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Engine buildups


 
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Code3TJ
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PostPosted: Fri May 07, 2004 2:34 am    Post subject: Engine buildups Reply with quote

Just wondering what everybody's thoughts are.
So, since we're not building for all out speed (at least not my wobbling, shaking heep Wink ) what are the best options? I know with the 4banger, a 4.0l throttle body is a step in the right direction, but generally, what else are good ideas? Porting heads, polished intake, headers? Discuss. Mr. Green
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ThePhantum
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PostPosted: Fri May 07, 2004 3:07 am    Post subject: Reply with quote

Well, I know with the 4.0L the injectors are pretty closely "tuned" to the stock setup. So it does not make sense to do any major work (top end porting, low end boring, etc) without putting in bigger injectors as well. I would think the same applies to the 4 banger.

As far as making it breate better: a muffler upgrade or a cat back coupled with a header and 4.0L TB should show some modest gains...especially with low end torque.

My $0.02

Steve
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WhatWasIThinkin
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Joined: 02 Jan 2004
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PostPosted: Fri May 07, 2004 3:28 am    Post subject: Reply with quote

Does anyone make a stroker kit for the 4 banger? Can bigger valves be put in it? Does EEP Grl realy love snakes and does she read the tech threads? Wink Bueller? Beuller? Most intake port polish work dosent do much unless you can get a cam that uses the extra flow. The air does move with less effort in a polished intake, but small valves with fairly small duration slows it up and counteracts what was done. Neutral
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'drack
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PostPosted: Fri May 07, 2004 12:00 pm    Post subject: Reply with quote

I gave up on the engine buildup ideas. I figured I could toss that money into something else rather than what it costs to tweak some extra HP outta the engine. Regearing made my life much more pleasant and now the 4.0l can do what it was supposed to (...well, it'd be even better with 4.88's, but live and learn). Only real mods I plan on are on the exhuast level. Replacing a cracked manifold outta necessity and swapping out the muffler and tailpipe for something custom when I add longarms to the mix. So, even those mods are just because "they have to be". Dunno Mr. Green .
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Code3TJ
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PostPosted: Fri May 07, 2004 1:12 pm    Post subject: Reply with quote

Here's a question, what'll headers do to your low end torque? Obviously anything is better than the DC manifold garbage, but you know what I mean?
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WhatWasIThinkin
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PostPosted: Fri May 07, 2004 1:42 pm    Post subject: Reply with quote

Code3TJ wrote:
Here's a question, what'll headers do to your low end torque?


Headers allow more air to flow smoother and faster, which in turn leads to a faster reving engine. The engine dosent have to work as hard to push the exhaust charge out, hense the faster moving flow. All this changes the powerband and usable HP range that the engine wants to make power at. So now you've got the engine making HP at a higher RPM range, this in turn lowers torque.

Now that said.....Headers by themself dont ussually give more HP, you have just changed the ussable range of where the HP comes from. The headers make the engine peakier. The higher HP range was always there, but it was limited by the OEM exhaust manifold.

To increase torque in any substantial amount, you generally need to increase HP a bunch. @ a 20% gain in HP will only net @ 5% gain in torque.

So would I replace my exhaust header w/aftermarket? Yes, but only when its cracked and needs replacement. But If I was looking for big gains in the torque department, I would let the torque thats allready there do its thing and regear to 4.56 or 4.88. The only way to make a significant HP and torque increase would be to swap in a V6 or V8.
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WhatWasIThinkin
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PostPosted: Fri May 07, 2004 1:44 pm    Post subject: Reply with quote

Code3TJ wrote:
Here's a question, what'll headers do to your low end torque?


oops....hehehe

The simple answer is: You lose low end torque
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'drack
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PostPosted: Fri May 07, 2004 8:54 pm    Post subject: Reply with quote

Long answer was more informative though Mr. Green .
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Code3TJ
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PostPosted: Fri May 07, 2004 10:06 pm    Post subject: Reply with quote

'drack wrote:
Long answer was more informative though Mr. Green .

Exactly. Mr. Green
I'm at the point that it's pointless replacing another cracked manifold with one that will undoubtedly crack again in a few more years, but what options are there other than waiting for banks to come out with my 2.5 headers. Wink
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