[runn141]

i have several nascar diecast model cars. and i noticed that the ones from 1995 and up have 2 H pipes in the exhaust and the ones 94 and older have only one. now i can remember the 95 season when the sound of the cars started to sound more like the indy cars. i remember it was the #4 kodak car sterling marlin drove at daytona that had the sound first, then about mid season the secret was out. i just cant remember what it was, but i remember it was something about a crossover in the exhaust. and looking at these model cars made me think. does anyone know what it really was? or was it the 2 H pipes that made the sound?

[poncho62]

The exhaust on NASCAR cars changes from track to track........I suppose for the different RPM ranges, but mostly it is clearance issues when they go around the corners......

[trees]

The #4 was Sterling Marlin's ride when he was the short lived King Cong of the restrictor plate tracks, Daytona, in particular. It is my understanding his team had come up with some old, but proved, exhaust theory that worked well for them until the others caught on. Their system was header tubes of the same length followed by a siameased X pipe located at a calculated distance from the collectors based upon when the exhaust gases become subsonic. This theory works good for racing where there are long periods of near constant RPM ranges and NASCAR big tracks and Indy cars fall into this category.

Trees

[runn141]

Originally Posted by trees

The #4 was Sterling Marlin's ride when he was the short lived King Cong of the restrictor plate tracks, Daytona, in particular. It is my understanding his team had come up with some old, but proved, exhaust theory that worked well for them until the others caught on. Their system was header tubes of the same length followed by a siameased X pipe located at a calculated distance from the collectors based upon when the exhaust gases become subsonic. This theory works good for racing where there are long periods of near constant RPM ranges and NASCAR big tracks and Indy cars fall into this category.

Trees

ok, that makes sense, but would there be any benefit of having 2 H pipes?

[trees]

I don't know of any. Are you sure there are 2 H pipes? The advantage of an X over H is significant enough to not even consider an H at all. I am not sure even a X pipe would be beneficial on a short track where high revs are not maintained over a relatively long period of time.

Trees

[runn141]

Originally Posted by trees

Are you sure there are 2 H pipes?

Trees

just what ive noticed on the diecast model cars i have. i didnt know if there was some sort of advantage of having 2.

[johnsongrass1]

YES, there is a good reason. However it is not spoke of. Each cam profile likes a difference in exhaust pipes on those cars as well.