L Gancho

Slant- Page 4 still shows a before and after from Imagine Auto. I considered the AFM process (after my brother brought it to my attention) but I didn't think it was really worth it. Jet-Hot coatings (ceramic coater) blasted the crap out of the internals of the exhaust headers. Although it wouldn't hurt... I just thought it was overkill.

cpu77

Wow never knew AFM existed! Imagine building and engine and doing oil, water and air passage ways! You could make a very efficient engine! If we could do a group buy I would be down if the cost was closer to say $350. I wonder if they could our TB and plenum?

slant911

Thanks for pointing to the pictures for me. Not sure how I missed them DUH!

I'm with you CPU. If going through the process of making the holes bigger for more perfect flow why not just go ahead and extrude hone the things while they are off. However, it appears the cost is something like $750 to do it so not sure that is money well spent. If a group purchase could be arranged at a more reasonable cost I would be interested.

I'm pretty familiar with the process from a user standpoint. In putting together our race boats we would always send intake and exhaust manifolds out for extrude honing. It made a noticeable difference in how fast the boat would get out of the hole. To me this would definitely relate to getting the turbines to spool up faster. JMHO.

Kevin

It's not worth the effort to extrude hone the insides.

Thee has to be a human element to grinding and porting. After the headers have been hot tanks you can really see how smooth the inside stainless is..

gunther1

http://cgi.ebay.com/ebaymotors/Porsc...00921072QQrdZ1

These are just a touch more than $50.00. Mine is half of what ebay is asking

slant911

Gunther,

Are you saying that the headers you have are already modified? I understood that yours were bone stock. If they are already modified I am interested.

skippy

Quick question - I noticed the metal gasket seems to be more restrictive than the headers (particularly after the mod.) - Is this an issue? Do you need to use it?

roadsterdoc

The gasket should be used unless you have each surface machined 100% flat...and repeat every time a leak develops. If you port beyond the dimensions of the gasket then you've gone too far. You will need to modify the gasket in that case (not easy as it is stainless steel).

Kevin

If you are porting beyond the metal gasket outline your are removing to much material.

You need to replace the metal gasket everytime you remove the headers.

slant911

I was reviewing this thread again and have a couple of questions:

Is there a set of stock headers floating around as semi-indicated above. A sort of "train" from one person to the next. If so, can I get in line

Or are there any stock ones someone has laying around for sale?

Kevin, do the gaskets at the turbos need to be replaced also in addition to the gaskets at the heads?

Also Kevin, are you planning to be here anytime soon? Having you over my shoulder on this one sure would be appreciated as I'm a bit nervous about grinding away on some headers. Certainly you can convince your wife you NEED a trip to Las Vegas.... In lieu of you NOT coming to help me would you do the grinding/coating for me? How much??


Thanks.

johnyg

I have a set of stockers as I bought different ones to port in case I messed something up. It was not that hard to do but does take some time. THe ones I have for sale look better than the ones I bought. I did not see the insides until they were off the car being replaced. I would have saved some time on the ones that came with my car. I was pleased with the end result. THe other site suggests they might be worth at least 100 bucks. Any takers?

DublinOh

I may be interested...send me an email

Kevin

This was one of the erased pictures. This picture shows how much weld is in the factory headers.

GreggT

We have to keep this thread current ....I only see 5 pages and a good topic deserves at least 6

What about the cylinder exhaust ports?.....I mean while the car is up.....the headers are off. Looking up at those ports, it would seem those could be opened a few mm..... without dropping the engine.
Last night stumbled on an old thread where it sounded like S-Car-Go did same for CJV, with good results.

Any thoughts?

Zippy

Would you stuff something in the port to prevent filings getting in there before grinding?