Exhausts.

Renob

Registered User
I'd been doing some reaserach after blowing my head gasket and came across a page talking about how, at high RPM's, the SC's are running like 14-15psi back pressure in the cyl's from the crappy exhaust that ford put in to choke these cars down, and that the exhaust is one of the big contributers to blown headgastets. I knew that there was a problem with the stock, but now i'm kinda forced to look into fixing the problem so i don't blow another headgasket when i get this all fixed..Also, i'd like the added HP :)

So my question is this.

Does anybody know if a flowmaster 2 1/2 catback exhaust relieves enough back pressure to really alieveate the problem with the exhaust? Is magnaflow a better option? Or do i really need to go more than just catback?

And just on a question of personal taste... is the flowmaster really loud? or more of a throaty sound.. i don't want to have an obnoxious sounding car.
 
I have the flowmaster setup on my wifes '90 SC 5 spd, cats and all. It still sounds like a 6 cyl, but only really gets louder when you get into the throttle. It is a little throatier (is that a word?) but no one will mistake it for a V8. If anything, it sounds more like a really tough 280 Z or Porsche 911 from back in the 80's. It does have a bunch more kick then the stock exhaust did.
As far as the HG go, true the heads, check the block for flat, use ARP studs and Felpro gaskets, and take you time. Do good work. Whatever exhaust system you use will only screw up a badly done (Thanks Ford) HG seal.
 
re

how much differcens did it make and do you lose that much touque did you lose because i don't wan't tp loose that and i don't realy want to do any other mods just free up the exhaust i would like to know please
 
First of all the "cats" issue needs to be addressed on a stock setup. It's at a 90 degree angle and as you would imagine it's not good for air flow. Keep that in mind.

I have a 2.5" downtubes, no cats, into a magnaflow resonator that flows into a single 3" pipe, and back into dual 2.5" pipes.

When I went to that setup I lost about 3-4 psi of boost. I was down to about 10psi at WOT. The car felt very sluggish on the low end, but stronger at higher speeds. I added a 3% OD pulley to regain the low end power and to bring my boost back up to about 14psi.

Hope this helps.
 
When the exhaust was re-done on my wife's SC (we each have a '90), they put in new cats as well.
I haven't Dyno'd the car, but it feels as though the torque band is much wider. The car doesn't stumble or bog at all, at any rpm. It pulls much more smoothly throughout the rpm range, but you can really tell when you keep it in third gear on long on ramps and such. It is just much happier to rev. I really have to pay attention on the freeway, or I'm liable to forget to upshift to 5th gear.
I don't think you need to worry about torque losses unless you go to headers and a Big exhaust, and even then, like tbirdsc357 says, go to an OD pulley and get back your low end.
I am really happy with the Flowmaster setup. That being said, on MY SC, which is in the garage now going thru major mods, I'm going with the SCP big exhaust and headers.
 
Hey Renob, I just saw you're in Vegas. I'm going to be there on the weekend of the 24th. If you want to check out the exhaust system on my wife's SC maybe we'll drive that out. I'm staying at the Luxor.
 
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