R.P.M.

I pulled apart a j-spec motor that had a Garrett hybrid turbo. The compressor housing was so large that they actually had a half inch spacer between the turbo and the stock S5 manifold just so it would fit.



Once the motor was apart I found that they street ported the secondary irons but left the primaries stock.



Heres what the housings looked like:









Heres one compared to a stock housing







I've never seen exhaust ports like that before......what do you guys think?

RONIN FC

Seen it before, and its pretty interesting. Its more common to port wide in Japan than in the US.

I wonder how the apex holds up with such a wide port.

j9fd3s

maybe that works better with a stock turbine? dont htye have to pass smog now too?

guitarjunkie28

not much of a bevel...there's noobs in japan too



let's have a look at dem apex seals.

iceblue

I think they were trying to get spool up. I would like to see more of a bevel on the exhaust ports sides and lower. But thats my take.

R.P.M.

The apex seals measrued 7mm tall and seemed to be in great shape.....exept for horrible carbon build-up and rust everywhere. I swear the motor was used as a boat ancor.

One320B

Well he must have had some tips as squaring off the ports is typically something performed by somebody who can flow test that .... i've seen it before. As for the width, seems pretty extreme...but maybe something worth it if you've got a larger turbo....

diabolical1

aside from it being a tad bit rough, i don't really see much wrong with it if the apex seals show no signs of significant deflection damage or excessive wear. if i had the guts (really the money) i would have tried something similar on my last engine build.

RONIN FC

Yah, im dying to port outward, no timing change.



R.P.M., Did you by any chance put a straight edge to to the face of the seal? From the pics it looks like there are no wear marks on the outside of the port, like the seal was bowed.

BDC

That's what my gut says, too. Also, we're not certain on two things -- how many actual running miles the vehicle had w/ this engine in it as well as what its original purpose was (street driven grocery getter, road racer, drag racer, etc)



My thoughts on it revolve around the concerns of the apex seal possibly bowing out like a banana due to the lack of lateral support for the seal from the port being gobs wider. But, then again, it's just theory in my mind and it must yield itself to practical experience.. the next question that is begged -- has anyone actually done this with a closing edge seal bevel applied?



B