Chickenman35

Found you lots of copies

http://www.amazon.com/exec/obidos/tg...97552?v=glance

Matt87GTA

This is pretty good reading.....

So how about Pontiacs.... older ones like my 87. Our front bumper cover does not get very close to the ground even when the overall ride height of the car is fairly low. So what would be the easiest way to get more downforce/less lift on the front end? The hoods on the GTAs have vents in a few areas and then of course there is the removing the seal at the rear of the hood idea (which I have done)... But a car like mine needs a lot of cooling. I have a radiator, a power steering cooler, and an oil cooler (soon anyways when I figure out how to get the damn sandwich adapter to fit with my Canton pan and the Hooker LTs) that all need air. Not to mention I would like to put some brake ducting on it. So I need a lot of air and there is no grill opening at all on a Pontiac so it has to come from under the bumper cover.....

So what have people been doing for Pontiacs? All ideas are appreciated.

vsixtoy

Adding sprung weight increases the sprung to unsprung weight ratio. It is done so the higher forces that impact the unspung weight of the car(wheel and suspension in part) at top speed (on a land speed car) will not unsettle the chassis (suspension in part and chassis) as much as if it were lighter. That unsettling will lift the nose and cause the car to possibly take off.

Land speed cars don't turn corners so the added sprung weight does not affect peformance. It will slow the vehicle down with a lower power-to-weight ratio, but power generally is not the problem with land speed cars, areoforce is and stability. It doesn't matter that an extra 100lbs is going to take them 5 seconds longer to get to 300mph where the lighter car will get there 5 seconds quicker but flip.

Note; When they add chassis weight, they also add stiffer spings (and damper settings of course) to maintain proper ride height from the extra weight.

Edit: spelling-I need to learn how to type

Chickenman35

easisest way...and most effective is to add a front splitter. A 2" to 3" lip should be more than sufficient. You will have to brace the underside of the factory valance to stiffen it to handle the loads.

5'16" ABS sheet works fine. Honeycomb\Aluminium composite sheet works better...but pricey. You can sometimes find Honey Comb composite at surplus metal suppliers. A 4'x8' sheet is a good starting point.

It is actually best to use a large sheet that extends underneath all of the car to the forward edge of the front wheel well opening. Cut our a rectangular area in the middle section to feed the rad. Also acttach some vertical " strakes" underneath the splitter to direct air into the rad opening. Attach the strakes with Structural adhesive ( 3M makes it in the Pro-Form brand ).

The addition of the directional strakes to the rad dramatically helps with cooling. You must be running a deep Tongue of course.

I'll try and post some pics of my Hillclimb setup later.....

iansane

iTrader: (1)

I was just going to ask about a 91-92 bird front end that is totally different. A front spoiler would be almost impossible to add w/o destroying the look of the front end. I had thought about the splitter idea; the birds w/GFX have two dividers that hand down on both sides. Would a something that connects the two and stick a little farther out be helpful at all? I' can't figure out any way to really explain it... Obviously designed correctly it would direct much more air to the rad... Would any more downforce be applied?

Stock:
Idea:

TexasLT1

I think if you want the function, you're going to have to for go the looks. Also, simply getting more airflow to the radiator is of no use if you can't also get rid of the air from under the car.

Matt87GTA

So would this splitter just bolt/screw/rivet to the bottom of the existing bumper cover/front ground effects surface or would it need to be closer to the ground and be suspended down off that surface some? Reason I ask is that my bumper cover is quite a ways off the ground.... I need to measure it, but I would bet it is an easy 10" off the ground even though the car is pretty low..... As in not really possible to be any lower with my particular exhaust and torque arm setup. I always figured that a splitter needed air to flow over it and under it in which case I am thinking it would need to be suspended under the front end somehow.....

Oh well, I think some pictures of yours would help me understand it better....

TexasLT1

It definitely needs to be close to the ground. The car the comes to mind for me is the Viper GTR racecar with a very prominent splitter that is only and inch or 2 off the ground. Having it up near the bottom of the stock bumper would be pretty much useless. You might see a little benefit from it, but it won't be near as effective as if it were down low. I think.

Chickenman35

Yep...the Viper GTR splitter is a good example. The Panoz LMP sports racer is also another good example. This is what I and another Hillclimber based our designs on.

http://www.mulsannescorner.com/panozlmp1.html

Splitters work on the principle that a high pressure area builds up in front of the car. If you build a horizontal extension out into this high pressure zone, you add surface area for this high pressure to act against. The downforce created by a splitter can be considerable, that's why most sanctioning regulations limit there use or size.

In classes that do not regulate thier size, a large splitter can add huge downforce to the front....hillclimbs come to mind

TexasLT1

I would love to see photos of your car if you don't mind, sounds like you've done a lot of work and fine tuning to it. Also, what is your suspension setup like? I can understand if you don't want to give out all the details, I'm just trying to get some kind of an idea of where to go with this.

flyboy367

wow, i feel like i can get a degree in aerospace after reading all that. how about taking it back to the grass roots? remeber the daytona charger/superbird?? what about extending the nose out foot and rake it? lower the front like an air dam but install 4 vents. hook 1.5" tubing to the vents and run to your brakes. add a pump and a small cooler to your diff and mount it to the bodypan? run a trannycooler in front of the radiator. (i did that on my gtp, i see 6-10* better cooling then one mounted behind the rad) the main focus is you want the air to move faster around the car without slowing down. theoredically you need to really change the car then to do it. the purpse of the vents is you will always have air blocking you. any change in air temp/track temp will change the pressure in front of you. if you allow the air to move thru the tubes you not only release resistance from your front end, but you also aid the cooling of your brakes. then help me for this but a "****" spoiler cut about an inch from the roof line will help keep the rear planted. im in no means an expert on this. i bs with fellow racers and some technical guys. i wish i could draw something up for you but i suck at drawing. its just a thought but i know ducting does work.

Chickenman35

I've posted a link to some pics HERE

This is a pretty basic front splitter that I made in one day out of
5\16" ABS sheet. Cheap and easy to cut. The vertical " strakes" add stiffness and also channel air to the radiator inlet " Tonque". They are VERY effective. Car never ran so cool in a race before.

Not the prettiest thing in the world....but man did it work. Front end was just GLUED to the track. Effective from about 45MPH up.

I'll add some more pics later of it actually installed, but I have to scan some stuff and it's 1:00 AM in the morning!! Time to go sleepy bye....ZZZzzzzz

Chickenman35

Here's one Picture:

askulte

Chickenman - that looks good! A few questions:

1. How are the vertical strakes attached to the undertray?

2. What is the total weight w/ the fasteners?

3. Do you have any installed pictures (showing mounting)?

I'm looking to do something similar to the Z28tt... Its good to see someone actually do it.

TexasLT1

Thats awesome. Is that all you have on the car or did you do full belly pans? Also, with that on there, did you keep the stock air damn with the splitter installed?

Chickenman35

1) Vertical strakes attached with Proform Pliogrip Structural adhesive. Available at most Automotive paint and body repair suppliers.

http://www.proformproducts.com/en/pr...detail/?id=118

2) Total weight is abut 10 lbs with fasteners. I had to use lots of fasteners because, by itself, the ABS sheet is not all that rigid. ( Aluminium honeycomb composite sheet is ideal....but very, very expensive ) The more points that you attach it to the front valance, the more rigid the whole assembly becomes. Also two vertical braces ( metal straps ) per side that attach to the rad support area and come down to attach to the rear sections of the splitter. You can actually work a diffuser profile into the underside of the splitter if you plan things carefully.

3) Installed Pics coming up.

Chickenman35

Not allowed to run Belly pans by our rules. Stock 1992 lower spoiler remains. Splitter is attached to that and can be installed or removed in about 10 minutes.

Matt87GTA

You da man CM35! THANKS for sharing!

Can't wait to see the installed pics.....

Chickenman35

New pictures have been added HERE

Detail in picture is not the greatest...but you get the general idea.

BTW...this little addition helped me to knock 1.5 seconds off my previous Hill record. That plus an absolutely flat out bad A** run by yours truly

TexasLT1

DAMN! thats a hell of a spoiler out back!

Chickenman35

Yep....and it works danged well. No restictions in our class as to spoiler height or splitter size.

Now there is a formula for calculating maximum spoiler height ( generally 85 to 90% of wheelbase )...which works out to a 9" overall height for the rear spoiler.

Rear spoiler attaches with Dzuz fasteners. I did not brace the rear spoiler. At high speeds it has this very nice tendency to " lay down " a bit

TexasLT1

Badass, now I want to make a splitter and spoiler just to try it out

flyboy367

yea details on the spoiler build. thats pretty sweet

Dewey316

And a few semi-trucks doing burn-outs just before your run

Chickenman35

Ha ha yeah...forgot about that . Course you had to recognise what was going on

Matt87GTA

So just to get this all straight... The splitter assembly you made is bolted to the stock front bumper cover only? With just bolts and some sort of nut or captured nut? And you still have the factory air dam installed behind it?

Also, do Camaros have the same kind of setup where the front bumper cover and ground effects extend underneath from the bumper cover back to the front wheel wells? The Pontiacs have large flat pieces that are part of the little ground effect pieces on the front fenders in front of the wheel wells that cover up that big open area in front of the wheel wells between the bumper cover and the wells..... I am asking because I think that would offer a lot of surface area to bolt the splitter assembly to but it is still relatively flexible. The air damn bolts to the core support though and these ground effect pieces that extend underneath also tie into the bottom of the core support which is obviously a good place to anchor it.....

Just thinking out loud here on how to get it to work on a Pontiac .

askulte

CM35-thanks for the extra pictures. What is the rake on the nose ground plane? The TransAm cars have 3/4" higher rear than front (the max, per rules). Are the hood louvers from a Baretta? Gotta do that too...

Chickenman35

Splitter attaches to '92 factory front spoiler with oversize fender washers and 1\4" bolts\nylocks. Tried using Riv-nuts but it didn't work. Large washers and bolts work just fine. The more fastening points the more rigid the assembly. I ended up with 26 attachment points in total. May be overkill...but it worked.

Camaro's do not have the flat panels that the Pontiac's have, although you can see that I have duplicated that in my design. Once things are bolted up with eniugh fasteners and four vertical braces, the whole assembly becomes much more rigid. You need that for the downloads placed on the splitter.

I used ABS because it is easy to work with and I was in a time bind. Something more rigid would be desirable. As mentioned, Aluminium\Honeycomb composite is ideal,,,,but expensive. Also you cannot form curved surfaces with it. If you wnat to get fancy you could try making a mould out of Carbon Fiber\Kevlar.

One thing on the Pontiac's to be aware of. Radiator inlet is bottom feed only ( Camaro's are bottom and nose feed ). With a Splitter you do not need to run an additonal airdam lower to the ground. Be sure to allow enough airflow under the front to feed the radiator air deflector ( Tongue ". Running vertical strakes to tunnel the air directly to the "Tongue" greatly improves cooling efficiency.

Chickenman35

Hood louvers are from a Mid-90's Grand Prix.

Rake on the front splitter is Zero degrees to the body. In the Turn 3 picture, that is a REALLY steep exit and the rear end is really squatting. Normally the car would not lift the nose that much. Note the black line left by the outside rear tire

Morley

Checkout the GTA that Gale Banks set the production car speed record with. If my foggy memory serves, he lowered it 1/2-1" and that was it except for tires...went 287 MPH.

paul_huryk

I have an old Hot Rod from 1989 that had a top speed GTA in an article. All they did was lower the car, put a 1.5" lower front air dam and remove the side mirrors. The car with a detuned NASCAR 358 (650hp) went 239mph with no added weight and it was stable at speeds above 200mph. Put that into perspective with the MacLaren F1 that went 241mph in a lot smaller car that weighed 1000lbs less with 625hp. Its all good.

RMK

Paul,

Have you got any pictures of this car?

TexasLT1

Paul, you've GOT to post that

paul_huryk

I'll have to find it and then take a pic - I don't have a scanner here.

Dale

iTrader: (12)

If you can tell me what issue, I have a fairly nice scanner I can use. I belive I have most the old hot-rods from 1989.

PM me on what issue it is.

racerc

anyone ever ponder just adding the rubber like on this car??
i was thinking of adding it to my rx7 as its same body kit and to my 89 rs anyone have any idea where to get such "rubber strips" it has consistency ofm radiator hose with reinforceing string

paul_huryk

I beleive its the issue with the sledgehammer Corvette in it - maybe July 1989?

Dale

iTrader: (12)

Checked July89, that is the zztop "cadzilla" issue.

I quickly glanced at the TOC in the front of every 89 issue. Didnt see anything directly saying "camaro, topspeed, aerowdynamics, etc".