99+ intake upgrade recipe

end results

99+ 4.0 intake manifold
new Edelbrock Header '91-'99 #65923
Used gasket that came with header
New fuel injectors from Precision auto injectors '96-'98
'96 original fuel rail
'96 Bored TB from the fastman
Smooth bore 62mm TB spacer
Gibson Airflow snorkel
Felpro TB base gaskets
Down pipe is 2.25 to 2.5 from a foot in front of the cat all the way back.
Magnaflow hi flow 2.5" universal cat
Series 40 Flowmaster.
 
Hey so after 6 months of running this how is it working out? I just picked up a '99 intake and am considering doing this to my '97. Might to a port and polish too... idk..
 
I changed mine out a while back when I put in an APN header, so hard to tell exactly how it affected the driveability/mileage.

There is no real power gain, though it seems like the torque band gets smoothed out. With the older style intake, it was like a turbo button was pushed at 3k rpms. Now, the torque is smooth from idle to redline.
 
Ok here are my results.

99+ 4.0 intake manifold
new Edelbrock Header '91-'99 #65923
Used gasket that came with header
New fuel injectors from Precision auto injectors '96-'98
'96 original fuel rail
'96 Bored TB from the fastman
Smooth bore 62mm TB spacer
Gibson Airflow snorkel
Felpro TB base gaskets
Down pipe is 2.25 to 2.5 from a foot in front of the cat all the way back.
Magnaflow hi flow 2.5" universal cat
Series 40 2.5" Flowmaster.


With the parts listed above i gained the following.

quicker starts
much quicker throttle response and RPM climb.
More power at bottom end and up thru about 3000 RPMs
gained back 2" of vacum at cruise.
no where near as much trouble climbing the hills on 87 to payson and back.
2 mpg gain avg.

Jeep is a 96 XJ 4.0 OBDII, 231 TC, 8.25R D30F,AW4 rebuilt about 15K miles ago with shift kit. and the mileage currently on the XJ is 148,xxx

I am still running 3.54s with 31s and a bunch of extra weight ie roof rack bumpers winch gear in back and 3/16" skids.

On a side note I was never able to sqwauk my tires in reverse on pavement... EVER. now I can no prloblem.

The whole idea of this project was to gain power in top end for cruise but i gained all around.

I hope this info helps you out.
 
I just did the following a few months back...

Heddman Header
99+ Intake Manifold
Flow Master
Electric Fan
AFE Stage II Intake

I noticed the same thing. More power accross the entire power band and +2 mpg. It wasn't a cheap round of upgrades, but it made my driving experience much better. Now my Jeep doesn't have to downshift going over some grades around here. If anything, I don't feel as if I'm beating up my XJ as bad.
 
jeep pox said:
I saw all that Rob I was more wanting to know if you think it was worth it or not?
Click to expand...


Sorry.

Short answer.... YES.

A lot of the obstacles i had to fight with for power in Payson were much easier and less throttle to get over them.

The purpose was to gain top end. I ended up gaining the entire range so for me it was very well worth it.
 
I cant wait to put my intake on i have been wanting to do this for years never had the money. But i now have one sitting at home waiting for me to put her on :yelclap:. I paid lil high but its competle with everything even an extra T.B. Might be my test TB for boring. So i guess that leaves alot of extra crap to :(
 
I got 2000 intake I'm waiting to drop in my 98 XJ. I've had it a while. Just gotta get the injectors and Throttle Body. I have everything else done. The intake has been ported and polished inside and out. Looks like its chrome. I want to send it out to have it ceramic coated before installing to reduce temperatures. My header is coated. I think it would be a good upgrade for the intake too be they sit on top of one another
 
Tim Dog said:
I got 2000 intake I'm waiting to drop in my 98 XJ. I've had it a while. Just gotta get the injectors and Throttle Body. I have everything else done. The intake has been ported and polished inside and out. Looks like its chrome. I want to send it out to have it ceramic coated before installing to reduce temperatures. My header is coated. I think it would be a good upgrade for the intake too be they sit on top of one another
Click to expand...


How much did the port and polish cost you? I bought some temp paint im going to put on mine and the air intake hose. I do have an extra TB BUT im over in the sandbox sorry. O Yeah was there an gains with the PandP job?:read:
 
coldforge said:
How much did the port and polish cost you? I bought some temp paint im going to put on mine and the air intake hose. I do have an extra TB BUT im over in the sandbox sorry. O Yeah was there an gains with the PandP job?:read:
Click to expand...

I actually found it on ebay already done. I think I got it for $80. It's been a while. There is one spot I have to have repaired. The guy did a lot of porting you can say. He did a quick fix with some JB Weld on the bottom. I'll just grind it and weld some aluminum back in there. This thing has a mirror finish.
 
I did an '01 XJ intake swap a few months back on my 9.25 compression, stock cam 4.6L "poor man's" stroker and ran my Jeep on the dyno (AX15, stock 27.4" tires, stock 3.07's) to compare the result to my old '92 intake:

Before: 200rwhp @ 4750rpm, 254rwtq @ 3500rpm
After: 202rwhp @ 4700rpm, 258rwtq @ 3400rpm

The torque gain was up to 5lbft from 1500rpm to 4800rpm, throttle response was improved, fuel economy was improved by ~1mpg, and I can run 87 octane. The newer intake made the engine run slightly lean so I raised the MAP voltage from 5.1v to 5.2v to correct it before running on the dyno. Everything else remained the same.
 
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