Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Reply
 
LinkBack Thread Tools Display Modes
Old 01-03-2019, 08:29 AM   #1
Registered User
 
The Radium King's Avatar
 
Join Date: Apr 2010
Location: Canada
Posts: 2,743
flowing, porting

anyone looked at the oem intake and exhaust to see if any benefit to doing any flow work on them? how well do they match up with the intake and exhaust ports on the heads?
The Radium King is offline   Reply With Quote
Old 01-03-2019, 08:46 AM   #2
Registered User
 
Join Date: Dec 2009
Location: Orange County, CA
Posts: 1,147
Quote:
Originally Posted by The Radium King View Post
anyone looked at the oem intake and exhaust to see if any benefit to doing any flow work on them? how well do they match up with the intake and exhaust ports on the heads?
Hello Radium,

You may want to check out the website of Len Hoffman as he specializes on this type of work: https://newsite.hamheads.com/porsche/

It has pretty interesting pictures, you will enjoy the reading :-)
Gilles is offline   Reply With Quote
Old 01-03-2019, 09:06 AM   #3
Registered User
 
The Radium King's Avatar
 
Join Date: Apr 2010
Location: Canada
Posts: 2,743
thanks - some potential inthe heads, hey? i was wondering more if there is any need to work the intake or exhaust manifolds where they mate with the heads.
The Radium King is offline   Reply With Quote
Old 01-03-2019, 12:03 PM   #4
Who's askin'?
 
maytag's Avatar
 
Join Date: Mar 2018
Location: Utah
Posts: 733
Quote:
Originally Posted by The Radium King View Post
thanks - some potential inthe heads, hey? i was wondering more if there is any need to work the intake or exhaust manifolds where they mate with the heads.
you're talking about what I've always called "port-matching". I have never seen a motor that was machined or cast so precisely that it couldn't benefit from a little work that way. But I'm sure the Porsche Purists will tell us that these motors were all hand-ported / matched before they were assembled on a shaker-table...... ::eye-roll::

If you don't have experience with port-matching yet, (you probably do? but just in case) one of the first rules I use when looking at doing the match work is that adding material is just as important as removing it, in most cases. Here's why: if you simply scribe the ports to each other, and then grind to the scribe-line, as most beginners do, what you'll inevitably end-up with is a "bulge" at the port, where you've made it bigger than the rest of the runner, on either side of it. This can be HORRIBLE for velocity. And depending on your cam duration / overlap numbers, it can cause some real rough-running issues under certain part-throttle conditions, where that bulge "absorbs" a pulse. Much better to blend those ports together by adding here, removing there, until your ports are the same shape and match perfectly.
If you check the best porting-work, you'll find the use of epoxies is very common.
maytag is online now   Reply With Quote
Old 01-03-2019, 01:47 PM   #5
Registered User
 
WillH's Avatar
 
Join Date: Feb 2015
Location: QC
Posts: 325
Home | JPrecision Is local to me and has done work on one of my KTMs,( custom porting, valves, and squish/planing), friends buells, and Hondas. Not Porsche specific but have it on good authority that he does Ferrari heads...
May be worth a call to inquire.
WillH is offline   Reply With Quote
Old 01-03-2019, 06:03 PM   #6
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,206
Quote:
Originally Posted by maytag View Post
I have never seen a motor that was machined or cast so precisely that it couldn't benefit from a little work that way.
100% agree!

Even something as simple as re-working the valve seats (5 or 7 angle) can provide an increase (small but measurable) over stock (3-angle).
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor

Last edited by thstone; 01-03-2019 at 06:08 PM.
thstone is offline   Reply With Quote
Old 01-04-2019, 11:11 AM   #7
Registered User
 
BYprodriver's Avatar
 
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,069
Garage
Quote:
Originally Posted by The Radium King View Post
anyone looked at the oem intake and exhaust to see if any benefit to doing any flow work on them? how well do they match up with the intake and exhaust ports on the heads?
The exhaust manifolds can use some smoothing, there was extra thick welds on mine at the entrance that seemed to be the biggest restriction, plus it's really fun to grind without getting shavings in the cats!
__________________
2000 S Speed YellowLN 3.6L cylinders & pistons, triple row IMSB upgrade, R&R connecting rods, billet tensioner paddle,oilpump driveshaft.Heads rebuilt by F6I with new valves & springs.Cayman airbox & MAF housing, 996 intake plenum & 75mm T/B. NHP sport converters &Dansk muffler
BYprodriver is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 04:00 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page