Twin Turbo Help

[ItDoRun]

I've talked myself into the twin turbo set-up for my 68 Camaro, but I need some recommendations on how to build the motor to support the boost. First, let me say that my goal is to have a streetable car that runs 10.50's. This should be easliy achievable from what I have heard. The car has a 350 2-bolt main block. I will be adding aluminum heads (not sure of what brand or cc). What I'm not sure of is what rotating assembly (forged or cast), pistons, and especially cam to use. I'm looking at probably 12-14 psi boost with GN turbos. Any help would be greatly appreciated. If there is any additional information that is needed from me, let me know.

Thanks

[slow4dr]

I've talked myself into the twin turbo set-up for my 68 Camaro, but I need some recommendations on how to build the motor to support the boost. First, let me say that my goal is to have a streetable car that runs 10.50's. This should be easliy achievable from what I have heard. The car has a 350 2-bolt main block. I will be adding aluminum heads (not sure of what brand or cc). What I'm not sure of is what rotating assembly (forged or cast), pistons, and especially cam to use. I'm looking at probably 12-14 psi boost with GN turbos. Any help would be greatly appreciated. If there is any additional information that is needed from me, let me know.

Thanks

Personallly I like to over build the engine because I know damn well that I am always wanting to go faster. Once you see what the car will do on pump gas & low boost you will be amazed at what happens with race gas and high boost.

I would get splayed main caps, steel crank, forged 8.0:1-8.5:1 pistons, & H-beams. As far as the heads are concerned there are way to many options to really pinpoint a specific brand(Everyone has an opinion). I would go with a 72 cc or higher chamber. Cam specs are more complicated but typically you are looking for something with very little overlap. I'd recommend you talking to any of the big manufacturers crane/comp/crower etc because they all have turbo specific cams off the shelf.

What are you going to use for fuel management?

[ItDoRun]

fuel injection. I have a friend who is an EFI wiz, and he'll be helping me piee together the EFI system.

[nitrorocket]

Youll have 15g in the motor besides the turbos.... A turbo LS1 all stock will make 700 hp all day long.....Stock!

Did you consider going LS1??

[ItDoRun]

15g??? I'm not trying to sound rude, but could you itemize what your proposing for a 15g motor?

[slow4dr]

fuel injection. I have a friend who is an EFI wiz, and he'll be helping me piee together the EFI system.

Good luck with the project!

[ilovefirstgens]

15g??? I'm not trying to sound rude, but could you itemize what your proposing for a 15g motor?

15g might be a bit north but it will be very close if you dont intend on blowing it up, for all the money to get alum heads, fuel injection, and any bottom end strength you would be way better off with a gen 3, considering you can find a truck 6.0 with an auto bolted up for about 1/3 the price of a ls1 and they can take lots of boost!

[camcojb]

15g??? I'm not trying to sound rude, but could you itemize what your proposing for a 15g motor?

Here's a list on an LS2 turbo build, cost was over $13K for the assembled long block. You still need all the accessories and oil pan, and obviously it could be done cheaper, but this was a good quality build.

new LS2 block
billet caps
ARP main studs
Callies 4" crank
Mahle turbo pistons
Howards rods
ported oil pump
MLS head gaskets
Morel lifters
custom roller cam
lifter trays
new rockers and hardware
custom restricted pushrods
heavy duty timing chain and gears, dampner
ARP head studs
ET Performance CNC 245 11 degree heads
LS2 front cover and gaskets
LS2 valley cover and gaskets
LS2 rear cover and gaskets
billet valve cover spacers

fully machined, balanced, and assembled by Wheel to Wheel.

[nitrorocket]

Here is a breakdown of all of the parts in my last motor I just sold. 427" sbc. It adds up FAST! This is a bullet proof combo, but you can see cost can add up fast for a real nice motor.

MY 427 SBC
BLOCK $2,000
CRANK $1,200
RODS $1,150
PISTONS $880
BEARINGS $170
GASKETS $130
RINGS $140
MACHINING $900
ASSEMBLY $600
BALANCING $300
OIL PAN $180
TIMING CHAIN $150
TIMING CHAIN COVER $15
FLUIDAMPER $250
ENGINE BOLTS $50
HEAD STUDS $130
DAMPER STUD $25
ROLLER CAM $275
CAM BUTTON $10
LIFTERS $480
PUSHRODS $140
VALVES $260
SPRINGS $250
RETAINERS $120
SPRING SEATS $10
VALVE COVERS $200
ALTERNATOR $260
GEN 7 $1,450
DISTRIBUTER $400
CRANK TRIGGER $230
HARNESS $50
PULLEYS $60
WATER PUMP $60
STEERING PUMP $200
INTAKE MANIFOLD $500
INJECTORS $500
THROTTLE BODY $800
FUEL RAILS $125
HEADS $1,800
SHAFT ROCKERS $1,150
HEADERS $400
AIR CLEANER $110
OIL PUMP $70
OIL PUMP SHAFT $20
ALT BRACKET $180
PLUGS $20
WIRES $80
P/S BRACKET $30
MOTOR PLATE $180
VALVE LOCKS $35
AN FITTINGS $240

TOTAL $18,965

[Reckless]

"Twin turbo", "reliable", and "cheap" do not belong in the same sentence

[nitrorocket]

"Twin turbo", "reliable", and "cheap" do not belong in the same sentence

Turbos are the most reliable way to makle BIG power, It can also be done much cheaper and more reliable then the same hp N/A or nitrous motor, You might want to rethink that mis-informed statement.

[MarkM66]

Turbos are the most reliable way to makle BIG power, It can also be done much cheaper and more reliable then the same hp N/A or nitrous motor, You might want to rethink that mis-informed statement.

So to you, $15k is cheap. Since you just told the guy he'd have that much in the engine.

[nitrorocket]

So to you, $15k is cheap. Since you just told the guy he'd have that much in the engine.

Noooo, I said he would have $15K in a SBC that would handle big power. You can do an 800+ hp Twin turbo ls1 for under 13K if you do it yourself and only get the correct stuff you need. That is cheap for a turbo setup! Check out what local shops want fot a complete TT setup! You will faint!
That is the main reason I switched to the LS1 is the low cost of them and the ability to handle more power with stock parts then a SBC.



Do reasearch on what you like and start buying parts, before you know it you wil be ready to turn the key! You will LOVE turbos! If you stay SBC you wil need a 4 bolt splayed block forged crank, billet rods, and forged pistons. If you put some good flowing heads on there, you are looking at about 900-1000 hp at the crank at 14 psi! I would go with 60-1 or 60-1 HI-FI turbos with a .69 tang housing with either a B or E compressor cover. Both will get the job done.

GOOD LUCK!

[Reckless]

Turbos are the most reliable way to makle BIG power, It can also be done much cheaper and more reliable then the same hp N/A or nitrous motor, You might want to rethink that mis-informed statement.

I want to see a 1500hp NA engine that is streetable

[nitrorocket]

I want to see a 1500hp NA engine that is streetable

There isn't such a thing as a 100% streetable N/A motor that could see any big miles or be practicle.


1000 hp (give or take a little) seems to be the magic # for most turbo and supercharged motors that are 100% street driven. Much more power then that and you have to start using non streetable high wear parts like huge cams and monster valvesprings just to name a few.

[Reckless]

OK, so show me a 1000hp NA engine that is streetable, or 800hp, or how many are even 700hp? Point is, you are talking about two different entities. We can build a twin turbo LSx setup that will make 1000hp on any day, but is it on pump gas? Probably not. People have to use a little common sense when asking for power levels for a street car. Anything over 550-600 rwhp is pretty much useless on street tires. Numbers beyond this are just for ego really. I can admit it

[nitrorocket]

OK, so show me a 1000hp NA engine that is streetable, or 800hp, or how many are even 700hp? Point is, you are talking about two different entities. We can build a twin turbo LSx setup that will make 1000hp on any day, but is it on pump gas? Probably not. People have to use a little common sense when asking for power levels for a street car. Anything over 550-600 rwhp is pretty much useless on street tires. Numbers beyond this are just for ego really. I can admit it

What are you talking about?? I NEVER ONCE STATED THAT ABOUT AN N/A MOTOR.

I am saying you CANNOT have a good high hp N/A street engine compared to F.I.

Do you have what I am saying mixed up??? Reread what I have said, I basically said that to make an honest real high powered street engine you need forced induction, and the limit is rougly about 1000 hp. You keep bringing up that you cannot make a high hp N/A motor, and I agree!

This guy wants to make about 14 psi on an engine with aftermarket heads. That will make 900-1000 hp at the crank depending on exact combo. I am trying to give him turbo advice.

And for the record, I have an LS1 motor making roughly 1000hp on 93 octane. It is pretty easy now a day's with the good heads and turbo technology out there, There are Mustang guys making huge #'s on pumpgas(1000 RWHP!), Seems things have come a long way in a short few years!

[Nutsy]

Im confused.

[ItDoRun]

Actually I'm just looking for about 500-550 hp at the rear wheels. I'm not trying to build a beast here. Just something with considerable power, different, and fun to cruise and play around in. I guess with this in mind, would a 4 bolt block with forged internals and h-beam rods be sufficient for this kind of hp and 12-14 psi boost?

[nitrorocket]

That power can be done with only 8 psi, so you dont need much of a motor buildup. Just a forged rod and forged piston with basic aftermarket heads. You will be able to do this fairly cheap, just know what you want to buy before you buy anything.