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:



Attachment 20746

Attachment 20747



Heres one compared to a stock housing



Attachment 20748



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

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.

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

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



let's have a look at dem apex seals.

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.

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.

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....

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.

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.

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

it's not that much of an extreme exhaust port, still left the sleeve in.



How's about this one!!



Running in about 8 or so engines so far, mostly street driven 12a, 13b, bridgeport, PP and turbos.



Have had NO apex failures.

Gotta agree with Peril 787b, not very extreme at all, I've done wider. You would be suprised how wide you can actually go. I've done 10mm from the edge of the housing with no noticeable wear, on a motor that was daily driven for over a year on stock 3 pc 2 mil apex seals. If you went up about 8mm and down about 3mm on that port you would have the port in my old car that spent the last 3+ yrs on the street at over 450whp regularly revved to 10k.

How far out would you port a street car? Anything special on the closing edge?.



When you say 3 years, how many miles would you estimate?

The customary bevel on the closing edge. I would port a street car the same as I described in my last post. When you build your own and replace whats warn, life is much easier(cheaper), I actually started hoping the damn thing would blow so I would have to take it apart and then try something else. The car is still on the road, it has about 50,000km since it was last rebuilt, and that was only because a freeze plug rusted out.

I'm finally going to assemble that engine https://www.nopistons.com/forums/pub...IR#>/bigok.gif