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Re: Tires (50mm intakes)
At 11:54 PM 10/2/00 , Brett Van Sprewenburg wrote:
>>16v Jason wrote:
>>
>> > Hmmm -- looks like VW outfitted the 'test' cars with upmarket tires
>> for the
>> > magazines. Doesn't surprise me in the least, because there's no doubt
>> that
>> > they also outfitted the cars with more powerful engines -- otherwise, why
>> > is it that none of us can come close to the published 0-60 times ranging
>> > from 7.7 seconds to 8.1 seconds?
>>
>>Some of the VERY earliest 16V's to reach our shores came outfitted with the
>>50mm intake. They were quickly recalled due to complaints of a complete lack
>>of low end. I *think* the R&T review I have sitting around here someplace
>>has a picture of their test car WITH a 50mm in place. Maybe despite the lack
>>of low end these cars were that much faster in a full-on 0-60 blitzkrieg?
>>I also have a copy of one of the very first 16V ads, with a close-up of
>>the motor, and it's tough to be 100% certain because of the angle, but it
>>sure looks like a 50mm atop that engine too.
>
>Here's an unpopular opinion for you...I'm willing to make an educated
>guess that a 16v with a 50mm intake is probably _slower_ in a 1/4
>mile or 0-60 run then an equivalent 16v with a 40mm. Top speed is
>likely a different story, but I'm thinking that the greater air
>velocity of the 40mm has got it where it counts the most...like where
>most people actually drive their cars most of the time. Don't quote
>flow numbers at me; as engine output is not a simple equation of
>airflow. An engine operates under a vast array of different RPM points
>and load ranges, what's super for high RPM, high speed performance might
>totally suck around town. Dyno plots, 1/4 mile or 0-60 times is what I'd
>like to have compared.
Well, actually Brett, I think if the 50mm intake helped over 5000rpm, a
0-60 or a 1/4 mile with a good launch would be quicker. Why? Well, under
full throttle like that, the only time you're considerably below 5000rpm is
on the initial launch -- and if you dump the clutch at 6000rpm, it's only
for a split second, if even. Each shift drops revs from 7200 to somewhere
around 5000, so the lower register isn't accounted for at all. That's the
reason that the Honda S2000 can pull off 6-second 0-60 runs but is nowhere
nearly as quick around town.
Or our cars for that matter.
>It's the same reason that hogging the crap out of the ports
>on your head can result is a total DOG of an engine below 5,000 rpms,
>but a real screamer from 5k to 7,500k. The same idea on wild cams, as
>the hotter the cam the softer the low end, but the stronger the high
>end. Obviously, the _potential_ air flow is greater with a 50mm intake,
>or a super ported out head, or long duration cams...but real world
>street performance usual suffers, while race track performance soars.
Bingo -- and the reason I don't have a cam in my car. If anything, I'd go
with a 2.0 that would give more lower-rpm driveability and retain high-rpm
pull. That way, I'd gain maybe a tenth or two on 0-60, but a lot more
power off the line without dumping the clutch off idle.
>Anyway see where I'm going with this? I'm probably going to get
>blasted for stating that I'm not a believer in the 50mm intake for
>the best street performance. ;)
Nope, fully agreed. Same with cams and P+P jobs. You're better off on the
street putting a bigger block in.
>As for the magazine tests? From what I understand they used to completely
>_punish_ those cars trying to eek out the best possible performance...
>high rpm clutch drops, and taking 2nd to 60 mph to avoid the last gear
>change for example. Few of us would do that now I suppose.
Tee-hee... I've done some pretty harsh launches...
But, for example, R&T got a 7.7s 0-60 run versus C&D's 8.0 run probably
because R&T shifted at 7200rpm, which was at 60+mph, where C&D couldn't get
past 7000rpm (their rev limiter kicked in early) so they had to shift at 58mph.
C&D has a strict policy about not going into Redline on instrumented tests
-- so regardless of where the limiter kicks in, they shift at solid red.
Jason
>>--
>>Kevin Collins
>>'86.5 16V 2.0
>>'00 Passat GLS 1.8T
>
>
>==Brett
>
>\/ '84 Scirocco (ITB racer 2B) | "Hot VW's, take two home. They're small"
>\/\/ '88 Scirocco 16v (Show), '92 Passat 16v (Winter+) | - brett@netacc.net
>
>--
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----------
1987 Scirocco 16v
1988 Mercedes 190E Sport Euro
http://www.scirocco16v.org
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