True Dual Exhaust

[WA9YSD]

Has any one put on a True Dual Exhaust system on your vehicle?

I have been tossed back and forth from people who knows about these systems but has not had one them self's.  Please straighten me out.

What do you like about them and what don't you like about them?

What are the advantages and disadvantages?

How long have you had them?

 

[Shayne]

Single exhaust can accomplish the same thing as dual.  It's basic principal is the same as 40, 50, and 50 model cars with dual exhast, less restrictions.  Same thing as providing a larger exhaust found on other units encluding those with Banks Pak.

 

[WA9YSD]

I have a 1995 Dodge Dakota V8 318.  It has fuel injection to each cylinder.  I replaced factory air filter with K&N filter for the stock Dodge air cleaner.  I replaced original plugs with Split Fires.

I never owned a truck before.  This is my first upright trailer I towed.  I had old trailer at a permanent camp ground and fixed everything on it but never towed it.  This truck should have snot in it like the ones in the old days.  I cannot afford a new one, but have money to put in this one.  What the biggest bang for the buck.

The next thing to do is change out the exhaust.  I am thinking dual exhausts with an H connection, maybe 2 1/2 inch pipes.  What happens with low-end and High-end torque?  I am looking at a FlowMaster system.

Why a have a good single pipe system as appose to a good true dual?

Will a larger Air filter and scoop improve things too?

I need to put in lower temp themostat that has larger water flow.

Fuel injectors will be cleaned individually.

Rotor cap and rotor will be replaced.

 

[WA9YSD]

For got some things.  Age here is 53.  I had the truck for 5 years now, it has 4 wheel drive, and have been towing my 16 foot 2000 lbs Shadow Cruiser for 3 years.  The trailer is not over sized for the truck.

I have towed popups with various cars and had not experienced such wind loads like this up-right Shadow Cruiser.  This is a totally new experience for me.

 

[John From Detroit]

I have to agree with Shayne, the advantage of dual exhaust is less back pressure and better exhaust flow, this does indeed net more Get up and Go, in every aspect (HP and Torque) though I'm not sure you could measure the latter one.

Now, pipes have a diameter squared factor, that is cross sectional area is related to the SQUARE of the radius (which is 2x the diamater) and thus the square of the diameter,  Replacing a 2 inch pipe with 2 2inch pipes gives exactly twice the same flow

Replacing a 2 inch pipe with a 4 inch pipe gives 4 times the flow (or more due to some stuff I won't go into)

however because you have all 8 cylinders feeding one pipe, there are still more factors in play which may offset that (My training does not go that far, I can see things that might happen, but don't have the training to explain or predict)

Of course... There is nothing quite like the purr of a well tuned, powerful engine, feeding dual exhausts,,  That is one sweet sound and in my opinion,  worth the expense all by itself.

There is also something to be said for redundancy

 

[Gary RV_Wizard]

The next big thing is exhaust, but you need a complete system from the headers to the tips.  Just changing the pipes won't do much except lighten your wallet (in my opinion).  Try Banks or Thorley, Gibson, etc. to see if anybody has a full kit for your 318. A Google search for exhaust headers should turn something up.  I just checked Gibson and they make both headers and exhaust systems for a 1995 318.

 

[John From Detroit]

Quick question:

I've priced Banks for my 8.1L gasser (2005 workhorse)

just wondering if there is a lower cost alternative

With the price of gas what it was this summer, Banks was getting close to break even.  But if there is a lower cost alternative, it might actually be cheaper than leaving it stock,  I don't need more HP (At least so far) but more MPG even 1 mpg would be significant.

 

[King]

The only time back pressure comes into play is wide open throttle and high rpm.  Under normal driving conditions the exhaust volume is small.  That said, with only a 318, you may be in that condition fairly often.  The experts (those who try to sell you the hardware) usually recommend a revised cam in order to take advantage of a header exhaust system.  I expect that if you spend the money, you will probably be disappointed in the results.
Art

 

[Karl]

Some of you may remember the 'scavenger' pipes that were very popular on 50's-early 60's cars; those long [pipes with the funnel shaped tips on the ends?? They actually did help increase power by creating a low pressure area around the outside of the pipe which scavenged the exhaust and sucked in a larger charge of air/fuel. This was way back before computers. Today we have tuned exhausts that work with all manner of ambient conditions to get the most power from the least amount of gas. Simply increasing the size of the pipe(s) is, in most cases, counter-productive, and may give you a gain within a very limited rpm range, but overall will be detrimental to economy and power. As John eluded to and Gary expanded upon, Back-pressure, resonance at specific rpm's, etc. must all be taken into consideration, along with computer mapping of the engine management system. Sorry, but gone are the days of backyard performance increases UNLESS you can specifically identify something that is improperly designed, sized, or otherwise not up to snuff. In my case it, was easy to see that the factory exhaust was necked down when crossing over the driveshaft, so an after-market (Walker) exhaust system (emphasis on system) gave me significant performance gains while maintaining or slightly increasing fuel economy.

 

[Shayne]

Don't be buying an exhaust system expecting great mileage benefits.  2 identical Pace Arrows  (Ours and a Friend of ours) match each other in all but 2 factors  Ours has a satellite dish and a Banks Pak since it's inception the other does not.  I out pull, out run, pull more weight, and get 6.5 mpg while our friend gets 5.9 mpg.  It's not much but you have to do a lot of traveling to make up the difference and benefit for mileage only, due to the cost of the Banks Pak. However with that said, I love the way it performs compared to the stock unit. Glad I have it, both are 460 Ford with about the same mileage.  We have traveled together and checked  trip in and trip out month in and month out to accumulate our results.  I pull a 24ft enclosed trailer with a Lincoln Town car inside and he a wheel down Geo Tracker.  So with that I probably get better than 1 mpg better than he.  both are 37 ft units.  Now the cost factor is about $4500 installed from what I'm told for factory installation before the shell in installed.  Can't vouch for that cause both of these units where purchased used, The only way I buy.  but as I say  I love it.  Not sure how much it would benefit a small unit.  Good luck in what ever you decide.

 

[motojavaphil]

A header system with dual exhausts would be cool and if you complimented it with a good air intake system you might see some improvement with a 318.  The cat tends to be a problem as it restricts airflow but can be replaced with a larger cat.  We are talking money here tho. Phil

 

[Gary RV_Wizard]

just wondering if there is a lower cost alternative

John,
Banks is the best known and therefore probably the highest priced, but you can probably put together a modestly less expensive system using Gibson or Thorley parts.  But I doubt if you will see much fuel economy increase on a late model 8.1L Workhorse.    They are already pretty well set up as far as mpg is concerned and the engine computer manages it closely. I would be surprised if you see more than a tenth or two improvement in mpg and that only if you spend a lot of time in the high power range. For typical driving it will likely be zero change.

 

[WA9YSD]

Dumb question will all this cause excessive ware and tear on the engine?  Or no difference?

Thanks for all the responces.  Really full of in-site and putting it all in perspective.

Dual CATs and Dual Mufflers after the crossover H, sounds like a bit of an over kill, but I read that I would gain maybe 5 HP as apposed to an after market single CAT and MUFFLER.  As long as this whole thing comes under 2k with installation I will be happy, I think.

I just might do a little more and put in a bigger air filter system and air ram.

It is sure nice to have people helping who knows about this stuff.  You guys have made me a believer.

 

[BernieD]

Don't be buying an exhaust system expecting great mileage benefits.  2 identical Pace Arrows  (Ours and a Friend of ours) match each other in all but 2 factors  Ours has a satellite dish and a Banks Pak since it's inception the other does not.  I out pull, out run, pull more weight, and get 6.5 mpg while our friend gets 5.9 mpg.

OK Shayne, now that we know how much the satellite dish does for you, what benefits do you get from the Banks ;D ??? ;D ???

 

[John From Detroit]

John,
Banks is the best known and therefore probably the highest priced, but you can probably put together a modestly less expensive system using Gibson or Thorley parts.  But I doubt if you will see much fuel economy increase on a late model 8.1L Workhorse.    They are already pretty well set up as far as mpg is concerned and the engine computer manages it closely. I would be surprised if you see more than a tenth or two improvement in mpg and that only if you spend a lot of time in the high power range. For typical driving it will likely be zero change.

Thanks, Well, Workhorse, for 2006, put on a "Banks knockoff" system,  basically it's a custom made equivalent to the Banks header, intake and exhaust, with a re-program of the computer chip.  They say it gives better millage and 15 or 20 more HP.

The question is this: Will I recover the cost of the mod in fuel savings over the time I own the ride?

And at current gas prices the answer is likely not.  At 4.00/gallon,,, perhaps, at 5.00/gallon (heaven forbid) yes

 

[Karl]

Assuming you pay $2.50/gal for gas and get 6 miles/gal, that's $.4166/per mile. If you were to get 8 mpg by installing a new exhaust system, the cost would drop to $.3125/mile. That's a net change of $.104 per mile. To recover the cost of the system (about $2400 parts, $1500 installation - total $3900 for a Banks) you would have to travel 37,500 miles. Even Banks says the increase in fuel economy is just 15%; not the 25% I used in these calculations, so that comes out to a net savings of only $.0543/mile. You wouldn't hit break-even until you put on 71,823 miles! For the 8.1liter engine, they don't even mention mileage increase numbers; just say "with better fuel economy" - whatever that means. Yes, they do say an increase of 17% on an 7% uphill grade or 8% on flat roads, but that's still below the 25% I used and you also have to ask yourself "How much time do I actually spend driving up 7% grades?". Probably not much - it may just seem forever. ;D

 

[Shayne]

LOL  I don't even use the Satellite Dish  I do without  TV most of the time, when in the MH ,. doesn't bother me in the least.

 

[John From Detroit]

Thanks for doing the math Karl.... Looks like payback is a bit more possible than I thought,  I do plan on keeping this for quite a few thousand miles, I mean my towed is well over 200,000 and counting just now and I see not reaosn other than the cost of gas that the MH won't go at least that far.

That said, it's still iffy at today's gas prices. and other factors will have to be considered so I'm still going to pass on Banks.

If someone comes up with a decent system that is lower in cost... I may re-consider, but I plan on taking a couple of years thinking about it myself (Warranty period)

 

[Jeff]

Karl:

On that basis I should go look for a 275HP Cummins that gets 10-11 MPG.  ;D

Our Banks powered Pace Arrow never got better mileage, I always had my foot in it! It just accelerated into traffic and climbed hills better!

 

[Karl]

Jeff,

IMHO, that's the main reason for upgrading. Mileage increase was minimal, but the $400 (plus a few hours of my labor) meant a big difference in hill-climbing performance. I did get the Banks TransCommand however, and that really tightened up the shifting. To me that means less transmission wear and longer life.

John,

Your (hopefully) doom and gloom $5/gal gasoline would cut the payback time in half. I just hope we never have reason to prove or disprove my math! ;D