Low end performance is good. This is a track car built specifically to
compete in the Grassroots Motorsports $2002 (and $2003) Challenge.
A bypass valve is an economy device. If I have an extra $30 in the budget
I'll probably put one on just to cool the intake while idling (less work
done by the blower means a cooler intake manifold). The rules limit us to
$2003 (including the cost of the car) so I'll probably have to do without it.
We'll publish details of our intercooler design after the event (April
4th-5th in Gainesville Florida).
Blower RPM (and hence CFM) is determined by the drive pulley ratio. You
choose pulley diameters to give the peak CFM you need. Roots blowers are
inefficient at low RPM. A car with a small blower will be faster than a car
with a big blower that's geared to deliver the same amount of air. At low
engine RPM the small blower will be more efficient. The area under its "RPM
vs. horsepower" curve will be larger.
(Train A leaves New York and accelerates to 120 kph at 1
meter/second/second. Train B leaves New York at the same time on a parallel
track and accelerates to 120 kph at 2 meters/second/second. Which train
stops in Washington DC first?)
We did find that using a narrow V-belt on a small diameter pulley was a bad
idea- the belt started to slip at around 5-6 PSI of boost. Going to a
slightly wider belt and proportionately increasing both pulley
diameters solved the problem.
(Answer: It depends on the brakes. If train A can delay braking long enough
it can catch up with train B and win.)
At 07:31 PM 11/26/2002 -0500, Mitchel Seff wrote:
>Erik-The M90 pushes about 20% more cfm at the sam SC rpm speed,
>something I hadn't thought about since the displacement rating brought
>me to the M62. I would imagine the lower initial CR allows for the
>greater pressure. How is the low end performance & are you using the
>by-pass valve.
> From my experience the plumbing for the intercooler might negate the
>benefit because of the extended piping . If you figured out a way I'm up
>for it.
>Is this a street car or track only? Fork over some details , I interested.
>
>--
>Mitch Seff
>Oceanside, N.Y.
>75 TR6
>http://www.angelfire.com/ny4/triumph5/
--
Erik Quackenbush, Midwest Filter Corporation
1-847-680-0566 http://www.midwestfilter.com
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