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

[JayG]

Definitely a FrankenBoxster
Very cool!!!!!

[1thenaton1]

Damn, just catching up on this, epic build!

Don't see many details re the engine swap. Which Audi V8 did you go with? What turbos? What management? I imagine you are also upgrading internals on the engine before going forced induction?

[truegearhead]

Originally Posted by 1thenaton1

Damn, just catching up on this, epic build!

Don't see many details re the engine swap. Which Audi V8 did you go with? What turbos? What management? I imagine you are also upgrading internals on the engine before going forced induction?

Engine: I’ve changed up the engine three times, sent one engine back and still have another sitting around but settled on an Audi ABZ 4.2l V8 which if I hadn’t already changed my mind so many times I would have moved onto a different platform. The ABZ bolts up to the Boxster trans which is nice but the real benefit is that it’s an incredibly short motor (same length as the Boxster flat 6 so it actually allows the trans to sit in the factory location. With the trans in the factory location you don’t have weird drive axle angles which is a big problem on a track car. The problem with the motor (I now know) is that forged internals are all NLA so for now it’ll be stock. People run stock internals up to 1,000hp so I don’t think my goal of half that will be a problem...we’ll see.

Engine management: I’ve also changed this up three times too starting with a reflashed stock Audi ecu, then mega squirt which I just sent back, now I’m waiting on a VEMs ecu which is being baseline tuned for my setup and they’re making a harness for me (totally plug and play besides three wires to connect to the boxster..how cool is that!). The companies called EFI Express, awesome guys!

Turbo’s: I just received the turbos this weekend. I ordered the smallest S200SX-E turbos they sold from Borg Warner but they shipped me the largest S200SX-Es so I’m not sure if I’ll return them or change my approach a bit. I’m targeting 520hp for now at 8psi. If I can find internals (or have them made) the turbo, fuel and cooling setup will take the engine to 800hp. I hope Im never stupid enough to try that.

[Quadcammer]

you are gonna run the stock 5 speed with 520hp?

How many do you plan to replace per event?

[truegearhead]

Originally Posted by Quadcammer

you are gonna run the stock 5 speed with 520hp?

How many do you plan to replace per event?

I'm hoping easy shifting and no launches and a cooler will get me through an event or so, I'm sourcing an S transmission to replace it.

I have a feeling this whole thing is going to look like the BluesMobile in the final scene. But hey...we’ll see. At a minimum you all will get a good laugh when everything explodes.

[78F350]

It's all awesome! I think it may be about time to change your signature:

1997 2.5 Boxster NASA Time Trial track car
2003 911 C2
NASA HPDE Instructor

I was talking with one of the GRM guys in person (pretty sure that it was 'Stafford1500') about boost with the Audi 4.2s. He mentioned changing the head gasket to adjust the compression. I don't remember the details, but I think that he recommended a thicker gasket to slightly reduce the compression. If you are boosting a stock 4.2 now, you may want to look into that for when you build up the replacement engine.

There may be a few guys on the AudiWorld Forums that have the forged internals tucked away. "audinutt" offered me a set about three years ago, but at the time I didn't plan to tear down an engine. It may be worth asking. If they see your build they will probably be happy to help out.

[truegearhead]

Originally Posted by 78F350

It's all awesome! I think it may be about time to change your signature:



I was talking with one of the GRM guys in person (pretty sure that it was 'Stafford1500') about boost with the Audi 4.2s. He mentioned changing the head gasket to adjust the compression. I don't remember the details, but I think that he recommended a thicker gasket to slightly reduce the compression. If you are boosting a stock 4.2 now, you may want to look into that for when you build up the replacement engine.

There may be a few guys on the AudiWorld Forums that have the forged internals tucked away. "audinutt" offered me a set about three years ago, but at the time I didn't plan to tear down an engine. It may be worth asking. If they see your build they will probably be happy to help out.

This is one of the reasons I went to e85, e85 has almost 3 times the evaporative cooling and reduces the detonation for high compression motors so there's no need to reduce compression. I also had EFI Express put the whole plan together, they have a tremendous amount of knowledge turo'ing these motors so I basically just returned everything I bought and bought their recommended setup.

Thanks for letting me know about the forged internals tucked away! I'm reaching out to them right now and will report back.

[truegearhead]

I'm super concerned about heat on this car so I've gone a bit overboard on a few things including these intercoolers. I've instructed a lot of students that had turbo cars, and almost all of them (including the factory turbo'ed cars) haven't survived a track weekend so I'm trying to be very careful. The intercooler setup I've designed should be good for over 2,000hp, it uses a huge water to air intercooler that is cooled by two large radiators that are squeezed into the rear fenders. I still need to fab up some aluminum plates to seal the doors up but its taking shape.

[Stroked & Blown]

Any concern with the rearward swept angle of the rads creating lift as the air goes down through them, or does the wheel well turbulence negate it?

[truegearhead]

Originally Posted by Stroked & Blown

Any concern with the rearward swept angle of the rads creating lift as the air goes down through them, or does the wheel well turbulence negate it?

So I’ll have to admit I really have no idea... look worst case I’ll add some angle of attack to the rear wing. The Front fenders stick out further than rears so it won’t be getting a ton of airflow. Good point though.

[Racer Boy]

Originally Posted by Stroked & Blown

Any concern with the rearward swept angle of the rads creating lift as the air goes down through them, or does the wheel well turbulence negate it?

That isn't an issue. The air exiting at an angle doesn't generate lift or downforce.

[itsnotanova]

Was this car a base or S originally? The S came with bigger coolant tubes from the back to the front.

[truegearhead]

Originally Posted by itsnotanova

Was this car a base or S originally? The S came with bigger coolant tubes from the back to the front.

It was a base 2.5, I thought about replacing the lines but I think I'm better just making custom lines that don't split since I'm not using the side radiators anymore. I'm hoping that the larger front radiator, large oil cooler and the evaporative cooling I'm getting from running e85 will make up for the small coolant lines. It helps that its almost never under 100mph so it'll have plenty of airflow.

[truegearhead]

Hardly worth a post but I got the intercooler test fitted and it looks..a bit small.

[Stroked & Blown]

The exhaust pipes are great! Are you planning to blow the wing?

[truegearhead]

Originally Posted by Stroked & Blown

The exhaust pipes are great! Are you planning to blow the wing?

Yep exactly! The exhaust will be angle up to speed the air under under the wing and the pipes will be shortened to hopefully prevent the wing from catching fire.

[ike84]

That's beautiful man, who put together the VEMS for you?

Sent from my POCOPHONE F1 using Tapatalk

[truegearhead]

Originally Posted by ike84

That's beautiful man, who put together the VEMS for you?

Sent from my POCOPHONE F1 using Tapatalk

EFI Express built the VEMs and supplied a ton of the parts. Absolutely awesome guys to work with. They knew exactly what I needed, steered me onto a much better path and bench tuned the VEMs for a e85 and for a flex fuel setup. They even modified my harness so this whole thing is plug and play. Can’t say enough good things about them.

[ike84]

Very nice progress! She's coming together beautifully.

What are the two air filters behind the passenger rear axle?

Sent from my POCOPHONE F1 using Tapatalk

[truegearhead]

Originally Posted by ike84

Very nice progress! She's coming together beautifully.

What are the two air filters behind the passenger rear axle?

Sent from my POCOPHONE F1 using Tapatalk

I’m actually using one of the two tanks there, it receives the oil after its pumped through the turbos. After passing through the turbos the oil is aerated so it settles in that tank before being pumped back into the engine via a scavenger pump. There’s two tanks because I got it off eBay(old NASCAR part) and it came with two welded together. I’ve bought a lot of eBay nascar parts, they’re well made and cheap. Not always great looking though. I have a similar tank on the engine that replaced the air oil separator.