Intake Horn Removal

[mholhut]

I just removed the intake horns on my car. Seems like this mod is becomming popular with the V6 SHO crowd so I thought that I'd take a stab at it. Their thinking is that the tuned horns restrict airflow and add turbulance to the intake so I went under the same assumption.

I don't know if any V8 owner out there has ever done this before. Given that removing the horns is a relativley simple task, I can't assume that I was the first one to try this. I'd be interested in hearing what anyone else's comments are at this point.

The tuned intake horns are designed to spool up air pressure from intake pulses before it enters the combustion chamber. Removing the horns doesn't seem to hurt performance one bit. My inital test drive/launch provided a little more wheel spin and a slight increase in mid-range torque. The car seemed to snap a little better, but this is only my first impression. I'll have to get the car to the dyno to see if I gained or lost anything with this. I'll leave the horns out for a while to see how the car is at highway speeds and to see if there's any high end ponies to be had or any long term consequences.

My only worry is the the use of nitrous with this mod. You need nitrous to atomize completely before it enters the surge tank, allowing for even distribution among all cylinders. Without the horns, more nitrous might get sucked into cylinders 4 and 8 leaning them out. We'll have to see.

<small>[ June 25, 2002, 12:47 AM: Message edited by: mholhut ]</small>

 

[stephen newberg]

OK, you devil you, I will bite. What does one do to see exposed these intake horns?

pax, smn

 

[Mac98SHO]

They are right below the surge tank intake runners on the surge tank. Remove surge tank runner with surge tank in car and remove the horns. Replace the runners of course

 

[RStalveyARFF]

Mac, you don't need the runners!

 

[Mac98SHO]

Well thats what I might be doing wrong. When I try Mike's mod, I will leave them runners out thumbs_u

SHO91MTX shoot

Possiblies are endless

<small>[ June 25, 2002, 12:16 PM: Message edited by: Mac98SHO ]</small>

 

[fredhurderjr]

Most of the V8 crowd has probably heard the running argument about the V6 intake horns. It's been pretty well accepted that you lose about 4lb-ft of tq, but gain about 4hp up top with the V6. I'd have a hunch that the V8, with its different intake design would reverse that actually. Again, it's just a hunch, with nothing to back it up on my end.

This may be something to check out while on the juice, Mike - see what the temps are at each intake runner while on the dyno on the bottle - wouldn't excess nitrous to specific intake runners cause a temperature difference?

 

[Mac98SHO]

Two things:

Fred please tell me you are going to salvage the front end and rebuild her.

Mike the NOS is inject before the TB right? If so I bet both those 90 deg bends in our intake may atomize the mixure enough. Were you having an lean problem on one cylinder before.

Thought: Possibly modify horns to shorter length with NOS. Just a thought. (kind like cut, bend , and hammer) thumbs_u

 

[SHODWN]

BEEP BEEP

 

[mholhut]

Stephen...

The blue runners (in the diagram) are the ones that need to be removed to access the horns. There are 5 bolts holding each set of runners to the surge tank. 10 & 11mm deep sockets are all that you'll need. Remove the back set of bolts (marked in red) and loosen the rubber runner clamps. The back set should then slide off easily and allow you to access the next set of 5 bolts for the nearer set of runners. After the runners are out, you'll see the two sets of horns, sandwiched between two gaskets. Remove the horns and replace the gaskets.

Fred... Why do you think the HP and TQ loss/gain would be reversed on the V8's as opposed to the V6's? Yes, the nitrous will cool the intake up to 60 degrees, so if one cylinder is getting too much nitrous, it will be considerably cooler... but at that point, the nitrous is already leaning out the cylinder. I'd hate to waste a piston just to see if I was right wink

Mac... Well, yes, there might be enough atomization to prevent leaning out cylinders 4 & 8, but I wouldn't want to risk it for testing's sake. Shortening the horns may also be an idea, but they are already "tuned" to some spec's that are supposed to provide a balance between HP and TQ. Try it on yours and let us know how it works

Kirk... Uhhh, I think you're looking for the Mopar forum for problems with your Road Runner (Beep Beep!)

No problems so far and the only thing that I notice is that the volume of the secondaries opening has decreased with the horns out. Strange. The V6's say that the horns added intake noise when removed.

<small>[ June 26, 2002, 05:28 AM: Message edited by: mholhut ]</small>

 

[mofosho]

Mike, if i remove that upper intake portion like you show, but also remove the lower intake can these come off as one peice without seperating them at the rubber connectors, and is this where the secondaries reside for cleaning? Thanks

 

[SHODWN]

Brent.. YEP you are correct

 

[Mac98SHO]

Mac... Well, yes, there might be enough atomization to prevent leaning out cylinders 4 & 8, but I wouldn't want to risk it for testing's sake. Shortening the horns may also be an idea, but they are already "tuned" to some spec's that are supposed to provide a balance between HP and TQ. Try it on yours and let us know how it works

I might if I ever get spare set of intake horns. Sinced you remove them you have already screwed that balance you talk about above. I thought you might have set left over from the old motor you would experiment with. (Thought thats all) thumbs_u

Your possible lean condition... you could always run slightly bigger fuel jet.

<small>[ June 27, 2002, 01:34 PM: Message edited by: Mac98SHO ]</small>

 

[mholhut]

Brent, what Kirk said... but, if you're going after the secondaries, then you have to remove the 90 degree bend by the IAB (mounted to the lower intake), disconnect or remove the TB, remove the fuel rail and injectors, disconnect the secondary actuating cable, etc. etc.... Just don't drop any bolts wink

Mac, I do have a spare set of horns... but I'm not ready to start hammering them down just yet. I'd need a smaller fuel jet to increase fuel pressure, but after hashing it out with Tom W at the dyno day, it doesn't seem like a feasible solution to the problem. I am working on other solutions though.

 

[Mac98SHO]

Mike you could always add second fuel pump inline somewhere, this was something I been pondering for awhile. If I run Nassss that is.

That would in crease your fuel pressure. Beside I havent tried it yet but I am pretty sure the 5.0 fuel adj regulator can be mounted on this car. There are several version to choose from. If I ever get money to play I will be trying that next. This might be something you might look into also.

Though I think you probally all ready thouht of the above options, but **** it never hurts to look at them again. thumbs_u

 

[SHODWN]

it will fit. we just need to make a new PS line or correctly bend the line.

 

[Mac98SHO]

Correctly reposition it......... This may yield better results.

 

[SHODWN]

repositioning the regulator is the only chioce presently

 

[fredhurderjr]

Mike -
My thought on the HP vs TQ is only due to the single runner per cylinder, unlike the dual runners per cylinder on the V6. I know, it's backwards from what you'd think, "longer is better" (go for it Kirk).

Again, I really don't have anything concrete to point to, it's just a gut feeling.