JayWest

I've been wondering this for a while and seem to get mixed opinions. Most all motor cars seem to either have a 3pc front or if they use the stock bumper, they have the gaps blocked off (pepsi, yosolo, sipes...). Would doing something like this benifit an all motor car trapping 116ish? I'm going to try it out anyways but just wondering if anyone has done any testing with it.

germanegturbo

even when my car was only trapping 120 i blocked off the foglight holes and lowered the car qnd gained mph..same with kyle..hes traping lower than you and i told him to lower the car and he did and the mph went up..less wind resistance..more mph lol

EJ1_Ex

iTrader: (1)

i'm interested in knowing this topic too..

bauergold

+1, in for more results.

Have a car that is only trapping 104mph, so I don't know if it would make that much of a difference in my case.

2k.civic.si

look at cars they run on the salt flats....that outta tell ya

pumafeet10

anything above about 50mph and your coeffcient of drag goes up, well your cd doesn't actually go up it just comes into play more.

Sealing the engine bay up will make a difference and lowering the car as well. Adding a belly pan will also help a good bit, but what most people don't realize is that the biggest improvement you will see is if you work on the back of the car

0xenocron

Your CD goes up exponentially as speed increases...but every just needs to make more power and that takes care of that

MrParks

our fwd cars are pretty aerodynamic from factory. typically ive personally seen as low as 60mph do dramatic things on a f1 car in tunnel testing at swift. but thats f1.

the lower and longer you can get the car, the better the cd will get.

Kevin

I believe every competitive car should work on the aerodynamics if at all possible. Your car is consistent enough that you should be able to make changes and monitor the improvement.

nonvtecallmotor

I raced allmotor years ago and I had an EF hatch that went 105mph switch to a heavier CRX and went 108mph with EVERYTHING the same from the hatch... The roof line is about 4-5"s lower on the CRX. So I think it matters a bunch at any speed.


When I started going 150mph I removed the duck bill for 1 pass, I slowed up 2-3mph and lost stability. I'll never do that again

heavy duty

What about the holes in the rear bumper is it better to do that or is it better to do a belly pan under the back of the car.

dustin528

this is an interesting topic! I have been planning on changing a few things like this on my car...

pumafeet10

very true i just couldn't quantify what i was thinking, but yes i does go up exponentially as the speed increases.

one of the biggest improvements to be made on civic in particular is the back of the car

being a hypermiler myself and worrying about gas mileage the thing that you need to try and do is keep the air attached as long as possible without making it turbulent and detaching from the roof.

Like the vortex generators on Evo MR's it keeps the air on the window the through the wing for added downforce, but for drag racing you really don't want rear downforce for FWD.

You really want the back end of the car to look like this >

It is the same shaped used on the back of the space shuttle when being flown on top of the 747

2fastGSR

Look at all the studies some have done about changing aero to improve gas mileage. These tests are typically done at constant speeds of 65mph. Even though in these tests, the flow of air is a constant force - and we only fight those speeds for a few seconds, I feel that the data is still relevant. If someone can change the way their commuter car looks and gain MPG it means its cutting through the air better. Exactly what we would want our cars to do.

Most of these tests will tell you to block the front of the car off as the first move. Some have said just taping it off will help force the air above or under the car instead of trapping it in the engine bay. Hope that answers your first question lol.

I have played around with a few underbody aero designs and havent really seen much change with them on and off. Just like Pumafeet ( a great source of info btw lol ) said - I think a lot of it comes into play with how the rear of the car shaped. The faster the air can exit the rear, the faster it will move from under the car.
However this can be a catch 22. Move it too fast and it creates downforce. Which on some Outlaw turbo cars going 180+ might not be a bad thing, It will not be something our 120mph all motor cars can deal with in a positive manner. That is just my opinion for right now, until my tests prove otherwise lol.

I will be doing some tests on the rear underbody at the end of the year as everything calms down to see what it really will do.

I think we can definitely gain some ET by changing the way our cars cut through the air, its just determining how far we will have to go or what parts will work well in conjunction with others. If you want some good reading, look up the "aero civic" or read a book called Competition Car Aerodynamics by Simon Mcbeath. A lot of what is out there does not come out and say it will work on a drag fwd application, you will have to decypher what you think will work.

pumafeet10

ii was just going to mention www.aerocivic.com

I know most will think that it is just insane but with the caveat that IT WORKS.

he has done 90mph and achieved incredible mph, stability, less wind noise, heck even a cleaner car, which is just kind of odd but shows that with the aero civic the air flows so smoothly and turbulence free .

I have seen that underbody aero does not change alot but as part of a complete plan it needs to be done. Also think about your wheels and wheel wells whether you add mooneye covers or wheel well spats/covers.

The shape of > atleast from my reading creates a neutral wake as it will only create negligible down force/ lift

we all know the shape of a wing so that the faster air moves over the car creating lift but if you lower it enough and keep the air from underneath then it won't create much lift so i think that will be ok, none of our street cars will be perfect but with doing these retrofits i think they can be pretty great.

BMo Tuning

I'd say about 0.0000000000000000000000000000000000000000001mph is where it comes into play.

Turbogixxer

Very good post. You hit a lot of good points.

JayWest

Thanks for all the info guys
I will definitely be putting a few things in effect for my next race in december

bigTom

for what its worth pepsi's bumper currently does NOT work very well... me and pepsi made it a couple months ago and while it looks cool and fits the car perfect; it actually slowed the car down MPH wise... the bumper is the only aero piece on the car though... other addditions IMO would help BUT... me n pepsi have discussed changing it but until someone else actually gives him a run for his money; theres no reason to fix it if it aint broke!

MARC P

^ Bello knows what to take off the bumper to make it work better.

But like you said, keep him slow lol

Marc P

JayWest

well damn, im glad you posted that. i took a **** load of pics of his front at nationals and thats what i was planning on going for lol

E Town DSM

Ive heard of the 3 piece fronts even slowing the all motor guys down.

MARC P

^ I would agree with the JOJO front, because it is so boxy in design.

Marc P

tony1

Not so much about boxy, just being wide. Norris' new car looks like it had some thought behind it in terms of aero. It's not 18 miles wide like most of these cars.

vtekthis

At the speed the all motor cars are running nowadays, its enough to sustain flight.
Just some food for though.

I can tell you that i am chaning my whole roof panel in the near future, and intergrating a LVDT from an airbus too it that can benefit in more than one way. **** brakes