She’s Got A Fat….I mean FLAT A$$

[Department Of Boost]

Thought you roadrace guys would dig this.

Huge thanks to 908SSP/Alex for doing this project with me. He worked his ass off on this. It wouldn’t have been possible without him.

Eventually the blue 2007 will be going for some big time top end in the standing mile (220+). And a lot of going fast is aero. We just finished the belly pan, which was a HUGE job. We have over 70 man hours and $600 in materials in the job.

We used 6mm aluminum honeycomb board for the panels then heat shielded the crap out of it with DEI stuff. The board is crazy light as well as very, very stiff. All the panels, brackets, fasteners, exhaust wrap, etc weighs under 20lb. Not too bad.

I may be crazy, but I swear I can tell that the bottom of the car is flat now. I did a high speed test run Saturday night and the car certainly didn’t feel like it was trying as hard to punch a hole. I’ve spent a lot of time racing in the 180-200mph range. I think I’m a pretty good judge of aero feel.

In the one pic you can see the splitter and the OEM 2010 “heat extractor” panel. Were going to test replacing the OEM 2010 “heat extractor” panel with a solid piece and see if it increases underhood temps. If it doesn’t we’ll use the solid panel, it should be more aerodynamic.

Next project, maybe next week, is to finish up the rear diffuser and add a trans cooler.

 

[stkjock]

the lift mounting points/pads were already on the car?


def looks like it should cut down on drag

 

[05yellowgt]

Looks great so far! Will the solid piece you are going to try in place of the stock 10' heat extractor be able to cover up any of the a-arm/suspension? Seems like the air is going to have a lot of chance to get stuck in that area. I also wonder if transmission temps will be affected at all and whether or not a fluid cooler might be needed?

 

[neema]

This looks awesome. I wish someone would make this stuff. Great job

 

[Department Of Boost]

the lift mounting points/pads were already on the car?

Yeah, those have been there for a while (2yrs). They actually attach the K-member to the rocker/inner frame rail and stiffen everything up. Them working as jacking points was a bonus.

Looks great so far! Will the solid piece you are going to try in place of the stock 10' heat extractor be able to cover up any of the a-arm/suspension? Seems like the air is going to have a lot of chance to get stuck in that area.

That is something we are going to look at/test. I would like to seal the whole underside up tight. But if that causes the underhood temps to go way up it won’t be an option. We’ll probably seal stuff up until temps ride then back it down a step. Being able to data log underhood temps is a very useful tool in this situation.

I also wonder if transmission temps will be affected at all and whether or not a fluid cooler might be needed?

Yep, I mentioned it above. I have all the stuff for a trans cooler…….a BIG trans cooler (about 2.5x the size of the BOSS302R) ready to rock. It will get incorporated into the rear diffuser/bumper cover mods. Until then I’ll run around without the center section of the belly pan on the car.

 

[Department Of Boost]

This looks awesome. I wish someone would make this stuff. Great job

We could make them, but they would be silly expensive and still require the end user to do some “more than bolt on” fabrication.

A quick guess at a price would be $1500-2500. And that is obviously no labor.

FR500GT could probably do them for $350 (inside joke some will get).

 

[JEWC_Motorsports]

FR500GT could probably do them for $350 (inside joke some will get).

Looks to be a killer setup. What standing mile event are you planning on doing?

 

[Department Of Boost]

Looks to be a killer setup. What standing mile event are you planning on doing?

We were looking at doing the July 4th Michigan Mile, but I don't think we will be ready.

I think that just leaves me with the fall Texas mile. Long drive.

The Ohio Mile rules are just stupid. I'm not running 2 chutes!

 

[BMR Tech]

AWESOME

 

[zquez]

Fucking awesome. Now that my splitter is finished I've been researching doing this myself on the time attack forums. Its nice to finally get a better idea of what it looks like on our cars. I'm excited to see what you come up with for a diffuser.

Did you finish the panel that goes on the axle like you were talking about doing or are you gonna run it open? I had wondered if having it sealed off and then suddenly hitting up bump disrupting the airflow would lead to a sudden (and potentially dangerous) loss of downforce.

Did you reinforce the honeycomb with fiberglass or anything? I assume you used riv-nuts for this job too.

 

[Roadracer350]

We could make them, but they would be silly expensive and still require the end user to do some “more than bolt on” fabrication.

A quick guess at a price would be $1500-2500. And that is obviously no labor.

FR500GT could probably do them for $350 (inside joke some will get).

Not those panels!! That's a LOT of freekn work!! Awesome job tho!! I do have a final price on the jacking plates if you want them..

 

[jayel579]

We used 6mm aluminum honeycomb board for the panels then heat shielded the. The board is crazy light as well as very, very stiff. All the panels, brackets, fasteners, exhaust wrap, etc weighs under 20lb. Not too bad.

I could be wrong but I remember reading something a while back about guys doing high speed runs on the salt flats and them saying weight was like "free" down force. IIRC it was a 3rd gen Firebird they were using, the car weight something like 6,000 lbs.

Light is good for turning, braking, and accelerating but is there anything to the thought of down force given you mentioned the high speed attempts?

 

[zquez]

I doubt he needs anymore weight with that big ass supercharger on it, not to mention the second heat exchanger in the trunk and god knows what else. Weight may be good for staying planted in a straight line, but it still takes power to move that weight and when you're trying to overcome drag at 200+ mph, you need all the power you can get.

Just by smoothing out the bottom, he should theoretically be accelerating the air under the car by virtue of less drag thus sucking it down to the ground. Once the diffuser is in place, it will further help to accelerate the air via the venturi effect as well as help the low pressure air under the car to re-attach to the high pressure air over the car. Drag reduction and downforce created.

Have you thought about any type of spoiler for the car Jason?

 

[05yellowgt]

Being heavier means that the lack of down force, or even lift inherent in a particular car won't become dangerous nearly as quickly as with a lighter weight car that exhibits the same aerodynamic qualities.

 

[Department Of Boost]

AWESOME

Fucking awesome.

Awesome job tho!!

Thanks guys.

Did you finish the panel that goes on the axle like you were talking about doing or are you gonna run it open?

Were going to finish the diffuser first and then see what we are left with. The plan is to seal that up though. We have plenty of panel left.

Did you reinforce the honeycomb with fiberglass or anything? I assume you used riv-nuts for this job too.

The honeycomb is CRAZY stiff! I’d wager you could stand in the middle of an unsupported (edges supported of course) 4x8 sheet and it wouldn’t budge. I won't be testing that on a $175 sheet though.

Yep, LOTS of riv-nuts in that bad boy. There are 30 fasteners and 26 of them are riv-nuts. It only takes about 5min to get them off though and they are set up so one person can get them on without help.

I could be wrong but I remember reading something a while back about guys doing high speed runs on the salt flats and them saying weight was like "free" down force. IIRC it was a 3rd gen Firebird they were using, the car weight something like 6,000 lbs.

Weight is not a penalty at a place like Bonneville, the standing mile is short in comparison. Acceleration is a factor so weight has a role.

is there anything to the thought of down force given you mentioned the high speed attempts?

Right now we are not planning on creating downforce by adding anything to the top of the car. We will if we need too though.

At this point we are spending our “aerodynamic dollar and time” on things that reduce lift. A splitter, belly pan and diffuser are “lift reducers”. We opened up the vents in the GT500 hood and added more louvers too. If that doesn’t get the job done we’ll see if a Tiger Racing hood will fit over the blower. That is a lift reducer too.

If after all that the car is scary to drive we’ll start adding things to the top of the car. I don’t think we will need too though. My tuner did the motor/blower/tuning on the S197 that went 252mph (or something close to that) and all it had for aero/stability on the top of the car were some of those “Mohawk” (or in this case Bi-hawk) strips on the roof and a drag race style wing. Everything else was just smoothing. The car didn't have a belly pan or a diffuser, just a air dam to reduce the air going under the car. It went 252 with "only" 1011hp.

I kind of like the Mohawk things if they are not too big and a drag style wing (a smallish one) wouldn’t break my heart either. It can always be set up to be easily removable.

Lots to learn.

I doubt he needs anymore weight with that big ass supercharger on it, not to mention the second heat exchanger in the trunk and god knows what else. Weight may be good for staying planted in a straight line, but it still takes power to move that weight and when you're trying to overcome drag at 200+ mph, you need all the power you can get.

Yeah, the car aint light! There is a lot of weight reduction type things going on, but your right. The huge blower, stupid number of coolers and water, safety gear, big this, that and the other thing add up. The solution for that is bigger tires, stiffer springs and MORE POWER!

Just by smoothing out the bottom, he should theoretically be accelerating the air under the car by virtue of less drag thus sucking it down to the ground. Once the diffuser is in place, it will further help to accelerate the air via the venturi effect as well as help the low pressure air under the car to re-attach to the high pressure air over the car. Drag reduction and downforce created.

That's the theory. We'll see if reality agrees.

Have you thought about any type of spoiler for the car Jason?

Maybe an understated drag style wing. Maybe a couple of different ones that can be swapped out. If I can do it with nothing I will. I like the "wingless" look for this car.

 

[ArizonaGT]

Very cool.

 

[Roadracer350]

Could you just use the APR rear diffuser instead of trying to make one from scratch?

 

[Department Of Boost]

Could you just use the APR rear diffuser instead of trying to make one from scratch?

908SSP already made one for his car that is about a million times more effective than the APR one. We don't have to work around the EVAP stuff like they do and we also "push" it up into the bumper cover. Plus the molds are already made. It's not THAT easy, but this time around its not entirely from scratch.

908SSP is the man.

 

[Roadracer350]

908SSP already made one for his car that is about a million times more effective than the APR one. We don't have to work around the EVAP stuff like they do and we also "push" it up into the bumper cover. Plus the molds are already made. It's not THAT easy, but this time around its not entirely from scratch.

908SSP is the man.

Would love to see a pic!!!

 

[Philostang]

That is really cool to see!! I have long since been itching to do something with the undercarriage and many an idea were along these lines. Really geeking out right now.

Can't wait to see what the rear diffuser looks like. Keep it coming!

Best,
-j