Gary Burrell writes:
> [ I wrote: ]
> > One distinction which I feel needs to be made here, and for some of you
> > it may fall into the realm of nitpicking, but I'll make it anyway:
> > Brake performance has nothing to do with engine performance. Sure, it's
>
> > The only case in which an engine upgrade necessitates a brake upgrade is
> > top speed. If you increase your top speed, then braking FROM THAT TOP
> > SPEED will require more energy dissipation. But it takes a whole lot of
> > horsepower to overcome the aerodynamics involved.
> .... Much deleted
> >
> > Please note that this is explicitly NOT a suggestion to take a cavalier
> > attitude regarding brake performance. You can never have too much
> > brakes, no matter how powerful your engine is or how fast you go. My
> > point is simply that there is no direct causal relationship between
> > motor and brakes.
> >
> I beg to differ here. A higher performance car will get you to
> a higher speed faster, thus giving you less time to brake, hence
> the need for better brakes. Illistaration 2 cars at a stop light
> 1 low power, 1 high power. Some distance down the road is a
> obstruction which can be see from X yard away. Both cars leave
> the light but don't have a chance to get to top speed before reaching
> braking point, high power car would be going faster hence need better
> brakes than low power car.
You didn't read what I wrote (and you snipped the most important part).
Fact: Higher speeds require the brakes to dissipate more energy than
lower speeds.
Fiction: More powerful engines force you to drive faster.
Understand?
> > > 3) Competition Style exhaust with Long Center branch Header
>
> > Actually, the dual-carb factory exhaust manifold is pretty darned good.
> > Does anybody have any hard numbers on the performance gain that a LCB
> > header nets?
> >
> Yup, see below
>
> > > 5) Electronic Ignition kit. I used the crane/allison kit
> > > but the new in the distribuiter type looks nice too.
> > > (cost $100) I also used a sport coil ($40)
> > > (More power to sparkplugs)
> >
> > All the electronic ignition really gives you is reliability and
> > stability. It doesn't actually make any more power. The Sport Coil may
> > allow you to open up your spark plug gap, which will make power, but not
> > a whole lot (again - anybody have any hard data, so I can quit making
> > such qualitative musings?).
> >
> Well no quanitiative data but qualitative data. Sport coil allows
> higher voltage at plugs.
Agreed.
> Electronic Iginition also supplies more
> power to plugs than points,
Disagreed. Electronic Ignition doesn't send a damned thing to the spark
plugs. Electronic Ignition ONLY tells the coil when to fire.
> Also at high RPM (5500) points suffer
> from point bounce)
Right; forgot about that one.
> A quote from "Performance MGB" about the
> Newtronic (Pirhana) Electronic Ignition: "We ran a rolling road
> comparison test against conventional points. The resultant power
> curves prove the Newtronic Ingintion system offered greater power"
> My results on my car (qualitative) support this.
There isn't enough information here to debate. And I still contend that
any increases in power due to "hotter spark" come directly from the
coil.
> > > After you've done this you probably want to change the carb
> > > needles on your SU's to something slightly richer
> >
> > I've never quite understood this thinking. If you need a richer
> > mixture, why not simply turn the jet screw a few flats?
>
> This only serves to richen the mixture at Idle not accross the
> entire power band.
I'm sorry, but this is blatantly incorrect. Do you know how SUs work?
And can anybody else tell me why engine modifications require a
different needle?
> O.K. Now for Some real # from MOSS UK "Performance MGB"
>
> Stage 1: K&N Filters, LCB Manifold
>
> And now the numbers measured on a dyno
>
> Stock: 74.1 bhp 105 ft/lbs
> Stage 1: 80.7 bhp 110 ft/lbs
>
> My obsevations 9% more power just by adding K&N and LCB header
Yes, but how much does the LCB header alone net you? K&Ns are routinely
claimed to yield 3 to 5 horsepower; how much does that leave for the LCB
header?
--
Todd Mullins
Todd.Mullins@nrlssc.navy.mil On the lovely Mississippi (USA) Coast
'74 MGB Tourer with unknown coil
Atheist #685 "Whatever, baby."
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