Who knows about turbo?

[SkysTheLimit]

Seeing as how I'm pretty well boned on the header issue and going to have to run custom stuff anyway, why not throw a turbo on there while I'm at it?

What do I need to build about 7-10 pounds of boost to feed a carb'd 496? I'd be more partial to two smaller turbos than 1 larger one. Maybe a pair of 50mm with a blowoff valve? I know I need a carb hat to feed into as well.

I know
just humour me.

thx

 

[bear76]

 

[BadBob]

I know I need a carb hat to feed into as well.

Can't help on the actual turbo, but you generally have a less bitchy system with a pressure box that encases the whole carb. That lets you avoid the throttle shaft leaks and all kinds of other fun stuff. It shouldn't be too hard to adapt one meant for a supercharged system. Pretty sure that Vortech has one, and ATI probably does too. You'll still have to boost reference your fuel pressure.

 

[76zimmer]

Seeing as how I'm pretty well boned on the header issue and going to have to run custom stuff anyway, why not throw a turbo on there while I'm at it?

What do I need to build about 7-10 pounds of boost to feed a carb'd 496? I'd be more partial to two smaller turbos than 1 larger one. Maybe a pair of 50mm with a blowoff valve? I know I need a carb hat to feed into as well.

I know
just humour me.

thx

Sounds like an awesome plan....good luck, and maybe this rookie can help

http://www.bankspower.com/Tech_twinturbo.cfm

 

[dyeager535]

GM tried blow through (carbed) turbo's, then figured out the way to make it work right is fuel injection.

Carbed turbo 301's and carbed turbo 3.8's were junk, (and not nearly the power) the 3.8 lasted long enough to get EFI and turbo, and look how they do.

 

[SkysTheLimit]

It always seems to come down to going FI. That just aint gonna happen for a while. I'd love to be able to throw a TBI unit on it and be done but the motor is just too wild. I gotta save my rupees for a megasquirt or commander unit.

I'm going to research the turbo thing and see what all the little gotchas are. The actual turbo itself is cheap. I would imagine all the other little things you need are what getcha.

 

[sled_dog]

if you can't afford EFI you probably can't afford a turbo setup worth a damn either man. In my mind, it should go EFI, then Turbo. Save your pennies, throw EFI on it, save your pennies and do a worthwhile turbo setup. Hot sides need to be made of good thick material and to maximize the setup should be good flowing tube style header setups. Cold sides aren't too complex, though a nice intercooler isn't the cheapest thing ever. And turbos that aren't junk can be expensive. Tons of little turbos off of imports out there, but a pair of 16gs wouldn't feed a Big Block and half the turbos out there people are selling are in some way shape or form toasted.

Whats the purpose of the turbo setup? Cool factor as well as a bit of power of course? A 496 doesn't strike me as the optimal turbo play ground. Really going to have to look for a turbo that will peak at lower RPMs than a lot of the ones out there.

Sorry I just don't know enough about Turbos and never have found a good source I felt I should bother to learn from.

Maybe I am being overly negative and someone will have a better informed response.

 

[W7NB]

Why not use a blower instead? Seems like I have seen several bolt on roots types for big blocks that would work carbed.

 

[4X4HIGH]

Don't forget that with a turbo you need lower compression ratio, forged turbo pistons, and preferable 4 bolt mains.

 

[SkysTheLimit]

Blowers are expensive. I could do a twin turbo set up much cheaper. CR is a little high @ 10.5:1 which is why i'd only run low boost. Everything is forged in this motor so that's not a problem.

I'm going to put together a shopping list of everything i'd need and see how much coin i'm talking about and probably abandon the idea and just get some headers welded up.

 

[sled_dog]

7-10 psi will still be pushing it on a carb setup with that much compression. Forged components will help, but I think you really should have planned ahead if you wanted boost. You'll be running race fuel to run that much boost with that much compression.

Blower setups run about 3k. 2 good turbos will probably cost you $1500 I'd bet. Never underestimate how **** adds up. Thats just turbos, not blow off valves, wastegates, hot side piping, fab time in the piping, or intercooler(s).

Believe me I am ALL for Turbos. I love the things, and really really want to build a small block with a big single booster on it, but I plan on building a strong fairly low compression engine, then upgrading to EFI, then puting together the turbo setup piece by piece. I've screwed myself by getting over my head too many times, I figured on everything costing an arm and leg, ha.

 

[4X4HIGH]

Turbo and blower pistons are different than a naturally aspirated piston. They are made of a different material, thicker piston heads, and the top ring is lower on the piston than a conventional piston. Also 10.5:1 is WAAAY to much compression for a turbo or blower unless you're running alcohol.

 

[ryan22re]

For some low buck turbo stuff check out this website:

www.toohighpsi.com

Mostly ford stuff, but lots of good info/tech for those interested.

Personally, I'd take two small import turbos with an interal wastegate, hang them off of a set of blockhugger headers flipped upside down, and let her rip. For a max output turbo motor you will need all of the stuff mentioned above, but for the little gains you'd see with smallish turbos, whatever you have for an engine will hold up fine.