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MALFUNCTIONING IAC???

Discussion in 'FAST Support Forum' started by 78 F150, Aug 9, 2018.

  1. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    So I'm going to check out the Pypes setup you have on their website. Your truck sounds real good. Correct me if I'm wrong, but since you had the rear of the truck in the garage and the door open when you recorded the video, I assume that it was louder than it would be not being in a garage and with the door closed???

    My wife's 2004 Dodge Ram 1500 she just got (traded her 71 Jeep CJ5 for it) has what I assume to be glasspacks (they are round like glasspacks are) and I LOVE the sound of it. I was initially going to get glasspacks, but now I'm second guessing it based on a bunch of comments in a Facebook post I read on how loud they are. But my wife's exhaust is not loud at all. However, I know her truck would be quieter than my truck because her truck has catalytic converters, which help to muffle the sound a lot. But I'm not 100% if they're glasspacks, but I'm assuming they are because they're round. My 67 Cougar has glasspacks and I love the sound of them, but they are louder than my wife's truck. I'm at a point in my life that I'm not wanting something loud. When I was younger, it was fine and I could tolerate it more than I do now. So that's important to me. But I really want that deep tone of a big block.

    Question.....is it true that the longer the muffler and the bigger diameter case gives you a deeper tone? Also, is it true that if I stagger the mufflers (not equally next to each other, one further forward than the other) that it will eliminate the "drone" sound in the cab? Also, do I want to put the mufflers farther back toward the rear of the truck? Will that give me a quieter sound? Or will it not make a difference?

    Yes, I listened to the video on my computer. I didn't hear the tinny sound you mentioned. It sounded deeper that what you thought it sounded like. And yes, I'll be using 2 1/2" tubing. I have 2 1/2" tubing from my headers to an H-pipe, but after the H-pipe it terminates into the smaller factory size exhaust and into the factory mufflers, but it is a true dual exhaust.

    Not sure if you get on Facebook or not, but I ran across a post by Tammy Barbe-Seigel and she is asking for suggestion on which exhaust to go with on her 76 F350 w/460. I've read through all the comments and have tried to ignore the personal opinions and just pay attention to facts. But I'm still not sure which way to go. You always get so many opposing opinions you never know which way to go. What one person likes about a muffler, another person may not about the same muffler. So I try to ignore that type of stuff. But there are suggestions in these comments that I think habr substance, such as "why" a certain muffler is recommended. Some of them even post videos of their exhaust systems and how it sounds. One of the suggestions is going with the Dynomax Super Turbo muffler, stating that they are quiet and flow nice. That's what I want, but I'm not sure how accurate that is because quiet to one person may not be quiet to another. A lot of them suggest Flowmaster and a lot say to stay away from them because they're loud and they have that "drone" in the cab, which I don't want. Here's the post if you're interested in reading through the comments. Maybe you can give me your opinion on these comments.
    https://www.facebook.com/groups/592..._id=1544892013869417&notif_t=group_highlights

    I need to watch your video a few times and pay attention to the things you pointed out on the handheld. And your advance being locked out makes sense vs what I saw on your handheld. And you're right, my settings will be a lot different than yours, but the function should be the same and that's what I'll be watching for on mine.
     
  2. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    Ok, so I was just looking at the Pypes Race Pro mufflers and I have one concern. At the end of the description it states the following: "Not recommended on lower horsepower vehicles as low end torque may suffer. Think of these mufflers as large inhalers for your engine." So my question is this: what do they consider "low horsepower"? My 460 is definitely not a race engine, but it's not stock either. And the Cobra Jet heads flow a lot more air compared to a standard 460 head. But I'm probably not going to be spinning the engine over 4500 rpm given that this is a truck I use for towing, not racing. So what's your opinion on using your mufflers on my truck given their disclaimer?
     
  3. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    By my door being open and the truck sitting backed in, You probably heard the exhaust more like it would have been standing by a rear tire. I should have dropped it in gear - that always increases the big block ring it has and changes the tone some.

    No worries. Your 460 is not considered low horsepower. It creates quite a large volume of exhaust gas from each cylinder. PYPES exhaust and mufflers will work well for your truck. You're making a lot of torque a lot earlier than 4500 and will benefit from the flow scavenging after the header. The size of the header tubes is more important in torque enhancement.

    A longer muffler is slightly quieter. Tone comes from the exhaust pulse, and a larger diameter pipe helps enhance and soften the pulse for a deeper tone. These are oval mufflers and unlike glass packs. If these are too loud, you can always add in a resonator. I like the Vibrant Performance resonators. They are stainless with stainless fill that never settles or blows out. The Vibrant Ultra-Quiet silences as well a catalytic converter without creating excessive backpressure. Glass packs settle and blow out over time which make them get louder. The get their name from the Fiberglas packing.

    Let me make it simple. ALL baffle type muffler are restrictive. The baffled ones that are less restrictive are LOUD. Dynomax is usually just a bit quieter than Flowmaster. These two companies tune for a different sound by the way they place the internal baffles and reflectors. They compete for the "loud kid on the street" market. The way a muffler builds heat also affects the sound. The perforated S-core style mufflers are among the best made. So are the Vibrant perforated straight core. I never liked loud exhausts - not even on my racers. I need to hear the engine sound. I started running Borla race mufflers early on. Borla was a lot less expensive in the early days. Ha! JC Whitney even sold them 50 years ago. Never had one go bad. You can actually think of a good muffler as a type of heat exchanger.
     
    Last edited: Dec 19, 2018
  4. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    Actually, I think I have Borla mufflers on my 92 Mustang Gt 5.0L and I love the sound of them. But honestly, I like the sound of my wife's mufflers a lot better. I just need to figure out what they are. We are going to try to contact the previous owner and ask him if he remembers what they are.

    So you think the Borla mufflers are good mufflers? So are the Pypes mufflers you have considered "perforated S-core style" mufflers? And can you explain what a resonator is and what it does? And will it create more back pressure than what I would want? Would it hurt exhaust flow and/or horsepower? And where do you mount them; in between the header and muffler or after the muffler?

    So if I go with the Pypes, I think I'll go with the MVR30. They are 18" mufflers which should be a little quieter. The only thing that concerns me is I want center entrance and exit instead of how they have them in the picture.

    So I got the heads off the truck tonight. Got them cleaned up and boxed up. So I'll get them shipped out tomorrow, then the waiting game starts.
     
    Last edited: Dec 19, 2018
  5. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    If you have room for longer mufflers, go for it. Borla doesn't have a million mile warranty for nothing. The PYPES mufflers are also stainless steel, so they probably won't ever need replacement. Resonators are just smaller mufflers added into each exhaust. They compliment mufflers to lower sound levels. Manufacturers have used the for years on vehicles with larger engines. They are low restriction. Some people remove them saying they make the exhaust too quiet. Others use them as a muffler alone. If you have any drone at speed with your muffler, a resonator will usually get rid of it. You can mount a resonator anywhere you can fit it. Just remember mufflers and resonators get hot.

    My mufflers mount the oval vertically, with the pipes horizontal. So sometimes a center inlet/outlet isn't required or a curved pipe can be used. Mine are center and offset. You can mount the Race Flo mufflers (and any perforated core muffler) in either direction.

    Mufflers with resonators in the exhaust will definitely be quieter with no loss or negligible loss of flow. Adding resonators would likely kill off the late 1960's OEM factory performance loudness my exhaust has. Pontiac used to advertise the GTO performance exhaust sound as a selling point. I have to admit the '69 400 GTO Judge did sound good to me.
     
  6. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    I've got plenty of room. My truck is a Super Cab with an 8' bed. It's a long truck; 155" wheel base. My mufflers are mounted in the exact same configuration as yours, but I have center entrance & exit. So maybe I'll try just the mufflers alone and if I think they're too loud, then I'll add the resonators. Question....does staggering the mufflers (one further back than the other) help to eliminate the drone issue?
     
  7. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I couldn't say about the staggering. I've never tried it.
     
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    My GMC is a standard cab with 8' bed. My crossover is just behind the front driveshaft yoke. That limits the length of a resonator if I installed them on my truck. But, I can still add them. I also set up my exhaust to sit high into the body - the only thing below the frame is the rear outlets. I used "shorty" headers specifically to keep the header outlets inside the frame. Can't stand low hanging exhausts that could ever hit a speed bump. My truck could easily be lowered and still have good road clearance, but I like the factory stance.
     
  9. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    So the heads are on their way to Michigan. They should arrive next Friday. In the mean time, we heard back from the previous owner of my wife's truck and it has glasspack thrush mufflers. Now I have some decisions to make because I really like the sound of them, but after listening to everything you've said about the Pypes mufflers, I'm not sure which way to go. Originally, prior to talking to you, I was going to go with Jones Exhaust Glasspack Mufflers that are 45" long & 4" diameter (in theory, quieter and deeper tone) and only cost $59 each. https://www.summitracing.com/parts/jex-a4540s/overview/ But because of what they're made out of, I don't think they will last as long as the Thrush glasspacks. So looking at the Thrush glasspacks, these are only 25" long, but are made out of T-304 stainless, but are only 3.5" in diameter. But these will last a lot longer because of the stainless. However, these are $105 each. https://www.summitracing.com/parts/wlk-24240/overview/ And then there is your mufflers I'm considering also. So I'm going to listen to your video again and try to decide which way to go. In the mean time, can you give me your opinion on these glasspacks vs your mufflers; basically a comparison?
     
  10. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    When I was a teen, I had a Thrush glass pack on a new car I drove to college. The factory muffler had come loose somehow and was badly damaged. The Thrush didn't rust out, but the Fiberglas packing settled and blew out in a years time. Got myself the only loud exhaust ticket I ever had - and driving only an inline six 120 horsepower car with full length pipes. I put a new, much more expensive, factory muffler back on. I had bought the Thrush the same day I lost the factory muffler, only because it was cheap and it fit - and was available at a nearby Western Auto store. The ticket made the Thrush expensive. I did use Cherry Bomb glass packs once later on - as cheap resonators for a two year old dual exhaust car with factory mufflers I was selling - the factory resonators on the rear had rusted out.

    My PYPES Race Pro mufflers are far quieter than any glass packs. The https://www.summitracing.com/search...formance-bottle-style-resonators?N=4294857541 never settle or blow out. The oval Ultra Quiet is more quiet and also never settles or blows out - https://www.summitracing.com/parts/vpe-1141

    The Vibrant contain stainless steel wire packing - by far better than Fiberglas.
     
  11. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I used to like the Western Auto stores as a kid on up. They always offered a little of everything. I bought my first set of aftermarket rims there - a set of triple plated chrome reverse with center caps, that never rusted and always looked good. Those sold by others always quickly started rusting.

    "Cherry Bomb - Disturbing The Peace since 1968" https://cherrybomb.com/project/glasspack/ sound test on page

    You may want to check these out - stainless with stainless wool packing. They last better than Fiberglas. https://www.summitracing.com/search...ortOrder=Ascending&keyword=Cherry bomb salute
     
    Last edited: Dec 21, 2018
  12. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    Ok I just googled resonators and I'm getting mixed results. Some say a resonator will help to quiet the exhaust but most say it's main purpose is to eliminate exhaust drone. Many say it makes the exhaust louder also.

    Question...what is the difference between a muffler and a resonator? Don't they both do the same thing; muffle sound? I assume they are constructed different and are used for different purposes????
     
    Last edited: Dec 22, 2018
  13. A A

    A A Well-Known Member

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    Jun 22, 2014
    They both muffle sound. Resonators less so. Second question - Yes, normally they are.
     
  14. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    So would it be a waste of money to install a resonator with a muffler if they really don't make the exhaust any quieter? I'm sure I just answered my own question, but I asked it in case I'm not understanding something.
     
  15. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    No. If, after you install the muffler, you decide the exhaust is too loud. Add a resonator. The PYPES Race Pro mufflers would be fine - you heard mine. Their large oval body makes them efficient at controlling unwanted sounds. The addition of the oval body Vibrant Ultra Quiet would make an excellent resonator if you want more silencing - it should last longer than others of this type. It is also polished. The Cherry Bomb Salute is a 4x9 oval that would also be an excellent choice as a lower priced resonator. None of these is anything that will rust out. If I decide to quiet my PYPES exhaust, I will use either the Vibrant or the Salute. If the Salute is too long to install, the shorter Vibrant will still fit in my exhaust.
     
  16. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    Ok I'm shifting my focus back to pinpointing my problem with the EFI. Since I'm pretty much starting over by having the heads repaired, I've been doing some brainstorming on how to pinpoint a problem (if I have one) once I get the engine back together. So my thought is this: Once I get it back together, I'm going to disconnect ALL sources that use vacuum, and that includes the distributor and fuel pressure regulator. And if the handheld readings look good, then I'll reconnect one vacuum component at a time until I either find the problem or have everything reconnected again. I'm thinking by doing this it will help me eliminate a vacuum leak as the source of a problem. I'm hoping my a/f ratio and all my other readings function like yours once everything is connected. I know for a fact if I had a vacuum leak it wasn't coming from the header, intake, or TB gaskets. So that leaves the brake booster, distributor, and fuel pressure regulator as a possible source.

    So here's my question....you mentioned doing this earlier in this thread but I wanted to ask for some clarification without having to search through the 31 pages of conversation we've had.

    You mentioned I can disconnect the fuel pressure regulator vacuum line and run the engine. If I can run the engine without this line connected, why do I need to connect it at all? What is it's function (providing vacuum to the regulator)? And since vacuum is required, then why is it ok to disconnect it when I'm idling? This kind of confuses me. Can you clarify the function of the vacuum line and why it's needed, but at the same time why it's ok to disconnect it when the engine is idling?

    Since I've identified a small vacuum leak in the regulator, I'd like to pinpoint this issue and see if this is what's causing my problem.
     
  17. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Don't worry with the "brainstorming". Everything is going to be completely different with the repaired heads - as long as you have the correct plugs tightened correctly. The only vacuum issue you might have left would be the brake booster or the vacuum controls for the cab - unless the regulator diaphragm is leaking fuel.
     
  18. fabr

    fabr Member

    Joined:
    Jan 23, 2017
    Forget about the absolutely insignificant vac leak at the regulator. To be safe look for any other possible source after you get it back together before running truck. I agree that eliminating any possible source and then reconnecting one at a time would be one course of action. FWIW though,I believe you have other tuning issues that can/will cause your symptoms. I also believe you need to take a much broader look at what may be the cure. I don't know what it is but it isn't something as simple as being off on the heat range from what I have read in this thread. There is some tune parameter that is needing tweaked to get it "perfect" and then the AL will just have to do it's thing from there on. Realistically,that's as good as it will get..
     
  19. 78 F150

    78 F150 Member

    Joined:
    Feb 6, 2013
    I hope you guys are right. Maybe I shouldn't worry about it right now until I get the heads back. But I've been fighting this issue for 7 years now and I've only had the inserts installed since March 2018, so I'm trying to figure out where to look besides the inserts. The plugs I'm using are only 1 stage colder than factory, so that shouldn't be an issue. The crazy a/f ratio reacts like a vacuum leak that's why I'm focused on vacuum issues. There isn't anything in the cab that is controlled by vacuum, just the distributor, regulator and brake booster; that's it. Maybe it's not a vacuum issue, but I have no idea.

    The ECU, TB, and O2 sensor are brand new so all the sensors should be fine. I no longer have the original components I bought in 2011 as they have been replaced by FAST/Comp Cams, excluding the wiring harness and fuel regulator.

    Question....FABR, you mentioned to broaden my scope.....So would an electrical issue (such as the alternator or ???) cause the A/f ratio reading to go crazy and seem like a vacuum leak?
     
    Last edited: Dec 23, 2018
  20. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    If you have odd frequencies generated by it, it can interfere with the A/F the ECU sets. Those head inserts were keeping us from finding any optimum ratios or even checking the timing. When the plug heat range is off like yours was, it tricks the ECU into all kinds of things it can't compensate for. You could have even had some leaking valves. Each repair has continued your progress. We'll be able to tell more about what is going on in the cylinders once the heads are back on. Put everything on a back burner and have a Merry Christmas. The rest will do you good.
     

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