I'm working on a '91 Talon for a friend that has been heavily modified including port work to the head and turbo. The restriction now is the exhaust manifold itself. I want to port it for more power, but there is no feasable way to get the cutting tool in certain areas of the manifold. Has anyone tried to "acid port" stock exhaust manifolds. What method and materials work best. Any other options will be greatly appreciated.
Thanks again.

There is extrude honing, but it's pretty expensive.

You could try acid porting, but I'd make sure I had a spare one just incase.

OOOPS, I forgot to mention that I'm too cheap to take the extrude hone route. I want this to be done as cheaply as possible, but still yeild impressive results.

Originally posted by bravewink:
I want this to be done as cheaply as possible, but still yeild impressive results. Doesn't that violate the 4th commandment of Automobilia:
"Thou shalt not expect divine results from the whole using less-than-divine parts for the whole."

:D

But seriously, I think that if this guy is heavily into getting his "DSM" to go fast, he will and should invest more serious money than whacking away at an existing manifold, if it is really that restrictive in the first place. Also, a header does more than just "open things up," in can be designed to improve scavenging, etc. Im sure you may know this, but he may not. Try http://www.dsmtuners.com/ , I just googled it and its what popped up.

"Doesn't that violate the 4th commandment of Automobilia:
"Thou shalt not expect divine results from the whole using less-than-divine parts for the whole.""
Where would a guy find the rest of these commandments?

My guess is that if you found any NHRA/IHRA Super Stock or Stock racer they would have no idea what acid porting is... :eek: Have seen the extrude deal, but I had no idea how many $s it cost to do.

Oldani,

Don't you just get a jug of either sulfuric or hydrochloric acid and pour the ports full and let them eat for a while.

Then pour it out and save it and check if it has eaten enough??

And if not, keep doing it until you get what you want...

BUT BE REAL CAREFUL WITH THE STUFF B/C YOU CAN GET THE H-LL BURNT OUTTA YOU REAL EASY!!!

Labratory safety gear should be worn to the MAX.!!!!

And you can stop the eating by flushing the stuff off with a 1/2" garden hose!!

pdq67

What about feeding long strips of material backed sand paper through the manifold. Then you could put the manifold in a vice and pull the paper back and forth sanding the tight corners.

Just a wild idea.

Extrude honing is horribly expensive. Acid porting, IMO, is not a good thing to do without following up with at least some sanding rolls because acid has no consistancy...with most metals you will end up with a very rough and heavily pitted surface that could actually hurt flow. When I worked in the plating shop, occasionly a part would lose current in a plating or stripping solution and the acid would leave wave patterns in the material surface...like the acid picked out certain metals out of the alloy and left others untouched. Maybe not such a problem with cast iron but definately plays hell with a lot of other alloys. I think you best solution would be to cut the manifold somewhere to gain access to the ports, port away, then have someone that can weld cast iron (assuming thats what it is) weld it back together. If you cut it horizontally from its normal position, it should give you plenty of room to port and still be easy to weld back up. Check the flange for straightness afterwards and you are set.

I've been on the dsmtuners.com forums, but they don't have near the ideas us "old schoolers" have. I thought of maybe even trying to sand blast the inside of the manifold (which is cast iron by the way) as an option, but I'm not sure if they make any medium aggressive enough to be worthwhile or if it would even work properly. The sand paper/vise idea seems pretty neat, but I know how long it takes with the cartridge rolls and a die grinder to get anywhere so I think that would take an eternity. As for the acid porting, I was a chemist for awhile and have plenty of lab experience dealing with hazardous substances and always use safe lab techniques. Thanks for the heads-up, I'm glad someone cares about my safety. Another idea from someone else indicated getting one of those snake like springy dealies that you use on the end of a screwdriver and putting the cutting tool on the end of that and let 'er rip. I think that method would be self destructive in less than 10 seconds. I could be wrong.
Keep the ideas coming.

I really like Travis' idea. Just cut it apart, port it and weld it back together. Cast iron really CAN be welded by the right person, you probably WOULD need to the the flange milled when complete because cast iron welding uses a LOT of heat and warps parts pretty easily.

Back again, I just went back and re-read the lead-in post again..

Brezinski's can weld cast-iron and do just what you want to do!! BUT I bet they will be at least, if not more expensive then Extrude A Hone!!

So what's wrong with doing this the old fashioned way AND just buying a turbo-mount header???

If it's going to cost an arm and a leg, then get the best you can get. Even Brezinski's stuff is only about 40 percent as good as a dedicated header so why spend money like that unless all you are after is stealth??? pdq67

PS., and I have ground the ports and outlet bigger on a pair of stock, '55 Chevy, log manifolds so have done a little of this myself.

I kept them for years and years b/c I had a Vega conversion in the back of my mind that never happened and they woulda been great to use instead of headers to do the install cheap...

The manifold was already purchased with an external wastegate already welded on. They're quite costly already. He was warned against turbo headers because they supposedly crack and have other structural issues.

We're just trying to get the most out of what we've already got without spending another 300 or more.

Gotcha, good luck with whatever you finish up with.

pdq67

You can buy a 95+ manifold and have the divider machined down to improve flow. This is a signifigant upgrade over the earlier designs.

-Joe

You could have it cut and welded, but it would depend on the quality of the cast just as much as the quality and skill of the weldor.