Extrude Hone
07-27-2005, 06:16 PM
#19
Rennlist Member
Thread Starter
Somehow or another I keep, uh "messing up" the Y pipe and EVO intake photo. I will make one last attempt. But basically what you are seeing is the modified exhaust manifold and the intake and Y pipe.
The Y pipe was extrude honed per the first set of pictures in the series. As recieved the stock Y pipe has an interior sand casting finish. That is it is pebbled, and the flow seperator at the junction of the Y retains this finish. The extrude hone opens the diameter only very slightly, but it smooths the wall surface to a very fine finish. I didn't measure any thing like an indicator run our or RMS but it is nearly polished looking. My theory here is that there will be better flow, and there is no need to promote any kind of mixing at this point in the intake.
After the extrude hone I sent the unit to my good friend Gregg Fuller (he used to be parts manager at Newport Porsche) at Coatings Research. This company does metallized coatings of a very high quality. For "prettiness" under the hood I had Greg do a chrome looking finish to the exterior, I think it looks nice and dresses up the under hood (or is that boot?) area nicely.
Also the exhaust manifold was stock, ported per Kevin's instructions, and after this extrude honed. Once again the improvment to the inner surface is marked. Subsequent to the hone the header was sent to Oklahoma for the 2500 degree extreme ceramic coating was added. This was done only on the exterior. The finish I chose was gloss black.
I also had GT-2 Intercoolers installed, and took a picture but it is not too illustrative.
The underhood temperatures FEEL reduced to me. And the spool up comes from a little lower in the rev range. The car seems "perkier" on the throttle tip in, if I can describe it thusly.
There is no scientific data I can report, only seat of the pants impressions. However most of these mods have been tried by others with measurement, and been successful. In any case it was fun to do and the results are nice enough looking!
The Y pipe was extrude honed per the first set of pictures in the series. As recieved the stock Y pipe has an interior sand casting finish. That is it is pebbled, and the flow seperator at the junction of the Y retains this finish. The extrude hone opens the diameter only very slightly, but it smooths the wall surface to a very fine finish. I didn't measure any thing like an indicator run our or RMS but it is nearly polished looking. My theory here is that there will be better flow, and there is no need to promote any kind of mixing at this point in the intake.
After the extrude hone I sent the unit to my good friend Gregg Fuller (he used to be parts manager at Newport Porsche) at Coatings Research. This company does metallized coatings of a very high quality. For "prettiness" under the hood I had Greg do a chrome looking finish to the exterior, I think it looks nice and dresses up the under hood (or is that boot?) area nicely.
Also the exhaust manifold was stock, ported per Kevin's instructions, and after this extrude honed. Once again the improvment to the inner surface is marked. Subsequent to the hone the header was sent to Oklahoma for the 2500 degree extreme ceramic coating was added. This was done only on the exterior. The finish I chose was gloss black.
I also had GT-2 Intercoolers installed, and took a picture but it is not too illustrative.
The underhood temperatures FEEL reduced to me. And the spool up comes from a little lower in the rev range. The car seems "perkier" on the throttle tip in, if I can describe it thusly.
There is no scientific data I can report, only seat of the pants impressions. However most of these mods have been tried by others with measurement, and been successful. In any case it was fun to do and the results are nice enough looking!
07-27-2005, 06:21 PM
#20
Rennlist Member
Thread Starter
Please be patient! A last try
Okay, a last try on the EVO and coated Y Pipe installation. I hope this one has sufficient detail and sharpness for you all. See my notes above on the specifications for this. 
