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sbc twin turbo build

19K views 17 replies 10 participants last post by  ibuildm 
#1 ·
Hey guys I have a very good budget to build a 350 sbc twin turbo , i want to be able to run 10 -12 lbs boost max , i need to find out how to get to the 600 to 800 hp range what engine combo do i need, whats pistons, cam, magneto, crank , rods, lifters, I want to run a 750cfm demon blow thru and two .96ar turbos, just want to get your guys input i wish they made a a exact step by step guide to building these, thanks for the input that way i know exactly what parts i need when i get it to the machine shop,
 
#2 ·
I would tell you to go to the book store or libery or the internet and read all you can about it. Hang out at the track or car shows and talk to people that have done it and take what you like from each one. I can't help you very much with Turbos but if you ever go with a Blower setup then just ask.
 
#3 ·
Blown is blown; only difference is in the plumbing and when the boost is applied. You want all forged internals and that includes a set of 2618 alloy forged pistons (note most forged pistons are 4032 which have more silicone in the alloy for street use). If you are looking for a high RPM motor you want an H-beam rod, lower speed RPM you want an I-beam rod which is the better of the two in a boosted application because it is stronger in compression than the H-beam). Chromemoly internally balanced crank and a solid roller cam so make sure your head choice includes room for stiff springs.

Intercooler (air over air or air over ice water) and impellers are what you have to decide upon as to how your turbo is going to perform. Most dual and four turbo race cars are built around the plumbing of the turbos as they need to be as close to the exhaust collector as possible to reduce spool up time (most turbo cams have a built in exhaust leak that vents a sizeable percentage of your motor's hot exhaust to get the turbos to spool up faster (a lot of exhaust duration). The only good thing I can say about a turbo is the power to boost the motor is free (it just doesn't work as well in drag racing as a supercharger does being driven off the crank due to lag time, but for the street or road racing you can not beat them).

If I were building one I would select a huge by large centripetal compressor and an air to air intercooler and hide everything beneath a flat hood. Only reason I don't use one is it works best with EFI and I'm married to a carb till death do us part.

Big Dave
 
G
#5 ·
i think that if you're not 100% sure of what you're doing then you'll be needing a new broom real quick after starting up the engine.

good advise... tape a few magnets to the front of the broom to ensure you sweep up ALL the shrapnel of the detonated engine ;)
 
#6 ·
ONLY MY OPINION :)
you dont need all the expense and complexity of twin turbos for that kind of power they sure do look cool and work well though.
you could get that range of horse power with a single turbo or Roots style blower depending on compression ratio,heads and cam and whether or not you want to run it on the street or just race it or a bit of both.
as a guide my 383 made 600bhp/548ft/lbs on 110octane with 4# of boost
at present its making 752bhp/600+ft/lbs @12# with 115maximal.
good luck with ya project:hurray: and ask lots of questions:yes:
also get ya plan on paper and stick with it its cheaper that way.:yes:
 
G
#7 ·
i'd like to get a little deeper here if i may and Roy can either agree with me or not as he's got a blower on his car...

it's not JUST installing a couple turbo's or a blower on the engine and say OK, we're ready to go...

the internal components of the engine need to be within the necessary quality standards and specifications to handle the boost. the strength of the rotating/reciprocating masses should be addressed, balancing, the compression ratio... the complete engine regarding the components, the machine work etc needs to be addressed. take an engine with too high of compression and/or not quality enough parts and machine work and install a blower or a turbo or two and wind it up a little and it's going to come apart.


but this is all just my opinion... ask Roy what he did to his engine to ensure it'd handle the boost and stay together...
 
#8 ·
Not to argue but you need do very little to a engine to run a blower that is going to have a small amount of boost. Here is a link to BDS they have been doing this for a long time and have great tech support this will help you understand what is need to run one.

http://www.blowerdriveservice.com/recommend.php

http://www.blowerdriveservice.com/faq.php


I run a 6-71 with 8lbs of boost that is as high as I can go with pump gas and makes a little over 800HP but the engine was built to handle 16 lbs.
 
#10 ·
Not to argue but you need do very little to a engine to run a blower that is going to have a small amount of boost. Here is a link to BDS they have been doing this for a long time and have great tech support this will help you understand what is need to run one.

http://www.blowerdriveservice.com/recommend.php

http://www.blowerdriveservice.com/faq.php


I run a 6-71 with 8lbs of boost that is as high as I can go with pump gas and makes a little over 800HP but the engine was built to handle 16 lbs.

yup your sorta right but once you taste the power especially torque off the line are you going to be satisfied with what you have My experience both with Bikes and cars where do you finally wanna be and build for thatthat way you only gotta do it once
I have a friend with a stock 350 and a 177 blower he loves it but now knows hes gotta spend some $ to go faster
 
#9 ·
Shifty and Dave are correct
it may look like a bolt on whether it be turbo or blower but theres a bunch of little stuff that needs working on to make it work and live more than 5 minutes .
On my engine its all forged racing stuff because i wanted to bracket race it,
big mistake i made was staying with the stock block with an on edge power level as now I will be biting my nails when i get to run it again a Dart little m is the next step when i get some $$$$$$$
if your budget is not fixed buy the best components you can and again ask lots of questions before you start or even think of buying anything based on the application you are using the engine in.
Team nova,stevesnovasite, dragstuff.com,speedtalk.com and yellowbullet.com are the main sites i use there are a bunch of people who have been there and done it and willing to share their experience one suggestion would be to think about your application write down what your thinking of using and go from there.
Good Luck
 
#13 ·
I'm still partial to the eight turbo car with all pollished tubing used to illustrate just how silly some people take the concept of building power without thinking about the consequences of where it goes or what it will do. (no it wasn't a race car it was show car in the theme of all show no go).

Big Dave
 
#14 ·
Well first off if you plan on running that much boost you wont be able to run tein turbo kit soo you know. But if you incest on running a twin turbo kit and making the smae mistakes i did .....Well then you should prolly go with with smaller turbos cause did the same exact build already. But if you wanna run a trubo set up with a SBC the you should run something like a 76mm or a lil smaller and then that way you can actually be able to push some boost out instead of them just spinning and looking cool otherwise thats what will happen if you put to big of a turbo on there.The horsepower you plan on getting is very possible so you know
 
#18 ·
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