'98 XJ 4.0L benefit of headers?

Hello, group -
While crawling under my XJ 4.0L, I have been amazed by the degree to
which the downpipe from the exhaust manifold is collapsed. It is 2/3
shut at the bend.

I have mentioned this at both the local 4WD shop and at the dealership
parts counter, and the replies have been something to the effect that
"Those 4 Litres seem to like the restriction", to "That's normal.
They're all formed like that".

When I read about modifications for power, those most popular seem to
be (not necessarily in their order):
1. Replace cat-back
2. Headers
3. Bored-out throttle body
4. low-restriction intake

What do the experts on this board think? Does this engine really
benefit from headers,since it seems as though it was engineered for
significant back-pressure?

Thanks.

jim

The 4.0 in my opinion has quite a bit of power for a V6. But I would also
like to find out some little mods to get some edge


<98XJ> wrote in message ...
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

My 4.0 is the Inline 6, not a V-6.

On Wed, 28 Feb 2007 00:00:09 GMT, "abomb69" > wrote:

>The 4.0 in my opinion has quite a bit of power for a V6. But I would also
>like to find out some little mods to get some edge
>
>
><98XJ> wrote in message ...
>> Hello, group -
>> While crawling under my XJ 4.0L, I have been amazed by the degree to
>> which the downpipe from the exhaust manifold is collapsed. It is 2/3
>> shut at the bend.
>>
>> I have mentioned this at both the local 4WD shop and at the dealership
>> parts counter, and the replies have been something to the effect that
>> "Those 4 Litres seem to like the restriction", to "That's normal.
>> They're all formed like that".
>>
>> When I read about modifications for power, those most popular seem to
>> be (not necessarily in their order):
>> 1. Replace cat-back
>> 2. Headers
>> 3. Bored-out throttle body
>> 4. low-restriction intake
>>
>> What do the experts on this board think? Does this engine really
>> benefit from headers,since it seems as though it was engineered for
>> significant back-pressure?
>>
>> Thanks.
>>
>> jim
>

98XJ wrote:
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Well when I had a custom straight pipe with a high flow Dynomax Turbo
muffler put on my CJ7's 258, they did a smooth bend instead of the kink
bend that was there on the downpipe and I sure thought I got a power
increase. I also think I got 2" pipes.

It sure sounds nice anyway....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

I'd surely fix the restriction, along with robbing you of power and
economy, it may burn an exhaust valve:
http://www.1aauto.com/1A/ExhaustMani...EM00146/400479
God Bless America, Bill 0|||||||0
http://www.billhughes.com/

<98XJ> wrote in message ...
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim



--
Posted via a free Usenet account from http://www.teranews.com

The XJ 4.0 IS the inline 6, not some weenie V6 <G>.

Jeff DeWitt

98XJ wrote:
> My 4.0 is the Inline 6, not a V-6.
>
> On Wed, 28 Feb 2007 00:00:09 GMT, "abomb69" > wrote:
>
>
>>The 4.0 in my opinion has quite a bit of power for a V6. But I would also
>>like to find out some little mods to get some edge
>>
>>
>><98XJ> wrote in message ...
>>
>>>Hello, group -
>>>While crawling under my XJ 4.0L, I have been amazed by the degree to
>>>which the downpipe from the exhaust manifold is collapsed. It is 2/3
>>>shut at the bend.
>>>
>>>I have mentioned this at both the local 4WD shop and at the dealership
>>>parts counter, and the replies have been something to the effect that
>>>"Those 4 Litres seem to like the restriction", to "That's normal.
>>>They're all formed like that".
>>>
>>>When I read about modifications for power, those most popular seem to
>>>be (not necessarily in their order):
>>>1. Replace cat-back
>>>2. Headers
>>>3. Bored-out throttle body
>>>4. low-restriction intake
>>>
>>>What do the experts on this board think? Does this engine really
>>>benefit from headers,since it seems as though it was engineered for
>>>significant back-pressure?
>>>
>>>Thanks.
>>>
>>>jim
>>
>

Thanks for correcting me...But either way the inline 6 has quite a bit more
power than most V6s I've ever owned including the 4.3 GM

"Jeff DeWitt" > wrote in message
...
> The XJ 4.0 IS the inline 6, not some weenie V6 <G>.
>
> Jeff DeWitt
>

That's because it's a better engine <G>.

I've really embarrassed a few Mustang drivers with my little Cherokee,
that sucker is pretty fast. I expect that above 50 or so a Mustang
would pull away but in one of those little stoplight contest I'm not
going any faster than that... I'm no idiot and don't want to lose my
license for something as stupid as racing.

Jeff DeWitt

abomb69 wrote:
> Thanks for correcting me...But either way the inline 6 has quite a bit more
> power than most V6s I've ever owned including the 4.3 GM
>
> "Jeff DeWitt" > wrote in message
> ...
>
>>The XJ 4.0 IS the inline 6, not some weenie V6 <G>.
>>
>>Jeff DeWitt
>>
>
>
>

"abomb69" > wrote in message
...
The 4.0 in my opinion has quite a bit of power for a V6. But I would also
like to find out some little mods to get some edge



I have to disagree..
I find mine slow. It has pleanty of torque, but as far as gettin on the
freeway or passing a car I have to pray for a tailwind and half a mile of
clearance.
Not to mention a gas GUZZLING 14-16 mpg! HFS!
I would definitely like to find some power in this little rig.
Of course, I went from a Mustang Cobra Convertible to this - so my judgement
mignt be just a little clouded that got 18 mpg with my foot in it all of the
time.

When it gets old and the engine finally dies, I am planning to transplant a
Chevy 350 into it I think.

But, I love myJeep, and wouldn't trade it for anything.
I think it's the most fun you can have with your cothes on.

Kate
2O|||||||O6 Rubicon

On Sat, 3 Mar 2007 06:01:52 -0600, "Kate" > wrote:

>
>"abomb69" > wrote in message
t...
>The 4.0 in my opinion has quite a bit of power for a V6. But I would also
>like to find out some little mods to get some edge
>
>
>
>I have to disagree..
>I find mine slow. It has pleanty of torque, but as far as gettin on the
>freeway or passing a car I have to pray for a tailwind and half a mile of
>clearance.
>Not to mention a gas GUZZLING 14-16 mpg! HFS!
>I would definitely like to find some power in this little rig.
>Of course, I went from a Mustang Cobra Convertible to this - so my judgement
>mignt be just a little clouded that got 18 mpg with my foot in it all of the
>time.
>
>When it gets old and the engine finally dies, I am planning to transplant a
>Chevy 350 into it I think.
>
>But, I love myJeep, and wouldn't trade it for anything.
>I think it's the most fun you can have with your cothes on.
>
>Kate
>2O|||||||O6 Rubicon
>
To the original poster, the 4.0L is a I6, not a V6.

Kate, the vehicle will rust/fall apart before the engine dies! I
can't speak for the '06, but my '92 &'97XJ have getup and go. No
problems getting up to cruising speed, or passing vehicles on the
road, even with 31"x9.5" Swampers on them!

E