Has anyone used a ZD gear for 5th in a 911? Just wondering if it may be to high a gear. Currently running a 73 1/2 CIS 2.4 motor with webers in my short wheelbase. Thanks in advance for the assistance.
Has anyone used a ZD gear for 5th in a 911? Just wondering if it may be to high a gear. Currently running a 73 1/2 CIS 2.4 motor with webers in my short wheelbase. Thanks in advance for the assistance.
I'm running a ZD 5th in my 67 912 POLO car. It's a 2.4 liter and makes about 160 rear wheel hp here in the Denver area. At sea level maybe 180 rear wheel hp, 200 ish gross.. My engine starts pulling well about 3000 rpm and is turning 3300 rpm at 80mph. Up here in the Denver area I don't find the gear useful below 60 to 65 mph and it works best over 75.. Under 60 the engine lugs. At sea level that might be 55 to 60mph and fine at 70. My engine is very torquey with 100mm pistons and 993 stroke. Driving the car between Denver and LA I find the gear useful out in the open country. But for normal and sporting driving in the tight Colorado mountain country I find it too tall. When I get inside the trans I will change it to a Z or ZA. As for 1st it will be changed to a B or C. The A reminds me of a granny gear in a 50 or 60's pickup truck. It's too low. Hope this helps. In AZ as long as you don't live in Flagstaff and are doing a lot of flatland freeway driving it might be fine.
Chris
Thanks for the great info Chris, I appreciate it. Currently running A F M S X and think I will go ahead and try an A F M V ZD setup.
Glad to be of help. Those look like 914 gears, or close. I'm running A GA N U ZD. I'll probably go B or C GA N U ZA. If your running a lot of sustained 75 mph plus driving the ZD is a nice gear. Most of my driving is vertical. This was a run my wife and I did through Vail and Aspen with a group of folks in various German cars.
The bottom picture is taken near my house. The mountains are about a 10 minute drive away then it's all up and down. At the base of the mountains is Boulder, Co and 14,000 foot Longs Peak to the far right. To the left of the picture is Golden, Co. And a little farther South you can drive to the top of Mt Evan in the Summer to 14,000 feet. A ZD isn't much good up there.
Last edited by Chris Pomares; 01-25-2015 at 08:28 AM.
A F M V ZD gear splits are OK, but would be better of you went with A F N V ZD. If you can get a hold of a GA mainshaft, event better is A GA N V ZD.
Kenik
- 1969 911S
- 1965/66 911
- S Reg #760
- RGruppe #389
Great advice! I will keep looking for the others and see what I acquire before I pull the transaxle.
I have all of these gears - let me double check and make sure I have spares. If so, I can let some go.
Kenik
- 1969 911S
- 1965/66 911
- S Reg #760
- RGruppe #389
Those are wide spread gears and work great at low altitude and modest inclines. I went up one to GA in second and down one to U in fourth to tighten things up. Now I want to do that in 1st and 5th. A ZA will increase my RPM's to 3600 from 3300 at 80. At 75 the speed limit on most roads I'll be at 3200 ish. A 4000 rpm shift in 1st will go from 21 to 28 mph with a C gear. My car has the torque to pull that easily and I don't ever jump on it hard in first anyway as it's a cantilevered gear. A (C, GA, N, U, ZA) gear set will let me stay in the power band and pull hard and still be at around 5000 rpm at 110. I don't spend much time above 115 to 120 in my SWB car. It's set up more for the twisties. I will admit a ZD is nice for covering long stretches at speed though.
Or you can buy one of my 904 mainshafts and really go hog wild with the stacks...
-Marco
SReg. #778 OGrp: #8 RGrp: #---
TLG Auto: Website
Searching for engine #907495 and gearbox 902/1 #229687
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