Wastegate Exhaust System?

[2000StreetRod]

electric cutout response time

I found a video demonstrating Doug's electric cutout. It appears to only take a second or two to open and close but it is a sliding valve similar to dump valves used on an RV. In my application it doesn't really matter if the valve doesn't seal tight since any leakage will exit thru the second tail pipe. I think I prefer the butterfly style which may fit better in the available space. I've asked JEGS via email for their product's opening and closing times. I found a post on the NASIOC (Subaru) forum stating that the McCord electric cutout (butterfly type) took 4 seconds to open when first installed and that later increased to 8 seconds. I found a video of a DMH electric cutout (butterfly type) that takes about 2 seconds to open and close. A video of the QTP cutout (butterfly) shows about 4 seconds to open and close. In my opinion, if the response time exceeds 2 seconds it's not worth automating.

 

[FIND]

Ah, shoot, sorry I missed that.

 

[2000StreetRod]

back to crossover valve

I'm disappointed with the electric cutout response time and have read that it increases with age. Also, I suspect they are not designed for frequent (as in automated) use. I'm going to take a second look at the vacuum actuated crossover valve.

The vacuum actuator is removable even though the shaft is not. Perhaps I can fabricate a new mounting bracket that results in a normally closed (no vacuum) position. It means I would be limited to a 2 inch diameter tailpipe (same as the retained stock one) so I would be doubling the total tailpipe area. The crossover valve will be installed after the Dynomax Ultra Flo X muffler that has two 3 inch diameter internal perforated pipes. As I recall the exhaust manifold outlets are 2 inches in diameter. The exhaust shop suggested 2.25 or 2.5 diameter downpipes to keep the bends at 2 inches or more. Even with 2.5 diameter downpipes, cats and muffler ports there will be a considerable increase in area inside the muffler. Exhaust expansion in the muffler should result in decreased flow velocity and cooling. Maybe dual 2 inch diameter tailpipes will be adequate for a max 216 RWHp SOHC V6.

 

[CDW6212R]

That kind of valve looks like a better idea for long term use.

With a good sized muffler exhaust system, the added outlets don't need to be as big as if the "valve" switched all of the flow in one direction or the other. Make the main system at least 2.25", duals, two pipes and mufflers, all the way back to the tips. That is not hard to do, or more expensive than any other size. There is nothing wrong with having extra airflow, but smaller is.

The stock pipes are all 2.25" from the cats to the tips. I've read that at each collector and the resonator, there is a pinch point at those 2.125" small. Take out those weak points, grind the header ball openings bigger to the 2.25" stock size, or close to it.

Doing that will minimize the difference between the tunes needed for the cut out and the rest, as you already said.

 

[2000StreetRod]

Getting frustrated

I keep running into implementation issues for each of my possible technical solutions. That's one problem with trying to do something different. I took the crossover valve apart and it would be very difficult to install inline after the muffler even if I made a bracket to alter it to normally closed. Neither side of the valve is designed for exhaust pipe mounting so there would have to be adapters on both sides. The whole idea is getting too complicated while increasing weight and reducing the reliability of the exhaust system.

I've been reading more about the Dynomax VT muffler. There was a fix to reduce valve clatter by adding a pad to the valve. I suspect much of the clatter was on true dual installations with V8 engines which have less continuity of exhaust pulses. I found an encouraging test article of a unit installed on an Infinity G35: Dynomax VT Muffler Dyno Test! Does Quiet Mean Slow? There was no mention of valve clatter and the dyno test results were good. The Dynomax VT seems well suited for a supercharged engine.

So now I'm looking for a high flow dual inlet/single outlet muffler. There aren't many advertised as such but the Magnaflow 12198 is a reversible 3 inch single inlet/2.5 inch dual outlet possibility. The Cherry Bomb Extreme 7427 is smaller but not reversible nor is the Flowmaster 9430452. The Dynomax/Thrush 17661 is an inch shorter than the Magnaflow 12198 but it is not advertised as reversible. It probably isn't since it contains two chambers. One muffler shop manager told me he thought I could get a single 3 inch diameter tailpipe above my rear axle and retain the stock heat shield. One 3 inch diameter pipe has a larger cross section than two 2 inch diameter pipes.

I'm getting anxious to get the exhaust system upgraded so I can start on the supercharger addition.

 

[2000StreetRod]

possible combiner

One of Flowmaster's Super 10 Series is a one chamber single inlet/dual outlet "muffler" (8430152) that could act as a combiner for the outputs of the cats. It is "intended for customers who desire the loudest and most aggressive sound they can find". It's probably nothing more than a box with a port on one side and two ports on the other and should be reversible.

I'll ask Flowmaster if its reversible. The body length is only 6.5 inches (9.5 inch width) and the overall length is 12.5 inches. The Dynomax VT 17962 (for a single muffler system with engine greater than 4.0L) has an overall length of 19 inches. I could butt join the Flowmaster outlet to the Dynomax inlet for a total length of 31.5 inches for a dual inlet/single outlet "variable performance muffler".

 

[CDW6212R]

That will be loud, and restrictive.

I think there is a need for some dyno tests of a few basic exhaust combinations on just mild 4.0 or 5.0 vehicles. A single 2.25" exhaust is what comes stock on all Explorers until at least 2001. They all have one 2.25" muffler, plus the various normal restrictions of the resonator and the connections to that and the headers. That is a basic single exhaust on a 4.0/5.0 Explorer.

No 5.0 Mustang since before the late 80's comes with less than a dual 2.25" exhaust. That's a pair of 2.25" mufflers, and tail pipes. Do the math, no single 2.25" exhaust is adequate for performance use for a 5.0, and maybe for a 4.0 just barely.

Do the math and find the equivalent area of a single exhaust to at least equal a pair of 2.25" mufflers and tail pipes. That is what every 302 Mustang has on it stock, and everyone knows that going bigger to even just dual 2.5" is an improvement, for a stock 302. Why would anyone go smaller than the dual 2.25" exhaust system used on all 302 Mustangs? I don't understand why.

If the goal is power, and efficiency, with sound control, why not pick mufflers to your taste, in the size that at least matches the known stock 5.0 Mustang systems? A 4.0 with boost will pump more airflow than a stock NA 5.0 engine. It should be pushing flow in the range of a 6.0 engine or more, that's assuming just 7.5psi of boost.

I understand the goal of a cutout system, you achieve the nearly restriction free exhaust flow, while having sound control most of the time. The stock exhaust on all Explorers is way too small, basically half the size of a stock Mustang.

If it's 50% of the minimum of what it should be to start with, it seems logical to me to at least double the flow area of the back half. A single 3" muffler is not double the area of a pair of 2.25" mufflers, but that is as large as anyone seems to ever go on an Explorer.

I'll drop the subject, it's clear that almost everyone thinks that a single exhaust for an Explorer should be far smaller than for a car etc. I'll eventually get to my truck exhaust, and dyno test it reprogrammed while stock, and then again after a dual 3" system. That'll be for just a bone stock high mileage 302, which should be lucky to make 190rwhp to start with. Night,

 

[JCase]

I think your original idea of using the stock diameter exhaust with a blow of valve is the way to go.

 

[2000StreetRod]

Mustang vs Explorer

Don, the published curb weight of a 2005 Mustang V6 coupe is 3,350 lbs with a standard rear axle ratio of 3.31:1 and a drag coefficient of probably 0.37. My Explorer Sport curb weight is 3,900 lbs with a standard rear axle of 3.73:1 and a drag coefficient of 0.43. The Explorer's 16% weight and drag disadvantage is partially reduced by its 13% gearing advantage. A vehicle advertised for sporty touring usually has high rev potential vs a load/towing SUV with low rev torque. The Infinity G35 (curb weight 3,400 lbs & 3.5L 260 BHp or more stock) tested in the Dynomax VT article had a custom high performance exhaust system. It was changed to the 3 inch diameter muffler and only dropped a few horsepower at max (203 RWHp). The max power I anticipate with the M90 supercharger and a custom tune is less than 225 RWHp. Dyno tests indicate that high flow @ high rev exhaust systems reduce low rev torque. My goal in modifying my exhaust is to increase low rev torque. Your exhaust goal is probably to increase high rev horsepower. I think my shift points at WOT are 6250 rpm and my rev limiter is set at the stock 6300 rpm. I don't plan to change them. I suspect you will set your 347 points well above that meaning more max airflow. My configuration does not conflict with your plans because we have different goals. I think a single 3 inch diameter muffler and tailpipe will be a good compromise for low rev torque, high rev power, weight, space and my goal. It should be a significant improvement over stock.

 

[2000StreetRod]

SCT PowerFlash update

I tried another data collection of just the Bank 2 O2 sensor voltages and noticed a "data passthru stopped" message on my SCT PowerFlash X3. I sent an inquiry to SCT and was notified that my last update was performed remotely via my computer by them on May 4, 2012. There have been several firmware updates since then and one of them is considered critical. I was aware of that but didn't want to update unless I had to because it requires restoring my Sport to the stock tune, updating the X3, and then uploading the custom tune. That takes time and makes me a little nervous but I understand having the latest firmware eliminates some unknowns for SCT. I'll swap my 850 Turbowagon parking position with the Sport so if I can't reload the custom tune at least the Sport will be in the garage out of the way. The engine won't even idle with the stock tune because of the 90mm MAF sensor.

 

[CDW6212R]

The SOHC 4.0 is a higher rpm engine than the OHV or the stock 302. Your SOHC is probably close to 200rwhp right now given the MAF/TB, and tune. I'll bet it gains 30-40% or more torque from off idle to 4000rpm or so, leveling off above that as the blower is less efficient or small. That will be a fun truck to drive anywhere.



I'll be shooting for a shift point below 6000rpm, hopefully in the 5800-6000 range, with what looks to be a 332 if a 302/306 can't be built for a whole lot less. I also want lots of bottom end power, and the positive displacement blower will do that very well.

I don't want a high winding engine in a truck, that's best left for a car if possible. Regards,

 

[2000StreetRod]

Y pipe

I talked with a Flowmaster technical support rep today who confirmed that none of their mufflers (including the Super Series 10) are reversible due to directional deflectors. That eliminates all of the combiner "mufflers" I've identified. The only alternative to a custom resonator is a Y pipe. Flow Monster sells one (pn FMY300250) specified with a 3 inch inlet and two 2.5 inch outlets.

Magnaflow sells one (pn 10778) specified with two 2.5 inch inlets and a 3 inch outlet.

Its 10 inches long.

 

[CDW6212R]

There is another choice that might work well. It's a Mac Flow chamber I think, or Flow path. They have one like that two into one that is a way to combine banks. I made a mental note of the mufflers, flow path I think, because they are the highest flowing, and could make a decent resonator. If it's just to reduce the sound a little more, that might be an answer.

Check those out and see if they have one which has two inlets and one outlet. There is tons of room under the truck for mufflers in series.

 

[2000StreetRod]

Mac Flow Path

There is another choice that might work well. It's a Mac Flow chamber I think, or Flow path. They have one like that two into one that is a way to combine banks. . .

Thanks for the tip Don. They sell very high flow mufflers. I went to their website and only saw single inlet/single outlet mufflers. But I found some when I downloaded their catalog. Their FP2513 is dual 2.5 inlet/single 3.0 outlet for up to 420 BHp engines. The body is 10 in wide x 18 in long or approximately 21 inches overall. In searching the internet for one it appears they have been discontinued. I'll contact them for confirmation. Remember, my Sport is 10 inches shorter than the 4 door so I don't have as much room to work with. I need a length of tube in front of the combiner to mount the post cat O2 sensors.

 

[toypaseo]

Not sure if this was discussed yet, but how about using a manual exhaust cutout?

 

[CDW6212R]

That's true you have a little less space. If you can find a picture of a 302 truck, check out where the four cats are. The front two are well ahead of the trans cross member, so the back pair are near where the V6's have theirs. I'd try to place one near the bell housing, and the other one just beyond that(staggered). I don't like how the V6 cat is below the trans pan, in the 302 it's just under the edge of it, but more to the side.

I hope that you can use that muffler if you can find it. I would also be interested to know if the extra muffler is similar to the Flow Path, and how much it lowered the volume etc. I think I will judge mine to be too loud when I finish it, I like less sound than most.

 

[2000StreetRod]

cats location

Don, for efficiency I think the cats should be as close to the manifolds as reasonably possible. I have to leave room in the downpipes for two sensors (O2 and air/fuel ratio meter). I'll get a bung and plug installed on the passenger side so I can move the a/f sensor if I need to monitor that bank.

My stock cats are rectangular with inlets and outlets on the corners. You can see the reduced pipe diameters at the tight bends. As I recall the outside diameter was only 1 7/8 inches including the thickness of the attached partial heat shield. Since I have 2WD with the shallow transmission pan I can remove the pan without removing the cat pipe but I like having each downpipe/cat as a removable assembly as in the stock configuration.

 

[2000StreetRod]

automated system

Not sure if this was discussed yet, but how about using a manual exhaust cutout? . .

My goal is to have an automated dual mode exhaust system for good torque under light to moderate load and low restriction under moderate to high load (boost) conditions. The fastest electric cutout I found took 1.36 seconds to open and to close and that increases with age.

 

[2000StreetRod]

2 inch manifold outlet

The exhaust specialist at my local shop looked at my Sport today. He said that since the manifold outlet is only 2 inches in diameter he suggested I purchase the 2.25 inch diameter cats. He'll expand the downpipe to match. OBX manufactures exhaust headers for the SOHC V6 with 2.5 inch diameter outlets but I've always preferred the sound of cast manifolds over exhaust headers and they usually last longer. He suggested purchasing the 2.5 inch diameter inlet Y pipe and he'll expand the pipe from the cats to match. I requested that the cat/downpipe assemblies be removable separate from the Y pipe. I'll get a bung installed on the right downpipe for the A/F sensor and then plug it. The 3 inch diameter will be maintained from the Y pipe outlet to the end of the tailpipe. I should receive the cats, Y pipe and muffler in about a week.

 

[2000StreetRod]

Unfinished Y pipe

The Magnaflow Y pipe arrived today.

The welds look to be of good quality but when I looked inside I was disappointed. The pipes were square cut and then welded in with no grinding after to match the shape of the cast upper and lower halves.

The protruding ends of the pipes will generate turbulence in the air flow. I'm less concerned about the inlet protrusions than the outlet but neither is desirable. It looks like I'll be spending some time with a grinder to finish Magnaflow's job. I'm glad the Y pipe came so fast since (hopefully) it will take the longest to prepare for the exhaust shop.