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Learn me some aero

Old 09-03-14, 10:25 PM
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SD Learn me some aero

Ok I have been out of the RX-7 game for a while and have been working on old datsuns. On that end of the spectrum we always wanted to reduce front end lift by directing the air flow either over the car or through ducting for the rad through the hood area and never under the car.

Move on to today and I am researching intercooler setups, which in turn had me looking at V-mount setups. Me being me I was thinking v mount meant verticle and for a split second I got vertical and horizontal backwards lmao. So V-mount is the shape of the mounting.

Onwards past my inevitable southern retardation and dyslexia. So the setup pushes air both through the hood and under the car correct? Isnt the air moving under the car a bad thing or did I miss something. Wouldnt a stacked radiator and IC be a better choice when vented properly and take away the push of air under the car?

Sorry if this is completely noobish just wondering.
Old 09-04-14, 08:56 PM
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This has always slightly bothered me too... but stock all the air goes under the car, so it's slightly better...

it also cools a lot better, it's always better to be able to go flat out because your car is now overheating Most people can't get away with front mounts on tracked rotary's because they block the radiator.
Old 09-04-14, 09:33 PM
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In the Z cars front lift is a major thing. I never felt like that in the old T2 way back when, but your also talking 20yrs difference in design. Maybe a stacked horizontal setup would work aswell, who knows, to the wind tunnles.
Old 09-17-14, 06:42 PM
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Read this thread: https://www.rx7club.com/race-car-tec...fuser-1069943/
Old 09-22-14, 09:52 AM
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There is alot more to aero then just that . if you look at the V mount's setup the lover part of the Vmount will produce downforce , while the upper part ( IC part will product some lift ) this is true .

but with a properly ducted bumper , and radiator . The downforce will be much greater then the lift just alot more surface area .

That being said your bumper is a BIG part of this . and so is any kind of lip

Also when you think of it like this . Lift is bad But blown engine is worse .
Old 09-22-14, 12:23 PM
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In race car engineering air flowing under the car is an opportunity to create downforce with the airflow. Search "venturi effect".

When shaping the car's underside is not allowed by rules, that is when you limit airflow under the car and go with a flat bottom to reduce drag and lift.

Problem is if the flat bottom car gains any angle of attack (hits bump etc) to the oncoming air it gains lift and flys away.

Search "flying Mercedes" or "Mercedes CLR". Not one, not two, but three Merceds CLR took flight in 1999 races in spectacular fashion before they canceled the program.

What racing will you be doing? The rules dictate aero.
Old 09-22-14, 12:42 PM
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Originally Posted by BLUE TII
In race car engineering air flowing under the car is an opportunity to create downforce with the airflow. Search "venturi effect".

When shaping the car's underside is not allowed by rules, that is when you limit airflow under the car and go with a flat bottom to reduce drag and lift.

Problem is if the flat bottom car gains any angle of attack (hits bump etc) to the oncoming air it gains lift and flys away.

Search "flying Mercedes" or "Mercedes CLR". Not one, not two, but three Merceds CLR took flight in 1999 races in spectacular fashion before they canceled the program.

What racing will you be doing? The rules dictate aero.
That and air getting caught in the wheelwells.. which is now why you see vents in the tops of fenders in all P1/LMP cars now.

This is also why NASCAR did away with the carbon fiber rear spoilers on their cars a few years ago and went back to blade spoilers. If a car turned around at speed the carbon spoiler created lift and the car could flip in some conditions.
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