Bored TB and Header question

Hey guys,
So I've been really considering throwing on some headers and a bored TB on my 2000 and I got some questions I was hoping I could get some feed back on.

1. As for the TB I was originally gonna get the basic 60mm bored which from what I've learned requires ZERO further modification. BUT now I'm looking into a 62mm because its not really much more price wise. So my question is this, is the extra 2mm worth it? I have intake and cat back exhaust system and 748 injectors but other than that its stock(with future headers) an if I rock the 62mm do I have to modify the intake manifold as well?

2. As for the headers my question is this, if I upgrade my headers is it a "lame" upgrade unless I fork over the additional dough for a larger down pipe and higher flow cat? I've been looking at (an have found a great deal on a NiB) banks header, but have found ALOT of bad things (cracking and more cracking) as well as ALOT of great things (no cracking, great product) which leads me to believe its quite hit or miss with this brand. I haven't looked into apn(?) but will do so soon as alot of the bad exp's say those are good. < this last bits more of a statement haha

Anyways, as previously stated any feed back would be much appreciated
Thanks,
Mike

1. I have a 60mm TB, I really didn't notice much of a improvement over stock, but that's because I didn't often drive at WOT (wide open throttle), which is where you will really notice the added flow. Normal driving, stop n go, cruising, etc it won't be much different... until you floor it, intake sounds louder, maybe a whistle, "feels" more powerful... for those 3 seconds or so.

2. I have had 2 Banks headers, first cracked, second... will see.
If you get a header, install a section of flex pipe not far down the line, preferably before the first exhaust hanger so the exhaust can flex/move somewhat independently from the engine. If you think about it, there's 8' or so of exhaust tubing and the only hard attachment is at the headers.
Also, I did the new headers, and it did nothing for me, because all those gases were still bottlenecked by the stock downpipe with that "indent" to clear the front driveshaft. Once I got a new downpipe, again, things felt a little more powerful... but I never dyno'd or cared much, I just enjoyed having the mods done.
if new header, then new downpipe, and piece of flex pipe

hope that helps

yea thats kinda wanna i wanna get the 62mm. im not looking for rubber burning power, just want my lil heep to be all it can be haha. im really more curious as to wether or not the 62mm requires intake modifaction.

after more and more research into the headers ive decieded that a doug thorley(the best money can buy?) is the route i wanna go. as for replacing the down pipe this brings conflicts that ive read about.
1. many say that replacing the down pipes a bad idea because some back pressure is a good thing?
2. i have a pre cat riddled down pipe. removing this would cause me to fail smog, although i have not looked into finding an after market one with them but im guessing they wouldnt be cheap.

as for the flex pipe ive found this to be a suggestion in other threads as well along with replacing motor mounts.

thks for the input Beakie!

no problem,

I can't remember if the intake is 62mm diameter or not, and I am not near my heep so I can't go check... but the TB comes off rather easy, if you had a set of callipers you could find out quick. if it needed to be bored out... well I'd want to ensure no filings/shavings got into the engine so I'd want the manifold right off before boring it out with a dremel or die grinder.

back pressure... this is my opinion only so take it with a grain of salt... but I disagree. Exhaust velocity is good, you want the gases to get out smoothly but if you're trying so hard to get air into the engine, why slow it's escape by causing back pressure?

pre-cats. I take it you have a 2000 or 2001, I forget which years had them, but yes if that's a problem... maybe you could just remove the dent and replace it with a piece of straight pipe. I really don't know, haven't looked at a Cherokee like that before... my '97 didn't have them.

yes motor mounts, I forgot those, also very beneficial, good thinking.

In my renix I went from the stock 52mm to 60mm and it was a difference, but I also have a cowl mod to my stock air box. Not really in MPG , but off the line, and also in 4lo.

I have the long tube paceshitter headers that are supposedly CA smog legal, but I am waiting to throw them on due to all of the complaints with them. I like the relocation of the o2 sensor away from the manifold and I orderd a flex pipe from Summit and the lava heat wrap from Summit as well.

Thks Jon,

Maan 92 views and no one knows if there's manifold modification required for a 62mm TB?

Maybe ill try postin this in the street and proformance section?

beakie said:

pre-cats. I take it you have a 2000 or 2001, I forget which years had them, but yes if that's a problem... maybe you could just remove the dent and replace it with a piece of straight pipe. I really don't know, haven't looked at a Cherokee like that before... my '97 didn't have them.

Click to expand...

The '00-'01 uses dual down pipes and the D30 is LP which got away from the single pipe impression so ditch that talk.

The intake manifold TB opening is 62mm.

Either the '00 or '01 will have the pre-cats. The '00 was about 50/50 and I was lucky enough to not have them. Due to the dual down piping, the Banks header for those years have few issues. Mine has been on for about 8 years now.

Forget whatever gossip you've heard about back pressure, check this http://www.myunibody.com/forum/viewtopic.php?f=13&t=504&p=6942#p6942

Have fun.

Epic, Thks... R starch?

Read it and the two links haha

Ill be picking up 62mm TB soon but ill probably hold off on the header till I can afford a Doug Thorley, some Brown Dog mounts, flex pipe and a high flow cat(BAM! One sentence that costs ALOT of money). And also research into what I can do about my down pipe in mean time

Thank you all for your input!

TBs, headers, downpipes, aftermarket cat replacements for the 00/01 with the precats, and related things, have been covered in pretty good detail in a number of threads. Google those things with "site:naxja.org" in the query, and you should find most of your answers.

I just put in a 62mm TB and its great. I could feel the change right away. If you bring your old one to a shop make sure they put the right size butterflies on it. If you want one shipped http://www.strokedjeep.com/tbody.html is a great site. They guy that owns it is pretty awesome too. Jeff keeps in contact with you and answers any questions.

Ive already researched that site i will be using it to obtain my TB.

but thank you anyways!

A gear change is a more effective and price conscious move