is high flow the way to go??

jackdup · 10-13-2008, 08:53 PM

is having a real high flow 4.0 really as good as you would think..my plans are a dynomax full mandrel bent system with a super tubo muffler..a header..and a magnaflow high flow cat...rusty intake..throttle body spacer...99+ intake manifold and DIY bored throttle body..now..will my low end torque suck? it would make sence to get better mpg, throttle responce, and hp and wide open throttle...but will my low end be lacking..worse than stock? thanks alot..i need this stuff clarified before i take action

Bugboy · 10-13-2008, 09:07 PM

You will probably get more power at higher rpms but lose a bit at the lower end of the scale. I am not sure how much it would be considering the 4.0 is pretty torqy to begin with. so probably wont be too bad.

SoloCamo · 10-13-2008, 09:21 PM

Your power/torque will be made at slightly higher RPM's but the increased flow will easily justify it with the power difference. You will still be making plenty down low

jackdup · 10-13-2008, 09:37 PM

alright cool...yeah i never thought that when wheeling if i need some more torque i can just punch it..haha...plus it should make passing on the highway alittle easier and the gas back and forth to schoo alittle better

DeepJeep · 10-13-2008, 09:46 PM

I personally wouldn't bother with the throttle body spacer.

Saudade · 10-13-2008, 09:48 PM

The TB spacer doesn't do squat for a MPI.

Bugboy · 10-13-2008, 09:49 PM

Quote:

Originally Posted by jackdup

the gas back and forth to schoo alittle better

Nice thought! you will be punching it to hear the sound and feel the pickup. but in theory it should be better! hell i would do the same thing!

ehall · 10-13-2008, 09:55 PM

Flow is the way to go but don't think that bigger parts=better flow because that isn't how it works. Borla has the highest flow of all and they use relatively small pipes.

Bugboy · 10-13-2008, 10:05 PM

Quote:

Originally Posted by ehall

Flow is the way to go but don't think that bigger parts=better flow because that isn't how it works. Borla has the highest flow of all and they use relatively small pipes.

yep it gets quite interesting if you really get into it. I used to port heads and make exhausts etc. there are alot of factors but it isnt a drag car so anything over stock should be better unless it is too big for the valve combination, intake etc. does anyone make a tuneable exhaust like the old supertraps for the XJ?

jackdup · 10-13-2008, 10:07 PM

well as i would like to realisticly i cant spend 2000 on a full borla system...i already have the spacer so ill just leave it...i got it before i was on the forum much to learn it was crap..but oh well..cant hurt...i dont see how you can get much better flow then dynomax's full mandrel bent system including a down pipe...and most headers look the same with some acceptions..some are just better quality..so that only leaves the cat and muff to restric..cant get much better than the magnaflow high flow..and ive heard the dynomax super turbo flows real good also..so i think it all sounds good

Bugboy · 10-13-2008, 10:21 PM

Quote:

Originally Posted by jackdup

most headers look the same with some acceptions..some are just better quality..so that only leaves the cat and muff to restric..cant get much better than the magnaflow high flow..and ive heard the dynomax super turbo flows real good also..so i think it all sounds good

to be honest it depends on the inside of the header not the outside. how the welds are if they are flow ported etc. but you will see a noticable improvement over stock. basically the standard 4.0 header is a 6 into 1 setup best flow would be achieved by setting the firing order to the exhaust and position them into a scavaging type header but then you are talking BIG $$$. for what most of us do you will be well ahead.

jackdup · 10-13-2008, 10:44 PM

oh i have one more question..after upgrades like this..you should reset the computer correct? what is the best way to do this...ive read a few methods

ep191 · 10-13-2008, 11:04 PM

im pretty sure you disconnect the battery for a while, not sure how long

88cherokeexj · 10-13-2008, 11:10 PM

one of my mechanic friends said to completely reset the pcm you need to disconnect both battery terminals then short out the cable ends. this drains any voltage left in the pcm and completely clears any memory it had before

ehall · 10-14-2008, 12:13 AM

My Cadillac FSM says to touch the positive battery wire to the body for a few seconds, which is the same basic effect.