High Flow Exhaust Overhaul

[mr cribb]

I wouldn't say useless, just not a lot of ROI. Depending on how you drive, you can see an improvement on mileage on a first gen. The biggest factor here would be a cumulative effect if you paired it with a decent flowing exhaust system and a reasonable induction system (like optimizing the throttle body and whatever other minor flow improvements you feel like doing, portmatching, smooth good flowing intake. Doing any of them by themselves will barely make a difference, all together and it will actually do quite a bit... though, the cost of it all is hard to justify for the small gains.

My only question is what's ROI.....hopefully it's not something obvious, LOL

 

[FIND]

Return on investment

 

[Anime]

The intake/exhasut mod does make a big, noticeable difference on a 91-94. Of course, it depends what you use. A KKM and a 2.25" Borla/Magnaflow/Dynomax with matching mandrel-bent pipe will make a bigger difference than a cheap muffler with crush bent pipe.

2.5" pipe seems a little large to me, based on the useable RPM range of a stockish 4.0OHV, and the flow of 2.25" pipe being more than adequate. If you did a lot of mods, maybe a 2.5" system would have some benefit, espeically at high RPM. Gibson makes a catback that uses 2.5" tubing, but it's mostly for show as the muffler used in the system has internal louvres and reduces the exhaust velocity too much to take advantage of the larger pipe diameter.

$265 headers? Not if they're Pacesetters. Total junk. Some members have used them, and the similar Hedmann headers, but they are just mild steel black painted stuff that isn't intended to last. They fit poorly, too. Decent stainless steel JBAs are in the $600 range. The only reason you'd want/need headers is to go along with head porting and a larger 410/422 cam and the mods that go along with it.

Overall the best bang for the buck is a catback system and a cold air intake. Cheap and easy, and with torque/power/mpg benefits.

 

[mr cribb]

Well today I removed the stockish looking muffler and tailpipe for a flowmaster muffler and 2.5 in pipe (prob 3ft total). I got this off a jeep guy for $20. HUGE difference so far... My engine breathes now!

 

[FIND]

The intake/exhasut mod does make a big, noticeable difference on a 91-94. Of course, it depends what you use. A KKM and a 2.25" Borla/Magnaflow/Dynomax with matching mandrel-bent pipe will make a bigger difference than a cheap muffler with crush bent pipe.

2.5" pipe seems a little large to me, based on the useable RPM range of a stockish 4.0OHV, and the flow of 2.25" pipe being more than adequate. If you did a lot of mods, maybe a 2.5" system would have some benefit, espeically at high RPM. Gibson makes a catback that uses 2.5" tubing, but it's mostly for show as the muffler used in the system has internal louvres and reduces the exhaust velocity too much to take advantage of the larger pipe diameter.

$265 headers? Not if they're Pacesetters. Total junk. Some members have used them, and the similar Hedmann headers, but they are just mild steel black painted stuff that isn't intended to last. They fit poorly, too. Decent stainless steel JBAs are in the $600 range. The only reason you'd want/need headers is to go along with head porting and a larger 410/422 cam and the mods that go along with it.

Overall the best bang for the buck is a catback system and a cold air intake. Cheap and easy, and with torque/power/mpg benefits.

Specifically what difference will you see? How much torque, horsepower and MPG benefit will you see realistically? Do you have any dyno or verifiable real world evidence to back up this statement and a reliable source to compare an OEM system to?

Well today I removed the stockish looking muffler and tailpipe for a flowmaster muffler and 2.5 in pipe (prob 3ft total). I got this off a jeep guy for $20. HUGE difference so far... My engine breathes now!

Well... given the condition you have described your explorer to be in, I am not surprised.... Anything short of jamming a potatoe in your tailpipe would have made an improvement. Now you just need to figure out why you still can't get your vehicle over 2500 rpms.... because under normal circumstances, it should easily make it to the redline.

 

[mr cribb]

Well... given the condition you have described your explorer to be in, I am not surprised.... Anything short of jamming a potatoe in your tailpipe would have made an improvement. Now you just need to figure out why you still can't get your vehicle over 2500 rpms.... because under normal circumstances, it should easily make it to the redline.

Lol well it seemed like there was a field of taters in my exhaust, because it's complete night and day difference.

It revs to 2500-3000 rpms w/no problems now, I guess I forgot to mention that.

And it's not that my X is in such disarray, she was just a little unloved that's all. I will say everything I've done to her so far I've thoroughly enjoyed. I'm waiting to see what new plugs and wires will do.

So invest in the $89 kkm setup over a $20-40 spectre filter from the parts store?

 

[Anime]

Specifically what difference will you see? How much torque, horsepower and MPG benefit will you see realistically? Do you have any dyno or verifiable real world evidence to back up this statement and a reliable source to compare an OEM system to?

Obviously such things vary with the vehicle they are on, not to mention the condition of the powertrain, and any other modifications that have been performed. Posting numbers isn't of any use to anyone since they may or may not get the same improvements, even if using the same exact components.

There is plenty of evidence that an exhaust and intake free up available power and torque on Explorers in many, many posts on this forum. Not to mention the entire internet. And the fundementals of internal combustion engine operation.

As for my personal modifications, the butt dyno and real world testing showed an incredible, incredible gain in performance, both in low-end torque, high speed acceleration, and overall throttle response with the decreased exhaust restriction from the Dynomax Super Turbo and matching mandrel-bent pipes. Realistically, the performance is probably back to what it was 10-12 years ago, but with some engine work to repair worn parts and tuning to make the most of the mods, it should be better than ever.

 

[FIND]

Obviously such things vary with the vehicle they are on, not to mention the condition of the powertrain, and any other modifications that have been performed. Posting numbers isn't of any use to anyone since they may or may not get the same improvements, even if using the same exact components.

There is plenty of evidence that an exhaust and intake free up available power and torque on Explorers in many, many posts on this forum. Not to mention the entire internet. And the fundementals of internal combustion engine operation.

As for my personal modifications, the butt dyno and real world testing showed an incredible, incredible gain in performance, both in low-end torque, high speed acceleration, and overall throttle response with the decreased exhaust restriction from the Dynomax Super Turbo and matching mandrel-bent pipes. Realistically, the performance is probably back to what it was 10-12 years ago, but with some engine work to repair worn parts and tuning to make the most of the mods, it should be better than ever.

Just wanted to make it clear that there is no REAL evidence of "a BIG, NOTICEABLE difference". There is plenty of evidence all over the internet that replacing your coils with a high performance coil gives you a big noticeable difference, but we all know that is a lie too.

As per the cold air intake. When you drive your explorer, is there a BIG NOTICEABLE difference in power when driving in winter vs Summer? How about when driving on a day that is 5 degrees colder than another day? Since your intake is already taking in cold air anyways..... an aftermarket CAI isn't really doing anything, and a KKM isn't a cold air intake anyways. It is drawing in engine compartment air. Much warmer air than your stock intake can draw in. The KKM can flow more air? Really, how much air do you think a 4.0 ohv needs? Do you think that the stock air box is that much more restrictive than the stock air tube from the MAF to throttle body?

As to the exhaust issue. Do you know how much exhaust is pumped out of a 4.0 OHV at a given RPM? What volume at what speed at normal operating temperature can the exhaust manifold flow? What volume at what speed can a piece of 2.25" exhaust pipe (straight) flow?


I'm sorry, I am not trying to get down on you. But I hate when people go on advertising butt-dyno results as proof. Butt-dynos are the most susceptible to placebo effect, and making your wallet lighter really does throw off the sensitivity of said butt-dyno. I would appreciate if people stop making outrageous statements without dyno results. The opinion of a bunch of people trying to justify to themselves a purchase is no substitute for scientific measurements.

Realistically speaking, you will be lucky to see 5 horsepower with the combination of exhaust/KKM (just going by my experience with tuning engines). There will almost certainly be no change in low end torque. Compared to a 20 year old system, yeah, there will be a big change, but putting on new OEM parts will provide nearly the same amount of change.

If you really want to argue this with me, I will buy the parts and put my explorer on the dyno. It has a new OEM-style exhaust and cat on it right now, so it is a perfect comparison rig. What are you willing to put on the line if I do this though? I ain't spending $500 without a chance at gaining something. Pretty expensive to put my POS truck on a dyno now that I don't have ready access to a dyno anymore and almost $300 worth of next to worthless parts. Anyways, open to anyone, they want to make a bet, I am game.

 

[mr cribb]

Just wanted to make it clear that there is no REAL evidence of "a BIG, NOTICEABLE difference". There is plenty of evidence all over the internet that replacing your coils with a high performance coil gives you a big noticeable difference, but we all know that is a lie too.

As per the cold air intake. When you drive your explorer, is there a BIG NOTICEABLE difference in power when driving in winter vs Summer? How about when driving on a day that is 5 degrees colder than another day? Since your intake is already taking in cold air anyways..... an aftermarket CAI isn't really doing anything, and a KKM isn't a cold air intake anyways. It is drawing in engine compartment air. Much warmer air than your stock intake can draw in. The KKM can flow more air? Really, how much air do you think a 4.0 ohv needs? Do you think that the stock air box is that much more restrictive than the stock air tube from the MAF to throttle body?

As to the exhaust issue. Do you know how much exhaust is pumped out of a 4.0 OHV at a given RPM? What volume at what speed at normal operating temperature can the exhaust manifold flow? What volume at what speed can a piece of 2.25" exhaust pipe (straight) flow?


I'm sorry, I am not trying to get down on you. But I hate when people go on advertising butt-dyno results as proof. Butt-dynos are the most susceptible to placebo effect, and making your wallet lighter really does throw off the sensitivity of said butt-dyno. I would appreciate if people stop making outrageous statements without dyno results. The opinion of a bunch of people trying to justify to themselves a purchase is no substitute for scientific measurements.

Realistically speaking, you will be lucky to see 5 horsepower with the combination of exhaust/KKM (just going by my experience with tuning engines). There will almost certainly be no change in low end torque. Compared to a 20 year old system, yeah, there will be a big change, but putting on new OEM parts will provide nearly the same amount of change.

If you really want to argue this with me, I will buy the parts and put my explorer on the dyno. It has a new OEM-style exhaust and cat on it right now, so it is a perfect comparison rig. What are you willing to put on the line if I do this though? I ain't spending $500 without a chance at gaining something. Pretty expensive to put my POS truck on a dyno now that I don't have ready access to a dyno anymore and almost $300 worth of next to worthless parts. Anyways, open to anyone, they want to make a bet, I am game.

I like the cold air intakes they a special "bling" factor.... I just can't justify spending $300 on something that doesn't provide a "helluva" improvement... To get the most you would have to port heads, add headers, and perform a cam swap, and port the throttle body. All this in addition to the exhaust. All of this combined you might get 15 to 20 hp tops. And that's after you shell out $2k to complete all this. Maybe a little less.

 

[FIND]

I like the cold air intakes they a special "bling" factor.... I just can't justify spending $300 on something that doesn't provide a "helluva" improvement... To get the most you would have to port heads, add headers, and perform a cam swap, and port the throttle body. All this in addition to the exhaust. All of this combined you might get 15 to 20 hp tops. And that's after you shell out $2k to complete all this. Maybe a little less.

I was talking almost 300 for the combination of the KKM and a mandrel bent cat-back with a decent muffler. KKM itself is only around $100 shipped... but for that, you are just getting a MAF adapter and a filter

 

[Anime]

Just wanted to make it clear that there is no REAL evidence of "a BIG, NOTICEABLE difference". There is plenty of evidence all over the internet that replacing your coils with a high performance coil gives you a big noticeable difference, but we all know that is a lie too.

There is evidence. Plenty of it. There are plenty of before/after dyno tests on Explorers and other 4.0L vehicles showing improvements. Some are questionable, sure, but overall even common sense would indicate that making an engine breathe better would produce an improvement.

As per the cold air intake. When you drive your explorer, is there a BIG NOTICEABLE difference in power when driving in winter vs Summer? How about when driving on a day that is 5 degrees colder than another day? Since your intake is already taking in cold air anyways..... an aftermarket CAI isn't really doing anything, and a KKM isn't a cold air intake anyways. It is drawing in engine compartment air. Much warmer air than your stock intake can draw in. The KKM can flow more air? Really, how much air do you think a 4.0 ohv needs? Do you think that the stock air box is that much more restrictive than the stock air tube from the MAF to throttle body?

The difference between winter and summer is rather slight, if there is one. However, there is a drop in power on very hot days, especially in traffic when the intake sucks hot engine air. This effect is for the most part not an issue, since once the vehicle is moving, the hot engine air is vented and is about the same temperature as the air outside the engine compartment. It's not about 'cold air' so much as it is the amount of air. A 4.0L is a pretty big engine, and can suck in more air than the square filter can adequately flow, otherwise a cone filter would do nothing. It's been proven time and time again that the stock Explorer airbox IS a bottleneck, mostly due to it's design being a function of fitting it into the engine comparement rather than for the best possible airflow.

As to the exhaust issue. Do you know how much exhaust is pumped out of a 4.0 OHV at a given RPM? What volume at what speed at normal operating temperature can the exhaust manifold flow? What volume at what speed can a piece of 2.25" exhaust pipe (straight) flow?

Sure, using basic math can tell you that. (Displacement x RPM / 2) The exhaust manifold can flow the entire exhaust volume, of course. Up to a point. 2.25" pipe flows ~457 cfm, regardless of the speed of the vehicle.

I'm sorry, I am not trying to get down on you. But I hate when people go on advertising butt-dyno results as proof. Butt-dynos are the most susceptible to placebo effect, and making your wallet lighter really does throw off the sensitivity of said butt-dyno. I would appreciate if people stop making outrageous statements without dyno results. The opinion of a bunch of people trying to justify to themselves a purchase is no substitute for scientific measurements.

It's okay, all of us enjoying the additional power and torque that come with basic mods like an intake and exhaust are having great fun over those of you who want to stick with your stock system.

Realistically speaking, you will be lucky to see 5 horsepower with the combination of exhaust/KKM (just going by my experience with tuning engines). There will almost certainly be no change in low end torque. Compared to a 20 year old system, yeah, there will be a big change, but putting on new OEM parts will provide nearly the same amount of change.

5 Horsepower? You must be tuning some really poorly maintained engines. There was a jump in horsepower and torque on mine, though I was surprised since I half expected the torque to go down slightly. There might have been a slight decrease in the 500-700 RPM range, or that might just be because the torque above that was increased. It depends on the OEM parts. Putting on a 2" stock exhaust and restrictive muffler would give a pretty negative change. Putting on a 2.25" mandel pipe and good flowing muffler would give an improvement in airflow. This is pretty basic stuff.

If you really want to argue this with me, I will buy the parts and put my explorer on the dyno. It has a new OEM-style exhaust and cat on it right now, so it is a perfect comparison rig. What are you willing to put on the line if I do this though? I ain't spending $500 without a chance at gaining something. Pretty expensive to put my POS truck on a dyno now that I don't have ready access to a dyno anymore and almost $300 worth of next to worthless parts. Anyways, open to anyone, they want to make a bet, I am game.

It depends on the OEM-style system you have. What brand? Walker? ROL? Midas? Mineke? Different configurations flow differently. A lot of aftermarket replacement systems flow more than the stock muffler and pipe. I'm not betting you anything, but I can guarantee that if you had a stock truck with a 2" pipe and 2" muffler choking the exhaust flow, and put on a 2.25" muffler and 2.25" mandrel bent pipe, it'd make a noticeable improvement.

I like the cold air intakes they a special "bling" factor.... I just can't justify spending $300 on something that doesn't provide a "helluva" improvement... To get the most you would have to port heads, add headers, and perform a cam swap, and port the throttle body. All this in addition to the exhaust. All of this combined you might get 15 to 20 hp tops. And that's after you shell out $2k to complete all this. Maybe a little less.

Which cold air intakes are $300? The KKM is under $100. You're right about the heads though, the 4.0L has poor airflow because of their design, so porting them is one of the biggest improvements to airflow, along with the headers. A cam and other stuff is only useful if you want more power and torque at a higher RPM. All combined you can get well over a 20HP improvement, but it winds up being at such a high RPM it's not always a desireable improvement in terms of driveability. I'd say the 4.0L is best improved with minor mods like an intake and cat-back, which give a bump to performance, without getting expensive or going beyond practical or cost effective. But there are people who like these motors enough to go all out and modify them, so it's still interesting to see what can be done.

 

[mr cribb]

I was talking almost 300 for the combination of the KKM and a mandrel bent cat-back with a decent muffler. KKM itself is only around $100 shipped... but for that, you are just getting a MAF adapter and a filter

What is the difference between the kkm for $90 and a $20-30 spectre filter from any of the local parts stores? Now compare it to the drop in k&n filter? Who wins this battle?

I only have a flowmaster cause I got it for $20... I would've preferred a magnaflow but the difference of $40 between what I got and the magnaflow didn't justify the price difference to me.

 

[FIND]

What is the difference between the kkm for $90 and a $20-30 spectre filter from any of the local parts stores? Now compare it to the drop in k&n filter? Who wins this battle?

I only have a flowmaster cause I got it for $20... I would've preferred a magnaflow but the difference of $40 between what I got and the magnaflow didn't justify the price difference to me.

A drop in K&N filter is snake oil. It does precisely nothing. The reason your paper air filter is so large is so that it can accommodate air flow without becoming a restriction. I tested this on a flow bench back in the day, and it isn't that hard a test to set up. I could probably build a ghetto bench if you want to see. Basically though. A Stock air box with no filter, a stock air box with a paper filter and a stock air box with a K&N filter flow more or less exactly the same amount of air. Basically the biggest restriction in a stock air box is the box itself, not the filter element. Like I said, this is why the filter elements are so large. You see those demonstration boxes at the parts store, well, they are really misleading, and that is the purpose of them. Sure the filter element itself can flow much more air than a paper element, but none of that matters when the paper element can already flow as many CFM as the box is designed to flow.

The difference between the KKM and Specter filters..... well, KKM has a higher quality adapter plate (idk if you can even get a correct adapter plate for an explorer MAF from specter BTW) and KKM is using a MUCH higher quality filter. I would trust the KKM filter as a lifetime filter element... the specter one.... well it is no better than a throw away.

Who wins the battle.... well, the KKM marginally. If you are planning some supporting mods, then the KKM's margin increases significantly or if you are setting up for hypermiling the KKM has an advantage as well. The specter in my opinion doesn't have the same advantage because of the low quality parts.

 

[FIND]

Yay, another person who is going to attempt to give me a physics or engineering lesson based on their butt dyno or what they have learned from the internet.

There is evidence. Plenty of it. There are plenty of before/after dyno tests on Explorers and other 4.0L vehicles showing improvements. Some are questionable, sure, but overall even common sense would indicate that making an engine breathe better would produce an improvement.

Links. Common sense may not be as common as you think. Yes, making an engine breathe better can produce an improvement, but usually not as much or not the same improvement as you think, and some things can hurt it.

The difference between winter and summer is rather slight, if there is one. However, there is a drop in power on very hot days, especially in traffic when the intake sucks hot engine air. This effect is for the most part not an issue, since once the vehicle is moving, the hot engine air is vented and is about the same temperature as the air outside the engine compartment. It's not about 'cold air' so much as it is the amount of air. A 4.0L is a pretty big engine, and can suck in more air than the square filter can adequately flow, otherwise a cone filter would do nothing. It's been proven time and time again that the stock Explorer airbox IS a bottleneck, mostly due to it's design being a function of fitting it into the engine comparement rather than for the best possible airflow.

That little square filter can easily flow 450 cfm. Besides, even if that box could only flow 300 cfm, making it flow more won't make any difference in power until the engine needs more than 300 cfm, which is going to be at higher RPMs and therefore not make much if any difference at lower RPMs. As long as you aren't flowing so little air you create pumping inefficiencies you are golden. Plus, as I have said before, that intake pipe between the MAF and the intake manifold is a pretty big restriction that negates a lot of what you would gain from a free flowing air filter setup. Here is a hint by the way, the engine needs exponentially more air flow as the RPMs rise, so increases in air flow do less and less as the engine demands more air flow.

Sure, using basic math can tell you that. (Displacement x RPM / 2) The exhaust manifold can flow the entire exhaust volume, of course. Up to a point. 2.25" pipe flows ~457 cfm, regardless of the speed of the vehicle.

I was talking what volume of exhaust at what speed of the exhaust.... When you are determining exhaust flow, you are not just looking for cubic feet per minute, you are looking at the velocity of the exhaust charge as it relates to the scavenging effect of the exhaust. Where do you think the backpressure myth came from? People don't take into account the velocity of the exhaust.

Now anyways, since that is not an exact formula anyways as it does not take into consideration pumping efficiency or volumetric efficiency of the engine, I don't know why you bother with it.

Now, continuing, you are also not taking into account thermal expansion or the increased laminar flow area as the exhaust system curves. This is why I said that the optimal size for exhaust piping on an explorer is somewhat between 2.25" and 2.5", for an exhaust system matched with a good set of headers. By the way, 2" pipe can flow ~457 cfm as well, the exhaust just has to be moving at a higher velocity. You tune your exhaust system based on the average exhaust velocity you see existing your ports and headers to maximize scavenging at whatever volume of exhaust you are flowing at the specific RPM you want to operate at. This isn't just a bigger is better sport. This isn't even a one size fits all sport.

Still, you forget, you must also overcome the flow (volume and velocity) limitations of the stock manifold. Going larger on the pipe after the manifold can hurt you quicker than you think.

It's okay, all of us enjoying the additional power and torque that come with basic mods like an intake and exhaust are having great fun over those of you who want to stick with your stock system.

How bout some proof. Don't get me wrong, I plan on doing some of those basic mods and a few other breathing mods... but only in the interest of fuel economy. Therefore I am perfectly happy tuning for cruising RPMs instead of putting on exhaust that will give me a minor improvement at WOT.

5 Horsepower? You must be tuning some really poorly maintained engines. There was a jump in horsepower and torque on mine, though I was surprised since I half expected the torque to go down slightly. There might have been a slight decrease in the 500-700 RPM range, or that might just be because the torque above that was increased. It depends on the OEM parts. Putting on a 2" stock exhaust and restrictive muffler would give a pretty negative change. Putting on a 2.25" mandel pipe and good flowing muffler would give an improvement in airflow. This is pretty basic stuff.

You obviously don't know what you are talking about now.... You think that more than a 3% improvement in horsepower is nothing? You think something as simple as an air filter and a muffler is going to give you much more than that? Hell, you are lucky to see that large of a percentage improvement on larger engines when you are adding headers and full intake/exhaust mods. Why don't you tell me about your experience with tuning engines? Pretty basic stuff huh? Maybe you should try and spend some time around a dyno or tuning cars before you tell me about basic stuff. I've been doing it for more than a decade.

It depends on the OEM-style system you have. What brand? Walker? ROL? Midas? Mineke? Different configurations flow differently. A lot of aftermarket replacement systems flow more than the stock muffler and pipe. I'm not betting you anything, but I can guarantee that if you had a stock truck with a 2" pipe and 2" muffler choking the exhaust flow, and put on a 2.25" muffler and 2.25" mandrel bent pipe, it'd make a noticeable improvement.

Goerlich oem replacement style muffler on pipe bent according to OEM specifications... If you don't want to put up, then shut up. Besides, if you are so certain you are right, then you obviously have nothing to lose....

Which cold air intakes are $300? The KKM is under $100. You're right about the heads though, the 4.0L has poor airflow because of their design, so porting them is one of the biggest improvements to airflow, along with the headers. A cam and other stuff is only useful if you want more power and torque at a higher RPM. All combined you can get well over a 20HP improvement, but it winds up being at such a high RPM it's not always a desireable improvement in terms of driveability. I'd say the 4.0L is best improved with minor mods like an intake and cat-back, which give a bump to performance, without getting expensive or going beyond practical or cost effective. But there are people who like these motors enough to go all out and modify them, so it's still interesting to see what can be done.

He was confused by my original post. He misunderstood me when I said the $300, he didn't understand that that included the price of doing catback system with mandrel bends.

 

[Anime]

Still, you forget, you must also overcome the flow (volume and velocity) limitations of the stock manifold. Going larger on the pipe after the manifold can hurt you quicker than you think.

Hence why I suggested 2.25" over 2.5" tubing.

How bout some proof. Don't get me wrong, I plan on doing some of those basic mods and a few other breathing mods... but only in the interest of fuel economy. Therefore I am perfectly happy tuning for cruising RPMs instead of putting on exhaust that will give me a minor improvement at WOT.

All the proof you need can be had by doing it for yourself. The KKM/Dynomax Super Turbo setup I mentioned IS tuned for crusing RPMs with the 4.0L OHV, hence why I'm using it, hence why I recommend it. Glad to see you actually agree with me despite your argument premise.

Why don't you tell me about your experience with tuning engines? Pretty basic stuff huh? Maybe you should try and spend some time around a dyno or tuning cars before you tell me about basic stuff. I've been doing it for more than a decade.

You must not be doing it too well if you have to start arguments over such basic stuff on the internet. My experience with tuning engines would take a looooong time to type out. But I've been tuning engines longer, if that matters.

Goerlich oem replacement style muffler on pipe bent according to OEM specifications... If you don't want to put up, then shut up. Besides, if you are so certain you are right, then you obviously have nothing to lose....

Sounds pretty bad. Hopefully you'll get some good gains or whatever you need to convince you when you replace your stockish OEM spec system.

Yay, another person who is going to attempt to give me a physics or engineering lesson based on their butt dyno or what they have learned from the internet.

Nope, just a person who thought it would be fun to feed a forum troll for a while. Have fun!

 

[FIND]

All the proof you need can be had by doing it for yourself. The KKM/Dynomax Super Turbo setup I mentioned IS tuned for crusing RPMs with the 4.0L OHV, hence why I'm using it, hence why I recommend it. Glad to see you actually agree with me despite your argument premise.

ok, then how about some proof of the gains. I know there are some slight gains to be had under some conditions. The point I had been trying to make is that they are small.

You must not be doing it too well if you have to start arguments over such basic stuff on the internet. My experience with tuning engines would take a looooong time to type out. But I've been tuning engines longer, if that matters.

right.... This is why you use the specially calibrated butt-dyno to verify your gains and believe 5 hp on an engine that makes 155 hp stock at the crank is far to little to be what you are actually gaining from bolting on a muffler and an air filter.

Obviously I was only talking about professional experience, I guess if you want to count time I have spent in my backyard, we could make a much longer list.

Sounds pretty bad. Hopefully you'll get some good gains or whatever you need to convince you when you replace your stockish OEM spec system.

I get 22 mpg on an entirely stock system in a 4wd 1st gen explorer. The exhaust will not be replaced. I may change the intake, optimize the throttle body or do some port matching.... but yeah.... I see no reason to change the exhaust. There is not an appreciable amount of back pressure when metering it, and the cost of changing to anything else would take far too long to justify based upon the miniscule gains. There is just not enough to gain in the exhaust without major changes.

Nope, just a person who thought it would be fun to feed a forum troll for a while. Have fun!

So you come into a thread making wild claims without using even a semblance of factual evidence.... right

You come in here with a claim of "significant, noticeable gains" but have nothing to offer to support that.... Especially talking about a company that makes cheap, junk flow-through mufflers.

I never said there would be NO improvement, I have always said it would only be a SMALL improvement.

 

[mr cribb]

Wow let's all argue who knows more about tuning and performance parts on a gen 1 explorer.....Truthfully I wanted a deeper tone to listen to as I run through the gears. So if one person KNOWS more by expirience or just "knows more" by reading from the net is really none of my concern.... I asked for an opinion and got it, thanks for all your answers.

 

[FirstExplorer]

These mods:
KKN CAI
Magnaflow Hi-Flo Cat
Magnaflow Cat-Back Exhaust
Throttle body flush

+13% gas mileage

The rest of the improvements are all perceived in terms of better throttle response, lighter weight on throttle, nice low growl, quicker off the line, etc., so now lay into me for the kiss my butt-dyno crap.

 

[FIND]

These mods:
KKN CAI
Magnaflow Hi-Flo Cat
Magnaflow Cat-Back Exhaust
Throttle body flush

+13% gas mileage

The rest of the improvements are all perceived in terms of better throttle response, lighter weight on throttle, nice low growl, quicker off the line, etc., so now lay into me for the kiss my butt-dyno crap.

I never said there would be no improvement. Also, you are comparing these to old WORN OUT parts, AND I thought you had gotten your injectors flushed as well or did something with your ignition.... Kinda hard to make a comparison and attribute it to one thing or another when you do so many things at a time or when you don't have a solid baseline for comparison.

Anyways... doesn't matter. Because I am tired of having to argue this senseless issue, I ordered a KKM intake kit, and I will do some road testing and a dyno pull if I get time. I will get around to testing the exhaust separately if I can find a dynomax system anywhere..... they seem to be... non-existent.... Well, I can always have someone do a mandrel bent pipe based on the measurements from the OEM exhaust, just like dynomax did. Waste of money, but meh, I'm tired of people arguing with me because their wallet tells them they are faster. I won't install anything until I finish my fuel economy computer, that way I can actively track everything.

Now, just for accuracy's sake. I am going to mention how unreliable road-testing is... I can get a 20% improvement in fuel economy just by changing driving styles.... So, no matter what numbers I get or you get... don't rely on them as the gospel for accuracy.

Also, I just want to do some math for you real quick.

Let's say your explorer gets 18mpg before the change and 20mpg after
That means before, you would burn 667 gallons of gas a year if you drive 12000 miles a year like an average american. After you burn 600... This means a yearly savings of about $200. That means, you pay for that catalytic converter in about 16 months if you bought the direct fit unit and installed it yourself... which it doesn't appear you did from your first post.... so I am going to assume it cost you more than the 260 you can get it from summitracing for. Now your exhaust... well, I have no idea what you did with your exhaust, you just say magnaflow cat-back... so I am going to assume an exhaust shop bent up some pipe for you and slapped on a magnaflow muffler.... $400 is a pretty fair estimate then, so another 2 years to pay that off. 6 months to pay off the KKM, and who knows what you spent on the "flush", but we will just pick an easy number $100, so another 6 months.... that means, the cumulative total for those parts was, according to you a 13% increase in fuel economy... Therefore, all those parts together will pay for themselves in a minimum of 5 years. Of course, since all gains are cumulative, one could not expect to see any of these parts offer the same "gain" by themselves, therefore, by themselves, they would take longer to pay for themselves....

Anyways, I guess that takes me back to my original point. They don't do a lot for the money, but you did replace old parts with new ones that will last for years. Your biggest gain here is a nice sounding system, so enjoy that for what it is. In 5 or more years, well.... if you still have the truck, then you can start enjoying the money you are saving.

 

[itslpjunior]

bat cat converter = loss of horsepower new cat vs old = hp gain and noticeable difference. I have a 2002 impala the cats went i couldnt even get it up to 55 on the highway it was so bad. thats what u feel..durka durka jihad jihad