I just aquired a 2003 F-250 supercab 4x4 with the V10 and an auto trans, and it seems like the motor sounds like a 6cyl under acceleration.Is this due to back pressure in the exhaust?
To me it sounds like this motor needs to be opened up (larger exhaust system) so it can breathe.
If you do open it up with larger exhaust is there a down side?
Or is there a reason for the back pressure?
Any and all replies will be greatly appreciated. Thank you

 

Thread moved to V10 Engine forum.

-Matt

 

the V10 will greatly apreciate the open exhaust!! i'd stay with the 3" set up, that way you don't lose much low end. i've installed BANKS headers, and Y pipe, w/ the CAT deleted lets say, and a FM original 40 series. i didn't lose much bottom end at all. my power band starts at around 1300 up to 3300 for torque.

remember the V10 produces 80% of its torque at 1000 rpm's so you woun't be disapointedby freeing up alittle back preasure!

check out the mod page of my web site ( MY V10 MODS ), and the sound clips in my signiture.

 

Depending on the mileage, you might want to check if the catalytic converter is clogging up.

The V10 has a unique sound all it's own, and changing the exhaust can make it WORSE.

My question: Does it ACCELERATE like a 6 cylinder?

If not, leave it alone ...

 

check out the SOUND CLIP page of my web and you can hear different V10 exhaust set ups besides mine! i think you can get them sounding REAL good! even if you decide to keep a CAT on there!

check 'em out and hopefuly it will help your desicion!

 

I18257

You seem to be describing a typical V10 motor and how they all sound... this motor fires sequentially every 72 degrees and when spun up, sounds like a v6 on steroids

your 2003 version is a 2 valve V10 and has a few restrictions in the beginning of the exhaust system that are not optimal. The cast headers are not designed for max flow and the funky two to one "T" before the catalytic converter is a travesty of engineering.

That all said, the stock motor does a damned good job of producing enough HP and torque for normal light to medium duty tow and haul. Some folks need a little extra grunt to tow very heavy or in the tall mountain passes. They usually have good results with just a better engineered two to one collector ("Y"pipe) and leave the rest stock. If they spend a lot of time towing heavy they can usually justify the high cost of a full Gale Banks system from the headers to the tail pipe. However for the typical infrequent towing use, in other words a truck that does 80% people hauling, the cost to benefit ratio is very poor.

Of course you did not really ask that...you were simply curious about the V6ish sound and thought to your self maybe there is a LOT of restriction in the system... there really is not.

EDITTED BY KREWAT - removed reply to TeamMudd, rest of post was very useful.

 

DOH!

I've put out that "80% of peak torque at 1000RPM" myself a few times. From a 2002 brochure, showing the "supposed" torque curve, it does put out 80% at 1000RPM.

But we all know the difference between real-world (Fred's experience) and fantasy (mine).

Oh, and by the way:

One of the unwritten rules I try to enforce here in V10-land is the idea that deleting the catalytic converter is not OK.

It's NOT! If you ever get pulled by DOT, or even just a state trooper, or the doughnut-munching sheriff on the rural roadside, you WILL suffer the consequences. It's not enough to get an inspection sticker and be happy.

State troopers are being trained these days to inspect the ricers for "off-road only" mods. I can imagine if they want to be a PITA, they'll check your truck too.

 

I could not agree more - there is absolutly no reason to remove the Cat on any on road engine. Off road, yes you might start a fire.

People who think Cats are so restictive need some re-education as they are misguided.

I am curuious though, if the engine is a torque monster, and does not need to be reved up to produce the torque needed for towing, how is opening up the exhaust going to help low end power? I mean the enigne is not turning any where near the RPM's that dictate higher flow and thus in need of less restriction?

Am I missing something here?

David

 

Thread sliced-and-diced.

Play nice in the sandbox.

 

Or you can live in a county with no emmisions, so Mr.Statie can't say squat about your truck. -myers

 

I'm no expert, but in the past when I've done research into this, I believe I found it's illegal to remove emissions devices if they came stock from the factory. Since they don't make "no cat" SD's (I could be wrong!) for the US, I can't see why a state trooper, DOT, or whatever other state or federal transporation authority can't ticket you for taking it off.

I'm not saying I've ever had the problem, around here on Long Island, they almost never do a visual inspection. Now, they just plug into the OBD-II port and if the PCM says something is out of whack (or the engine light is on), it won't pass emissions. They don't even test it anymore. Which means I can remove the cat on my '01 without a problem, it doesn't have a third O2 sensor and doesn't have the diagnostics to test the cat.

Will I do it? Heck no... I don't need the heartache... I travel some interesting roads, with the potential for a pocket Napoleon around every corner - and I don't mean Upstate NY or any other rural area... I mean Long Island

I see no reason NOT to put an aftermarket higher-flowing cat on it though

 

David, When you're towing down the highway and hit a big hill you won't stay at low rpms. The tranny will down shift to get into a higher rpm range where horsepower is being made. This is where headers/exhaust/intake really shine.

As one who had a "test pipe" in place of a cat I can say there were no gains to be had on my 1999 V10. Just lots of noise! The Superduty cat is monolyth in design (think 18" thick window screen) and has a huge surface area. I could see light through mine. I'm sure it has some back pressure but nothing like the pellet style of the late 70's cats.

 

V10man is correct

The Ford 99 to present catalytic converters contribute zero "back pressure" or any impedance to flow at all.... power levels at all RPM on dyno are identical with or with out the factory catalytic converter

It is a Federal Offense to remove or disable any factory installed emissions equipment.

Odds of getting caught are low. Cost if you get caught can be very high. This is not a misdemeanor charge... OTHO, more often then not the offense is taken care of by a "fix it ticket" with proof of original equipment and test even in smog test free areas.

There is no legitimate need to remove the catalytic converter except use in a hay field with a Farm use only registration.... for highway use registration but hay field use there are additional shields that reduce or eliminate the fire hazard....

Folks who insist on disabling emissions equipment put us all at risk of more Federal regulations and stronger enforcment...

As long as there is Zero benefit from the removal of the catalytic converter it is ignorant, selfish, and anti social to do it.

Simple searches from many state DOT sites or the EPA site or the CARB site have FAQs like these..... so if you think I am full of crap...post here and prove me wrong
------------------------------------------------------

Can I replace the OEM catalytic converter on my car with a "high flow" catalytic converter?

The catalytic converter plays a major role in the emissions reduction of a motor vehicle. The vehicle manufacturer has matched a specific catalytic converter to the vehicle to minimize emissions output. Both CARB and the EPA do not allow the replacement of a catalytic converter with non-exempt "high flow" performance replacement unit. In fact, it is technically not legal to even replace a converter unless it has been proven by technician to have failed, and then it can only be replaced with an exempt OEM equivalent unit. (However, enforcement of this requirement is almost non-existent and is the primary loop-hole that allows the usage of so-called "high flow" catalytic converters. Many of these units are sold with the disclaimer as being a "race" component and are not intended for street use.) Due to the hundreds of vehicle models produced over the years, it is virtually impossible to determine by glancing under a car whether the converter is the original unit, a legal OEM replacement, or a non-legal aftermarket "high flow" performance unit. Unless CARB or the EPA decide to take more aggressive enforcement action, the installation and usage of these non-exempt "high flow" catalytic converters will likely continue.

Can I remove my stock exhaust manifold/catalytic converter and replace them with a header/catalytic converter combination on my RX-7?

Not legally. As mentioned above, CARB or the EPA does not allow replacement or relocation of any of the stock catalytic converters. They require that all original catalytic converters be in their original positions, and replacement of multiple catalytic converters with a single non-exempt "high flow" performance unit is not allowed.


Edited in later:

Exact words from the EPA 1990 Clean Air Act, a Federal Regulation:

PROHIBITED ACTS

Sec. 203. (a) The following acts and the causing thereof are
prohibited-
(1) in the case of a manufacturer of new motor vehicles or
new motor vehicle engines for distribution in commerce, the
sale, or the offering for sale, or the introduction, or
delivery for introduction, into commerce, or (in the case of
any person, except as provided by regulation of the Adminis-
trator), the importation into the United States, of any new
motor vehicle or new motor vehicle engine, manufactured
after the effective date of regulations under this part
which are applicable to such vehicle or engine unless such
vehicle or engine is covered by a certificate of conformity
issued (and in effect) under regulations prescribed under
this part or part C in the case of clean-fuel vehicles
(except as provided in subsection (b));
(2)(A) for any person to fail or refuse to permit access
to or copying of records or to fail to make reports or
provide information required under section 208;
(B) for any person to fail or refuse to permit entry,
testing or inspection authorized under section 206(c) or
section 208;
(C) for any person to fail or refuse to perform tests, or
have tests performed as required under section 208;
(D) for any manufacturer to fail to make information
available as provided by regulation under section 202(m)(5);
(3)(A) for any person to remove or render inoperative any
device or element of design installed on or in a motor
vehicle or motor vehicle engine in compliance with regula-
tions under this title prior to its sale and delivery to the
ultimate purchaser, or for any person knowingly to remove or

228


render inoperative any such device or element of design
after such sale and delivery to the ultimate purchaser; or
(B) for any person to manufacture or sell, or offer to
sell, or install, any part or component intended for use
with, or as part of, any motor vehicle or motor vehicle
engine, where a principal effect of the part or component is
to bypass, defeat, or render inoperative any device or
element of design installed on or in a motor vehicle or
motor vehicle engine in compliance with regulations under
this title, and where the person knows or should know that
such part or component is being offered for sale or
installed for such use or put to such use;

 

I too recently bought a 03 250 crew cab 4x4 King ranch (v10, captains chairs, 56K for 22,700- that good?) Anyway I noticed the truck seems fast (85mph) if you aren't careful, but I noticed that on wet grass it won't spin the tires (tried in 4x4 hi and 2wd) it just launches. I have pulled out a stump (big as a 55 gal drum- old apple tree) and it spun a little, still 450ftlbs of torque should spin right? Maybe I should mention I am coming froma 4.0 ranger 4x4 w/4:11 rear that would LIGHT the tires on dry pavement completely through 1st gear (automatic tranny) Despite how this sounds I am not into spinning tires, still it seemed wierd that this truck wouldn't even churn a little grass. (BTW I tried it to verify the 4x4 system so I did have a legit purpose even though it sounds a little juvenile) Maybe just the truck is heavy? Rear gears are 3:73 in case that helps. Also love the forum- are the V10 FAQs returning soon?

 

i would have a good trans shop check out the trans and converter, sounds more like the converter is going south and not stalling at the correct rpm. your trans is a 4r100 a good unit esp if you want to beef it up with after market parts, just do not raise the stall speed of the converter that is where i have caused my self a problem, the stock speed works best.

the v10 should spin the tires with out any problem by simply nailing the go pedal. esp on a wet surface.
please advise us what is found.