My exhaust system could use replacing. I does not need replacing. What I have to replace is my manifold. I'm trying to figure out wheather I should put on shorty headers, or go to a more standard style and replace the the home system (except for the cat converter).

Its a work truck that'll never see wicked lifts, big tires and a chrome underbelly.

I'm thinking of getting the plain coating of paint/nothing. I can't see spending $150 on headers that people will not see.

Should I go with dual exhaust and dual cat converters?

What do you think?

 

Don't waste your money on shorty headers. They aren't worth the box they arrive in. Pick up a set of long tubes. The painted variety work well, but I'd recommend stripping the paint from the factory and replacing with a suitable VHT coverage. This will prevent rust deterioration.

Discard your stock Y-pipe and catalytic converters for a Y-pipe and single in single out exhaust and a suitable aftermarket hi flow cat ($50-75). The scavenging effect of a single exhaust would benefit your setup. Not to mention, would be a lot cheaper than running a true dual setup. Which is difficult, with a 4wd transfer case on our trucks.

If you talk to an exhaust shop prior to starting the swap, they should bend you up a Y-pipe for rather cheap. Also, they should have no problem welding in the bungs for the o2 sensor and egr input if you don't have access to a MIG welder.

Your motor will breathe much easier, and low end power will improve tremendously. Do it right the first time, and the system will last longer than the truck.

Just my opinion,
Mike

 

If your manifolds need replacing then either get new manifolds and bolt them up to the existing exhaust system or get long tubes and re-do the whole exhaust system. Shortys don't last as long as manifolds nor do they offer any gains over manifolds + they bring along hassle where as manifolds don't...so not woth it. Long tubes on the other hand bring alot of hassle, but they also bring some performance gains. The hassle involved is massive clutter and the rig then becomes more difficult to work on due to the amount of space they take up compared to the manifold + y-pipe set up. To some if not most people the gains are worth the hassle, it's up to the user to decide. Plus, manifolds outlast just about ANY header + they are more reliable (virtually leak proof if properly installed and the engine is running right)...another thing to think about. Lastly, from what I have seen for myself at the dyno + what engineers have told me (I am not an engineer myself), the vast majority of gain that headers bring take place at and above 4000 rpm...how much time do you spend up there?

As far as nobody seeing the headers and thus they don't need to look nice, it's not about looks. The more spendy versions are such because they will last longer, are more well built, have thicker flanges, higher grade of metals used, more precision manufatured and they are rust-through proof (the stainless ones anyways). The cheaper headers fall short in the above areas as compared to the $300 or so and up units.

 

Umm... you might want to do some of your own research. One of the best low end performance modifications you can do to a small block ford is long tube headers. This has been beat to death in 5.0 power, Mustang50Power and many other magazines.... with dyno tests to boot. Play with any popular dyno simulation with a Ford smallblock on stock manifolds vs. long tube headers. Overlay the two charts, and notice the gains below 3000 rpms.

Yes, the number (total quantity gained) is higher above 4000 rpm, but the percentage gains sub 2500 rpm far outweigh that above 4000. That is, the gains at 2500 rpm are proportionally larger than the gains at the top of the powerband. For example (I will keep the numbers simple for my feeble brain), if your motor makes 100 hp at 2000 rpms and 300 at 5000 stock... with headers an increase to 112 hp at 2000 rpms, and 320 at 5000 rpms. The top end had the greatest quantitative gain at an increase of 20 hp. However, your power increased 12% at 2000 rpms, where your top end power improved only 6.7% over the previous setup.

The performance gain is measured in proportion to the previous system, not just raw gains.

Contrary to what your engineers told you, one of the best LOW END torque gains for a smallblock is a long tube header system with a free flowing exhaust.

 

I have to agree with Mike here. I have a Dyno program on my computer and I plugged in all the values for a stock 5.8L, then switched out manifolds for longtubes and there were DEFINITE gains in the low range. I can get a screenshot of the dyno sheets if you want, the program maker claims accuracy within 5%.

 

First off.......headers...whether they be shorties or longtubes...are alot more efficient and lighter than stock manifolds......if you have the need to replace the manifolds anyways...why not make the truck breathe easier and give you a little more power to boot...probably give better mileage as well......I agree with Mr M. and Skandocious here.....wish I had a Dyno simulator.....where can I find one?

 

The name of the program I use is Dyno2000, although I think mine is a bit out of date, not that it matters for our trucks because our trucks are 10+ years old. Here's some snapshots of the dyno results I get from the simulation program:

STOCK:


Swap manifolds for LONGTUBES:


Now I know that these aren't 100% accurate because there are a lot of fields in this program that I didn't have the exact numbers from my truck to input, so I used my best judgment. The stock diagram shows about 200hp which is just around where my truck puts out so I consider it to be pretty darned accurate.

ON EDIT: Notice that even at 2500rpm we have increased from 150hp to 175hp. Even more so, look at 3000rpms, we've gone from 175hp to 220hp. Yeah there are very considerable gains above 4000rpm but there are considerable gains below it too...

 

The torque gain at 2000 rpm with long tubes is damn sexy! From 310 to 365... and who said long tubes are only applicable to 4000 rpms'?? Keep that engineer away from any of my builds.

Tq- How much work gets done.
Hp- How quickly the work gets done.

 

If you want to go toe to toe with me on this, you had better quote me correctly and never again take my words out of context. I said, exactly, that "the vast majority of gain that headers bring takes place at and above 4000 rpm...how much time do you spend up there?" This means that gains are present throughout the powerband, but more pronounced above 4000 rpm and in no way does this mean that "long tubes are only applicable to 4000 rpms". On just about every before and after header to manifold dyno test I have been to, the gains were marginal below 4000 rpm and above 4000 rpm the gains were more noteworthy. The vehicles tested were GM, Ford and Chrysler, small and big block V8s some stock and some modified. The headers were made by Stainless Works and primary tube diameter ranged from 1 5/8 to 2 inches. The higher the powerband of the motor the greater the diameter so that the header used and motor used had as good of a match as possible.

Standing feet from the dyno, a real dyno no less, and watching the screen is much more reliable way to research than magazines and dyno simulations. Again, yes I know there are gains below 3000 rpm. I have seen it for myself on the flywheel and the rear wheels and at the tests that I witnessed it was nothing to get excited about but like I said "To some if not most people the gains are worth the hassle, it's up to the user to decide."

 

First off... calm down tiger. Secondly, I quoted you verbatim. Thirdly, numbers and their application towards the real world can be skewed by who and what is reading them. This is known as statistics.

"Marginal" is a relative term. This word has absolutely no quantitative and/or qualitative measure behind it. Again, your idea of marginal... 10-15 tq at low rpm versus 20-40 tq at max output is completely subjective. These gains may be marginal for someone turning 40" tires and running a 3000 rpm stall converter... but not the everyday guy running a stock 5.0 with a 1/2 ton frame.

When used in the context of improvement over a known stock regime, these "marginal" gains (as you call them) are quite vast in the world of bolt on performance. Especially in terms of moving a 5000# plus pickup.

This is a summation of results. Your analysis of this gain is elementary here. In terms of proportional gain, this is nominal in comparison to low rpm.

Let me reiterate, I do understand that the overall numbers (i.e. peak tq and hp output) have a larger distance on the number scale than the before dyno above 4000 rpm. This does not translate to a "better gain." Or conversely, to a "marginal" gain at lower rpm's.


The magazine setups use a fixed motor, with a known output. The only variable that is changed is the exhaust manifolds. These are repeated experiments. I think that would be quite unfair of you to imply that these repeated experiments are incorrect or based in deceit.


A 10-15 gain in tq/hp below 2500 rpms is a big deal for a 5.0 in my book. Also, this kind of gain is highly productive for a pickup truck in comparison to a 30+ tq/hp gain at 5000 rpm.

You shunned away the idea of longtubes as "potentially" not worth the effort for someone already forced to replace cracked manifolds and/or exhaust. Not only that, you implied that they were a poor low end performance bread winner. And mainly applicable to 4000+ rpm adventures.

Having ran headers before and after on various pick up rigs. Also, having installed various other modifications (from cams, to aluminum heads, to mild blowers) ..... by far, without a doubt, the BEST low end torque and grunt modification you can do to a smallblock pickup, is long tube headers and free flowing exhaust. Period.

I'm not going to post anymore regarding this. Far more qualified builders than you or I have researched, dyno'ed and reported these results in various rigs from camaros, to falcons, to full size broncos.

If you continue to take this as a personal assault, I apologize. Not at all was that my intent. Feel free to PM me and I would be happy to start our own dialogue.

This discussion is not worthy of the forums.

I apologize to the OP for straying from his topic.

Good Luck,
Mike

 

Go with the long tube headers.
They are worth the buy to get away from cheep replacements for the 5.0's and the 5.8's

IF you HAVE to absoultely stay with the setup you have. I've heard countless people say to go get the headers out of the 5.8' and install them on the 5.0, they bolt right up, and they are a bit stronger, so you will not get that nasty crack on the passenger side bank, like the cheep 5.0 cast ones get.

There are probably some nice cheep flowing headers you can get out there which are already coated for you, and will bolt in, with some exhaust work.
5.0 is pretty popular engine, its in lots of vehicles. There will be all sorts of options for you in the long tube market.

 

The ideas and thoughts that make up the text contained within the above quote are wrong and asinine in new and amazing ways which I can not fully articulate.

 

OK.. you guys are being petty now... knock it off.

FWIW.. a motor with long runner EFI induction such as what our trucks use and a carburated motor produce very different TQ curves. A carb'd motor won't see as much of the low rpm TQ gains an EFI motor will with long tube headers because fuel atomization is so poor at lower rpm, and particularly under typical dyno conditions(WOT). This may or may not explain some of ECO's observations, if not no harm intended, I'm just throwing it out there. Also consider that the powerband of these truck motors is under 4500rpm for the most part, so you want to boost everything from idle up if possible. Longtubes accomplish that in spades, it's easily the second best thing you can do to these motors for typical truck usage, following a cam upgrade. The only reason I rate it second is because it'll cost more due to the additional exhaust work needed.

 

Thanks Paul. =)

 

Aww all right... but I was truly enjoying myself prior to getting spanked by you Paul.



As always, your logic is impeccable.

Cheers,
Mike