what do u think about this 2.5 horn?

[wild drag racer]

I have seen svs but I think that mad horn is more wild??
its just idea came to my mind??? I have one spare 2.5
air horn... so can I cut the original 2.5 horn and move
it 2 inches up and then fix the spare hors down
so the motor look with a dual phone instead of one??
what do u think about this?? instead of spending more
money on svs... do you thinks its goint to work??

please dont laugh at me its just an idea:D

[Tony Brucato]

I wonder why Mercury Racing never thought of that.;)

[Liqui-Fly]

Just make sure you don't block off the middle cylinders. The seam would be covering 3 and 4 and the other 4 will be getting stuffed. Better option is to simply bore one a little bigger.

David

[espen]

good idee :-)
Test it and let us know how it works !
if you use 3 you have a MAD intake...

[TB21]

Actually it still wouldnt be a MAD intake because of the injectors mounting in the case.......The MAD has the injectors in front of the reeds and that is much better. TB

[Trikki1010]

I got a reply to this once before. I believe you will find, that with 2 horns, you will reduce air velocity at low/mid ranges causing the motor to be sluggish....

[Raceman]

Just dumping in more air isn't always better. Tests have consistently shown that just boring a 2.5 horn causes a loss of topend on most engines compared on. Adding a second one is almost sure to turn 2 good horns into scrap metal.

[Liqui-Fly]

What tests are those that have shown a bored horn causes a decrease in top end on most motors?? Pretty generic statement...just looking for the info.

David

[PhastBoat]

http://www.brucatosvs.com/hp_results.html

[Tony Brucato]

Here's the story behind those results.

http://www.brucatosvs.com/hp_sept.html

[Raceman]

Fly, are you gettin' to be a heckler? You know my memory ain't what it oughta be, but if I coulda' remembered the source I'd have posted it myself, rather than the "generic" statement. Incidentally, I have both 1 bored and a standard horn on 2 of my tweaked 260's which have almost identical upgrades, so I ain't totally takin' somebody else's word for it either.

The point that I was trying to make is that throwing an additonal horn on a motor would almost certainly hurt it. I'm sure Tony's opening sizes are carfully selected, rather than just a random increase in size like adding another full horn would be.

[Trikki1010]

See, Ported horn loses jump

I understand Tony's SVS=direct flow and the venturis are sized appropriately.

David needs some sunshine and liquid water.

;)

[Liqui-Fly]

I like to hear what people's results were. I meant generic in the sense that it didn't say what the motors were (modified, unmodified) and what the results were. I appreciate for the further explanation and link. Would also like to know if anything was done to the cowl. It seems like a a bored horn may slow down the intake velocity but is it pressure or vaccum that gets air into a motor? Maybe I was trying to insight a discussion:)

David

[wild drag racer]

dear tb 21

thank you for your information about mad horn..
i didnt know that the injector are in fron of the reeds..
i will test and let you know about my dual horn

[TB21]

An engine is no more than an air pump , the more it can take in and expell the more power it will make.
BUT when you add more air and the air speed doesnt gain or atleast stay the same then it will be very lazy. Most that have tested , agree that the SVS makes better low and high rpm power than a merc horn , and i know the MAD intake makes more power than a merc horn.....anyone that aint blind can see that the SVS and MAD are going to be able to pass more air and the real positives are that the air speed also picks up. Problem with mercs horn is that the air speed sucks and your going to worsen that by adding another entrance. Just support our American companys and buy a MAD or an SVS and be happy.

Oh , and you can make more improvements to a center horn with a center punch and hammer than any other thing you do to it:D

TB

[Liqui-Fly]

So one big hole means less air speed while three small holes with a combined volume equal or more than the single big hole in the air horn means as much volume with more velocity?

David

[Trikki1010]

David, It's not evan as much as one big hole, it's more like one big hole in line with the center two cylinders. The upper and lowers suffer slightly. Some grind out behind the reed cages to make it flow easier to the upper and lower cylinders.

MAD & SVS basically "line-up" with the cylinders causing a less disruptive flow.

Somewhere in there, there is a fine line between flowing easy and creating turbulance to adequately atomize the fuel/air mixture.

Just my read on it :D

[TB21]

Yes the upper & lower cylinder pairs suffer in flow , but some of the mahinist's like JSRE or Diamond do an excellent job of helping this problem. The biggest problem is that the air enters into a velosity stack shape then tapers down to the actual throttle bore diameter which builds air speed , but then it opens into that huge plenum and what speed it gained in the throttle bore was just lost because of the rapid transition size . Plenum chamber intakes are just not performance oriented! Do all the mods you want its still not going to perform as well as a MAD intake , it really amazes me that there aren't more boats running Taylors intake :confused: I know theres rules to contend with in racing , but for hot lake boats you won't find a better easier to work with intake than the MAD.
TB

[stoker2001]

the svs is a proven peice and someday i will have one,but i would like to see some acceleration tests done comparing stock horn to big bore horn ussing ODBA pro gas powerhead.i do believe the big bore would win:cool:

[Liqui-Fly]

Next year I hope to have the full deal....stroker too. My horn is punched for my 2.7. Maybe if time permits this summer I'll do a little swap. I'll run the big horn in the spring and the little horn in mid July:)

David

[Tony Brucato]

stroker2001,

I've been supplying Mercury Racing with SVS's for their Drag Motors and F-1 motors for several years now. They were very diligent in their evaluation of the SVS compared to alternate choices.
I'm sure it would have made their day to discover that with no additional expense, they could bore out their existing air horn to equal the performance of the SVS.

Of course the SVS has to be dialed in accurately with fuel to match the improved air flow, Usually about 4% additional.

[TB21]

Tony brings up a very strong point , Im sure it hurt mercurys pride to use an aftermarket intake but they would not have made that decision without tons of test time......something Brucato should be very proud of and definetly a feather in his cap.

What i'd like to see is someone that has an adjustable ECU that knows how to tune , do a SVS v's MAD intake shootout.
TB

[stoker2001]

Originally posted by PhastBoat
http://www.brucatosvs.com/hp_results.html no doubt about it the svs rules over the air horn,but i am a little skeptical that big bore would lose that much acceleration to standard bore in this test.i am still sticking to my guns that if the test was cunducted with competitive pro gas motor with 20cc heads the big bore would come out on top of the stock horn

[Liqui-Fly]

Bigger horn means the air gets to flow to the top and bottom straighter...has less of a bend ya know.

Nobody get all upset this is just a discussion. Remember it started as a guy wanting to make soemthing different and/or cool.

David

[Liqui-Fly]

The gage on the reported test is horrible. You can't have results where two systems have a difference in performance where one wins one time and the other wins the other time. The only thing conclusive in that test was that the SVS was always better than both. You cannot draw any conclusions from the horn data about the horns. It wouldn't be good science:)

David

[Tony Brucato]

I don't blame you for being skeptical. I would have to find out for myself too. Your results may very well be different than what others have found.

Fly, I agree that the results between the stock horn and bored horn were so close that it could be a toss up.

BTW that horn was bored and the spacer plate had angle cut openings.

Nothing wrong with trying something new.

[Liqui-Fly]

This will be my first year with a big bore conversion...I'm running a bored horn and angle cut spacer

[wild drag racer]

I would like to thank you all for your recommendations
and comments... i am not upset, i respect your reply
but there is an arabic saying which say...
(( ask the one who tried?? and do not ask the doctor??))
actually, i like the mad horn.. but its too expensive
could you pls provide me withe mad horn web site??

thanks allot

wdr

[Liqui-Fly]

Here it is

www.madefi.com
Careful ...there are lots of Wild goodies over there.

[PhastBoat]

Cut the Chit- Pry open that fat wallet, and buy the MAD Intake and forgedabadit!
Or if your nice I'll sell you a cheap SVS.;)

[Liqui-Fly]

One step at a time. Nobody will want to come to the Romp anymore if I spend the event whooping everyone's ass with a Stratos:)

David