Vortec 8.1 (496 bored .030 over)....turbo'd?

[65chevelle''ss'']

Firstly I have to give my disclaimer..... I really don't know much about engines or how they work so if I sound like I don't know what I'm talking about you know why... However, I'm wanting to turbo my 8.1 that I'm building for my Chevelle but I have no idea if my motor would even be suited to handle it? Can you guys give me some input on this? Here is what I have...
HEADS

-Exhaust ported and bowls cleaned up
-Went from stock 1.74 exhaust valves to Manley 1.88 stainless
-2.19 intake

BLOCK

-Decked
-Line bored
-Balanced
-Eagle rods
-Stock 4 3/8'' crank
-BHJ balancer
-JE pistons (9:1 comp .030 over)
-Comp Cams hydraulic roller w/561 lift (if my memory is correct)

I will be running a Hogan's manifold and F.A.S.T for the engine management. I have the F.A.S.T setup already although I have yet to order my manifold... What are your thoughts???

[DeltaT]

Sounds like a great platform for a turbo or twins.

I highly recommend Corky Bell's book "Maximum Boost" for anyone starting a turbo project. Takes you through the questions, step-by-step.

Another, simpler option would be a centrifugal supercharger, like a Vortech or Procharger. Plumbing is a lot simpler, and frankly, power is not going to be your problem anyway. Turbo is going to add more midrange than the blower, but midrange power on a hot 496 is rarely something people complain about, eh?

Jim

[pdq67]

Remember this motor is!!

Tall decked, at 4.25" b x 4.37" s = 496".

Personally, I'd blow it using a 250/256 roots type supercharger...

It WON'T create max. boost like a 6 or 8-71, but what the hey, it will do FINE imho..

pdq67

[GetMore]

The thing you need to do is determine what your budget is and how much power you want to make.
Your engine will handle a turbo as it is now, without any problems, but only to a certain point. It is totally inadequate for a big turbo.

FWIW, supposedly twin turbos are great if you need low end boost, but one big turbo is better for top end power. Both are great for midrange.
With a big block you probably won't have any lack of low end power, so a single turbo is your best bet.

Personally, I like turbos, so I think it's the best way to go. Centrifugal superchargers are less efficient (mileage wise), and Roots-style blowers are the least effective. (All my opinion.)
That being said, the Roots blower will give the best power off idle, as it is always pumping and doesn't have to spool up. They are great for burning tires at will!

[pdq67]

And I think they have cast cranks??

pdq67

[deuce_454]

you should be fine with a big single... if you can do th eplumbing yourself it is also cheaper than a roots... im not talking crazy boost here, but a 6-8 psi setup will put you well into the 600´s HP wise and if you need more than that you need to go full tilt on everything, engine, tranny, brakes, rearend, furl system and so on.... and at 600 Hp your engine should be fine, as long as you dont increase the rpm´s or detonate...

[DeltaT]

Better start saving for that built 4L80E, too!

Sell the 60E while it's still alive and kicking...

Jim

[4OfaKind]

Firstly I have to give my disclaimer..... I really don't know much about engines or how they work so if I sound like I don't know what I'm talking about you know why... However, I'm wanting to turbo my 8.1 that I'm building for my Chevelle but I have no idea if my motor would even be suited to handle it? Can you guys give me some input on this? Here is what I have...
HEADS

-Exhaust ported and bowls cleaned up
-Went from stock 1.74 exhaust valves to Manley 1.88 stainless
-2.19 intake

BLOCK

-Decked
-Line bored
-Balanced
-Eagle rods
-Stock 4 3/8'' crank
-BHJ balancer
-JE pistons (9:1 comp .030 over)
-Comp Cams hydraulic roller w/561 lift (if my memory is correct)

I will be running a Hogan's manifold and F.A.S.T for the engine management. I have the F.A.S.T setup already although I have yet to order my manifold... What are your thoughts???

65,

Your setup is fine for boost. The only thing I would change is get a forged crank instead of cast. Every build is only as good as the foundation. If your rods and pistons are forged, get a forged crank.

On the compression ratio 9:1 is good 8.5:1 is better. An easy way to adjust it up or down is the thickness of your head gaskets. A thicker head gasket can lower your compression for a fraction of the cost of new pistons. And you can change back and forth during tuning as you desire.

Power, wether you turbo or supercharge will always come from your heads. No matter how powerful your lungs are, you can't push alot of air through a small passage. Think about those small balloons that make everyone red in the face. The better and more efficient the heads the more power. All the pistons do is pull in and push out air. If your heads are too restricting, the rest of the motor's potential is wasted.

Just some things to think about. Hope it turns out well,

Mal

[nightrunner]

ive never seen a 8.1L, built or not, be able to take over 8psi without popping.


remember the vortec 8.1L does NOT take regular BBC parts. as of a few months ago, only ONE (1) company made an aftermarket intake manifold or cylinder heads for it and there are less than a dozen cams available for it. not very aftermarket friendly