Extrudehone anyone?

[Starman]

Getting ready to hopefully remove plenum and injector housings and have them ported to 35mm. Have spoken with a few folks about traditional porting and have a plan along those lines. Has anyone used Extrudehone for their LT5? If so, please share your experience. Thanks.

[XfireZ51]

I actually had my 84 xfire manifold EHd after having done some port matching. It was not cheap. When I got the ZR, I inquired about having the plenum and IH done and was told by EH they would not do it becusse of previous experience. I was told that the presure from the process separated the runners from the plenum area.

[A26B]

I wouldn't recommend extrude hone due to casting core shift,which may or may not be present in you engine. I have seen significant variance in port alignment. Extrude hone will follow the cast port.

Machine or hand porting should correct port alignment to the specified dimensions taken from Lotus production drawings. Jerrys Gaskets used those dimensions to produce die-cut gaskets, which can be used as a template to scribe from.

[XfireZ51]

And just to add to Jerry’s point. Extrude Hone will remove material indiscriminately. As some of us who have done porting on the plenum and IHs, u find out all too late that the core shift Jerry talks about creates uneven material thickness. A knowledgeable builder like Haibeck or Dr. Greekenstein (aka Pete) know where those areas are. And even they will sometimes take too much material off and perforate the exterior. I took enough material out of the plenum in one area that the material was practically paper thin that needed welding to repair.

[HIZNHRZ]

The original owner of my 91 had it extrude honed at ~1500 miles. "While they were there" a number of other problems were introduced that had nothing to do with the extrude hone process. When I got the car running again at ~2800 miles the dyno revealed the extrude hone did virtually nothing.

[Starman]

Thanks for the feedback everyone, was simply curious why had not heard it discussed.

[LGAFF]

My 92 was originally an extrude hone from Doug Rippie the ports are very smooth and enlarged slightly, Vette Magazine did a progressive test with an exhaust etc the extrude honed intake moved peak power from 327 RWHP to 345 RWHP with a 28hp and 29ftlb increase at 5100...….the dec 1997 Vette magazine is a great magazine to pick up its also has a ZR-1 drag racing shootout including Phil DeJohn running an 11.79

[LGAFF]

http://www.zr1.net/forum/showthread.php?t=16693&highlight=extrude+hone

[Pete]

My 92 was originally an extrude hone from Doug Rippie the ports are very smooth and enlarged slightly, Vette Magazine did a progressive test with an exhaust etc the extrude honed intake moved peak power from 327 RWHP to 345 RWHP with a 28hp and 29ftlb increase at 5100...….the dec 1997 Vette magazine is a great magazine to pick up its also has a ZR-1 drag racing shootout including Phil DeJohn running an 11.79

Most likely HP gains were not from EH but from chip programing.

Pete

[LGAFF]

Doesn't look like they tuned it all..... they said it was next on the list to do

[LGAFF]

As a side note you could get it ported probably much cheaper and also must better flow....