Headers and other exhaust options

thewood

Registered User
Hi,
I just picked up a 1990 SC with about 66000 miles on it. It's completely stock head to toe, in real nice shape and run like a top. I was wondering what performance options there are for the street worthy machine? I've been looking at headers and other exhaust options but the ones I found recommend on this site are extremely expensive and appear to be a bit excessive for a street machine ($600 for a set for headers and $750.00 for a replacement exhaust system). I only paid $3500.00 for the SC so I don't want to spend another 1400.00 for an exhaust upgrade. Is there other exhaust options for a stock SC that's a bit more sensible that outputs and upgrade performance?
 
The factory exhaust manifolds can be ported (tbird88 does it, and so do I when I actually have the time). A local exhaust shop can usually make and install a complete exhaust system from the manifolds back for $400 - $700 (approx) depending on your setup, with cats and resonator/mufflers. I spent $565 on my setup, which includes:

Ported manifolds
2.25" downtubes
2.25" Catco High Flow cats
18" Magnaflow resonator
Single 3" to dual 2.75" with turndowns

Exhaust2.jpg
Exhaust3.jpg
Exhaust4.jpg
Exhaust1.jpg


-Rod
 
:p Looks nice, how's it working out for you? Did you get the performance you were looking for or was the sound what you're looking for.
 
Headers are not a performance upgrade to consider at this time. After you do the exhaust, some underdrive pulleys for your accessories, a lightweight jackshaft pulley and a a 5% OD pulley for the supercharger are the way to go. You will get a nice 30-40 rwhp for your efforts.
 
thewood said:
:p Looks nice, how's it working out for you? Did you get the performance you were looking for or was the sound what you're looking for.

Well, between the exhaust, an ASP UD crank pulley, and switching from 87 to 93 octane, I was able to pick up 19.9 rwhp and 10.4 rwtq. So yes, I'm pleased with the power I picked up, and I really like the sound as well.

-Rod
 
True, I forgot to bring up that point. And, those gains were compared to an already modified exhaust setup (resonator delete y-pipe and an aftermarket muffler). So the gains would have been even larger compared to a stock exhaust setup.

-Rod
 
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An option that I would suggest is either deleting your resonator or getting yourself a high-flow resonator. Everyone says that the resonator is the most restrictive part of an SC exhaust, and taking care of the resonator should give you a better sound, maybe a few ponies, and most importantly - help your head gaskets last a little longer!

Matt
 
I got my Resonator from Super Coupe Performance along with Hi-flow cats, mufflers, and the rest of the exhaust except for the headers. I am very happy with the setup AND sound. I haven't dyno'd it yet. Fit like a glove! Though after seeing the stock SC's exhaust, it had to get some sort of gain. No pics of it installed in the car off hand.
 

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Ok just so I'm strait on this. Do everything except the manifold and I'll have a happy head gasket?
 
I have a (so far) stock '90 SC. I am about to get a high performance exhaust system. Do you guys see it neccesary to replace my gas tank with the '92 and up tank. I know it is a straighter shot to the rear end. But I'm just trying to get your opinions.

Also- Is true dual exhaust possible on the SC's. I've been trying to see if I can do a true dual or possible side exhaust system. Have you seen any side or true dual exhaust?

Thanks alot!
 
Obviously you will get a lot of opinions on this, so let me just say that there is more than one configuration that will get you what you need.


First off, exhaust back pressure is not the biggest factor in headgasket problems. Engine cooling and lack thereof is a much bigger factor, but that is another topic.

True duals are possible but not easy or recomended on an early style tank. It is much easier on the later style tank.

Side exit exhaust is not practical due to the low sills on the car, but if you really want to you could.

As for the exhaust on the car you have, the factory manifolds can be opened up to a 2" collector, and 2.25" downtubes made. A pair of dual cats mounted downstream about 18", a large dual 2.5 in single 3" out resonator, 2.25" rear pipes and some straight through 2.25" mufflers in the back will support up to 350rwhp with no issues while sounding good.

This system will weigh less and flow as well as any dual system while keeping velocity high enough to maintain good torque.

:)
 
I've got agree with MIKE 38sc.

When you get a good look at the stock manifolds, you'll see that even with the max porting, they're pretty bad.

The exhaust is THE first thing that should be done to an SC. The problem is that once you get started on one of these, it's kind'a hard to stop. You'll need the full exhaust to allow everything else to work properly.

I got the complete SCP "Big Dog" system 5 1/2 yrs ago ($1500). It was part of what was called the 350hp kit. It supports everything I did then and since.

Doing it half-a$$'d will just give you headaches in the long run.
 
Re: I've got agree with MIKE 38sc.

rivlee said:
When you get a good look at the stock manifolds, you'll see that even with the max porting, they're pretty bad.

You'll need the full exhaust to allow everything else to work properly.

Doing it half-a$$'d will just give you headaches in the long run.

Ok, I started this and I want to clarify something. KISS! For those that don't know what that means.. Send me an email. I don't want 350 pony’s. I only want to make the car run without the stock back pressure, add longevity to the heads, and add a few pony’s and sound to the already fine running machine. So with that said is there an expert out there that can make a detailed recommendation on the manifold and exhaust, and possible other intake items that may need to be change if any exhaust modifications are made.

Thanks in advance,
 
racecougar said:
The factory exhaust manifolds can be ported (tbird88 does it, and so do I when I actually have the time). A local exhaust shop can usually make and install a complete exhaust system from the manifolds back for $400 - $700 (approx) depending on your setup, with cats and resonator/mufflers. I spent $565 on my setup, which includes:

Exhaust1.jpg


-Rod

Rod,
I didn't notice it before but your running an LX not an SC. Are the exhaust options the same as the SC options?
 
XR7 Dave said:
Headers are not a performance upgrade to consider at this time. After you do the exhaust, some underdrive pulleys for your accessories, a lightweight jackshaft pulley and a a 5% OD pulley for the supercharger are the way to go. You will get a nice 30-40 rwhp for your efforts.

I'm considering this.. as soon as I can find a good price on some max flow exhaust parts. Anybody got any input?
1990 SC STOCK!
AOD
66xxx miles
 
thewood said:
Rod,
I didn't notice it before but your running an LX not an SC. Are the exhaust options the same as the SC options?


Yes, you can run the exact same exhaust setup on your SC as what I have on my 94 LX splitport.

-Rod
 
All the talk about headers, but the 3rd highest HP car in this community runs ported factory manifolds. In fact several 300rwhp++ cars run them. Headers are not worth the money unless you just like them (like me). The SCP exhaust is fine, so is the work of just about any good exhaust shop. Here is a pic of an excellent exhaust system.
 

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As far as HG's longevity, consider this;

I went 100K on the original HG's before I added ANY mod's and I certainly didn't baby it.

As far as releasing back pressure and deeper sound, the resonator and CAT's are all you need to do.

Lee
 
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