Rear exhaust pipes ?
Discussion
steve-V8s said:
The standard arrangement adds to already rather poor areo under the car. The boot floor is nicely diffuser shaped but the flow is all messed up with the splayed out pipes. Two coming straight back gives much improved flow under the car.
I think you have slipped into the twilight zone....I don't think air passing under your car will effect performance in Speed Camera Britain. I do hope that was tongue in cheek?Shezbo said:
I think you have slipped into the twilight zone....I don't think air passing under your car will effect performance in Speed Camera Britain. I do hope that was tongue in cheek?
Not really tongue in cheek, air flow under the car and particularly how it exits at the rear has a considerable effect. Try sticking you hand out of the window at 60mph to feel the forces then consider the surface area of the exit pipes compared to your hand. To be fair I was thinking of track or competition use as improvements are more noticeable above 90 mph or so but even at lower speeds drag and lift are quite significant. The Griff has an almost flat floor but it is spoilt by the anti roll bar arrangement and the exhaust exit pipes.
To make the air flow work properly it ideally needs a splitter at the front to send more of the air over the top and speed up the remainder that does go underneath, then it needs a nice clean tapered exit at the rear and ideally small spoiler on the boot lip, the easiest of those to do is the exhaust.
Almost all recent car designs have some sort token effort at deflecting air at the front and getting it out cleanly at the rear, the better ones actually have flat floors and diffuser shaped boot floors to reduce drag and lift. Mostly the entire exhaust system is tucked up out of the air flow.
Standard looks great and personally don't like four. Only other option I'd consider, ( if I still owned one! ), is side exit if car was suitably modded but not sure if could exit below rear end of sill or would need to be poking through wing just ahead of rear arch? If so could a subtle diffuser/flat floor leave a nice finish at rear? Just a thought
My home grown rear diffuser. Not for the faint hearted but it does work. I have modified my exhausts to be straight and centre exit to avoid impacting on the airflow as well. You can just see the tips of the pipes in the middle. It is a very easy mod to do. Just cut them before the bend sideways add a small straight section and use the original curve rotated 90 degrees to kick them up slightly at the back.
My front splitter
My front splitter
Edited by jesfirth on Sunday 1st March 18:13
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