I had saved up some money to buy new header to replace my RRM 4-1 and as some of you may have seen...i blew my clutch, pressure plate, tob, and cracked the housing on the starter ...on that note, i was upset that i could no longer afford a new 'set-up' so i made my own. i know it will not yeild the same performance gains but i don't think you can beat it for $20.

all i did was pick up a set of stones for the air gun, brass wire wheel, and a polishing brush. i gutted out the cat simply by drilling out (one of those door knob bits) the center of the cat and chipping out the rest with a screw driver. afterwards, i ported the 'lip' out of each runner, took off as much inside the runner as i could (keeping in mind not to grind through the weld to the flange, and shaved off between 1/8 - 1/4 inch of the lip on the exit port of the manifold...lastly i polished it up...let me know what you guys think.

 

noticed any gains?

 

one thing about porting, its not how big you make a hole, but its how well air can pass through it. air passes over a smooth polished uniform surface faster and with less turbulance then a rougher surface. your grinding looks choppy and not uniform so i don't know how much, if any, gain you would get. maybe even a loss?

 

i haven't installed it yet. i still have some finishing up to do on it. i need to make the grind in the curve of the runner more subtle and resurface all the entrance ports. the majority of it is very smooth and even to the touch. there are a couple spots that need to be worked out but they arent any real problem areas that i cant get out.

 

smooth exhaust ports primarily inhibit the buildup of carbon from the escaping gasses. True that smoother ports will flow better, but enlarged ports that are rough will flow better than smaller ports that are smooth.

 

wow great idea. +1 for originality.

 

any ideas for removing the excess carbon in the runners that i cant reach? tryied carb/choke cleaner and it took off very minimal amounts...also, anybody know a place/site that i could get a very fine stone to smooth it out more. the ones ive got are a bit notched and abbrasive.

 

you need to switch over to sanding rolls. 120 grit will do a nice job of smoothing it out. beyond that, you can go to regular wet/dry sanding paper and do it by hand (that's how I finished my head). To get into the runners, you need a special type of sander that has radial arms so when it spins it will sand on the outside edge of the spinning cylinder..... kinda hard to describe. get your hands on an eastwood catalog, they have all the good stuff

 

120 grit? will do. thanks for the good info...if i can get all of it done this week ill put up new pics this weekend with it all smoothed out...this is turning out to be a fun project haha

 

when ur done i'm doing this.

 

It's not an original idea, but he is the first to post pictures and explain how he did it. One of the first turbo guys did this because he didn't want to spend the $$ on an RRM header. Kudos for getting your hands dirty

 

yeah well that's what i mean.... haha. obviously porting has been around for a while but he's the first to document it on evom with good pics and everything :P

 

Quick question.

What would be the gain differences between:

Header + StockCat

Stock Manifold + No Cat

 

header + stock cat would give you gains (probably only a couple hp) across the board

stock mani + no cat would only give you high end gains and you would lose torque overall.

correct?

 

With a stock cat a header is a great mod, I have one and I love it. With no cat at all you're just straight piping it, which is great for turbos and race cars, but horrible for street cars.