Why do Italian & American V8s sound different?

the lamborghini jalpa has an amazing exhaust note....... something makes them sound like a Cosworth v8 from the 70's .

 

Absolutely one of if not the best sounding mid engine V-8s.
I've been studying that engine and exhaust system some while designing one for my car. The engine is also a transverse 4 cam 2v V-8 (with chains!) and a flat crank I am told. The one thing that hits you about it that the Ferraris do not have is that the exhaust system is LONG comparatively. Transverse Ferrari V-8 exhaust systems have very little in the way of straight pipe - mostly just the small acoutic box muffler with a short turn in from the header and turn out to the tips. The Urraco/Jalpa had long sections of pipe that then went to two separate mufflers. I've attached a photo from the Larini website showing the Urraco/Jalpa configuration (interesting, as they do not market an app for that car). You can see that the tubing goes around the muffler entering medially then exits on the sides, giving a long section of pipe to resonate in. Also notice the long secondary pipes on the header.
Just some casual observations.
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How do you make a "flat crank" with a V-10?

 

Large CID engines are large engines

Small CID engine are small engines

To build a large engine, you need a lot of metal

A lot of metal = heavy

Generally speaking, US car manufacturers don't place as much emphasis on handling as Euro car manufacturers do. This is because the average US street is a straight line, whereas the average Euro street is more crooked than Lombard Street in San Francisco.

So.... because in Europe we have these crooked streets, we want a nice handling car, which requires a nice lightweight engine, and in order to get this engine light, we give it small displacement and in order to get the horsepower we want, we rev the hell out of it.

So, there you have it, in a nutshell

Hans (from Euroland)

 

I absolutely agree. the little lambo's exhaust note is intoxicating...but they aren’t flat cranks. all P111, P200 P250 P300, P118 silhs/jalpas are 90 degree cranks. Its quite an exrodinary sound for a non flat crank car. I have always wonder why it doesn’t rumble like a yankee V-8 (thank goodness).

ive found the P300 sounds the most savage with only a thin plan of glass separating the driver from that beautiful shrieking motor. its the closes sounding motor next to my old GSX-R. the jalpa is a somewhat more civilized with the longer stroke , lower CR and milder cams. Having a engine deck lid suppresses the sound also. its sadly even more muted with the USA cat equipped cars. I havent driven the P111,P200 or silh drivetrain to comment on.

best V8 sounding motor outside an old DFV? IMO F355 with aftermarket exahuast and a F360 a distant 2nd. even in this company, the urraco holds up well.


hf

 

Just like food, european cuisine is all that and american is good tasty crap that gets the job done.

 

If anyone here has the September 2007 issue of HotRod magazine laying around there's a great expanation-in-a-nutshell regarding header design theory. It takes up pages 150-157 and it's said in a way that even a beginner can understand if read carefully. They touch on 90 vs 180 cranks, 180 vs 360 headers, firing order complications, different kinds of pressure waves, collector shapes and lengths, and how firing order affects collector efficiency. Good write up!

I especially like the comment, "In theory, the ultimate solution to the V-8 firing-order conundrum is the single-plane crank (aka, a 180-degree crank)"

I personally think the F355 is the most awesome sounding car I've ever heard at WOT.