too little back pressure???

[tbelisle]

My wife got home and the pipe right before the Cat was completely brocken off.
Her Talon now sounds like a boieng 747.

My real question is that she called me today saying that the car seems to not have any power. i told her to skip work and I would look at it tonight.

Could the lack of back pressure cause a lack of power going uphill???

I am a newby where exhaust is concerned.

[tbelisle]

No reply needed. I answered myself by fixing it. God damn car never worked better. Not bad for 350'000 km on her!

[sfg]

Jeez, that was a pretty fast exhaust fix.

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[tbelisle]

Well to be honnest, the car was already jacked up, all I really did in the hour was cut/bent the pipe and welded her on.

I keep a laptop in my shop and was online, I tought I would ask as I was a bit hesitant (Scared) that my problem was much worst and needed reassuring.

You guys are so slow to respond (lol) that I just grabbed a beer and the welder and let loose.

[sfg]

[QUOTE= I just grabbed a beer and the welder and let loose.[/QUOTE]


Thats what i like to hear :)

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[smilingjack]

Actually TB it was not a lack of back pressure.

The exaust has sensors up the WAZZO, my Crown Vic has 1 in front of the muffler, 1 behind the muffler and another one on the cat itself. With no exaust going through the system and all 3 reading as bad you are lucky you did not need a tow truck as the dam computer almost shuts the engine down.

Don't feel bad the Crown Vic Police Interceptor of mine has dual exausts, 6 of them fucking sensors just on the exaust.

@ $75 each

[jojoroxx]

That's nothing on the cost of a cat for a Crown Vic

[smilingjack]

I Have not had to replace either of them yet. I am sure they cost up the wazzoo.

I just paid $30 for a rubber gasket on the gas tank and $ 200 for a plastic 3 way fitting on the gas tank.

[BirdieMod]

Part of the engine tuning includes a amount of backpressure on stock vehicals.

[sfg]

your exhaust is a balance between exhaust flow velocity and backpressure. Ideally you want the highest flow velocity matched to the largest reasonable pipe diameter. If you go to big a pipe then your flow velocity drops too much and you aren't able to evacuate your combustion chambers properly and your efficiency drops off, hence the lack of power when your exhaust fell apart.

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[tbelisle]

I alsoi forgot to mention that I took the fuckin cat off. I think the fucker was clogged up as well. don't know if it's just me, but it seems fuckin peppy now.

[sfg]

Didn't you have o2 sensors in the cat?

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[tbelisle]

Fuck all!

Zip
Nada!

Pipe broke right at the rusted out cat connection, cut it out and welded on a straight pipe.

[sfg]

Cool. Where I live we have to have the cat in place (or at least something that looks like a cat :) )

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[tbelisle]

Oh... don't get me wrong, we do also. Ontario is likely the strictest place for this polution crap.

Fuck em! What are they going to do? look under my car when i am at a red light?

My emition test is not due for 11 MONTHS OR SO. I doubt the car will last that long anyways.

If it does, I still have the cat so I could always put it back on if need be. I just did not feel like it.

I was cutting into my beer drinking time!

[smilingjack]

Actually for the most power put the largest set of headers you can find on it and run straight pipes right out the front wheel wells.
Of course you will have to go back to a distributor or magneto and shitcan the computer....and of course it will never pass emission inspection.

Any back pressure costs horsepower.

But it will have more power. !

[tbelisle]

I was told be many in the past couple days that I need a certain amount of back pressure otherwise I would not have much low end. After what happened with the pipe breakin in half... I tend to agree with that!

I could barely make it up the hill.

[smilingjack]

That's because the computer dam near shuts down the engine if things are not to it's liking, that makes sure you will get it fixed to factory / emission specs and why I said to get a old style distributor or a magneto and throw away the computer.

On drag recers and drag boats you will notice the entire exaust pipe is only a foot or so long and big as a house, back pressure = less H.P.

No exaust system, no back pressure, maximun horse power.

[BirdieMod]

Put a high velocity cold air intake on it, straight pipe exhuast and make sure to add just the front o2 sensor into the line so it can adjust fuel air mix, If it is a 97 or newer with the second O2 sensor after the cat convert, Make the sensors reading happy by rigging it to stay at .4 to .6 volts at all times back to the PCM.

[BirdieMod]

Now don't blame me when you cannot keep tires on it..................LOL...

My little 4.6 liter eats anything on the road, Well heavilly modded 32 valve northstar 4.6 at 425 horses from 276 cubs is respectible still turning in 18.3 MPG HWY with 11.5 compression. Only caddy I have ever seen that will burn the tires over 1 1/2 blocks.

[tbelisle]

Well guys... my shit box (actualy the wifes) is a 93 eagle talon. I did not see any sensors visible anywhere close to where the cat is.
I can honnestly say that the shit box really runs better since I took it off. not quite "whiplash", but sure as hell goes compared to what it used to do.

[smilingjack]

My problem is usually too much back pressure.

Then I have to let one off

Must be all those cowboy beans I eat with my steaks.

[BirdieMod]

LMAO.. Thats funny.

[smilingjack]

Hi !
you are around early today, thought you were out late partying last night.
hehehe