[DeTomaso] Engine Noise

Wed Apr 4 12:21:27 EDT 2007

Here's a picture of the engine bay:

http://www.saabklubben.com/arkiv/traeffar/classic_car2005/050827072.jpg

I remember now that the exhaust is not a true 90 degree, although it 
sounds correct :-)

And modulating spark timing would probably have more and faster effect 
than modulating idle air. The Ford EFI:s use a combination of air and 
timing to set the proper idle.

Thomas

Phil Lockett skrev:
> I'd have thought that mudulating (lmao!) the airflow would make the engine hunt as opposed to acheiving lumpiness - as the air involved is fluid. I suppose a bigger cam for one of these is gonna be difficult - but you never know with our German friends and those Autobahns.
>    
>   Phil
> 
> Ken Green <kenn_green at yahoo.com> wrote:
>   If you really want the lumpy idle, I'd guess something could be added to an EFI with an idle air valve to mudulate the air flow at idle and get a lumpy effect. Kinda like the fake blow off valves the kids get. Is a lumpy idle (or the conditions which create it) hard on plugs?
> 
> Ken
> 
> adin at frontier.net wrote:
> When I was young Moses told me that lumpy idle was due to cam overlap. 
> Now Dan J says it is manifold affected. Weber/EFI probably won't 
> have the rumparumpa of a big Holley.
> 
> I do know the rumparumpa idle prevents street racing! ("I'm not 
> racing THAT thing!") True story.
> 
> Dan: did the Florissant gig go through? Have the Cobra - its a beast!
> 
> David in Durango
> 
> 
> 
> 
> Quoting Charles McCall :
> 
>> Phil -
>> Lumpy will be related to cam and throaty to exhaust, more or less.
>>
>> You may lose some lumpiness going to a stock BMW due to the cam and the FI.
>> I remember that Kirby Schrader had a fairly aggressive cam in his 377
>> stroker, and he commented that some of the lumpiness went away when he
>> installed EFI. He sounded kinda bummed about that! :-)
>>
>> I'd recommend separating lumpiness from sound level. A more radical cam will
>> give you a lumpier idle. The noise level, and to some extent noise quality,
>> depends on the exhaust. Stock Ansa Pantera exhausts are (relatively) quiet,
>> GTS a little less so, and some of the aftermarket mufflers like Mind Train
>> are, well, really really loud! When going from a Mind Train equipped Pantera
>> to one with a stock GTS system it sounded as though someone had stuffed a
>> pillow in the muffler.
>>
>> Describing sounds is really hard. The best way to decide is to go to a DTDC
>> meeting and go out in the parking lot and listen! Ask the owners what
>> exhaust system they have. Everything else will be subjective. How do you
>> define "loud", or "lumpy", or "awe-inspiring" or "wussy"?
>>
>> The only other advice I can give is that I have driven BMW-powered Guaras,
>> and a 5.0 liter powered Pantera Si. While both of them were quick, probably
>> quicker than a stock Pantera, I missed the rumble of the Cleveland, and
>> specifically the vibration that you FEEL more than HEAR. A Pantera shouldn't
>> just be loud, but should treat ALL your senses. You feel the Cleveland
>> rattling your fillings - not in a negative sense, but you can feel it in
>> your bones. The other powerplants felt too isolated. May be due to the
>> difference in construction of the later model cars, but that was my
>> impression.
>>
>> -----Mensaje original-----
>> De: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] En
>> nombre de Phil Lockett
>> Enviado el: Wednesday, 04 April, 2007 11:55 AM
>> Para: detomaso forum
>> Asunto: [DeTomaso] Engine Noise
>>
>> Guys, I've been listening to some Panteras on Youtube - mostly Euro based I
>> think. Most of them seem to have a seriously lumpy tickover with the
>> "splickety splack" noise (technical term) when throttled. Other ones are a
>> lot quieter and less lumpy - I expect being more standard setup. Is the
>> lumpy tickover due to tuning and aftermarket exhausts? The big question
>> being am I going to lose all of this if I fit a BMW engine? The BMW engined
>> Sprinter on Youtube sounds like a Wailing Banshee - but it's just not
>> throaty enough.
>>
>> Comments please (I've been offered a cheap BMW 4.0V8 engine.)
>>
>> Phil
>>
>>
>> Bigger,louder, faster, better.
>>
>>
>>
>> ---------------------------------
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