Twin Turbo Second Gen - Official Project Thread

[Insomnya3AM]

I'm all excited about starting my project so I'm going to start the thread today. Being it's 12:20AM, technically I'll be working on it later today. I'm going down to the warehouse to take all of the spare parts out of it and see what I've got to work with.

It's currently a 1978 Chevrolet Camaro with a built 350 with a double pumper Holley 650 Carb, tons of aftermarket parts, a built TH350 trans with a Hurst slapper shifter with headers and full true dual exhaust. She also has a 3-inch Goodmark Fiberglass cowl hood. I've never even driven the car this way and I never will. She's getting torn down today and I'm selling off most of what I have.

Here's a tentative list of what I'm going to do to her:



Twin-turbo Chevy 400 4-bolt block with aluminum heads

Custom Electronic Fuel Injection and a mounted laptop for on the fly tuning/duckhunt

Air-to-water intercooler

72 Split-Bumper front end

Full spec cage

Two racing seats with harnesses

Trunk mounted fuel cell

Four-link mounted 12-bolt Moser rearend with 3.73 gears and a Detroit Locker

Tubular control arms up front

Coilovers at all four corners

Drastic weight reduction - Full race prep

Hooiser cheater slicks with white lettering

Smooth perfect black primer - Let's me paint it superfly later but I can rock a cool color in the meantime

Custom projector headlights in the stock buckets - These will be very cool

Exhaust dumping from the turbos through 3.5inch pipes coming out of the fenders

Shaving most everything unnecessary - Won't have a single piece of chrome trim


That's about it I guess. It's a bit late and I'm dizzy from delicious exhaust fumes, so I've probably forgotten a ton. I'll update later with starting pictures and we'll see how it goes from there!

[greenmachine]

deffanitly sounds like a kick ass project

[Insomnya3AM]

Thanks

It's going to be a serious amount of coin, but I'm expecting to be at Milfbody.com Meet N' Greet 2007. That's the plan.

[MattODoom]

It would be wise to dump the Gen I platform for boost. If your planning to run a factory ECM youll need a Sy/Ty ECM or of course some aftermarket one which is about $1300 for the ECM it self.

Have you considered taking the leap to the LS platform? There are plenty of great opportunities in that field be it LS1, 2, 6, 7, 5300, 6000 you get the idea.

[DETROITMUSCLE]

Sounds wicked I can't wait for pics.

[phoenix_rising]

Wow sounds like a bad ass project! Do you already have buyers lined up for those parts?

[Orange Terror]

Yeah, what's the plan with the parts that are in it now. I have an 80 so I'm sure I could use something.

I think I would either look into the gen 3 LS platform or at least destroke that 400 to a 377. You need to build rpm's with a turbo motor. The duttweiler twin turbo engines are under 300 ci if memory serves and I believe they can make well over 1500 hp. just my $0.02.

[Insomnya3AM]

Yeah, I'm thinking of going with less cubes. I don't have the details perfected but they're close.

Big update later

[MrMojoRisin681]

I've seen picks of Twin Turbo Trans Ams (2nd Gen). They all used the Turbo 301's.

[Insomnya3AM]

I've seen picks of Twin Turbo Trans Ams (2nd Gen). They all used the Turbo 301's.

More of a reason to go with a 400

[Insomnya3AM]

The only place you're going to get audio updates is my blog at gasfed.blogspot.com

Whenever I have a revelation or get some sweet part I'm going to call in and update

[93formulalt1]

I'd love to see some pics after you start putting that sexy beast back together! Do you have a CarDomain site?

[Insomnya3AM]

I will soon.

I'll start up a cardomain but I'm going to create an actual website for her.

[81DaytonaPaceCar]

I've seen picks of Twin Turbo Trans Ams (2nd Gen). They all used the Turbo 301's.

I've not seen a 2nd gen twin turbo TA run a 301 (with good reason...things go ka-Boom).

Banks build a very small handful of twins, but they were based off the 350 cu in motors. Macho also built a couple of single turbos, but those were using 400-455 Pontiacs.

I am greatly interested in this project. It's actually the exact same thing I've been contemplating and researching.

A couple of thoughts:

1. Don't be afraid of cubic inches - The more torque a motor has, the easier it is to get the car moving, and the less perceived turbo lag you'll have. Torque is your friend. There's another board I frequent where a veritable tubo master posts, and he builds BB Pontiac motors (455+ cu in) for customers with a single turbo that make 900 hp with 7-8.5 lbs of boost. He's building a twin for himself that he expects to pull 1400+ hp and still be streetable.

2. One big turbo can be better than two small ones - Don't get caught up in the twin turbo bling. Yeah, it looks cool, but depending on how you set your application up, you may not be gaining much other that weight and heat. Smaller motor, contemplate twins. Bigger motor, may not be necessary. There's a potential cost savings here as well.

3. Be careful on how much boost you really need - Boost is destructive. The more boost you want to put through a motor, the motor costs go up exponentially. Built right, especially a V8, you can make an exceptionally fast car with relatively low boost. Remember that your motor is just an air pump. There's two questions you need to answer here...1. How much air do I want to push?...and...2. How much air is my motor capable of pushing?

4. RPMs are not critical for larger motors - Small motors need to spin more (i.e. 2.0L vs. 5.7L) to make up for displacement. If you stick with the V8, I'd doubt you need to turn more than 5000-5500 rpms to make max power. Estimate a 6000 rpm redline max (with a 400sb) and match your cam lobe overlap to match that. Anything much more than that and you're out of your powerband and gasping for air (several factors appy, of course).

5. Computers/intercoolers not necessarily required - You can run carbeurated motors with single or twin turbos without computers or intercoolers. The system is based solely on pressure. Not as tunable as a computerized system, but then again, once you get it set, how many times are you going to tweak it? Just a cost save option.

I like your concept of starting with the 400. Plan on spending a lot of money on a crank and aluminum heads on top of the turbo cost. Additionally, I'd think about budgeting for a 12-bolt rear, upgraded trans and a quality cooling system.

Also, before spending tons of money, invest in Desktop Dyno software. Best $30 you can spend.

I'd love to swap stories on this one. I've been obsessing about it for 5-10 years now...

[JoeliusZ28]

lol dont use a 301 for a TT project, youd be better off with a 3.8 v6 lol