Exhaust delete option

[billt]

The muffler on my '99 V-8 was removed by the previous owner but sent to me in a box in case the inspection police got picky. If anyone is thinking of doing this you don't have to worry about excessive noise as the turbos and cats do a nice job quieting by themselves. The car passed inspection though I wouldn't take it to someone too familiar with Lotus's. The muffler is surprisingly heavy so this is a plus too. I've got to say the sound is quite pleasing and not at all loud. I'm 56 years old and gawd I love this car!

[mangel]

good on ya!!!

[oneshot]

If that's a V8 then bear in mind that the exhaust (muffler) forms part of the rear diffuser aerodynamics and removing it will affect the rear aerodynamics (and I guess stability at high speed). People I know that have removed it have fabricated a replacement part for the aerodynamics.

[DBredS4]

ideal opportunity to have a glass fibre diffuser knocked up, something subtle and efficient to replace the weight of the exhaust with simple downforce.

[Dave Freeman]

I like the idea of a rear diffuser, would not mind the challenge of making one up. Does any one have any sketches, drawings or tech info to show how it works and why, dimensions etc.

Be interested to know.

Dave

[molemot]

Brawn GP seem to know a bit about diffusers....!

[Bibs]

The diffuser makes the air under the car leave quicker. By the time the air has made it to the back of the car the pressure has increased dramatically so causes a degree of lift aka a reduction in downforce. The diffuser aims to drop this pressure and reduce lift on the rear of the car.

As for the design, bear in mind that you can't change the angles much, they have to be fairly straight but have a slight and gentle upwards curve and include strakes which smooth the airflow and increase the rate at which the air can leave. The actual minutae of the design depends on the configuration of the car, what effect the underside already has, wheel positions etc so for an Esprit you'll either need an engineering degree and be familiar with the Navier-Stokes equations or just have a best guess based on typical designs.

This one is from Mike Sekingers old GT1 rep.

[russellbosier]

A properly designed diffuser will not just reduce lift, it will create downforce. It will speed up the air exiting from under the car. If the mass of air is constant, but the velocity is higher, the result is less pressure, hence downforce.

[Bibs]

I think that one could argue that reducing lift and creating downforce are the same thing.