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

[Quadcammer]

Hey man i ended up doing a very similar exhaust design, but im finding it very loud and frankly doesnt sound good in my garage.

Do you have a better pic of yours and how does it sound?

[truegearhead]

Originally Posted by Quadcammer

Hey man i ended up doing a very similar exhaust design, but im finding it very loud and frankly doesnt sound good in my garage.

Do you have a better pic of yours and how does it sound?

Here's a close up of how I attached mine. I just the cat delete pipes and slid the 2" exhaust over them. It sounds great but its too loud for the street, I do have headers and no cats which doesn't help. I'm sure with the right mufflers it would be streatable.

[truegearhead]

While I'm waiting for hardware I decided to play around extending the roof line. I'll just move the plexiglass rear window to the aluminum, this will also allow me to ditch the roof cover which is surprisingly heavy

[truegearhead]

I made it back from VIR with good news and bad news. The good news I didn't die... the homemade control arms and various other one off suspension changes didn't break. The bad news is it was slower... by 5 whole seconds. The first heat the car was incredibly loose, its now square (front track is equal to rear track) the front is 7 inches wider than stock and the rear is 4 inchs wider than stock so I expected this to be a big change. I stiffened the front sway bar several times through the day and ended up close to a balanced car. Its still on the narrow 235 series time trial tires so I'm going to wait for wider tires before I make any more adjustments. As it sits its still loose which resulted in a spin at Oak Tree but overall it has far more grip. If I took the widebody off (with its huge fender intakes) I'm sure the car would be faster, I'm loosing a lot of speed down the stretches. I'm now weighing engine swaps, the Audi W12 is an interesting option. Its the same length as the boxster motor and would bolt up to the Boxster S transmission.



Here's a couple shots from the weekend, it was a small social distancing event so the organizer let me and the buddies I run track days with try and recreate the Car and Driver Lightening Lap photo. Super fun weekend, it was great to get out there and bring back a working car.

[paulofto]

Originally Posted by truegearhead

The bad news is it was slower... by 5 whole seconds.]

But it LOOKS faster!

[78F350]

Best looking car in that group shot.
Can you get any sort of analysis of the airflow to see what is helping with grip and what is just creating extra drag? Maybe you could recruit an engineering student to do a CFD model - I'm thinking of the groups that do the $2000 challenge like Georgia Tech or similar.
Engine swaps can be enticing, but most of the cases I've seen, when they are done and all sorted out the cost/benefit is not much different than just going with a higher power Porsche engine. Maybe you should try cutting a deal with some jerk on the forum who keeps pushing his rebuilt engine at a highly inflated price.

I'd love to see your car with the W12 sorted out in it.

[truegearhead]

Originally Posted by 78F350

Best looking car in that group shot.
Can you get any sort of analysis of the airflow to see what is helping with grip and what is just creating extra drag? Maybe you could recruit an engineering student to do a CFD model - I'm thinking of the groups that do the $2000 challenge like Georgia Tech or similar.
Engine swaps can be enticing, but most of the cases I've seen, when they are done and all sorted out the cost/benefit is not much different than just going with a higher power Porsche engine. Maybe you should try cutting a deal with some jerk on the forum who keeps pushing his rebuilt engine at a highly inflated price.

I'd love to see your car with the W12 sorted out in it.

I've done a few engine swaps and ya, they never go well. The 3.4L 911 motors are starting to get cheap but I'm really looking for more power. If there was a cost effective Porsche solution I'd go for it. That being said I also really like the challenge of something odd like a W12, building the car is half the fun for me.

[JayG]

All the new aero could be having a big impact.
Without wind tunnel or CFD modeling, you really don't know if it is good or bad.
Does look really cool however

[Racer Boy]

At the next track day take the splitter and wing off and see the change in lap times. Also note your top speed compared to the later/previous session with the aero stuff back on.

Do you know what the top speed difference is between before and now?

Just looking at the picture, I'd say you have added a lot of surface drag; the flares and possibly the new radiator duct layout, besides the front splitter and the wing may be killing your straightaway speed enough that the increased downforce (hard to say how much increase) doesn't make up the difference.

Another thing to ponder is the air intake for the engine. It's on the back window, correct? That is in a really low-pressure area, so that may be hurting horsepower, which isn't going to help.

[truegearhead]

Originally Posted by Racer Boy

At the next track day take the splitter and wing off and see the change in lap times. Also note your top speed compared to the later/previous session with the aero stuff back on.

Do you know what the top speed difference is between before and now?

Just looking at the picture, I'd say you have added a lot of surface drag; the flares and possibly the new radiator duct layout, besides the front splitter and the wing may be killing your straightaway speed enough that the increased downforce (hard to say how much increase) doesn't make up the difference.

Another thing to ponder is the air intake for the engine. It's on the back window, correct? That is in a really low-pressure area, so that may be hurting horsepower, which isn't going to help.

The flares are the problem, the wing and splitter have been tested on and off, they're worth almost 3 seconds at VIR. I need to have more power, thats the only solution. Especially now that I have these absurd 12" wide rear wheels on the car

[steved0x]

Nice, those are some nice looking wheels, what tires are you going to run on them? What is the widest 17" you can get?

[paulofto]

Are those wheels or beer kegs?

[truegearhead]

Originally Posted by steved0x

Nice, those are some nice looking wheels, what tires are you going to run on them? What is the widest 17" you can get?

Thanks, I’m putting on 315/35/17 Hoosiers today, and 245s in the front. Same setup I have on my 911, I’ll eventually need a wider front tire

[steved0x]

Originally Posted by truegearhead

Thanks, I’m putting on 315/35/17 Hoosiers today, and 245s in the front. Same setup I have on my 911, I’ll eventually need a wider front tire

That's a monster tire! I bet that is going to feel good!

[truegearhead]

Well I've also had some enormous scope creep. I decided that lifting the car 2 feet off the ground to pull the engine from below is absurd and I don't have enough faith that I can service the Audi V8 with the factory engine cover in place so I did some cutting... I removed he entire engine surround and fire wall, rear trunk and moved all the electronics to the cabin I'll make an aluminum firewall that goes all the way to the roof and will either install a plexi window or install a hidefinition rear camera that uses the a rear view mirror as a screen (oddly the cheaper option). With the rear trunk removed I can now just wheel a new motor in instead of lifting the car up and pulling it from underneath (especially valuable with the tall V8 compared to the flat 6)






you can see in the above photo I'll need to add some rear chassis reinforcement, I'm going wait for the engine to go in and then tie something into the cage to strengthen it


I also added a third radiator that’ll sit under the hood scoop (feed from the front of the car and cut out the original rear quarter panels (that now sit under the widebody) to make room for...intercoolers

[JayG]

Its a very slippery slope

[truegearhead]

Originally Posted by JayG

Its a very slippery slope

It is, and you never get to the bottom. For example I bought an Audi V8 for it today...

[truegearhead]

Out with the old. Anyone need a 2.7? The Audi V8 arrives Friday (I think), 8 weeks or so until tools down and baby arrives.

[Quadcammer]

You got some nuts man...no one can argue that

[truegearhead]

Parts for the turbo build have started flowing and I’ve started the mock up. Here’s one of the two side intercooler radiators (the water cooling rad).



Air will enter here


And exit here (the gap between the outer fender and tail light


I’m a little bummed about the weight, they’re probably 25lbs a piece. I’ll have close to 100lbs in my intercooler system including the water. All in all I’m probably adding 200-250lbs to the car in engine, turbos and cooling, so far I’ve found about 40lbs in steel that I was able to remove. Hopefully I can find some more. I still need to remove the HVAC system under the dash, anyone know what that weighs?