Secondaries

[Paul]

At what aprox. rpm do the secondaries open?

 

[nik97]

Right around 3400.

 

[naval-avi8or]

I read 3400 rpm.

 

[Mr. SHO]

At what aprox. rpm do the secondaries open?

You've been asking questions that have been covered over and over on this site and on V8SHO.com. You might want to use the search function in the future before starting a new thread on an "asked and answered" issue. If you are new to the V8SHO, you owe it to yourself to spend an afternoon or two scouring the V8SHO.com website. There's a ton of info there (even though it's not organized very well )

...just a friendly reminder before someone really chews you out.

 

[Paul]

3400 is the quick answer. I have limited time, access, and ability with PC's. I was'nt born with this knowledge. I apologize for asking. Is there a SHOfourm for idiots?

 

[SuperHO]

Paul, don't feel bad....half the people on SHOForum are idiots...the other half spend quite a bit of time harrassing those without proper knowledge. Don't worry about it....everyone's a n00b (newbie) once in their lives.





On a side note, not to hijack the thread, but what's this I hear about people removing the secondary butterflies?

 

[stangeater]

There is NO dumb question, but there are some dumb people who like to give everybody a hard time because they don't search before they ask................Do yourself a favor and always search before you ask a question, that will keep all the "kids" on this forum from harassing you!

 

[Mr. SHO]

There is NO dumb question, but there are some dumb people who like to give everybody a hard time because they don't search before they ask................Do yourself a favor and always search before you ask a question, that will keep all the "kids" on this forum from harassing you!

Precisely what I was trying to say. Maybe I came off more like one of "those guys" but I was just trying to get the message out before someone started blasting the new guy.

 

[Paul]

I can appreciate all that. The importance of this topic is lesser than the other questions I have recently posted. I am not sure what the purpose of this forum is? I'm looking for help.

 

[Paul]

Why do that? how would that help?

 

[SuperHO]

I dunno.....I've been hearing about a few people doing that....something about the secondaries on a GenIII being a restriction...

 

[Mr. SHO]

The primary/secondary setup doesn't help low-end torque on the V8.

The V6 has two runners per cylinder, so they can utilize the longer runners at low rpms and the shorter runners at higher rpms. The V8 has only one runner per cylinder. So having the secondaries open doesn't **** power at lower rpms like it would on the V6. So the real question is why the heck did Ford even put secondaries on the V8?

The fuel rail configuration has the injectors coming into the LIM at an angle, and the injectors only feed the primary intake valve. So when the secondaries open, all it does is let air into the secondary intake valve for better high-end breathing. If you do this at idle on a very cold engine, it causes a slightly rough idle for the first minute or so until the engine warms up. I believe it has to do with the air not all being directed right by the fuel stream. At any rate, it is not a problem at temps over 25*F or so, and even in colder temps it's not a problem once the engine is warmed up (after driving a block or two). For Ford to allow a 1996+ car to perform like that by design wouldn't have been acceptable for most people living in colder climates. I personally don't care, nor do most people who are enthusiasts and actually understand that it doesn't mean the engine is broken.

So if you can deal with this, then yes, the secondary butterfly plates, along with the shafts, are just taking up space in the LIM and are theoretically just a restriction. I don't know that getting them out of there actually improves performance, but it doesn't hurt it. And since the butterflies have a tendency to get gunked up with PCV gases, and the EGR then bakes the PCV gunk into a hard crust, they start to stick open or shut. Before long, the IMRC cable and/or wheel breaks from the excess strain. Better to just toss the whole IMRC since it's not helping performance and it's so troublesome. And then either get rid of the butterflies or at least wire them open so you aren't choking the engine at higher rpms.

 

[SuperHO]

I see........I was only wondering because my IRCM cable was busted when I went to GA....apparently it had been since I bought the car, which explains its pathetic performance. Needless to say, the secondaries were hideously nasty and the first time I opened them, the neon behind me's check engine light came on from all the crap that blew out the tailpipes....

 

[PFA]

So, the secondarys are only there to keep the engine rich when cold. So if the seconds are always open, you are then metering more air (I assume it has MAF) and the injectors will keep up so you don't run lean with too much air entering the chamber.??

 

[SHOZ123]

The car will run slightly lean when cold due to the open, exposed larger secondary valve causing a slight stumble or miss. A bit more fuel and timing will cure this.

The real killer and this is for all SHOs (but mine ) is the timing and fuel are both held back until 3400 rpm. Hence the sluggish take off of the V8 SHO.

The secondary rod is over 3sq" of area. Nice to have it out IMHO. I would do this with any V8 SHO that I have. But you should get a tune for it specifically to really get the benefits. Plus you never have to worry about that pesky IRMC cable or gears breaking and you will never clean the butterflies again.

Of course if you have a PCV catch can you don't have to clean the butterflies either, ever.

 

[Mr. SHO]

The car will run slightly lean when cold due to the open, exposed larger secondary valve causing a slight stumble or miss. A bit more fuel and timing will cure this.

The real killer and this is for all SHOs (but mine ) is the timing and fuel are both held back until 3400 rpm. Hence the sluggish take off of the V8 SHO.

The secondary rod is over 3sq" of area. Nice to have it out IMHO. I would do this with any V8 SHO that I have. But you should get a tune for it specifically to really get the benefits. Plus you never have to worry about that pesky IRMC cable or gears breaking and you will never clean the butterflies again.

Of course if you have a PCV catch can you don't have to clean the butterflies either, ever.

*******!

Gotta rub it in dontcha? :banghd:

 

[SuperHO]

Looks like I gotta invest in an X-Calibrator and ditch them secondaries.

 

[Paul]

3 sq. in is a considerable amount.

 

[nik97]

Hmmm. I guess I'm gonna have to disagree with some. The secondaries do serve a valuable purpose to the 3.4 as they do with many other Ford motors prior to the variable cam timing era. They have a direct relationship to the cams and the flow characteristics of the heads. They do help low end TQ by increasing the velocity of the airflow to the chambers via the venturi effect. Then, when the additional airflow is required (around 3400) they open and the inj. pulse width and proper spark advance can be utilized. The manifold is tuned and dumping fuel early won't help. The butterflies are also open during cranking as they are with the V6 to improve start up. Ford diddn't just throw these things in for fun

I do agree that the shafts and hardware do hinder airflow when it's needed and get gunked up but I suppose that's the beauty of variable cam/valve timing.

 

[Mr. SHO]

Hmmm. I guess I'm gonna have to disagree with some. The secondaries do serve a valuable purpose to the 3.4 as they do with many other Ford motors prior to the variable cam timing era. They have a direct relationship to the cams and the flow characteristics of the heads. They do help low end TQ by increasing the velocity of the airflow to the chambers via the venturi effect. Then, when the additional airflow is required (around 3400) they open and the inj. pulse width and proper spark advance can be utilized. The manifold is tuned and dumping fuel early won't help. The butterflies are also open during cranking as they are with the V6 to improve start up. Ford diddn't just throw these things in for fun

I do agree that the shafts and hardware do hinder airflow when it's needed and get gunked up but I suppose that's the beauty of variable cam/valve timing.

I'm not trying to be argumentative, but your theory doesn't seem to agree with the real-world results that have been reported back by dozens of SHO owners. The theory makes perfect sense as you explain it (at least in my mind) but the net effect seems to be negligible. Wiring the secondaries open vs. keeping the IMRC has no known effect on performance once the engine is warmed up. This is something that I've observed (I had it set up both ways several different times) and others have confirmed. Paul Nimz did back to back 1/4 mile runs to compare the two setups, and his results were the same either way. There is some speculation that there may be a marginal difference at part throttle, but so far no one has been able to actually feel or measure this. I guess we'd need dyno testing at various throttle settings to find out for sure, but the bottom line is that if there is a difference, it's not significant enough to be noticable on the street or at the strip. No one has been able to measure a fuel economy change either.

So far, the only reason for Ford/Yamaha using the quasi-secondary setup that we've been able to put any credit behind is the cold startup drivability. Even the "loudness" theory doesn't hold up, since the engine doesn't get loud until right around 3400 anyway (even if the secondaries are open all the time.)

Again, I'm not saying that Ford was stupid for putting them in, but I think it's been shown that the intake on this engine was a compromised design due to contraints of space under the hood. And it seems that Ford's HP/TQ goal from the very beginning was always just a modest improvement over the previous generations, which they did achieve. If there had been room under the normal 1996 Taurus hood (or if Ford had made a special SHO hood) for a front surge tank and 8 more intake runners, things would have been different.