Quick question on limits of SC engine

BIGDOGCQ2

Registered User
I drive a V6 mustang and hang out on 3.8mustang.com and v6power.net. I already have high performance parts on my 6 and just made a friend that can work the tubing for a turbo set-up.
So I am looking to upgrade my block but don't want to spend the money on forged parts. I will basically be swapping out the SC block and rotating assembly after rebuild.

How much boost can the SC engine hold up to reliably? I guess keep in mind its a turbo not the M90.
Whats the best year as far as reliability of block/internals?
Whats the first part I should upgrade ? like double roller timing chain?
Just let me know what you can. I want a really reliable engine but want to crank out some serious power. Anyone have experience with turbos info on a selection of parts would be great!
thanks
 
Thanks, I have heard the blowers were better on the 94-95 but what else makes it better as I will not be using the blower.

Big question here is what kind of boost you guys are running with a stock engine and what mods you do to run more.
 
15 psi on a daily driver? Have you made upgrades to your internal parts or are they stock?
Guess I should also ask where your rev limiters are.
 
The only mods that I have that would effect the boost is cone filter, 76mass air meter, custom true dual exhaust, and intercooler fan. When my car was stock I was still getting around 13-14psi.
 
BIGDOGCQ2 said:
15 psi on a daily driver? Have you made upgrades to your internal parts or are they stock?
Guess I should also ask where your rev limiters are.

15lbs of boost is pretty common on these cars with very little work. And yes, I am pushing more than 15 on my daily driver. However, you have to keep in mind that boost is nothing more than a measure of backpressure. Ford engineered these cars with some serious limitations that greatly affect backpressure. First off is the exhaust. Until next week, I'm running pretty much the stock exhaust. Once I upgrade that, I will be loosing roughly 3 lbs of boost. Another thing that affects backpressure are the heads. Once I get those, the boost will drop even more.

These cars can handle 15 lbs of boost on a daily basis. The internals were designed for that. From the factory they were pushing 12-13 as it was.

You will want a '94 or '95 engine. They did have better internal components and are not as likely to blow headgaskets as the earlier models. But since (I assume) you are doing a rebuild, head studs and fel-pro head gaskets pretty much eliminate your head gasket worries, unless you have and extremely modified car...Like those running high 10's and low 11's.
 
89 through 95 blocks are fine. What you want are the full floating pistons and connecting rods from 94-95. If you are planning for under 400 rear wheel horsepower, then the stock pistons and rods should be fine. Planning for over 400 rwhp, I'd look, at the very least, at sturdier rods. From the discussion in the member forum you may be able to get aftermarket SB Chevy rods an use them with stock pistons if you cut the piston tops down a tad bit.

Otherwise go Forged custom pistons and good connecting rods. (stock connecting rods being the weakest point of the bottom end)

Assuming new head gaskets and new head bolts (arp studs if possible), you should be able to handle 21psi all day as long as the charge is kept cool and there is ZERO detonation on a fairly stock motor.

Detonation is rough on motors running high effective compression ratio's, which is exactly what you have with SC or Turbo motors.
 
The idea of backpressure bothers me a bit as I already have pretty much the best flowing heads, intakes, an exhaust I can get for the 3.8. I also have a great cam for this app. So it seems to me that on a stock engine if I had 15lbs of boost and after mods had only 12 I would still be putting just as much stress on the engine because I am actually pushing the same air. So really should I just be concerned with how much power I lay down to the wheels?


After putting in forged rods what would you set my limit at? basically how much would the pistons and crank hold up to at that point?
 
BIGDOGCQ2 said:
The idea of backpressure bothers me a bit as I already have pretty much the best flowing heads, intakes, an exhaust I can get for the 3.8. I also have a great cam for this app. So it seems to me that on a stock engine if I had 15lbs of boost and after mods had only 12 I would still be putting just as much stress on the engine because I am actually pushing the same air. So really should I just be concerned with how much power I lay down to the wheels?


After putting in forged rods what would you set my limit at? basically how much would the pistons and crank hold up to at that point?

No one knows.
 
XR7 Dave said:
No one knows.

Because no one has broken a crank, piston, or rods due to too much power with such a combination. Thus far the primary failure of most of the high power SC motors has been detonation due to an overly lean condition in one or more cylinders. Or spun bearings.

As far as HP to the wheels. There is likely a pressure you could hit that would be too much for the head gaskets. Our heads do have issues with applying consistant clamping force due to the layout of the head bolts. But if you can keep temps in check for both coolant, oil, and air charge, no one has found the limit the block can handle.

There probably is a limit, but no one has yet been willing to invest the money it would take to find it with this motor. Though I see at least one guy working on a turbo setup for his SC Block that might help us find our limits.
 
Almost sounds like a challenge. I am going to start working on the turbo setup as soon as my friend is able to help bend the pipe. I will be keeping an eye out for a supercoupe engine and some forged rods. Hoping to keep this on the cheaper side.
 
SC Rods are forged. In fact most rods in automobiles are forged, at least these days. It's more an issue of the amount of metal and the architecture of the rods.
 
007_SuperCoupe said:
Ford engineered these cars with some serious limitations that greatly affect backpressure.

Ford did this so the SC would not have more power than the same model year Mustangs. Unreal!
 
mduralia said:
Ford did this so the SC would not have more power than the same model year Mustangs. Unreal!

Not true my sc (1994) has more hp and torque than stangs up to 1997
 
x182dan said:
Not true my sc (1994) has more hp and torque than stangs up to 1997
Right. The restriction and bottle necks are more a result of an innefficient R&D process, and the fact that they were never really addressed is the result of the top brass at Ford taking a dim view of the MN12 in the first place. JMO :)
 
Ok, I've been wrong before (ask my wife)

I swear I read that somewhere that the "numbers" (hp & torque) for the Mustang 5.0 GT in 94 & 95 were just slightly higher than the same model year SCs. Had the SC exhaust been properly designed, there would have been a huge difference in the "specs" in the literature. That was the reason for the restrictive exhaust.

Oh, well...just don't tell my wife I missed another one...k?
 
Using a mechanical means to limit HP is silly when a simple re-cal of the EEC would accomplish the exact same result without possible damage to the engine. The stock 89 exhaust system is actually very good with the exception of the resonator and even that is not a real problem with stock boost levels.
 
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