Extrude hone - xpost from AF
09-25-2003, 07:29 AM
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Extrude hone - xpost from AF
Sent the below to the S car list of audifans. Hope it helps some save dollars...
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Ok, I'll lob some EH quattro btdt, since between myself and a few nuts customers, a lot of experience here, as well as wallet enlightenment on both sides of the counter.
DO NOT EH COMPRESSOR HOUSINGS OF TURBOS. BTDT years ago. The problem is that you increase the clearances between the wheel and housing, you get a turbo that whistles alot, but actually reduces output quite measurably. I wasted a damn fine RS2 comp cold side looking in vain for this "increase". For a while afterwards I used this shiny piece to hold down flying invoices when I opened the garage door....
I've done a couple of intake manifolds on S4/S6's. Not claiming a damn thing, but it stays shiny. I've done a couple of exhaust manifolds on 10vt as well as 20vt. Waste of money doing anything to the EM's of either car. Same with coatings on the interior of the EM's, exterior coatings are a waste as well, but I digress. Any EM work will get black soot like material on it within 1000 miles, and will perform just like a stocker. Further POR, Ned stopped EH of his EM's shortly after his first run of them. It also changes the nozzle ratios, which isn't good. It also makes really sharp edges at the nozzle convergences which tend to break off and chip turbo hot sides, btst.
My own conclusion over the years with this process... The Extrude hone process of the IM appears to be the only component that will actually give better numbers on the torque and HP side of a given turbo car. The reason I make no claim of it tho, is that I'm pretty convinced that fine tuning the components vs chip on any given S car could probably yield the same results. EH of heads is probably second (maybe first depending on what else is on motor) on the list of good things to do, but the rule of thumb on either heads OR IM's is that you want to do your porting FIRST, then Extrude hone. This process and it's benefits have been around a long time. Somewhere I have a racecar engineering article that compares this stock silicon silly putty process to the 30year Ruf artisans, and EH was within a couple percent on flow and HP.
Spend your EH dollars wisely. Every race team that wins is familiar with the process, most just don't easily share these secrets to speed.
HTH
Scott Justusson
QSHIPQ Performance Tuning
Chicago
------
Ok, I'll lob some EH quattro btdt, since between myself and a few nuts customers, a lot of experience here, as well as wallet enlightenment on both sides of the counter.
DO NOT EH COMPRESSOR HOUSINGS OF TURBOS. BTDT years ago. The problem is that you increase the clearances between the wheel and housing, you get a turbo that whistles alot, but actually reduces output quite measurably. I wasted a damn fine RS2 comp cold side looking in vain for this "increase". For a while afterwards I used this shiny piece to hold down flying invoices when I opened the garage door....
I've done a couple of intake manifolds on S4/S6's. Not claiming a damn thing, but it stays shiny. I've done a couple of exhaust manifolds on 10vt as well as 20vt. Waste of money doing anything to the EM's of either car. Same with coatings on the interior of the EM's, exterior coatings are a waste as well, but I digress. Any EM work will get black soot like material on it within 1000 miles, and will perform just like a stocker. Further POR, Ned stopped EH of his EM's shortly after his first run of them. It also changes the nozzle ratios, which isn't good. It also makes really sharp edges at the nozzle convergences which tend to break off and chip turbo hot sides, btst.
My own conclusion over the years with this process... The Extrude hone process of the IM appears to be the only component that will actually give better numbers on the torque and HP side of a given turbo car. The reason I make no claim of it tho, is that I'm pretty convinced that fine tuning the components vs chip on any given S car could probably yield the same results. EH of heads is probably second (maybe first depending on what else is on motor) on the list of good things to do, but the rule of thumb on either heads OR IM's is that you want to do your porting FIRST, then Extrude hone. This process and it's benefits have been around a long time. Somewhere I have a racecar engineering article that compares this stock silicon silly putty process to the 30year Ruf artisans, and EH was within a couple percent on flow and HP.
Spend your EH dollars wisely. Every race team that wins is familiar with the process, most just don't easily share these secrets to speed.
HTH
Scott Justusson
QSHIPQ Performance Tuning
Chicago
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