Exhaust Systems....Researched

[Redtag20]

Originally Posted by mrnickleye

As for cold air intake, I've read lots on the net, magazines, and forums. With the AFM like our n/a has, you'll end up putting a K&N (or similar) either directly onto the AFM (mine), or on the 3" pipe you'll use to run out front somewhere (behind the headlight?).

I ducted air with galvanized sheet metal up from the front grill to the opening for original airbox, behind headlight.

Then I made a plastic box to seal off the heat from under the hood from getting into the K&N.

You DO NOT want hot air going into the air cleaner, it cause HP loss !!!

Of these mods, what is legal in CA? I really don't want to pay $50. or so for a stock rubber intake hose to replace the damaged on I have, if I can install a better flowing intake pipe from my air-box.

[mrnickleye]

Well....the smog tech will want to 'see' the AFM under the hood. He's not gonna care if you use K7N type filter, or PCV or metal or whatever piping from AFM to the throttlebody. Just so its connected tight, with no air leaks.

Some people have used those 3" metal piping kits from internet or Pepboys, or custom, etc. But I don't because it sits right over the exhaust manifold and the metal will get very hot, which heats the intake air.

As for the $50 hose off the throttlebody, I later saw some 3" rubber, and PCV elbow pieces at Home Depot & Lowe's that would have worked. $10-15.

[Redtag20]

What is AFM? Great idea about the pvc and rubber hose. I'll take it one step further and wrap the pipe with insulation to help control intake temp and protect the piping. What do you think?

[mrnickleye]

The AFM (Air Flow Meter). The metal and plastic electronic component that the air filter is mounted to. Near the power steering reseviour.

Insulation wrapping is good if you remove the original equipment and use other piping materials. There is some you can buy from internet performance stores just for this purpose. Looks good too.

[whitequasimodo]

marnickeye were is your shop in ca. like i said earlier i used to live in pdale so maybe one day i would pop by and to show you my mk3. maybe give some tips on what i should do with it and were to start.

[dannydavi]

wasnt quasimodo already white..... haha just noticed your name, and yes mr nickeleye thanks for all your input on this forum, it helps, but i do have a question about exhausts, what is the horsepower difference between cat backs and with headers etc.. im a noob, and would love to know as much about these things as i can, not only horsepower difference but maybe why someone would add headers and full exhaust over cat back, also an average price difference, if anyone knows please share, thanks.

[mrnickleye]

Well, it is estimated that going cat back , and larger pipe (2 1/2" in our N/A's), will get you about 5-10 hp.

In alot of cars, it is estimated that putting headers on will get you about a 10% gain. But that because those cars had restricted exhaust manifolds.

The N/A motors have a nice, free flowing, and light-weight manifold from the factory. Toyota spent a lot of time and $$$ developing that manifold to give you the best "bottom-end" torque, with out a big loss on the top-end.

I still have my factory one on. I drive it every day, city mostly.

As you read in the first post, "Before this exhaust mod, the car would max out at 125mph.

After this mod, I can easily go 145mph any time I want."""""

Some of the other folks here may be able to tell you about their experiences with headers, and what gains they have gottn,

[dannydavi]

thank you very much for your input, helps me understand a lil better, but is cat back basically everything is stock except the cat converter and everything behind it, cause that's what it sounds like haha, and are headers and downpipes the other exhaust upgrades you can get, or are there additional? thanks for any input guys. im being thorough cause im getting ready to do it in a few weeks

[mrnickleye]

Cat back does not mean replacing the cat. It means...from the cat ...back.

No 'down pipe' on a N/A car, only turbos.

Headers for our cars go way back, to a pipe, then the cat.

There are performance cats, but not needed unless you are building a 300hp + car.

[dannydavi]

thanks nickeleye, i now know what i need to get, now the only other question i have is sound.... i do not want a large sound so that every one looks at me like im a loser, or a ricer sound, i'll probably youtube some exhaust sounds soon, but any suggestions would be nice as well guys. Maybe even something like yours mentioned earlier nickleye.