[DeTomaso] Engine Noise

Wed Apr 4 12:23:16 EDT 2007

Maybe someone can describe the dynamics of a lumpy idle?  If switching to an IR system changes it, I suppose it's at least partly the interaction between cylinders.  If EFI reduces it (with a similar manifold) it would seem to be a fuel modulation issue?  But I think EFI just likes a different cam also, and maybe the cams which EFI likes just don't produce as lumpy of an idle? 

  Time to go back to school.

  Ken

Phil Lockett <montecarlo296 at yahoo.com> wrote:
  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 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.
>
>
>
> ---------------------------------
> Don't pick lemons.
> See all the new 2007 cars at Yahoo! Autos.
> _______________________________________________
>
> 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
>
> _______________________________________________
>
> 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
>

_______________________________________________

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

_______________________________________________

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

Bigger,louder, faster, better.

---------------------------------
Sucker-punch spam with award-winning protection.
Try the free Yahoo! Mail Beta.
_______________________________________________

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