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Registered
Join Date: Jul 2002
Location: Ontario, Canada
Posts: 165
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Hand throttle as cruise control?
I realize some of you may find this a risky proposition - I am still undecided which is why I'm asking.
Anyone had any problems using their hand throttle as a cheap method of cruise control? After a few long freeway drives with a cramped throttle leg, I would love an alternative. I don't have cruise control, and thought of the hand throttle is appealing as a solution. I drive a '79SC which didn't come with the hand throttle (although my boot has a hole for one ironically). I am thinking of replacing my hand brake assembly with an earlier one that includes a hand throttle. Perhaps I can just add a throttle lever to my existing one, not sure. I am not sure of any legal concerns with this idea, if there are in fact any. Older cars have one so I should be able to have one, no? Perhaps rules differ for various models - comments please. BTW, as far as relieving the cramped leg, letting my passenger drive is never an option.... 
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If opportunity doesn't knock, make a door. |
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10-30-2002, 06:34 AM
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Alter Ego Racing
Join Date: May 2002
Location: Florida
Posts: 5,553
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Thast's what I do with my 69, full hand throttle equals 70MPH ...
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International GT Champion; Porsche GT3 Cup Trophy Champion; Klub Sport Challenge Champion; Rolex Vintage Endurance Series Champion; PCA Club Racing Champion; National Vintage Racing Champion |
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10-30-2002, 06:53 AM
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Back in the saddle again
Join Date: Oct 2001
Location: Central TX west of Houston
Posts: 56,236
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Having a DME controlled car with cruise this isn't something that I am familar with. Is the hand throttle actually the throttle or is it a choke? I had always assumed it was just a choke, but from the sound of things I was incorrect.
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Steve '08 Boxster RS60 Spyder #0099/1960 - never named a car before, but this is Charlotte. '88 targa  SOLD 2004 - gone but not forgotten
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10-30-2002, 06:58 AM
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Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,497
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Doesn't hurt anything. Just keep in mind that if you step on the brake or the clutch the accellerator linkage is not going to release. Could lead to a nasty overrev.
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Kurt V No more Porsches, but a revolving number of motorcycles. |
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10-30-2002, 06:59 AM
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Registered
Join Date: May 2002
Location: Portland, Oregon
Posts: 12,667
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In my '73, the hand throttle does two things, opens the throttle plate a bit and turns on my 7 th injector. This causes the mixture to get richer and your gas mileage to plumment. I would not use it for this function.
My $0.02
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic Last edited by HarryD; 10-30-2002 at 07:10 AM.. |
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10-30-2002, 07:02 AM
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Join Date: Oct 2000
Location: Nor-Cal
Posts: 4,403
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Personnaly I think it is a bad idea. In the case of an emergency stop, you have to back off the hand throttle, and apply the brakes. That's why I think it is a bad idea.
We have hand throttles in all of our fire engines, and I know a lot of the people use it for cruise control. In fact we had an engine wreck down in so-Cal this summer, and the opoerator was using the hand throttle as a cruise control. This contributed to the engine going off the freeway and almost killing all 3 people on board. |
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10-30-2002, 07:04 AM
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Location: Nor-Cal
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Here's a pic of a result of using the hand throttle:
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10-30-2002, 07:08 AM
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Registered
Join Date: Jul 2002
Location: Ontario, Canada
Posts: 165
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I appreciate the replies everyone.
Nasty pic by the way Dr. Matt, thank you. I have thought about safety concerns of course, and I am comforted by the fact that in an emergency situation one could simply step on the clutch and brake as one would normally. However, the fact the engine would go to redline would add considerable stress to an already stressful situation, and may result in poor judgement while attempting the brake and avoid (I imagine trying to fumble with the hand throttle). I intend to use the 'cheater-cruise' on nearly empty freeways only, for safety reasons. I take comfort of course that my little 3L could handle 10sec of redline, HOPEFULLY.... In any case, I would love to hear more from anyone with comments/suggestions or nasty deterring pics. Hardware: Can anyone comment on differences between earlier hand brake assemblies with hand throttle vs. that on the SC? I assume I could interchange them without issues of heat-flapper cables or parking brake cables.
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If opportunity doesn't knock, make a door. |
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10-30-2002, 07:27 AM
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Re: Hand throttle as cruise control?
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10-30-2002, 08:17 AM
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An interesting post..
Bones:
Just an idea.. could you post some details on your car controls, maybe in a seperate thread? I've always been curious how that works... I think it would be cool to see from an engineering POV. Thanks! Chuck
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1980 911 SC Targa *Sold!* 2003 Boxster 2013 Beetle Turbo cab |
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10-30-2002, 08:25 AM
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Join Date: Aug 2002
Location: Illinois
Posts: 356
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Not familiar with the hand throttle on the 911's (have an 87), but had a hand throttle on a 74 Fiat 124 Spider. Used it as a cruise control but had to remain aware for the reasons listed above - didn't disengage, didn't want to overrev. It was really a nice way to relax your right leg on a long trip.
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RKC 1987 Guards Red Targa |
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10-30-2002, 09:11 AM
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Re: An interesting post..
Quote:
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10-30-2002, 09:28 AM
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Join Date: Feb 2000
Location: Dallas, TX
Posts: 4,612
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The hand throttle in my early 911 maxes out to about 3000rpm. It only partially opens the throttle so there can't be any over rev. It's essentially like putting 1 inch of travel on the accelerator.
The hand throttle definitely not something you want to use if you aren't paying attention to traffic. Then again, if you aren't paying attention to traffic, you shouldn't be driving.
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Neil '73 911S targa Last edited by Neilk; 10-30-2002 at 11:47 AM.. |
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10-30-2002, 09:39 AM
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Crusty Conservative
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I am in the group that think it is a BAD idea.... It changes the dynamics of a panic stop in ways that you may not handle properly in a panic stop situation....just what you don't ever want to happen.
In the good old days when I was young & immortal, used to tighten down the friction adjuster on my Norton handgrip throttle, made a great cruise control, at ANY SPEED YOU WANTED. Somehow, i am still here. Drunks & fools & all that I guess... If you want to cruise, take the cruiser, that's what I say... 
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Bill 69 911 T Targa, 2.4E w/carbs (1985-2001) 70 911 S Coupe, 2nd owner (1989- 2015) 73 911 T Targa, 3.2 Motronic (2001- ) |
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10-30-2002, 10:54 AM
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I think the cable on my hand throttle just broke. Whenever I try to use it, it does nothing and I don't see how the pedal is moving once it's pulled. What will it invlolve to fix it?
Thanks, Max. 75 911s 89 325 ix 89 M3 91 325 IX - for sale |
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10-30-2002, 11:26 AM
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Location: Ontario, Canada
Posts: 165
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BONES
Hats off to you for making your porsche yours to enjoy. I am also very interested in details with some pics, coming from an engineering background myself. My gal would also be very interested, as she is an occupational therapist. Finally I can get her into some porsche talk!!!!!! I hear everyone's arguement on the safety aspect with the hand throttle as cruise control. I agree with them and therefore I have thought of a comprimise/solution. Because I am a safety-conscious NERD who likes to tinker, I will encorporate a solonoid (much like a power-door lock actuator) into the design. Activated by stepping on the brake pedal, it will "pull" the hand throttle lever down. I will ensure the solonoid will activate only when the hand throttle lever is in the 'up' position. If I can get it right, this will prevent redlining during braking with the clutch in, and will provide for some extra safety. I think it can be done for under $30 if I'm careful but who knows.
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If opportunity doesn't knock, make a door. Last edited by Shawzy; 10-30-2002 at 11:36 AM.. |
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10-30-2002, 11:34 AM
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Location: Dallas, TX
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Max,
There is a small plastic piece in the transmission tunnel that goes from the throttle handle to the accelerator linkage. It is possible that the piece either broke or somehow fell off the cable, or the stop on the linkage came loose. You will need to pull off the hand brake assembly and take a look in there. The part # for that plastic piece is 901.424.317.00, at least for my '73.
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Neil '73 911S targa Last edited by Neilk; 10-30-2002 at 11:52 AM.. |
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10-30-2002, 11:45 AM
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Thanks Neil, I guess I know what I will be doing tonight...
I seem to slowly move back into the years of my cars. This is my first car with hand throtle. I was wondering , while the hand throttle is not functioning, what is a good way to start the car and actually have it reving and not dying on me 10 times before it will stay alive? I was even thinking of putting a heavy shoe on the throttle pedal while the car is warming up! It is not my daily car and so the problem is not that big.. but still a pain.
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10-30-2002, 11:57 AM
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Bird. It's the word...
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Shawzy, for all the trouble you are considering going to, would it not be simpler to install a cruise control? An after market one is only a few bucks. Bugger setting up solenoids and the like if you can just use the real thing....
Cheers
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John Forcier Current: 68L 2.0 Hotrod - build underway Last edited by Fishcop; 10-30-2002 at 01:48 PM.. |
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10-30-2002, 01:44 PM
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Join Date: Jan 2000
Location: South NJ
Posts: 2,516
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I use mine that way, '71S engine with MFI. The stock setting is something like 3400 RPM when warm, which is 1500 stone cold, slowly coming up after 10-15 minutes. Even if you leave it up and hit the clutch there's no damage.
I tried cranking mine up higher so it would work as cruise better (won't do much more than small hills on the highway) but the travel is limited. |
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10-30-2002, 07:35 PM
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1978 Porsche 911SC Targa 3.0ltr
1970 Porsche 911S 2.2l MFI
1969 Porsche 911T 2.7RS Spec with Webbers
