I have some time on my hands and it stopped raining. I need to
change a weeping drivers side valve cover gasket, so I was going
to do both sides and take off the headers and smooth out the inside.
Kevins says there is quite abit of power there and I heard from a reputable
race (who now races GT3 cups) that there is 50HP in there.
anybody do it??

 

Paul:

I did this "clean up" recently when I did my turbo install. It's quite simple once you have the exhaust manifolds dropped down and makes common "blueprinting" sense. The biggest issue doing this work was getting things nice and clean so you're not breathing a bunch of exhaust spooge when your grinding the rough stuff down. My manifolds looked pretty similar to the photos Kevin posted.

To do the work, I started with a carbide roiund tip burr bit and switched to course and medium emery cloth over a rubber drum to finish.

FWIW, I HIGHLY doubt there is 50 HP in this clean up, despite who is saying so. If we belived all this "hoo haw", we be seeing claims of 750HP stock motor TT's (well I guess we are, but no good pull down engine dyno charts... ;^) ... ) There's just not that sort of flow issue going on here to gain that type of HP increase (10-12 percent???). We're in the range of better throttle response and maybe 5 or so HP with these weld clean up things, IMHO. Kevin might chime in on this if he did any before / after flow tests...

I also, did my valve cover gaskets while I was there. Be prepared for the sheet metal turbo heat shields to be cracked at the bolt holes. Both of mine were so I replaced those too. Not too much $$$...

Have fun !

 

Paul

Good to see you are getting intimate with the car again If you are taking the headers off, I would definitely do it. 993 stock headers are very good and as Jim said it is not about the hp you will get but some improvement in throttle response..and a lot of fun!.

Jim, (sorry for the OT) any news on your intercooler saga? pls keep us posted
Jean

 

Did it as well.

 

The factory headers are designed very well. However, if one receives a heat exchanger from the factory with the primaries over-lapping on #2 or #5 (middle cylinders).. The velocity of air flow will be reduced and disrupted. Not only can one clean up the collector transition, but one can smooth the weld at the header to turbo flange. Doing this mod with any turbine housing/turbo mod will result in faster spool-up or lag reduction. This will translate into seat of the pants acceleration.. Torque will benifit from this mod, HP will benifit on the topend of the RPM scale.. Mods like this will improve your throttle response, putting a HP value on it, I'd have to differ to an actual HP run.. For me to give a NON factual guess, I'd say 25 extra foot lbs, and 5-10 ponies... more so with a built engine with cams and larger turbochargers..

 

What is the best tool? dremmel? air grinder? Coffee grinder?

 

I use an air grinder.

 

Paul:

I use an air "die" grinders to do porting work on steel / iron pieces. If you are talking about a Dremel with the 1/8 inch bits, it has too little power (MORE POWER as Tim would say) to get much bite on the bit for this kind of work. As reference, the die grinder bits are usually 1/4 inch shark with cutter diameters ranging from 1/4 to 1/2 inch. I am prettt sure I used a 1/2 inch ball tipped caribide burr to do the bulk removal. The emory sleeved rubber drums can be found at Ace Hardware as used for final finish. If you have access through the base or ??? to an electric 1/4 inch collet hand tool (such as a Fordham), many folks use them with good but slightly slower results.

Also, a few words of advice if you have not done this type of work before...Definately wear a lond sleeved shirt like you would be for welding and good eye protection. You'll have little chards of steel that are sharp and most of the time hot, steel coming off the bit as you grind. Have some tweezers handy on the work bench if you pick up a metal splinter doing this. Try keeping the work contained as these metal chards like to go everywhere...

Hope this helps !

 

Go to Home Depot and buy a cheap air die grinder.. You will need to go to a tool supply store for the carbide bits.. The you can get the emery cloth rolls. I like the 3M brand rolls... Eastwood sells most of the needed tools, bits and sanding rolls with arbors.. Just as Jim mentioned get eye protection and ear protection.. You can use latex glooves to reduce slivers in your hands.. Have Fun!

 

KEVIN DID MINE, BUT I DO GRIND MY OWN COFFEE

 

AND CLEAN THE HELL OUT OF THE HEADERS WHEN DONE, TURBOS DO NOT LIKE METAL
SHAVINGS!

 

I have a air grinder. Just no carbide bits. My wife is pretty easy to fool when getting tools
"Dear you need me to plant tomatoes? I need an air tool set from Home Depot for
digging the holes properly" Disclamier Should my wife see this I did NOT write it!!
I got a compound miter saw when she asked me to re grout the shower!!

 

Paul,

Let me see here.... I have your home phone number, and I'll betcha you could be in some serious trouble if I call Merritt. So.... hmmmm.... what sort of extortion do you think is appropriate? I'm willing to negotiate.

 

Cold Steve, but justified. Paul was getting a bit big for his britches!

 

Hmmmm, I am going to see if I can get a plasma cutter to "adjust the plasma TV".