Acid porting

I’ve heard of it many times but I can’t find anything on the net about it. I believe the purpose behind it is for cheating in racing competitions where you are not allowed any head work. The acid removes material while still leaving the ports rough like stock. So any experts on here versed on the topic?

If you're racing in a class that says you can't do it then you're cheating. If the class you race in doesn't care, why not just do regular porting?

Well the whole purpose would be to cheat. If the race officials become suspicious, they would pull off the intake and see ports that they would believe are stock and nothing would happen to you.

I asked this a few years and it got deleated.
yes there right about it being a porting methoid that leaves a some what natural casting finish.

If you are using cast iron heads and/or manifolds, try Brzezinski.

Brzezinski Racing Products (http://www.einfo-net.com/motorsports/brz/intakes/)

You could do similar stuff with aluminum. Getting an "as-cast" look back on a modified port isn't all that difficult.

Just flowing acid thru a port won't necessarily remove material where it needs to be removed. IMO, one of the reasons you won't find a lot of information on the net about "cheater porting" is the obvious one: the best practitioners don't want to be identified.

My $.02

The "acid" in acid porting is a reference to the cover-up that is done to modified heads. It is wide spread in a lot of racing that requires stock castings. Other things that are used are coarse sand blasting, salt water, and spray welding. If you run a search on it, I am sure that you can find a how-to book on the subject.


Daren

Originally posted by Socrates
Well the whole purpose would be to cheat. If the race officials become suspicious, they would pull off the intake and see ports that they would believe are stock and nothing would happen to you.

If they were suspicious of you cheating they would do more than just 'look' at the intake or ports or whatever you moded. Most sanctioning bodies are aware of acid trickery.

well, you probably wont find too much info on it as compared to the legal types of porting. i don't see this "acid porting" improving your flow by that much. cheating is boring anyways, its alot more fun to use the clever ways to get more hp without cheating. a friend of mines dad does scca, it was cool to hear about some of the tricks. they're not big secrets, you just have to know your stuff relatively well. its one of the benefits of doing research and having experience. :)

Acid-Porting was the reason NHRA finally allowed Head Porters to
port & polish chambers in Super Stock classes

the few pairs i've seen were done exceptionally well , probably hard for an NHRA Tech guy to discover , but easy for a Head Porter to see :)

in SS Classes w/SBC closed-chamber heads, you can use acid-porting to unshroud intake valve mostly and also exhaust valve, but then you have to angle-mill a lot more to get back to the NHRA minimum CCs...but this works great because now you have more to mill off the intake sides of the head making the port volume smaller..and that leys you port/shape more in the intake port to get back to the NHRA maximum allowed CCs

So in NHRA SS Classes, acid-porting cheating worked
1-Valve unshrouding
2- moving intake valve away further from cylinder wall at Hi-Lift
because of "more" angle-milling
3-more angle-milling allowed more intake side to be milled,allowing more material to be ground out for a better port shape/Flow

overall i like the new Rule, because every once in awhile i get a pair of rare SS castings to find someone started polishing a chamber..and that work ruined the head under the old NHRA Rules...just happened to keep a few rare castings that were like this and now these castings will be Legal in SS

in a few days or so i'll post a Link to acid-ported SBC #041x chamber and see if you can tell its been acid-ported :)

Originally posted by MaxRaceSoftware
in a few days or so i'll post a Link to acid-ported SBC #041x chamber and see if you can tell its been acid-ported :)
Nice, We'll all be looking forward to that :)

Link to acid-porting Picture below

http://www.maxracesoftware.com/041x_Chamber_after_Acid-Porting_1.jpg

if you were to transfer a combustion chamber outline template of a stock 041x chamber ontop of this chamber ..it would matchup pretty close near deck/quench areas , but lengthwise near the nearest shrouded parts of the intake and exhaust valves, this chamber has been acid-ported about .050" at intake & .040" at exhaust.

the most acid-porting is done near spark plug area and around both intake and exhaust valves.....where +.150" metal is removed
straight down from original template.

in other words the template would still matchup closely, but from "below" that point there is +.150" metal removed deeper into the chamber to unshroud valves ..starting at about .050" on valve sides to .150" moving around valves towards spark plug area.

what will set the limit to acid-porting and new NHRA rules on some SBC heads is a close look at the spark plug hole..as you can see the angle-milling is getting closer to entering the spark plug holes, and sometimes a crack developes under use.

also look that coolant holes have been cast-iron tapered plugged up and there is no more small quench pad area left nor any coolant passage left between the 2 cooling holes that have been plugged.

this is a Pic of an acid-ported chamber that was easy to spot :)
this sort of mod led NHRA to allow Chamber porting & polishing

What kind of acid do you use and how fast acting is it? Do you also have pics of ths inside of the ports?





BTW I notice that you have a Tornado dyno test, did it actually do anything?

http://www.maxracesoftware.com/Tornado_Dyno_Test_2.jpg

Originally posted by Socrates
What kind of acid do you use and how fast acting is it? Do you also have pics of ths inside of the ports?

BTW I notice that you have a Tornado dyno test, did it actually do anything?

http://www.maxracesoftware.com/Tornado_Dyno_Test_2.jpg
============================================

Can't show the Pics inside the ports (secret stuff)
never used Acid to port heads..pretty dangerous :)

that picture was a competitor's head..not my work .


the Carb model Tornado does "one thing" exactly like in the advertizement..it generates "tremendous swirl" !!!! :)

it will "peg" my digital strain-gauge swirl meter at only 2 inches of water test pressure...thats oustanding amount of swirl ,
but when placed ontop of a 4 barrell carb...the swirl gets broken up into 4 holes, and the 4 holes effectively cancel out the swirl effect ....now the digital swirl meter reads "ZERO swirl" below carb ..even when tested to 48 inches

that Pic was test on methanol SBC w/Tornado
in all the methanol carb tests the Tornado made zero difference

in all the gasoline carb tests the Tornado made a few 5 or more HP & TQ gains

just the opposite of what i thought would happen...i thought since there is double the amount of methanol coming out carb boosters -VS- gasoline the Tornado would make more of a gain if any on methanol carbs ..it was instead the opposite .

the only effect i can see the Tornado might be having is the help atmomize or breakup fuel droplets immediately in the venturi/booster area ..as ZERO swirl is below at throttle plates

the Tornado gas mileage tests on my Chevy Suburban for about 4 or 5 months i could not measure any differences in gas mileage
or tell in performance.

when the carb is between idle and part throttle crusing the flow rate is low and throttles/barrell bores will definetly cancel out any swirl produced by any device above the throttle plates .

overall the Tornado => a $80 dollar or so "chance/gamble" it will make a small 5 or so HP gain on your carb engine