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I have a 2.3L I want to turbo but it was built for N/A. what is the highest compression I can run on a turbo and what size turbo should I am for. I have one that I think is around the 30mm range.
 

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on a stock N/A motor, you shouldnt run more than 6-8lbs of boost, and even that could be pushing it. Your best bet is to pull the engine and build it with forged pistons and better rods.
 

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the factory n/a engines are not a good head design for boost. There is a problem with the way the heads are designed, and no matter how strong the rods and pistons are, eventually the head design and any fair amount of boost will cause an engine failure.
 

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You mean like valve train is weak? I'm running a solid lifter cam and I think the springs are beefed up, I'll have to check. I'm still just wondering if it is safe to run a turbo on something like 10:1 or more compression.
 

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A turbo can be run on 10:1 compression with a great tune and greater fuel...

but the design of the n/a 2.3 head, specifically the combustion chamber, will cause all your problems. It will run for a while at low boost but eventually it's gonna granade.

check out this site for more information on why they don't work well with boost, and just good all around info on the 2.3T engines.

STINGER PERFORMANCE ENGINEERING - 2.3 Turbo Performance Parts for Mustang SVO, Thunderbird Turbo Coupe, Merkur XR4Ti, Pinto, Ranger, and Sand Rails
 

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I have a 2.3L I want to turbo but it was built for N/A. what is the highest compression I can run on a turbo and what size turbo should I aim for.

Hey Jesse, can you give us a few specifics on your engine; Cam, Valve sizes, Head work, ect. Tell us what you would like to get out of it, realistically.

I have one that I think is around the 30mm range.

30mm, unfortunately doesn't tell us much about your turbo. How about a brand name, and some part numbers off the turbo.
Turbo sizing/ performance, depends on a variety of factors and can be a tricky process, even for the well informed. If you are planning a full on
racing build up or a mild street build, it would be wise for you to plan a power goal and work toward that. Building a turbo motor can and will
get expensive at some point and I would encourage you to set some kind of a realistic budget that you can live with, so that you don't wind up
with a stalled project in your garage.


Yea the motor is built and we planned on running race gas on it. It was built for circle track so it will probably end up around 10:1. Is a 30mm Turbo size alright?

You mean like valve train is weak? I'm running a solid lifter cam and I think the springs are beefed up, I'll have to check. I'm still just wondering if it is safe to run a turbo on something like 10:1 or more compression.


Your current N/A head, might very well be usable, depending on the intended use. No dis-respect to 03 R Code or BoPort, it really just depends on what your HP goal is. 10:1 IMHO is a bit high for pump gas, but with a race only motor, that might be a different story.

Craig.
 

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I have a 2.3L I want to turbo but it was built for N/A. what is the highest compression I can run on a turbo and what size turbo should I am for. I have one that I think is around the 30mm range.
Is your 2.3L out of a Mustang? If it's out of something else, you may actually be better off with head design or how much boost it can handle without s***ing a piston.

If you're using pump gas, aim for ~9:1 static. That's a pretty rough figure and that's only a static ratio. If you're good with timing, you may be able to push it to 10:1 static with high boost pressures and still run pump gas.

The SVO Mustang originally came with a T03/T04 turbo, that would be what I would use.
 

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The SVO Mustang originally came with a T03/T04 turbo, that would be what I would use.

I am pretty sure the majority of SVO's sold, had the Garret T-3 with .60 A/R on the inlet side. I have only seen the smaller Warner ISHI/IHI turbos on the T-bird turbo coupes, but that might be because they were not as reliable as the Garret turbos. I seem to recall one customers SVO that had the Warner turbo on it.

But now you have me wondering, which production cars, came with the T-3/T-4 turbo. Hmm, I got it..the 87 Buick Grand National and....:dunno I can't think of the other one
 

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The SVO Mustang originally came with a T03/T04 turbo, that would be what I would use.

I am pretty sure the majority of SVO's sold, had the Garret T-3 with .60 A/R on the inlet side. I have only seen the smaller Warner ISHI/IHI turbos on the T-bird turbo coupes, but that might be because they were not as reliable as the Garret turbos. I seem to recall one customers SVO that had the Warner turbo on it.

But now you have me wondering, which production cars, came with the T-3/T-4 turbo. Hmm, I got it..the 87 Buick Grand National and....:dunno I can't think of the other one
I looked into it, both the Grand National and the SVO used a T-3 turbo. I am having a hard time finding if any cars came with the T-3/T-4 hybrid from the factory.
 

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the factory n/a engines are not a good head design for boost. There is a problem with the way the heads are designed, and no matter how strong the rods and pistons are, eventually the head design and any fair amount of boost will cause an engine failure.
+1 this is very good advice to listen to!
 

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The factory N/A engines are not a good head design for boost. There is a problem with the way the heads are designed and no matter how strong the rods and pistons are, eventually the head design and any fair amount of boost will cause an engine failure.

I think you might be miss-reading the point 03R code was making. His point is valid, in that the factory turbo motors seem to be the best and most economical platforms to build a turbo motor from. They were designed with turbo charging in mind, after all!

From a scientific point of view, the N/A head has a clear advantage by having a smaller combustion chamber.
Take a look at any modern racing head you will notice something in common with their designs. That “something” is the chamber size.

Peak operating cylinder pressures are always governed by the cylinder head materials and the design of the combustion chamber. Detonation, is ultimately what will determine how much power can be developed in any engine. There are methods that can be used to push these limits, regardless of the design. Water injection, inter coolers, high octane fuel “read slow burning” fuel and small chamber size, are all valid methods of controlling detonation, within an engine. Again, detonation being your biggest limiting factor.

Ok Craig, why the hell do I want a small combustion chamber?

My short answer is “quench” No I am not talking about your thirst, I am referring to the flat areas surrounding the combustion chamber.

Flat areas?

The quench area is the flat part of the piston and head that would make contact, if you had .000" clearance between the 2 surfaces.

Most racing engines run a minimum of about .035" clearance between these surfaces. This decreases to the chance of a collision between the piston and cylinder head. The pressure wave from this near collision, drives gases at high velocity through the combustion chamber. This movement of gasses cools hot spots, lowers the chamber temperature, reduces detonation and increases power. This is why most late model heads run very small chamber sizes and are able to run substantially higher compression ratio’s than their predecessors.

This is why a lot of racers use thinner head gaskets, even though they give up gasket strength doing it.

Now that I have bored all of you to sleep, I have just a couple more observations to make about the N/A head.

There are many turbo 2.3 engines out there running the N/A heads. When properly ported they flow really close to what the turbo heads do and if you cut up a turbo head and a N/A head and lay them side by side, you will see, that the wall thickness is almost identical between the 2. In fact I might go out on a limb and say, that the smaller chambered head would provide greater stiffness surrounding the chamber and therefore it might be less prone to cracking. Having a smaller chamber means there is more material surrounding it and well, cast iron isn’t very elastic stuff.

Have you tried to find an un-cracked turbo head these days?

Sorry for the long winded response.

Craig.
 

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The factory N/A engines are not a good head design for boost. There is a problem with the way the heads are designed and no matter how strong the rods and pistons are, eventually the head design and any fair amount of boost will cause an engine failure.

I think you might be miss-reading the point 03R code was making. His point is valid, in that the factory turbo motors seem to be the best and most economical platforms to build a turbo motor from. They were designed with turbo charging in mind, after all!

From a scientific point of view, the N/A head has a clear advantage by having a smaller combustion chamber.
Take a look at any modern racing head you will notice something in common with their designs. That “something” is the chamber size.

Peak operating cylinder pressures are always governed by the cylinder head materials and the design of the combustion chamber. Detonation, is ultimately what will determine how much power can be developed in any engine. There are methods that can be used to push these limits, regardless of the design. Water injection, inter coolers, high octane fuel “read slow burning” fuel and small chamber size, are all valid methods of controlling detonation, within an engine. Again, detonation being your biggest limiting factor.

Ok Craig, why the hell do I want a small combustion chamber?

My short answer is “quench” No I am not talking about your thirst, I am referring to the flat areas surrounding the combustion chamber.

Flat areas?

The quench area is the flat part of the piston and head that would make contact, if you had .000" clearance between the 2 surfaces.

Most racing engines run a minimum of about .035" clearance between these surfaces. This decreases to the chance of a collision between the piston and cylinder head. The pressure wave from this near collision, drives gases at high velocity through the combustion chamber. This movement of gasses cools hot spots, lowers the chamber temperature, reduces detonation and increases power. This is why most late model heads run very small chamber sizes and are able to run substantially higher compression ratio’s than their predecessors.

This is why a lot of racers use thinner head gaskets, even though they give up gasket strength doing it.

Now that I have bored all of you to sleep, I have just a couple more observations to make about the N/A head.

There are many turbo 2.3 engines out there running the N/A heads. When properly ported they flow really close to what the turbo heads do and if you cut up a turbo head and a N/A head and lay them side by side, you will see, that the wall thickness is almost identical between the 2. In fact I might go out on a limb and say, that the smaller chambered head would provide greater stiffness surrounding the chamber and therefore it might be less prone to cracking. Having a smaller chamber means there is more material surrounding it and well, cast iron isn’t very elastic stuff.

Have you tried to find an un-cracked turbo head these days?

Sorry for the long winded response.

Craig.
I understood the statement perfectly fine. You have to look at the smaller chamber is also going to make more pressure. If you run 18 lbs of boost in a turbo head, then run 18 lbs in a N/A head the pressure is going to be much greater in the N/A head putting greater stress on all parts. It will be actually around 20+ish lbs of boost with the n/a head.. I myself would not run 10:1 compression on a turbo motor. Unless you have strong parts and a well built engine. I myself would run 9:1 or lower! From the way I read the thread is making it sound like Its ok to run alot of boost,and a N/A head with alot of combustion! This will make for a very bad day.IMO
 

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My apologies, not meaning to cast insults in any way, but it is sometimes hard to convey information over the internet and still temper the tone of your message, especially when you are tired, which I have been.
I guess I should have included more in my last post as well. I just ran out of energy.

In no way am I an advocate of running a high compression ratio with a turbo, using conventional pump fuel. I'm not saying you can't, but I wouldn't advise it. You will produce more power using more boost, as the "effective" compression ratio would be higher with more boost and less "mechanical" compression.

My past experience as a machinist and engine builder, has shown the high compression turbo combination to be less powerful and less reliable, without exception. The point I was trying to convey previously, is that the N/A head is more than adequate, for use in a turbo application. I would say that most people, who are going to invest in a well built turbo motor, even for the street, are going to opt for some decent pistons, which will support a reasonable compression ratio and offer a bit more strength.
For a street driven turbo car, I advise my customers to keep compression ratios in the 8-8.5:1 range, with quench clearances between .035-.040" and a center dished piston.

So the bottom line here, is that I am in total agreement with you on the compression.


Craig.
 
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