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Discussion Starter · #1 ·
There was a thread on I-club a while back discussing the advantages of "knife-edging" the intercooler inlets. I'm also soon recieving some Samco intercooler hoses soon and will probably look into this mod when installing hoses. Has anyone else tried this already?

Big Sky
 

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I have knife-edged the intercooler elbows, the throttle body and ported the turbo. I did all the work myself in my shop, so all it cost was my time.

I also took the opportunity to put in an up-pipe and add Samco intercooler and inlet hoses.

The difference is phenominal. And I am back to running stock boost until my custom-programmed Unichip arrives on Friday.

I highly recommend it.
 

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Discussion Starter · #3 ·
Bob,

Sounds like a good mod and the price is right:D . Was it pretty straight forward w/ the intercooler? Any reccomendations on how to proceed? Dremel, die grinder?

How difficult was the throttle body?

I'd really like to do this. I have access to a dremel or die grinder, but not the expertise on where to remove, how much etc.

Any suggestions would be greatly welcomed. Photos even more.

Thanks,

Big Sky
 

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Long, windy reply... as usual

BigSky: Everything is straight forward, at least to me. Basically, the elbows are held to the IC with two 10mm bolts each. Take them out and then find a firm but delicate way to hold the elbow (gentle vise, woodworking clamp, etc.). Then, just smooth out any irregularities on the ID of the elbow, of course, being careful not to remove too much material. The most important thing to do is the knife-edging. I am speaking of the area where the IC hose from the turbo attaches. That spot has got to be about 3/16" thick. I just taper-ground that to an "almost" knife-edge, so the air won't "see" the edge of the elbow. The same goes for the throttle body, only you have to use a little more caution, since it's got more moving parts and is not as robust in general. I also, very carefully, bull-nosed the throttle plate itself on the leading edge. I was careful not to change the overall OD of the plate, I just made it less square and more like the leading edge of an airfoil. Unfortunately, as usual, I did not take the time to snap any photos, mainly because I don't own a digital camera. And, by the way, I used a variable speed Dremel with the flexible shaft attachment, which is just nice to get into certain places. I really took my time and even polished the aluminum surfaces using polishing compound and the cotton pad attachments for the Dremel! My throttle body is SLICK. Oh, yeah, when you open the throttle plate and look through the bore, you will notice that the two screws that hold the plate to the shaft extend through the shaft over 1/8" each. I also ground these down flush to the shaft to smooth things out even further. I can't see where this would hurt anything, it just takes some cojones to do it. Email me for more info if you'd like.

Dark_rex: I assume you are talking boost controller? If so, I was (before any porting, etc.) using a homemade ball check/needle valve combo BC. Because I am in between gauges right now (my pod just arrived yesterday and will go in this weekend), I decided to use the stock EBC until I can get a boost gauge on there to see what's up. Plus, with all the mods I just completed, I want to have my EGT gauge in there as well so I can see how the engine is reacting to my mods.

Hope all this bantor helps.
 

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Discussion Starter · #6 ·
Thanks Bob. Great info. What dremel attachment did you use to do most of the work?

If only you had digital camera:) .

TristineLim: Are you waiting for hoses from Gunn Performance? If so, have you heard anything? I'm going to try calling today.

Big Sky
 

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Let's see... from what I remember, I started out on the aluminum pieces with a course drum sander and worked my way to the finer drums and ending with the polishing pads. On the throttle plate, I used the smalled abrasive stone that I had for control and to avoid damaging the throttle body from something large slipping in there.

For the turbine side of the turbo, which I also ported, I used a carbide bit in a Roto-Zip, which turns enough RPM to work properly.

I would recommend the Dremel flexible shaft attachment, though. Well worth it to get into tight spaces. If your Dremel is the right type to accept it, the shaft is only about $25 if I remember correctly. If you want to really polish the inside of the compressor side of the turbo or the intercooler elbows, you will need it.

Have fun.
 

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bobgrice,

Sounds like you are really hardcore about getting all of the horsepower you can from your EJ20.

I wouldn't go after my throttle body with a dremel on a forced induction car. It's largely unnecessary at that point in the intake. If I'm wrong, we'll meet some some day and if we are mod for mod, you'll take me in a race.

This sound like a last mod when all the money is spent and you still want to monkey for 1 more lb-ft at 6000rpms. ;)

-Jim
 

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I guess it's the nerdy Fluids Engineer coming out in me. The "step" on the edge of the throttle body inlet has to be about 3/16" thick. I'm always of the mantra: "lower pressure drop wins the race". Or something like that.

I agree that the mods I've recently undertaken are a little petty individually. But, all of them together seem to really wake the car up in the 5500-7000 RPM range. I can honestly tell a HUGE difference in the linear pull up there. ANd I haven't increased the boost back to where it was before I did all this. As I mentioned, I went back to the stock EBC until I get my new gauges in this week.

Of course, for me to be able to win in our virtual race, I would have to be able to drive!

Have fun & perhaps I can report back once my custom-mapped Unichip from Vishnu arrives today or tomorrow and I can crank up the boost a little.

Later-
 

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I might try porting my TB out and tappering that but I doubt I'll knife edge any of the piping. I have 7 pieces of piping on my Blitz front mount but they all seem to connect to each other very smoothly and I doubt I'd gain much from all that work.
 
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