Hiya :) Of course I am reading you rants. Although the VR6 in my car
does not have this variable intake stock there is an aftermarket one
that boosts low and midrange torque 30%. But in the case of the big
V8's I still think it's a win/win situation. Without using variable
intakes. Reason being that all the things you can do to increase high
end performance (intake porting, head porting, bigger valves,
higher/longer lift/duration cams) tend to hurt low end HP. True
enough...But when you talk about a BIG V8 you are dealing with an engine
that is already making say 300 ft. lbs. of torque @ 2500 rpm. Now,
after all your mods it is still making 300 ft. lbs. but now at 3500 rpm.
Okay...But think about it....There will be a definite loss in low end
torque but I do not think it is anything that would make a big
difference. So you are not making 220 ft. lbs at off-idle but now 180
at off-idle. Does this really matter? My VR6 makes 100 ft. lbs. at
off-idle and my 2800 lb. car still runs from 0-60 in 6.6 seconds. So
what's the big deal? True, gearing plays a role but nothing significant.
My point simply being that for day to day, a well tuned V8 is a SUPERIOR
choice to a well tuned 4. Of course, an inline six is still the
absolute best choice. Keep in mind I used to think pushrod V8's are
pieces of crap and that American's couldn't build a motor to save their
life. But after really learning about what makes a motor work I have
learned to change my opinion. Oh, one more qualification, I don't care
whatsoever about fuel mileage. Just one of those things. Okay...Sorry
for the long post. Oh, I am still looking for a Tiger!!!
>From tigers-owner@autox.team.net Thu Feb 4 14:22:38 1999
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>Message-ID:
<801C5619C066D211AC430008C75675E55D9C2C@ntsrv004.corp.novatel.ca>
>From: Theo Smit <TSmit@novatel.ca>
>To: "'Bob Palmer'" <rpalmer@ames.ucsd.edu>, tigers@autox.team.net
>Subject: RE: Rather have a Big One
>Date: Thu, 4 Feb 1999 15:12:37 -0700
>X-Mailer: Internet Mail Service (5.5.2232.9)
>Sender: owner-tigers@autox.team.net
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>Reply-To: Theo Smit <TSmit@novatel.ca>
>
>Hi Bob,
>
>Good to know someone is reading my rants ;). Like you say, most of the
current
>high-RPM engines use some kind of variable intake tuning to broaden the
>performance (I won't call it torque or power) band: Yamaha with the
dual-runner
>setup, Toyota with their TVIS (like on my '85 GT-S), Honda uses their
VTEC
>variable valve timing thing, and so on. The best one (and most
unmaintainable)
>I've seen is what Mazda was using on their GTO rotary a few years back,
where
>they had carbon fiber ramstacks that slid in and out according to the
engine
>RPM. Mark commented that he'd seen V-8 engines that made lots of power
at high
>RPM, and so have I, but I'm sure that same engine would not do so well
putting
>around downtown (not without a lot of the technology you mentioned).
The nice
>thing about a big engine in a small car is that 'not so well' is
usually still
>perfectly acceptable.
>
>My point (other than to tweak the big-v8-is-best gang) was that the
smaller
>engines are generally set up in a higher state of tune than most V-8's,
and that
>results in them being more finicky to drive. It has also resulted in a
lot of
>development being directed at solving the driveability "problems"
associated
>with these engines. You are right when you say that you can drive them
at 2500
>rpm and below, but if you need to go anywhere quickly, you'll need to
get the
>RPM up to where you're making some power, and some people resent the
fact that
>they have to row the gearbox all the time even when they're not
pretending to be
>Jacques Villeneuve.
>
>#2:
>I knew that the farm implement thing would get someone going. I agree
that the
>transmission is a fine piece of work (can we get an all-aluminum case
for it?)
>and well-matched to the engine, but the shifting action is, well, a
little heavy
>for everyday traffic-jam use. Compare it to a mid-seventies Toyota
Corolla or
>Celica gearbox if you ever get the chance.
>
>#3:
>Well, I'm not sure that I was making a statement on that subject one
way or the
>other in my post. I'll guess that most people associate low-rpm
performance
>(what they call 'torque') with around-town traffic-light situations,
and
>high-rpm performance (what they call 'horsepower') with racing, and so
everyone
>says 'torque is king for street cars'. Not true, since you can use
rear-end
>gearing (and that shift lever thing) to optimise the engine RPM for the
driving
>conditions you encounter most often.
>
>Warming things up from the Great White North,
>
>Theo Smit
>tsmit@novatel.ca
>B382002705
>
>> -----Original Message-----
>> From: Bob Palmer [SMTP:rpalmer@ames.ucsd.edu]
>> Sent: Thursday, February 04, 1999 2:08 PM
>> To: Theo Smit; 'Mark Radelow'; johnson@ids.net; JPKKMK@aol.com
>> Cc: tigers@autox.team.net
>> Subject: RE: Rather have a Big One
>>
>> Theo, et Listers,
>>
>> While I think you are generally correct Theo, you've managed to hit
at
>> least three of my "hot" buttons with your latest posting. In the
order in
>> which they appear, let's start with your statement: "Any piston
engine
>> built to develop maximum power "well above" 5000 rpm is not going to
>> perform worth beans at 2500 rpm and below." Now I haven't ever driven
the
>> Honda 2.0L/240HP screamer, but the 3.0L DOHC Yamaha motor in my SHO
is
>> probably the sweetest engine I've ever driven. You can rev it up to
7,000+
>> rpm and still lug it around at ridiculously low rpms, way below 2500,
>> without it ever complaining. It puts out 220HP at 6,400 rpm and max
torque
>> at 4,800 rpm; probably not too far different from the rpm points of
the 289
>> in my Tiger. And, cruising at 75 or so with the air conditioning
running it
>> gets pretty close to 30 mpg. The SHO engine is naturally aspirated,
has
>> four valves per cylinder of course, and has two intake runners for
each
>> cylinder; a long one, and a short one that opens up above 4,000 rpm.
I
>> don't think the valve timing changes with rpm, but I assume there's
some
>> dual pattern setup at least. This whole package comes about as close
as I
>> can imagine to having your cake and eating it too. And, of course,
this is
>> not the only modern engine out there with these kind of manners. To
get my
>> 289 to run this well over the whole rpm range I'd probably want to
start
>> with a set of Gurney-Westlake heads, fuel injection, dual runners,
etc.,
>> etc., and lots of $$$$$. BUT, it could be done, and be very
driveable, and
>> make 400+ horsepower, and even get decent mileage too (20+). So, in
>> summary, I think you're way to pessimistic with the referenced
statement.
>> Even just a roller cam will give you a motor that runs well over
quite a
>> broad rpm range; i.e., just like a new 5.0L.
>>
>> On to hot button #2: What's this about the toploader being a farm
>> implement? Hey, I love this brutish piece of machinery. Can't imagine
>> having a wussy tranny behind a big bore motor; just doesn't fit. Kind
of
>> Zen thing you know. And hey, this tranny is so good, they even make
>> adapters to put it behind Chevys! Sure, it takes a firm hand to use
it, but
>> it downshifts a 7000+ rpm just as easy as at 2500. And, of course,
it's
>> probably the most rugged tranny you can find in a passenger car or
truck.
>> You're absolutely right about the Mazda tranny though; that's what's
in my
>> SHO. BTW, the new 5-speed boxes are a lot smoother shifting, although
I
>> haven't tried the Tremec which I believe is more like the toploader
(so of
>> course this is the one I want).
>>
>> And finally, I'll bait you with this question: Just where in the rpm
range
>> does the important parameter go from being horsepower to torque? The
answer
>> is nowhere, but for some reason most people talk about torque in the
low
>> rpm range and horsepower in the high rpm range. Just seems
unnecessarily
>> confusing to me. Just look at the horsepower versus rpm curve and it
tells
>> you everything you need to know.
>>
>> Just tryin' to stir up some trouble in San Diego,
>>
>> Bob
>>
>> At 11:07 AM 2/4/99 -0700, Theo Smit wrote:
>> >The funny thing about engine power is that you can't make it
everywhere. Any
>> >piston engine built to develop maximum power "well above" 5000 rpm
is not
>> going
>> >to perform worth beans at 2500 rpm and below. And that means you
can't use
>> 2.88
>> >gears anymore. Not having 2.88 gears means you get to row the
gearbox driving
>> >around town, and let's face it: The toploader shifts like a farm
implement
>> >compared to any Japanese transmission (okay, not Mazda's :) built in
the
>> >last 30
>> >years.
>> >
>> >And what's GOOD power in a V-8? 1 hp / cu.in? You won't get much
over that
>> >using
>> >factory heads, even with porting and oversize valves. Even making
400 hp
>> out of
>> >a 302 only gets you 1.3 hp / cu. in., and I would like everyone who
has a
>> real
>> >400 hp Tiger that is pleasant to drive around town to share their
secrets,
>> >please. The only thing that saves high-RPM V-8's is that even if
they are so
>> >tightly tuned that they only make 60 ft-lb of torque at idle
(compared to say
>> >300 at peak), that's still enough to move a Tiger off the line with
>> reasonable
>> >vigor. With a smaller engine, having that kind of peak to idle
torque ratio
>> is
>> >going to make the car hard to drive. Not that it can't be done, you
just
>> >have to
>> >drive like you're on a mission everywhere you go.
>> >
>> >Theo Smit
>> >tsmit@novatel.ca
>> >B382002705
>>
>> Robert L. Palmer
>> Dept. of AMES, Univ. of Calif., San Diego
>> rpalmer@ames.ucsd.edu
>> rpalmer@cts.com
>
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