• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

99+ intake swap q's

C

callmebobbyt

NAXJA Forum User
Location
Virginia Beach, VA
ive searched, havent really found the exact answer im looking for either. Ive got a 95 HO xj got a 00 XJ intake mani, bracketry and ps pump. my question is will the 95 injectors fit the 00 intake? or should i modify the plug like the write up ive seen, or even splice the the 00 injectors to my existing wiring? HELP!
Hasta
 
The November JP magazine claims that the install of a 99 intake on a 98 4.0 gave a 5 hp decrease. It says there is no point unless you are running a cam and a ported head.

That's the first negative reporting I've seen on that intake? Anybody have any experience. I saw the post reporting no change, which seems to agree with the mag. 5 hp is well within measurement error.

Fred
 
I have a ported head and a cam in addition to the 99 intake, but I liked it on my 96 4.0 w/fipk, 62mm tb, borlas, and jet2.
 
Last edited:
Dino had his dyno'ed and got a small increase of both HP and Torque. The 99+ intake has 11.5" runners, about 2.5" longer than previous intakes, that alone pretty much guarantees an increase in lower RPM and mid range torque...

Where the 99+ shines is making more average torque all through the 4.0's normal RPM range.

There's plenty of real info on Jeepstrokers forum, I'm not sure what JP mag did wrong but it should be noted that the 0331 head which that intake is matched, has larger intake ports that have a slightly higher roof... which means without "port matching" the intake to an older HO head like the 0630 or the 7120. It will probably have exposed hard edges at the roof where the head port begins and the intake runner ends. This is a serious flow killer and the roof is the highest velocity highest flowing part of a 4.0 port/Runner. This would definitely drop higher RPM hp.
 
I read all that years ago. I remember Dr. Dino when all he had was a desktop dyno program and he thought that it meant something. I'm not asking for expertise, I'm asking for experience.
 
No Dino actually installed the 99+ not that long ago got it dynoed and posted the results. smalls gains but a far cry from a loss of 5 hp... Like I said JP did something wrong. Which really isn't too surprising.
 
Well, you can't just bolt it on. There is definitely some massaging that needs to be done. The ports are far enough off that I could totally see losing power if you just slap it on. I spent a lot of time with templates and a die grinder when we did this on our racer.
 
It should be noted that the Mallcrawling Dyno session has been known to be suspect for a long time. The stock "baseline" pull dyno'ed WAY under what it should have (by around 40hp and torque).

The "after" pull with mods looked on the low side of normal for a stocker with no mods at all. His AFR's are Possibly his engine was tired, his Auto was slipping (or maybe his trasfercase if he has one of those viscous coupler TC's) or the dyno operator is sloppy as hell.

The 10hp differences between the sets of runs with the same mods (109 peak hp and 119hp in the baseline, and 146 vs 158 in the second set of pulls) tells me somethings not right.

Well run dyno's can repeat within a hp or two from one run to the next, and can be much more precise than that by averaging three or more runs.

IMO I would expect 10-15 more foot lbs off idle to about 3000 RPM's and a slightly improvement in hp. Dino also reports a MPG improvement which goes hand in hand with a low torque improvement.

These are Jeeps even if the intake lost 5hp at 4800 RPM's that is more than worth it for an additional 10ft lbs where you use it off idle to 3000rpms
 
Fred said:
Anybody have any experience.
Click to expand...

Yeah, I saw a peak to peak gain of 1.9rwhp and 4.5rwtq with the '01 XJ intake on my 4.6 stroker with the HP/TQ peaks shifted to slightly lower rpm. I gained about 5rwtq from off-idle to ~3400rpm with smaller gains from 3400-4800. Feels like it by the SOTP too. Above 4800 there was a small loss.
Fuel consumption also improved by ~1mpg. I'd port-matched my intake to my 7120 head (minimal work needed there) and ground some material from the injector bosses to improve runner flow in cylinders 1,2,5,6.
 
Dr. Dyno said:
Yeah, I saw a peak to peak gain of 1.9rwhp and 4.5rwtq with the '01 XJ intake on my 4.6 stroker with the HP/TQ peaks shifted to slightly lower rpm. I gained about 5rwtq from off-idle to ~3400rpm with smaller gains from 3400-4800. Feels like it by the SOTP too. Above 4800 there was a small loss.
Fuel consumption also improved by ~1mpg. I'd port-matched my intake to my 7120 head (minimal work needed there) and ground some material from the injector bosses to improve runner flow in cylinders 1,2,5,6.
Click to expand...
Is there a writeup on this and what injectors were used?
 
I didn't do a write-up but you can find more details on http://www.angelfire.com/my/fan/updates.html

I only swapped in the '01 XJ manifold together with PS pump and mounting bracket. When I initially ran the engine with the new manifold, it ran slightly lean but I corrected it by increasing the MAP voltage from 5.1 to 5.2v. Everything else remained the same and injectors are Ford Racing 24lb'ers.
 
You must log in or register to reply here.

Similar threads

B
97-99 Engine into 88-96 Jeep Cherokee XJ
Replies
4
Views
2K
POSrenix
P
F
Replaced almost Everything
Replies
5
Views
886
FastEddie505
F
S
88 4.0L Renix to 96 4.0L HO swap...full swap?
Replies
8
Views
6K
swommack2
S
S
Renix to HO swap...please help!
Replies
10
Views
2K
Rockpig
R
O
Help needed for intake swap!!!
Replies
13
Views
2K
DieselSJ
D
Back
Top