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schaff90xj
April 17th, 2004, 02:23
i have come to the conclusion that it is now time to replace the exhaust header on my 4.0.. i have been looking on the net for some decent buys and all that i have found so far is the borla setup which will cost me upwards of $400 and on Jeg's i found a hedman for about $260.. i know that alot of others have experienced this upgrade and would like to know about some other options out there..i certainly don't want to spend the $400 for the borla..any input would help a bunch..if it makes any diff, my xj is a 90..

tugboat
April 17th, 2004, 02:38
try banks,pretty reliable

MrShoeBoy
April 17th, 2004, 10:45
Go with Banks or Borla. I just got done removing my Hedman header last weeekend. I had the hedman for 2 years and it started to crack a few months ago. After I got it out, there where about 4 or 5 cracks total. If you want someting cheap and want to replce it in a couple of years go ahead and get the hedman, you will dislike it later.

I installed a Banks header in place of the Hedman and am EXTREMLY happy with it. I wish I had spent the money for it up front. It looks and feels better than the hedman and the exhaust note sounds better and it feels quicker. I installed bigger injectors and an adj map sensor and dyno tuned it when I did the header so maybe thats why:D

AARON

sjx40250
April 17th, 2004, 14:41
MrShoeBoy,
which injectors did you install?

BIG98XJ
April 17th, 2004, 16:00
I can vouch for the banks as well! :scottm:

Wa Woody
April 17th, 2004, 20:27
I really like the Borla, excellent fit and good performance. I paid like $350 from Rusty's three years ago so I don't know what they are going for these days. Good Luck

Woody

AuburnoffroadXJ
April 17th, 2004, 20:48
I have Borla and love it. No complaints at all. Well worth the money in my opinion.

jeff

MrShoeBoy
April 17th, 2004, 23:21
MrShoeBoy,
which injectors did you install?

I installed the Ford Motorsports #24lb/hr injectors. With the intake, head porting/polish, cam, and exhaust it still runs a little bit rich even with the map. Tuning it on the dyno with a wide band O2 sensor in the tailpipe, I can lean it out and gain top end horsepower (above 3,000) as much as 5hp but I loose an average of 3 to 5 hp and torque below 3,000rpm. I have the map set almost at the factory 5v which doesnt effect the low end power and slightly leans out the top end. The only way to get everything running perfect would be to install a piggy back ECU like an Apexi AFC or simmilar unit. That way I can adjust the fuel per RPM and richen up the low end and lean out the top end to gain power all around. From messing with the map, I can bet theres about 10hp to be gained by installing a AFC. I just dont have $300 for one yet.

AARON

Dr. Dyno
April 18th, 2004, 13:27
I've had my Borla for 6-1/2 years, 98k miles, and I'm very happy with it. It's probably one of the longest serving Borla's in an XJ.
Aaron, you probably need to lean out your A/F mixture a bit more. I have the same injectors as you and I have my MAP adjuster set at only 4.25v. On that setting the engine runs great right across the rpm range and it really kicks when the tacho hits 3400rpm. I average 20.8 miles per imperial gallon in mixed driving. That's almost 2mpg better than with the MAP adjuster switched off.
My A/F ratios were in the 15.5-16.3 range at idle/1500rpm/2500rpm cruise when I had the MAP set at 4.15v for the emissions test six months ago. Now I have it set slightly higher so I may be about 0.4 of a ratio richer which is just about right for low load conditions.
__________________________________________________ _______________
- 1992 4.0 XJ Laredo UpCountry with modifications (http://www.jeep4.0performance.4mg.com/mods.html) - 173k miles - AX15 (http://www.off-road.com/jeep/tech/trans/ax15.html), NP231 (http://www.off-road.com/jeep/tech/xfer/np231.html), D35c (http://www.off-road.com/jeep/tech/axle/d35c.html), D30 (http://www.off-road.com/jeep/tech/axle/d30.html)
Estimated 240hp@5250rpm/280lbft@3500-4000rpm, 1/4=14.98@93.1, race weight 3465lb
- Future mods -
4.6L stroker (under construction)
- Websites -
Jeep 4.0 performance (http://www.jeep4.0performance.4mg.com), 4.6L stroker build-up (http://www.angelfire.com/my/fan/stroker.html)
- Tech Webpages -
CTS resistor trick (http://www.angelfire.com/my/fan/CTS.html), Dual electric fans (http://www.angelfire.com/my/fan/electric.html), IAT sensor relocation (http://www.angelfire.com/my/fan/IAT_sensor.html), Intake manifold heatshield (http://www.angelfire.com/my/fan/manifold.html), MAP adjuster (http://www.angelfire.com/my/fan/MAP_adjuster.html), Oil temp. gauge install (http://www.angelfire.com/my/fan/oiltemp.html)
- Info Pages -
Automotive formulae (http://www.angelfire.com/my/fan/formulae.html), Jeep 4.0 cam specs (http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm), Jeep engine dyno graphs (http://groups.msn.com/desertxj/dynocharts.msnw)

schaff90xj
April 18th, 2004, 14:39
I think that i am going to go with the Borla setup..sounds like the way to go. I'd much rather spend the $$ now then to do it all over again in the future..now all i have to do is get it past the wife!! i have also heard of some people replacing the injector o-rings in the process?? is this a must-do??

GI-John
April 18th, 2004, 16:02
If your wife starts balking, have her call the dealership and price a new STOCK manifold. 6 bills last time I checked, not including install.

I did a full exhaust with that.
(Borla, Hi flow Cat, Dynomax Cat Back)

ChiXJeff
April 18th, 2004, 18:34
I've had my Borla for 6-1/2 years, 98k miles, and I'm very happy with it. It's probably one of the longest serving Borla's in an XJ.

Over 140,000 miles on mine in around 5 years. No difficulties with the Borla, and their customer service is top notch.

old_man
April 18th, 2004, 18:53
I'm running Clifford headers and have run them on various 6 cylinders for the last 40 years. I love their quality and they work great on my stroker. Great low end torque and passes emissions hands down. They have tons of good stuff for 6's of all brands and the jeep stuff is great.

MrShoeBoy
April 19th, 2004, 11:59
My A/F ratios were in the 15.5-16.3 range at idle/1500rpm/2500rpm cruise when I had the MAP set at 4.15v for the emissions test six months ago. Now I have it set slightly higher so I may be about 0.4 of a ratio richer which is just about right for low load conditions.


Dino,
How did you measure your A/F ratio? When I did mine, I was using a wide band O2 sensor on the dyno. I got it done here: www.P1auto.com on their Mustang Dyno. At steady driving like highway driving the A/F is just like yours but at wide open it really runs rich top end. I made multiple runs starting at 4.10 volts and increased the voltage by .10V each dyno run and the loss of power under 3k was around 5hp on all runs until I got close to the factory 5v. When I leaned out the top end, I got 4 or 5hp out of it but the loss to the low end was drastic. My map is now at 4.9V which doesnt loose much hp under 3k, maybe 1hp, and gained 3hp above 3k even with the engine still running rich. For optimum preformance, I would need to richen up the low end and lean out the top baised on RPM but the MAP only adjusts the entire curve and not just parts of it. That is why a piggy back would be ideal from a preformance standpoint. I think another issue is that the computer has not had enough time to adjust to the new injectors and header. Also I think the factory down pipe from the header to the cat is causing some preformance hindering. My next step is to change the downpipe and dyno it again and see what has changed. Then if money allows, put on a AFC and tune it again and be happy. Be happy? Ya Right :rolleyes:

AARON

rsalemi
April 20th, 2004, 05:21
What you proved on the dyno is that 24# injectors are too rich for a 4.0 - and that the MAP can't compensate for that. You need to either get a controlable (programable) fuel flow computer or go down to HO (21#) injectors and adjust the regulator pressure to get the proper WOT mixture. My 4.0 made 189 rear wheel HP with 19# injectors and 48# regulator pressure.
Once you have WOT at proper mix then you can lean out with the MAP for idle.