Aerodynamics for VW golf drag racing?
 

Hey guys... found this forum on google. Seems like a great place with knowledgeable helpful people.

I know some of you may not like this.. but I was wondering if anyone had any ideas or info on making my car more efficient for the 1/4.

I am currently trapping at 106mph..and should have a little more power soon so lets say 110mph traps for a nice round #. At these speeds drag has to be playing a factor, no?

After that, more power will be much harder to come by so I was thinking of aerodynamics to make the most out of what I have.

My car is a 2004 mk4 Golf R32.

Here is what I have thought about so far-

#1 remove the side mirrors and put on block-off plates
#2 full wheel cover disks
#3 block off grill
#4 make a pan under the rear of car to stop air from catching up inside back bumper

Thoughts?

Thanks- Josh

Sounds good to me, but I don't know much. Only thing I have to say is, if you're doing a full grill block...watch out for overheating. Most of us don't go pushing our cars like that...I think. :)

Welcome to the site. I think you'll find many members on this site are also into high performance in some form. I also do some drag racing just for fun. Keep reading this sub-forum, there's plenty of good aero ideas that'll help when applied to your car.

Removing side mirrors would help.
Wheel covers may not be allowed on your track, it depends on how strict they are. The NHRA rulebook prohibits wheelcovers, but sometimes I'll see an old classic hot rod with moon disc hubcaps.
Grill block will help. You might be able to get away with a full grill block since you have time to let the motor cool down in between runs. Just make sure you don't overheat while waiting in the staging lanes- you might have to EOC or push the car in the staging lanes like a true hypermiler! :)
Bellypan or partial bellypan would help. If it needs to be steeper than about 20 to 25 degrees in order to meet the bumper, then the bumper isn't catching much air.
Also look at the underside of your car for any bumps or protruberances that catch the air. They're good candidates for some form of smooth cover.
Lowering the car also helps.
Adjust the windshield wipers so they sit lower, or remove them if they stick up above the level of the hood.

Welcome aboard
 

In general, any aerodynamic mod that will result in improved mpg will also result in decreased trap times, so you're in the right place.

Funny how the SCTA and others allow scewed-on hubcaps on 400 MPH cars and the NHRA won't allow them on a moped.

Check the rules. But wheel covers are kinda far down the list from the other items mentioned in terms of effectiveness.

I never raced a front-driver but another thing you might try is running higher air pressures in your rear tires since they're just along for the ride, and only as low in the front as needed to keep from breaking traction. I'm also assuming you're running the narrowest rear tire and rim that you can.

A chin spoiler may or may not be nearly as effective as a belly pan on your car. Run it as low to the ground as the rules will alow and try it, only your e.t. will tell. I ran an S-10 Blazer spoiler on my Geo wich was good for nearly 2 mpg. Now that have have belly pans my mileage has slightly DECREASED. I feel this is due to increased underhood stagnation resulting from the sealed engine compartment, which means I need to cut holes in the car. Every car will react slightly differently.

Put your car on a diet, if you haven't already.

Welcome !

Look in any of the SportCompact magazines at what others are doing.
I notice a lot of folks will completely close off the entire grille
As you know, removing the mirrors will help a tiny fraction of a percent. ( And reduce weight )
If you haven't already, you might think about lowering the car.
Besides giving the car a cool look, it will actually help lower the drag quite a bit ( and help the car handle better as well )
As far as wheel covers, I'm not sure it will help much ( perhaps as much as the mirror removal )
I'd guess that you will see the most improvement from simply blocking off the grille and cleaning up the area around the back bumper.
Later you might a spoiler extention to the back of the hatch.
Traditional spoilers angle upwards and act like an upside down airplane wing pushing the back of the car down. ( This is great for traction on a rear drive car, but in your case I don't think you have traction problems at the rear of the car. A down side to having a spoiler that angles upwards is that it swoops the air upwards behind the car and makes it harder for the car to pull forward because of the increased "wake' ( the turbulent air behind the car which acts like a vacuum pulling on the car )
In your case, what would help would be to simply extend the roofline out a good foot aor two and perhaps angle it DOWNWARD a bit. This will actually create lift at the back of the car, but shouldn't be enough to make you lose traction.
I have seen several cars in the past with this type of spoiler.
If I have more time later I'll try and add to this e-mail with pictures.

I hope I didn't come off as some " know- it -all " talking crap.
I'm just repeating what I have read.

Cool car by the way. I actually have a model of your car sitting on the desk in front of me.

I used cable ties to hold my nearly full disk caps on when attempting membership in the USFRA 130 mph club. My poor little diesel dub barely got to 109 mph by the end of the standing mile. I had been to 125 at closer to sea level.
btw: it took just two fuel stops to get from home in Mass to the salt flats for that weekend.

Mk4 .:R32 grill block? Check out my topic on the Volkswagen OE grill block kits:

https://www.gassavers.org/showthread....ighlight=grill

:thumbup: :)