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questions on intake manifold and downpipe

oneredxj

NAXJA Forum User
Location
socal
I did a header on my 97 and i was just curious on what exactly is the downpipe. i have heard of people replacing this or adding another one or something of this sort. Im just not sure what this is. Another question i had is where can you find a performance intake manifold? Sorry but i just dont know all that much about engine stuff. (pictures would be great)

thanks alot for the help,

cory
 
The downpipe is the part of the exhaust system between the header/manifold and the catalytic converter.

The stock one is restrictive, and its a good part to replace if you want better performance. If you plan on doing mild mods then a 2.25" will do fine, but if your planning on doing a high revving 4.0 or a stroker 2.5" would be better.


I don't think I've ever seen performance intake manifolds for the 4.0 except some that have holes bored to accept a 4 barrel carburetor. But I'm assuming that won't be emissions legal.

But you should consider the 99+ intake manifold. They are worth about 3-4 hp and 5-6 lb-ft of torque and should keep emissions legal.
 
do a search for "99 intake" you should find lots of the 'performance intake' you speak of.
and as stated, if you just replaced the header get yourself a new downpipe mandrel bent and 2.5" all the way to the cat.
I did both those mods on my 97 and I didn't notice a dif after installing the header until I got the new downpipe... the restrictive stock one did let it breathe properly... better sound and GO with new downpipe.
the 99 intake was simple, for us with the 97 its just remove old and put in the new one. no worries about the PS pump bracket.
 
actually I went to Midas and had them fab one up, few things to remind them when they build it:
when they put it on the lift, make sure its the lift that lifts the tires up, not the frame. they did mine on the frame first, and the droop made the guy think he had lots more room. when I drove away it rubbed the front drive shaft a bit, so I took it back the next day to fix it.
If I was to do it again I would either watch the guy do it, or make sure the person doing it knew what he was doing, cause mine lookes like crap. His first try (with rubbing) looked like it was prefabbed and he welded pieces on either end to match up the lines... and his fix the next time was to simply cut a little off one end and weld another ugly little piece on the back side... when my welding skills improve I may make my own later.
hope that helps
 
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