Front splitter discussion

[skivittlerjimb]

So I'm looking for a way to functionally add more airflow to my radiator, intercooler, oil cooler, and planned brake ducts inlets located at the factory fog light openings. Ricing out the car is not a goal and really the resulting looks after installation are not that important to me either.

So far the only truly good look at a splitter I've seen on a GVR4 is CJ Moses' old race car:

CJ reported this to be a "JSP functional front splitter (Carbon Fiber)." Some quick Googling shows that this type of universal splitter with support struts may still be available but I haven't seen anything currently available from that company in this exact configuration. Also, really a CF piece is not ideal because when it takes a hit it'll likely splinter instead of just scuff and crack like fiberglass or ABS plastic might, and b/c it's more expensive.

I know a fair amount of folks have created many different varieties of front air dams from various materials like landscape edging plastics, metal filler panels (the part between the top of the bumper and headlights/grill), and modifying front air dam pieces from other cars like 90-93 Accords. However, a front air dam only seems to accomplish one of the goals of a splitter, which is to cut down on airflow under the car. A true splitter piece like the one shown should accomplish this as well as provide more airflow to the areas I mentioned above, as well as provide some downforce at higher speeds (100mph +.)

Given that my car will likely see Tremblant, Watkins Glen, and perhaps other high speed tracks next season, I see more high speed front end grip as real benefit outweighed by the extra weight a splitter would add to the front of the car. The way the front end is configured now, with no air dam and no splitter, I'm guessing much of the airflow simply slips under the car and very little is actually fed into the three major inlets in the front bumper. That being said, I have very little knowledge of aerodynamics and would love to hear folks' opinions on the subject and hopefully some example of what others have done either on GVR4s or other track cars with similar front bumpers. Universal application front splitter recommendations are also welcome. What I have read on the small research I've done is that any true splitter that will create any measurable high speed downforce really needs support struts to quell and control the vibration that will occur at high speeds.

Opinions welcome! I know many of you will have some...

-Jim B.
280/1000

 

[atc250r]

If you could get a hold of a JDM bumper it would be much more conducive to something like that IMHO. Whatever bumper you go with, I would see if I could find a large enough piece of ABS plastic that is 3/16" or 1/4" thick and make one out of that. You could mock it up with a piece of cardboard until you got something you liked then trace the cardboard piece's shape onto the plastic and jigsaw it out. Then get some turnbuckles to support it. I'd imagine a circle track shop would stock something like the turnbuckles used on the new NASCAR cars.

John

 

[CarRacer]

Instead of those exspensive adjustable braces, might I suggest a ghetto fabulous solution I've personally used?

On our Late Model racecar we used SAE brake line tubing for body braces. I'm not entirely sure on sizes, but I think we used 1/4 and 3/8 inch line. The smaller line fit snuggly in the larger line and allowed us to make length adjustable braces.

They're really simple to make. Measure the length you need and add a couple inches to to half the distance for the length of each tube. Flatten one end in a vise to make a mounting tab. We used pop rivets (with backing washer) to mount in plastic and bolts to metal. To make a adjustment/locking nut, drill a hole according to the size of bolt you're going to use (we used 1/4") in the larger tube. Tack weld a nut on top of that hole. Tack weld a washer on end to the head of the bolt you're using for a ghetto wingnut. You don't need the wingnut, but it prevents over tightening. You want the tube to hold the air, but move when hit to save the panels it's attached to.

We used that setup for the nose, fender, and tail body panels on a car that saw 100+ and high aerodynamic forces. It holds up to that, yet moves and gives under contact with other cars. It's not pretty, but that doesn't seem to be a priority for you.

 

[ApexHunter]

The jdm front bumper does seem like a better choice to mount a splitter on because the "chin" is reminiscent of a splitter. As far as splitter construction, i'd say atc250r hit the nail on the head with making a template from cardboard. Maybe use abs plastic with sheetmetal riveted to the bottom for added rigidity/strength/wear resistence?

I've seen some support rods/turnbuckles on APR's website. I found them here at vivid for an alright price. click

As far as increasing airflow through heat exchangers or brake ducts, i'd probably do some shrouding w/ sheetmetal like in the pics below. I haven't done this myself yet so i don't know how easy it's gonna be on the gvr4.






If you end up going with the jdm bumper, i would open up the holes on the lower left and right corners a bit and use those for brake ducting. Or maybe the spots where the fogs are? I'm not sure what the path is like behind those.

If you stick with the USDM bumper, I agree the stock fog light holes seem like the best bet.

 

[kartorium]

I think if you are going to do it right you need both an air dam and a splitter. Just attaching a splitter to the stock or JDM bumpers doesn't seem like the best way to do it.

I also think the further you can put the leading edge forward, the more effective it will be. So don't just mount the splitter close to the bumpers lip, even though that looks less obtrusive, when it comes to downforce and airflow it usually is more effectve the more obnoxious it looks. Find some good touring car pictures and build around those setups, or copy them.

 

[skivittlerjimb]

Thanks for the link to the support struts. As cool as the homemade version sounds I don't have ready access to welding stuff, and the ARP ones aren't overly pricey. I'm pretty sure I could source sheets of 1/4" ABS locally.

Again, looking for opinions, on a white GVR4 would white or a black look better? Also, what mounting hardware for splitter-to-lip or splitter-to-bumper would make for the easiest on/off procedure but still be tough enough?

-Jim B.
280/1000

 

[curtis]

As for ducts for the IC simple remove the IC and take it to a welding shop and have them tig on some 90 degree angle pieces you can bolt to. Then after its back on the car simply cut some cardboard as a template running perpendicular to the core. Angles don't work and actually make the air bounce off, being perfectly square will help the air pass through. Then on the back side do the same thing except running the pieces up against the radiator. You can use the stick on foam door seal stuff or just cut a piece of hose to put over the metal when done. That alone has made 1st and 2nd gen cars go from over heating in traffic to running at perfect levels.

 

[RedTwo]

Apart from around the wheel arch, there's nothing but plastic in the bottom half of the JDM bumper. It would probably collapse with very little force.

 

Hey guys, Haven't been on here in a while. I just pulled the GVR4 apart for a quick head gasket job, so I figured I'd check in.

As far as the splitter goes, the orginal one is still on there so it has proven to be pretty strong (it is CF backed by fiberglass). I've used it a few times to cut the grass and/or plow gravel. Now having several more years of intense experience at the national level in the Evo, I'd do it a little different (and likely will here shortly). Basic things I'd change would be that the splitter itself would be much thicker and strong enough so that you could stand on top of it. I would use small yet strong rods to create quick disconnect attachment points so that the splitter connects to the frame of the car, not just the bumper and cross frame. Adjustability is key so make sure you use some sort of threaded rod (struts) on the front. Take in to consideration the wing/spoiler that is placed on the rear of the car as a proper balance is needed or you'll spend a lot of time and money fighting handling gremlins that were aero induced.

I'm looking for a non-abs, awd brake partitioning valve etc. so that I can dump that ABS lawnmower engine while I have the head off the car. Anyone have some or all of the parts laying around for sale?

 

[Bimmubishi]

Jim, we've been using Alumalite for our splitters- very strong! Light and not expensive.

It's also easy to cut. Available through sign shops.

click

Alex

 

[ApexHunter]

^Do you guys use the 1/2" or 1/4" thick?

 

[cOmpressor]

How do you clean up the leading edge with that corrugated stuff? Little plastic weld molded smooth or just keep it looking like cardboard?

 

[mooserage]

tape /ubbthreads/images/graemlins/dunno.gif