[Healeys] Exhaust system advice needed

[Eric (Rick) Wilkins]

That totally makes sense.

Being well versed in the mechanics at the high level, have you ever  
dyno tested a simple exhaust "upgrade" on Healey?

On Sep 11, 2009, at 1:27 AM, Oudesluys wrote:

> If it is a properly designed freeflow exhaust you may. What I wanted  
> to get accros is that the surface area of the exhaust opening being  
> smaller than that of the carbs does not say anything. The speed of  
> the exhaust gasses passing is a lot higher than on the carb side so  
> you cannot compare. Similarly the exhaust valves are smaller than  
> the inlet valves. A stock engine needs a certain amount of back  
> pressure and resonance. If you reduce the back pressure to zilch it  
> will not function properly without other mods to at least valve  
> timing, carburation and ignition curve.
> I have done enough tuning in my time on a dyno on many engines to  
> have found out.
> Kees Oudesluijs
> NL
>
>
> Eric (Rick) Wilkins schreef:
>> I understand what you're getting at. The "what" is that 50 years  
>> later we know that a Healey came from the factory with a fairly  
>> restrictive exhaust system. We also know that by increasing flow,  
>> we can gain a bit of added horsepower--without changing anything  
>> else.
>> Sure, with newer cars being tuned pretty well from the factory,  
>> gains from a simple exhaust "upgrade" are very limited. It's not  
>> rocket surgery.
>> Get a dyno, measure a stock spec Healey, and measure one with a  
>> freeflow exhaust. I'd bet that you'd see an improvement.
>>
>> On Sep 10, 2009, at 1:53 PM, Oudesluys wrote:
>>
>>> Yes, so what?
>>> Kees Oudesluijs
>>> NL
>>>
>>>
>>> Eric (Rick) Wilkins schreef:
>>>> I'm pretty sure that in the case of a factory Healey, the added  
>>>> flow is going to give an increase in performance as the stock  
>>>> system--BN4-BJ7--is smaller than the opening allowed by the carbs.
>>>>
>>>> Wilko
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