Thread: twin turbo 383

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hello fellas, this is my first posting on this forum. my name is evan, im 21 and i work as a basic mercedes technician... ive worked on lots of modern european cars. but my heart lies with classic american muscle...

i have lots of experience swapping engines and transmissions. i have never built one my own engine i am going to buy a early 80s late 70s cadillac fleetwood... basically a full sized heavy cadillac... i want a small block with tons of torque and hp... i really am dreaming for 550 bhp and 600 ft. lbs. tq.

before i buy the car, i want to have the engine all ready to drop in it. im still young and just need to make sure i get the biggest bang for buck. i dont really know how to fine tune engines for high performance applications. i need you experienced guy's feedback because i am learning..........

i want to buy 383 crate engine long block and install twin turbos on it...
is it possible to put something like this togther for approx. 6,000?
i have no expirence installing turbo chargers or any forced induction system.

this is the engine i was planning on using....

BluePrint Engine Long Block Crate Engine Chevy 383 6.3L 420HP/450TQ 4-Bolt Main | eBay

and i would love to install these turbos on it...

CHEVY SMALL BLOCK TWIN TURBO/CHARGER KIT SBC T3/T4 T04E | eBay

what do you guys think?
will i be able to get the numbers im hoping for, or close to those numbers?
i notice the motor says 420 hp, will it not be able to handle more?
any advise or comments?
are these turbos good quality or junk?
can i use a carb?
or is fuel injection better?
am i crazy

thanks guys.

i plan on doing all this work myself...

Good morning Evan.

I can't offer you advice on your envisioned small block project but I can tell you that you are in good company.

There are plenty of "been there done that" folks here who can give you expert counseling when it comes to practicality, realistic modifications to your engine to keep your car "streetable" (if that's a word), transmission and gear ratio decisions you will have to make, and the considerable expenses you will have to face ....... just to mention a few areas of expertise that are available to you, free of charge!

You indicate that you want a "torque monster" engine. It will definitely take some torque to move a Fleetwood. Are you totally locked in on a small block? If that's not an absolute requirement, why not look at a 500 cubic inch Caddy and go from there? Those brutes make big torque even if stock as a stove. With modifications the figures go out of sight. I was given a '76 De Ville a few years ago. A guy gave it to me because his wife wanted the ugly beat up wreckage off the property.

I got a running (more or less) engine and the TH400 transmission that was hooked onto it. Then the scrap metal guys gave me $90 for the rest of it.

Just a suggestion.

Good luck with the project!

Jim

Evan, welcome to CHR. I'll defer to the more experienced "engine experts" that we have here, but I'd say Jim's on the right track with his suggestion of considering a big block vs the SBC. You'll get lots more "grunt" in stock form, and can push it farther without limiting the reliability factor. One comment on your cost question - you say "Can I do this for around $6,000?", but then you list two "packages" that total over $5400? That's simply not realistic, in my book. You're leaving yourself $600 for all the incidentals that will come up as you make it a complete package.

How are you fixed for tools and a place to work? A turbo job is going to have a bunch of TIG welding for those pipes, especially if you want them to look pretty. Do you have welding equipment? A shop or dedicated garage to work in? Not trying to rain on your parade, but before you start tossing around $1000 bills for pieces/parts you need to have a firm plan in place for the project, and then build it right once to the plan. Just my $0.02 having stutter stepped through some projects before.

First, welcome to CHR, good having you here. Seeing as how you're looking for torque, I'd suggest (as the others have)taking a look at big block... The numbers you're after would be quite easy with a big block Chevy or the big 500" Caddy engine..

However if you're set on a small block, then with all the boost that twin turbo's make you would be much better starting out with a Dart block for the added strength. Turbocharging also requires a camshaft ground specifically for turbo's, and the compression ratio of the engine needs to be down around the 8:1 area. Turbocharging also requires a lot of carburetor mods, so you'll need one that is set up for "blowthrough" operation. Also on your shopping list you'll need an ignition system that puts out at least 40,000 volts to fire that highly compressed mixture and also an ignition box with it that has a retard feature for the timing...

I would also suggest before you part with any of your hard earned money that you start the project with a lot of studying on turbo systems and their requirements, lots of good books out there that cover the subject and aren't just written to sell you parts like the neat ads and pictures are intended to do...

Welcome to CHR –

As mentioned above, lots of good folks here and a lot of experience. I’ll sound like a broken record here and throw my 2 cents toward a big block for your Cadillac. There’s a lot of BBC expertise here and Pat McCarthy will be able to guide you through a big block build.

If you do go SBC, I don’t think you dollar numbers are realistic. As Roger mentioned, there’s a ton of welding and pipe bending to make a turbo exhaust properly. I know the “wowzer zowzer” factor of a twin turbo motor is high, but the cost associated with building and maintaining one is also very high. You need top a drawer reciprocating assembly for turbo applications. I think $10K (or more) is likely what will be needed to do a twin turbo properly.

The SBC you referenced from Summit would not be a good fit as the compression ratio is 10:1. In my opinion, you need to aim for around 7:1 or 8:1 compression ratio for a turbo; anything above 9:1 you will have problems. You will need to run the highest octane fuel that you can find as the higher the octane the less likely you’ll experience engine knock.

Again, welcome and let us know what you decide!
Glenn