I have a question

[flyingthunder]

Hi, I am a new SC owner, but have been looking at this club for a while. I have a question or two for you all. I have read alot about how you have to open up the exhaust on these cars with aftermarket systems before you start modifying the car. I am not trying to sound like a smart*** or a dumb***:o when I say this, but I have seen some on this site that are running up to 20psi boost with the aftermarket exhaust, what is the difference(besides the added hp with the aftermarket)than running up to 20psi boost with stock exhaust? Any help is appreciated!:D

[thirdbird]

Welcome,

It is my understanding that you will quickly blow your headgasket[s] by increasing compression and not opening up the exhaust to compensate.
--That's if you are lucky.
A veteran may chime in on worst case scenarios...

paul

[95pearlbird]

The reason you have such poor response to your question is because you are in the wrong Forum. If you have a question about SC performance, ask it in the Technical Question Forum,not new owners. This Forum is where we throw out the Welcome mat for New Owners of SC's. And So, Welcome to the Club!

It's not about compression, its about the back pressure of the stock exhaust system. In short, its a bit plugged up. Overdriving the supercharger is the same as trying to force more air into the engine. FORCED AIR INDUCTION, right? If you try to force more air into the engine with a restrictive exhaust system(stock)somethings gonna blow, and that something will be your head gaskets. On an SC you MUST modify the exhaust FIRST before you try to pump more air into it. THEN you can do mods to the intake side. When you free up the exhaust, you will lose some boost because the engine is breathing better.You can then regain that boost by overdriving the supercharger to compensate. Most common is installing a 5% Overdrive pulley on the supercharger to restore your boost pressure to previous levels. It is also possible to change the jackshaft pulley, and achieve either 5% or 10% additional overdrive there.
You may not understand completely when some people are talking about a 20% overdrive setup on their blower. This is with a different blower(an MPIII) and many many more intake mods, CAI, MAF, TB, Plenum, 3/4 Top, FMIC, etc.
If you do not know what any of these things are, read up, there is a lot to learn about how these cars are built, and what works to make more HP.
You can't just slap things on, this is on the level of a mechanical art form.


If you are NOT technically, or mechanically inclined, my suggestion is to install a K&N Filter, leave the rest STOCK, and take good care of your baby. Give it good clean fluids and 91 Premium for life, because you own a classic.

If you ARE however,tech/mech knowledgeable, welcome to a very interesting and expensive adventure!
>>>> FIRST,if you have questions, READ EVERYTHING that is already here.
Especially the FAQ(Frequently Asked Questions) section.
Use the Search function for your topic.You will find your answer.
You can read this site for two weeks straight, and barely scratch the surface. There is a huge amount of Ford SC-specific information on this site, more than anywhere else! You will learn more about supercharging than you ever imagined. You will begin to understand the passion that we hold for these SC's and Cougars. Check out the Forums to see how the problem-solving process works, with everyone's input helping you. Please don't waste their time, its as valuable as yours is. There are some absolutely brilliant minds at work here, and they respond better to smart questions than to dumb ones. Do your own homework first before jumping in with a question, it's all free.

Aren't you the lucky one to have found such a wealth of information? We all are. Check it out for a month, chances are you will like it very much! Then JOIN ON UP. Spend the $15 bucks, its the best 15 bucks you can spend, if you own an SC or XR7. Thats what keeps all this up and operating. All the rest is pure go-fast fun. This site has the best bunch of smart, funny, friendly and passionate racers and wanna-be racers to be found anywhere in the world. But don't just take my word for it, find out for yourself.
You like Ford SC's, you're a brother here...>>>WELCOME, and Enjoy!
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