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melville Samba Member
Joined: August 09, 2006 Posts: 1242 Location: Just Outside the Redwood Curtain
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Posted: Mon Sep 28, 2009 10:02 am Post subject: Re: Am I safe to go 60? |
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lookitsjeff75 wrote: |
My '72 Transporter has a four speed, but whenever I try to go the speed limit (60) the engine seems to just be screaming, and I can't imagine that being a normal noise to hear at that speed. Do I need a 5-speed tranny, or just a lower gear ratio? I'm open to any suggestions! |
You've got to recalibrate your ears. You've got a relatively tiny engine moving a gigantic box. That tiny engine needs to be in its power band to achieve highway speed, and to cool properly.
The "Maximum and Cruising Speed" in the manual is a nod to German conditions with speed limitless Autobahnen. Keep in mind that our favorite vehicles were developed for those conditions. _________________ 2000 M Roadster
79 R100RS
78 R100/7
75 R75/6
65 Standard Micro
57 Sedan |
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WestyPop Samba Member
Joined: February 08, 2005 Posts: 1732 Location: SoCal
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Posted: Mon Sep 28, 2009 10:42 am Post subject: |
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Might be a good idea to get a tach on there, at least long enough to determine at what actual rpm the engine sounds like it's 'screaming'. Could be OK, or... ?
Big box + small engine = 'big noise' to some, but "sweet music" to others! YMMV _________________ Never underestimate the power of stupid people in large groups.
______________________________________
J.R.
68 Westy
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vdubyah73 Samba Member
Joined: July 05, 2003 Posts: 2541 Location: somewhere in Texas, my house has wheels
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Posted: Mon Sep 28, 2009 2:20 pm Post subject: |
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do you have the correct size tires? if so cruise along at the recommended speed for your year. _________________ burning down the house
73 bounty hunter, sold.
'77 transporter, junked had crotch rot.
Dubless, but have a CPR built stroker waiting for a new to me Beetle
'93 Fleetwood Bounder 34' |
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lookitsjeff75 Samba Member
Joined: September 27, 2009 Posts: 3 Location: Napa, CA
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Posted: Mon Sep 28, 2009 9:01 pm Post subject: |
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Well I took another ride on the freeway today and it didn't sound too bad now that I really listened to it.. But it still seems to be at too high an RPM. Is it possible VW made them to do that for some reason? _________________ "Driving it is only half the fun, fixing it in some far-off rural area when it breaks down is the other"
-Pappy
'72 Transporter |
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melville Samba Member
Joined: August 09, 2006 Posts: 1242 Location: Just Outside the Redwood Curtain
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Posted: Tue Sep 29, 2009 7:29 am Post subject: |
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lookitsjeff75 wrote: |
Well I took another ride on the freeway today and it didn't sound too bad now that I really listened to it.. But it still seems to be at too high an RPM. Is it possible VW made them to do that for some reason? |
Yes:
melville, a couple posts ago wrote: |
You've got a relatively tiny engine moving a gigantic box. That tiny engine needs to be in its power band to achieve highway speed, and to cool properly. |
To elaborate: the motor has to spin 4K rpm at freeway speed, and turn a large important fan, and the valves are going to rattle a bit, and the fins are going to ring a bit. Your typical modern vehicle turns 2K rpm at freeway speed, probably shuts down its little electric fan, has hydraulic lifters, and is water-cooled and has no fins to ring. It probably has better sound insulation and a quieter muffler. _________________ 2000 M Roadster
79 R100RS
78 R100/7
75 R75/6
65 Standard Micro
57 Sedan |
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lookitsjeff75 Samba Member
Joined: September 27, 2009 Posts: 3 Location: Napa, CA
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Posted: Tue Sep 29, 2009 9:08 pm Post subject: |
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Alright thanks, that makes sense. But what effect does it have on fuel economy? Will it turn my car into a freeway gas guzzler, or does it not make too big a difference? _________________ "Driving it is only half the fun, fixing it in some far-off rural area when it breaks down is the other"
-Pappy
'72 Transporter |
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WestyPop Samba Member
Joined: February 08, 2005 Posts: 1732 Location: SoCal
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Posted: Wed Sep 30, 2009 4:24 am Post subject: |
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Aerodynamically, you're driving a barn! It will consume more fuel at 75mph than it does at 55, even if you've swapped in a Porsche 6-speed that drops the engine to 2500 rpm @ 75mph.
It's a whole system that VW engineered nicely for the speeds they thought people would/should(?) travel at... 30-40 years ago. The combo somewhat works for those same parameters today, for some people. But if that doesn't satisfy you, it's still a whole drivetrain 'system' that really needs to be modified, not just throwing in higher final drive gears, or monster tires to drop the 'cruising' rpm. (one of my diesel VWs gets about 54mpg @ 2900rpm/60mph in 4th gear, but only 39mpg @ 2900rpm/80mph in 5th gear, and it's much more aerodynamic than a bay bus!)
It won't necessarily get you better mileage to drop the 75mph engine speed to 2800rpm, but you may find that the relative 'lugging' effect doesn't allow proper engine cooling. That's sure a lot more costly than losing a couple of mpg. Of course, there are those here who would just advise us to 'slow down' and enjoy the ride.
OTOH maybe an appreciation of the sounds of a nice T1 or T4 VW engine just cruising @ 3000-3700rpm is an acquired taste.(?) I've been known to turn off the stereo just 'cause the engine sounds so sweet. There are also some great threads here on the Samba re. added sound insulation for our baywindow buses.
Hope you can find the right combination to enjoy your bus at any roadspeeds you travel. _________________ Never underestimate the power of stupid people in large groups.
______________________________________
J.R.
68 Westy
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