Maybe that they used a cast iron pressure plate, as opposed to the aluminum one on the 2.4s? Is the "omega spring" the helper spring? That didn't show up until '77. (And was on all 930s from their start date.)
So, in summary in the US: '74 had the Carrera and S with the 175HP CIS engine, or the non-S with the 150+HP. '75 was the same, just the lousier exhaust causing the power drop. '76 and '77 were S only, exhaust and emissions dependent on whether 49 state or CA.
And I won't even get into Kobelschmidt v. Mahle p/c sets that came in the cars with no rhyme or reason................
03-23-2011, 06:01 PM
#35
I haddah Google dat
Rennlist Member
Rennlist Member
Thread Starter
^ Excellent post, thank you !!!
According to Frere, these were the first to use light alloy cylinders because the irons cylinders were considered to be heat saturated, although that sounds strange and unverified to me.
According to Frere, these were the first to use light alloy cylinders because the irons cylinders were considered to be heat saturated, although that sounds strange and unverified to me.
03-23-2011, 06:13 PM
#36
Rennlist Member
Moving forward to the 2.7, they all had alloy cylinders. The KS was an Alusil barrel, the Mahle was Nikasil. (Which meant the KS were throwaways; I never re-ringed one on the advice of those who were way, way, way more knowledgeable.) Now I'm blanking out on if the KS piston was cast or forged; and KS were only CIS application. Mahle were either CIS for MFI, and am pretty sure the CIS piston was forged. The MFI was absolutely was.
03-23-2011, 07:23 PM
#37
Nikasil was used in the 917, which was a proven test bed.
I think it had more to do with frictional horse power loss and wear.
04-06-2011, 02:02 AM
#38
I haddah Google dat
Rennlist Member
Rennlist Member
Thread Starter
Well, he bought it!! It's at my other friend, Tony's right now getting a tune up and a thorough inspection. Hopefully pics to come only for you guys, my Renn "family".
