[DeTomaso] [Fwd: Re: automotive related questions!]

Dave Londry davel at emspace.com
Wed Dec 10 18:19:36 EST 2008


Good enough.
I understand the way exhaust pulses occur OK; it was the 'each exhaust 
pipe' part I slept through in Paul's email.
They are 180s because there is one exhaust pulse every 180 degrees 
*****from each collector*****.
(4 evenly separated pulses every 720 degrees per pipe)
dave

adin at frontier.net wrote:
> close.
>
> In the 180 headers two cylinders fire out of one pipe. You will get a 
> pulse every 180 degrees of crank.  To satisfy your math fetish . . .um 
> I just realized I can make numbers but there is no justification or 
> logic to the equation.
>
> You're going to have to have some faith . . . .
>
>
> Quoting Dave Londry <davel at emspace.com>:
>
>> 720/8 = 180 ??
>>
>> asajay at asajay.com wrote:
>>> It takes two revolutions to complete four strokes for all eight
>>> cylinders, yes.  Each cylinder must make four strokes:  Intake (piston
>>> goes down), compression (piston goes up), ignition (piston goes down),
>>> exhaust (piston goes up).  So you see, exhaust only happens every
>>> -other- time the piston comes up, so the crank has to make two
>>> revolutions to complete one cycle.
>>>
>>> :)
>>>
>>> Asa Jay
>>>
>>> Quoting Dave Londry <davel at emspace.com>:
>>>
>>>
>>>> 8 cyl every 2 revs or 720 degrees??
>>>> dave
>>>>
>>>> Paul - Home wrote:
>>>>
>>>>> I have a few guesses and they are only guesses because the standard
>>>>> Chevy firing order also supports crossing the banks to get 180 degree
>>>>> headers.
>>>>>
>>>>> 1. It didn't fit well in the body work
>>>>> 2. They just didn't care to optimize that closely
>>>>> 3. They were running a flat crank which doesn't need to cross banks.
>>>>>
>>>>> For reference they are called 180 degree headers because each exhaust
>>>>> pipe will output once every 180 degrees of crank rotation.
>>>>>
>>>>> Paul
>>>>> #9270
>>>>>
>>>>> michael frazier wrote:
>>>>>
>>>>>
>>>>>> Thanks for the info.  Any response on the 2nd question?
>>>>>>
>>>>>> Michael...it was in the 30s last night and the 50s today.  Looking
>>>>>>  for a winter project since it's too cold to go outside.
>>>>>>
>>>>>> (2nd question: After looking at photos of GT-40s, Lolas, McLarens,
>>>>>>  Chapparals, etc, I noticed the Ford poweredvehicles used 180s
>>>>>> while the Chevy powered ones did not (generally). Any thoughts
>>>>>> about that? Boat type headers?
>>>>>> I asked about building a set of Pantera headers like that awhile
>>>>>> back. You could run longer tubes, a crossover pipe,
>>>>>> less connectors and simpler build while still getting the zoomy
>>>>>> racy look for those who go just for that. Any thoughts on that one?)
>>>>>> _________________________________________________________________
>>>>>> Send e-mail anywhere. No map, no compass.
>>
>>
>> _______________________________________________
>>
>> Detomaso Forum Managed by POCA
>>
>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>
>> DeTomaso mailing list
>> DeTomaso at list.realbig.com
>> http://list.realbig.com/mailman/listinfo/detomaso
>>
>
>
>
>
>

-- 
Dave Londry
Embedded Spaces Inc. (ESI)
davel at emspace.com

604 589 9183 phone/fax
604 721 2278 cell
Skype:embeddedspaces





More information about the DeTomaso mailing list