Ok, i just ordered a Downey Header for my 86 4Runner so i can replace the stock 22 year old exhaust system and possibly gain some more power in the process. My question is about the exhaust from the header back, from all of the reading ive done here (yes i did alot of searching) most people go with 2 1/2" pipe, even on a stock engine. should i go this size when i have my exhaust replaced ?, or should i go a bit smaller like maybe 2 2/5" ?. I will be adding a cam later on and it will probably an engine builder 261C cam. My 4Runner has 37" tires and will be driven on the street as well as doing some rock crawling on the rubicon. Any opinions or help is appreciated.

 

I think 2 ½ is a little too much..if you read a little more you will see that most people actually use 2.25".......Personally I went with the 2.25"....I also have a Downey header to a flowmaster (Hushpower), 36" tires and an engnblder low end cam in my 22re

 

Most people on this forum prefer the 2.25" exhaust. I have Downey's header and 2.5" exhaust system and really noticed the engine breathes much better than before.

The one caveat.....it is LOUD! So if you are a little shy about exhaust noise or have ordinances against that in your area, just be aware of that fact.

I would repurchase my system if I had to do it over again.

 

i run a 2.5" crimp bent so it not a true 2.5" (and it has a lot of bends) runs geat with my set up

 

What kind gains did you notice with the header/exhaust and cam ?, your set up sounds just like what i have in mind for my truck.

 

Well, I also did a SAS, bigger tires and regeared to 529s at the same time so its hard to tell......

The low end is quicker than it was on 33's (488s) around town.....I can hold 5th gear on the highway at about 80 mph...

Oh....and it sounds totally bad ass...thats the most important thing...

 

I noticed a difference with my downey cermic header and 2.5" exhaust. I'd put up a clip I have of the exhaust running but I'm at work and all the nessasary websites are all blocked... I recommend that you check the stud nuts on the header after a couple hundred miles. Then check them at every oil change. Mine came loose and I blew out the gasket. I'll try and post that clip when I get home.

 

It is a toss up from what I have read to. So take a quarter heads 2 ½ tails 2 ¼. Let me no how load they really are because I have herd they are to load?

87 4-Runner 4X4, New Engine, 2 Inch Body lift, 32X15.50X15 Pro Comp Mud Terrain Tires
Hooked
http://www.jaroca.com/4RUNNER/Hooked_4runner.htm

 

Please post the clip when you can, id like to hear how it sounds.

 

Im in the process of doing a solid axle swap also, im using 5" trail gear springs in front and 63" chevy springs in the rear, i will be running 37" tires and stock 4.10 gears with duel inchworm cases.

 

Im still waiting to hear the clip.

 

I have ridden in the downey company truck first hand as a passenger. I know my description is not the same as a sound clip, but here is my review and comparison of the truck vs my stock 22re and stock exhaust

Downey Truck 22re Downey intake, header, exhaust. 4.88 gears 33's

The truck felt very powerful, and the acceleration was alot faster than mine, however not comparable to current toyota tacoma v6 models. However the motor seemed to run better and accelerate faster than current 4 cylinder models. The exhaust tone was very deep and muscular at low RPM's however at the midrange I believe that the muffler was a little loud for my taste, and begin to sound a bit higher pitched, but this is the same for any 4 cylinder with a straight through exhaust. I believe that the intake header and exhaust combo definitely helps the engine breathe better maintaining the power throughout the rpm range.

 

I have ordered and recieved my Downey Header, i got the chrome header because i didn`t want to spend the extra fifty dollars for the ceramic coating.
it will be a couple of months before i get it on my truck, were still working on the suspension.