Time Trial Build Thread (aero, widebody, any other nonsense)

[truegearhead]

Instead of filling this forum with individual threads I'll just keep this post updated.

I've been reading way to much about aerodynamics (if you couldn't tell from my aero hood post or diffuser post) and decided to try and increase airflow to the rear wing (and to the intake in the rear window) by installing vortex generators on the hood just ahead of the stall line on the roof (or where the airflow leaves the roof's skin). I've never really been a fan of how these look but they turned out pretty good.

The diffuser and the widebody are progressing too. I'm still waiting on the last pieces of hardware but decided to limit it a 4" increase (no spacers in the front 2" spacers in the rear. I should have update on Wednesday.

[Robert986]

Pretty sure this will be a great thread.. Keep it coming!! :dance:

[jaykay]

Any thought to ducting air directly to the filter from the outside rather than the round louvers in the rear screen? I have seen side NACA ducts on either side piped to the top of the engine where an oil cooler sat. This arrangement could work for engine intake air.

[truegearhead]

I feel like this is starting to get pretty ridiculous looking, but its getting closer...

[911monty]

If you mean ridiculously cool then yeah I'll second that!

[truegearhead]

This weekend I was able to make a little progress, I got the intercooler and piping roughed in and finally received my modified engine harness, flex fuel kit and the VEMs standalone which has been preloaded with two tunes (E85 and gas) for my turbos, engine, etc. The harness is now totally plug and play, no wiring required! Definitely the easy button. I have to show off these injectors too, probably the most expensive part of the build but designed for both tunes and tested for both tunes. Its the little things like this that have really added up.

[JayG]

You are doing proper analysis.
Kudos to not just throwing stuff on your can and using a butt dyno
Aerodynamics is at least a little complicated and without modeling or wind tunnel testing, you can easily do something that makes it worse

Well done

[truegearhead]

Originally Posted by JayG

You are doing proper analysis.
Kudos to not just throwing stuff on your can and using a butt dyno
Aerodynamics is at least a little complicated and without modeling or wind tunnel testing, you can easily do something that makes it worse

Well done

Thanks, I can’t take any credit for the aero model though. Nine8Six Shared it with the forum months? Years? Ago. I should have given him credit. It’s incredible
To have this available. Aero is very tricky, I’m sure what I’m doing isn’t anywhere near as effective as it could be (or maybe even at all) but it’s time consuming which is exactly the kind of thing we all need now.

[truegearhead]

I'm really getting into the danger zone now I've started another project while I wait for parts. The first picture (credit to Eric who took the photo) is what I'm after. Flares are arriving on Friday and I'm going to incorporate this vent into them. I have a replacement for this banged up fender so worst case I have a backup.

[truegearhead]

I started the flare install yesterday so far the $30 Amazon flares are working out

[itsnotanova]

I have fender flares and wider tires on my rallycross boxster. I had to do some trimming on the rear wheel well for clearance. For the front I also had to cut the rocker panel back flush with the wheel well and some of the bumper cover. I don't have the side radiators anymore but the wide wheels would not have fit in the front if I still had them.

I notice you have a wing and a large spoiler on the rear. I've never seen anyone have both and I've never seen anyone use such a large spoiler on a boxster that races at a high speed. The only guys I see using large spoilers are in autocross where they rarely even get out of third gear.

I forget what they're called but that picture of the cup car has them in front of the front tire. I've been told you can find them on eBay for cheap. Do you have those on yet?

[truegearhead]

Another small update. With the help of a buddy of mine we started actually welding stuff together. This “exhaust” plan is crazy, I hope I don’t regret it.

[Stroked & Blown]

I like that spoiler - willing to share any details on how you made it?
Also - have you tried slathering flowviz over the panels to see what the surface structures look like?

[itsnotanova]

FYI, I bought the same radiator as the one you're using in the frunk and was very pleased with the build quality for how cheap it was. The only problem with it is the pressure valve on the cap is too weak. It will release pressure around 190 and continues to drip even when the car is cold. I'm going to weld it closed as it's not needed for my situation. I also plan on installing a radiator hose with a cap built into it at a high point in the system to help relieve air pockets.

[truegearhead]

I have a major setback, I rotated the engine before I bolted the transmission up but now with everything assembled it won't rotate....ugh. I'm going to pull the transmission off tonight and see what the deal is. Did any of you guys swapping Audi V8s have a similar problem?

[78F350]

When I first mated an AUX (40 valve) with a Boxster 5-speed transmission I had that exact problem. It required a small spacer between the engine and transmission to provide enough clearance for the flywheel/clutch.
It's been a few years, but I had these links bookmarked:
https://www.audizine.com/forum/showthread.php/766013-Audi-Engine-To-Transmission-Spacers-Function-When-Are-They-Needed
https://www.audizine.com/forum/showthread.php/508044-V8-Models-What-Flywheel-And-Clutch-Combo-Are-You-Running/page2?

[truegearhead]

Whew its been awhile but I finally got it out to a test and tune (AKA: drift event).
I went out to take it easy, being the first time I've driven the car with this engine, the limited tune, the unproven suspension etc etc but as always the red mist took over and it wasn't long before I was chasing drift cars and spinning it off into the gravel. It was 30 degrees and the Hoosiers were rock cold but the wow is this thing scary powerful. I can't wait to get it out on a real track.


A buddy of mine made a quick video of the run.
https://www.youtube.com/watch?app=desktop&v=i_vnMOY8x9c&feature=youtu.be

[78F350]

Finally... I was starting to wonder what had happened to you and the car. Can't wait to see how it does at VIR. Thanks for the update.

[Stroked & Blown]

Have you thought about finding a wheel with the right width + offset?
Here's a handy calculator: https://www.1010tires.com/Tools/Wheel-Offset-Calculator

As a reference point, the 997 Cup came with the following (EXPENSIVE) wheels:
Rear 18x12 ET30 (997.362.140.97)
Front 18x9.5 ET37 (997.362.136.96)

These dimensions would get you +4" in the rear but you would need some hefty spacers (which it looks like you already have) as the inside has 42mm less clearance.

[truegearhead]

Originally Posted by Stroked & Blown

Have you thought about finding a wheel with the right width + offset?
Here's a handy calculator: https://www.1010tires.com/Tools/Wheel-Offset-Calculator

As a reference point, the 997 Cup came with the following (EXPENSIVE) wheels:
Rear 18x12 ET30 (997.362.140.97)
Front 18x9.5 ET37 (997.362.136.96)

These dimensions would get you +4" in the rear but you would need some hefty spacers (which it looks like you already have) as the inside has 42mm less clearance.

I do eventually want to put some wheels on the car that fit, unfortunately (as you pointed out) 911 wheels won't work. I actually have 18x12" wheels on the back on my 911, all of the extra width is on the inside of the wheel. This is possible on 911s since they have a multi-link rear suspension and don't have the long track arm that gets in the way of the wheel. If anyone knows of a cheap 17" wheel that can be ordered in custom offsets please let me know.