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RE: High RPMs at highway speed?
I'm running a 10V, so I'm even worse off in the low-end torque department,
but like I said, 4th gear in my 90 is only a few hundred RPM off of 5th,
thus if you had a taller 5th gear, you'd simply keep the car in 4th longer.
In fact, I've read numerous road tests where the top speed was attained in
4th rather than 5th on a 5-speed tranny regardless, so making 5th a little
taller would seemingly be irrelevant under "performance driving" conditions.
For instance, I never try to pass anyone in 5th. It's possible given that
my engine is pulling 3500 RPM at 70 in 5th, but when I want to punch it, I
always drop to 4th first, always will. So why not make 5th a little taller
so I could wring out another 4-5 mpg and kick the noise level down a decibel
or two? Guess it's all academic, but 3500RPM at 70mph seems buzzy and
excessive to me. Guess I'll be fighting Huw in the junkyards for that scrap
1988 Audi 90, 70K mi.
Walla Walla, WA (soon to be Portland, OR).
From: firstname.lastname@example.org [mailto:email@example.com]
Sent: Monday, June 07, 1999 1:39 PM
To: Dan Sinclair
Cc: Clough, Samuel; 'Audi Quattro'
Subject: Re: High RPMs at highway speed?
the only problem here (at least with the 90Q20V) is that you would never
get to the operating region where the engine seems to be most effective
(above 4000RPM) until you either ran out of highway or wound up in
jail...............I think with taller gearing, performance results would
.........especially with a 'high-end' motor like the 20V with a redline of
Dan Sinclair wrote:
> I too have wondered about this one. I understand that a close-ratio
> provides better acceleration and power, especially from smaller engines,
> I've always thought a taller 5th gear (or perhaps a 6th gear) would be a
> welcome addition in my car. Clearly, if you're driving the car hard and
> fast, your typically using 2nd, 3rd and 4th gears anyway, so why not make
> 5th a true overdrive? As it is in my 90, 5th is just a few 100 RPM taller
> than 4th. My girlfriend's '88 Accord, however, loafs at 55 in fourth and
> absolutely lugs in 5th at 55. She reserves 5th for interstate cruising at
> 70+mph, and even then she's only pulling 2,600 or so. 5th is a big jump
> from 4th in her Honda.
> When my parents bought their 4000 in 1982, we were told by the Audi dealer
> (I know, lips moving - lies emanating...) that the European models had
> taller gearing than the US models because the Germans believed that the US
> market would never be driving over 55MPH by law, thus they maximized the
> ratio for a limited spread, topping out at about 65. My parents' 4000 was
> in fact designated a 4000S-4E. The 4E included a taller eurospec 5-speed
> gearbox. In fact, the '82 4000 had a much taller 5th gear than my '88 90
> does now, and it was running a 1.6l 4 cylinder. I certainly think my 2.3l
> would be able to manage with a little taller gearing. Can anyone confirm
> different gear ratio for European spec equivalents?
> Dan Sinclair
> 1988 Audi 90, 70K mi.
> Walla Walla, WA (soon to be Portland, OR).
> Pics&details: http://22.214.171.124/a4.org/registry/details.asp?car=761
> -----Original Message-----
> From: firstname.lastname@example.org [mailto:email@example.com]On
> Behalf Of Clough, Samuel
> Sent: Monday, June 07, 1999 5:01 AM
> To: 'Audi Quattro'
> Subject: High RPMs at highway speed?
> Importance: High
> Ok, so I've always wondered this, but I've never asked anybody and I
> it was time to submit my question to the infinite wisdom of the list. Why
> do our cars run such high RPMs on the Interstate? In the A6 at 80mph it's
> turning 3,600. Should you cruise around 90 (of course totally
> the RPMs are just about on 4,000. None of the American or Japanese cars
> I've ever driven turn anything like this. Most of them seem to just be
> getting to 3K at around 80/85. It seems to me that a German car designed
> the Autobahn would have a higher top gear. If I drove this car like I
> assume it was intended to be (ie Autobahn) and assuming the gearing
> USA and European cars is similar, I'd be cruising at or over 5k. I mean
> long can the motors last being driven that way? It just seems to me that
> with the gearing on the car I'm putting unnecessary wear on the motor with
> long highway drives. Am I crazy, or are these cars so bulletproof that
> are immune to the wear affects of higher RPMs?
> 95 A6Q (loves the far side of the speedo)
> Samuel W. Clough
> INVESCO Retirement Plan Services