Did the Intake manifold swap

I just did the 99+ intake manifold swap to my '97 XJ. I was supprised at just how easily it went together. It truely does work great with the Banks Header and K&N intake. Now all I'am missing is a bored throttle body.

While I was at it I had the head and new intake ported and polished. The engine really seems to run and idle much better now. I also replaced all of the Ignition with Mopar Performance products. I was wondering about spark plug gap, currently they are set to stock specs. Is there any advantage to overgaping them??

Also, is there any advantage to changing cams??? I had a different cam in my stroker, but this engine is still a 4.0l. I would be looking for something that would help at the higher end, more than low end.

Brian

Is that the same intake the WJs use with the weird looking runners and all?

Brian,
Did it really make that much diffrence power wise. I have talked with others that said it made a diffrence but not as much as they were figuring on. Does it seem to be worth the time and $ for the parts??
Thanks
Tim D

i'm running the same setup on my 91. with a flowmaster, hi flow cat and the bored throttle body as well as the banks. it did tame the low end response of the bored tb. it was a bit sudden of the bottom before that. as to how much it helped i would say that it was not the "V8 like power" i was thinking. it definatly runs smoother and idles better. there is an increase in performance though not imense. on my setup i gained about 1.5 mpg around town and that is after several weeks of checking so it is real in my case. there was not much real mpg improvement at freeway speeds for some reason.i imagine it makes somebetter poiwer low so i don't have to get on it as much... it pulls much smoother through the entire rpm range and makes much more even power. these are what i am getting from this swap, results may vary!

If you just swapped that manifold onto a stock older engine you would probably feel very little, if anything at all. It just helps in conjunction with other mods. Some say it is worth 15 horses. I really dont think that is true. I can see the logic, but I'am not feeling it while driving. I'am trying to get as much power from it while keeping it naturally aspirated. I would not think it is worth it for just wheeling or daily driver.

Like we both posted, it really does seem to smooth out the idle. I haved not had it long enough to estimate fuel milelage. And it does seem to pull stronger down low. But I think that banks adds to that some too.

Was it worth it to me?? Yes.

To you, I really dont know. It is virtually a free mod, or whatever the junkyard charges you for the manifold, plus cleaners and other assorted items.


Brian

MN,

Opening the gap on the plugs will not help. The OEM's tried that in the '80s when they went to HEI and found it hurt more than helped. I personally am not even a big fan of CD ignitions for stock applictations. When you add high compression and high RPM's that's another story but for mostly stock applictations on FI cars I think CD ignitions are a waste of $$$, my opinion though.

As for a cam change you definitley should see some benefits over stock with the right cam. My personal belief is the 4.0 could really use help in the mid range, where most of your driving is done. A call to a good cam grinder like Crane, Comp or even Isky should yield you a much better cam than stock. Only problem is if your motor is a '97 or newer you may have a problem getting a new cam. Seems Cryco changed the cam setup and no one makes one for it yet. There is also no way to convert to an early style cam. You can send your cam in for a regrind though which should be no problem. Plus than you can get a custom grind made just for your needs.

HTH,
B-loose

MN-Cherokee said:

If you just swapped that manifold onto a stock older engine you would probably feel very little, if anything at all. It just helps in conjunction with other mods. Some say it is worth 15 horses. I really dont think that is true. I can see the logic, but I'am not feeling it while driving. I'am trying to get as much power from it while keeping it naturally aspirated. I would not think it is worth it for just wheeling or daily driver.

Like we both posted, it really does seem to smooth out the idle. I haved not had it long enough to estimate fuel milelage. And it does seem to pull stronger down low. But I think that banks adds to that some too.

Was it worth it to me?? Yes.

To you, I really dont know. It is virtually a free mod, or whatever the junkyard charges you for the manifold, plus cleaners and other assorted items.


Brian

Click to expand...

I am preparing to do the same intake swap. By comparing the two intakes side by side it makes sense that the 99+ intake boosts low end response and efficiency through the rpm range. I can't figure out why some people say that by installing the newer intake you will lose low end response? Unlike the older intake, this one has equal length runners alike most common V8 intakes, giving each cylinder the same port velocity. I also noticed that the newer intake has smaller port cross sectiononal area, 1.26"x1.53" vs. the older style 1.625"x1.375". This also aids in boosting the low speed intake velocity, turning out better torque numbers. Smaller is almost always better unless you've got a 7,000rpm race motor. And definitely the way to go for daily drivers. I think it's a far better design. Overall I think it's just one more thing that will give the 4.0 more potential gains from other mods. I'll bet that the 4.0 will really wake up with the 99+ intake along with a good low-mid range camshaft like a Comp 4x4 Xtreme grind. As for the 15 horse gain on a stock motor, I doubt it. But, it all depends on your motor's appetite. On a built motor I wouldn't doubt 15hp one bit. It's not all about horses though. Torque gets you moving

FUNKYTEE5

I agree, I really dont see where it would add 15hp. But it is slighty noticable. And I think the more the engine is modded, the more it helps.

The only side effect that I can tell so far is a noise issue. I can here the air whistleing. Not so much in the car, but around it. I realize the K&N intake adds to that also. It does not bother me. But you can tell it is there.

Brian

MN-Cherokee said:

I agree, I really dont see where it would add 15hp. But it is slighty noticable. And I think the more the engine is modded, the more it helps.

The only side effect that I can tell so far is a noise issue. I can here the air whistleing. Not so much in the car, but around it. I realize the K&N intake adds to that also. It does not bother me. But you can tell it is there.

Brian

Click to expand...

Are you running a bored TB? or spacer? I hear that some of them make annoying noise. One more thing to add. While doing a mock setup of my project 4.0 head, I found that the older Borla header that I've got had some clearance issues with the #6 runner on the 99+ intake manifold. I had to torch and bend the #6 primary tube on the header to make some clearance. That stainless sucks to work with! Anyways, just a heads up to anybody using a older Borla header that's considering the intake swap

FUNKYTEE5

So your saying that the manifold did not seal correctly to the head with the old Borla header?? I will have to check that out and make sue it is on mine.

I do not have a bored throttle body yet, I'am still runinng the stock one.

Brian

expect a lot of whistling with the bored out t.b. mine is annoying at either side of 2000rpm. above and below fine, right there when pulling hard a big whistle. i forgot to mention eialier that i have the turbo city air tube. i know the turbo city bored tb's cut some grooves inside the body where the sensor ports are inside. this was supposed to tame the noise because it changes the air flow characterisics over the knife edge. i do not know how much it helps but it makes some sense that it should. there is no fit problems with the banks header. it went in great. i did have a weld problem with the banks recently. it cracked at the collector and one of the welds at the between the "3 to 2" colllector blew out out (melted part of the plastic wire harness holder for my injector wires). i live pretty close to banks so i brought it in and they were absolutely fantastic in taking care of the problem. customer service was great, but it helped because i was close and had the day off. keep an eye out there if the exhaust seems noisey suddenly. when i asked they said a few had these problems but that it is mostly a non-issue. i believe them.

MN-Cherokee said:

So your saying that the manifold did not seal correctly to the head with the old Borla header?? I will have to check that out and make sue it is on mine.

I do not have a bored throttle body yet, I'am still runinng the stock one.

Brian

Click to expand...

It would seal with the head, but as you tightened up the bolts the #6 primary came in contact with the #6 intake runner. So actually the seal on the #6 tube may not be as tight as the others. It seems as though the newer intake's runners take a slight drop after coming off the head, making things a lil tighter as compared to the old intake. If your planning on header wrap then definitely check it! I can't quite figure out that whistle thing either? I have a 93 XJ now and it's quiet. I had another 93 XJ and it was noisy above 3k. There's probably some sharp edge somewhere that needs some attention?

FUNKYTEE5

I think I found the whistle. The gasket for the throttle body was not sealing properly. It was kinda turned to one side. I took it apart and reassembled it and it is much quieter. Now it just makes the low whistle from the filter.

Brian

MN-Cherokee said:

I think I found the whistle. The gasket for the throttle body was not sealing properly. It was kinda turned to one side. I took it apart and reassembled it and it is much quieter. Now it just makes the low whistle from the filter.

Brian

Click to expand...

The "low whistle"? You mean the good sound right?

Yeah, the sound it normally makes with a K&N filter. The other whistle was louder and much more high pitched.


Brian

I have been considering this swap, my question to you guys is where is you peak torque now? I am not really interested in peak horsepower but more looking for low end and a wide power band. I heard these are the two benefits of this intake manifold. Has anyone seen any dynos of this mod?
thanks

Bloose said:

MN,
As for a cam change you definitley should see some benefits over stock with the right cam. My personal belief is the 4.0 could really use help in the mid range, where most of your driving is done. A call to a good cam grinder like Crane, Comp or even Isky should yield you a much better cam than stock. Only problem is if your motor is a '97 or newer you may have a problem getting a new cam. Seems Cryco changed the cam setup and no one makes one for it yet. There is also no way to convert to an early style cam.

Click to expand...

DC changed the cam set up from '99 onwards and that is why aftermarket cams are only available up to '98. If you have a '99+ 4.0 don't despair because you can still fit an aftermarket cam for earlier years. All you have to do is buy the '94-'98 camshaft sprocket with retaining bolt/spring/thrust pin and you're good to go. You can buy them either from the stealership or from a junkyard (much cheaper). You can keep the '99+ timing chain and crank sprocket.
If you want to boost torque more at low/medium rpm on the 4.0, go for the Crane 750501 cam (248/260 duration). For a medium/higher rpm torque boost, go for the bigger Crane 753905 (260/272 duration). Summit Racing have both under part nos. CRN-750501 and CRN-753905 respectively. The smaller Crane is more expensive because it's less popular but don't let that put you off. You can keep the stock valve springs and retainers with this one and that'll offset the extra cost of the cam. If you get the bigger Crane, plan on spending another $160 or so on Mopar Performance valve springs/retainers/keepers to cope with the extra lift.

While we're talkin' cams, I've been tempted by the 753941 since I want to build the 4.0 I've currently got for all out high end power. Short of going with a full stroker build (which is what I plan to do down the road, and will definitely want a more extreme cam like the 941 at that point anyways), is there anything else I need to make sure the 753941 will work besides new springs/retainers/keepers as mentioned for the 753905? Still trying to learn all the details behind the dimensions and specs inside Everything I've learned up to this point has been external, so now it is time to go internal.

Just FYI, my '98 head had valves with 3 ring locks, and were not compatible with the Mopar performance springs/retainers/locks. I had to wind up buying a whole new set of older valves to make them work. I don't know if anybody has run into that one before or not.

bump!

Still hoping Dino might be able to shed some light on my question about the 753941 camshaft? Or maybe someone point me in the direction of a good site with info on how to do all the calculations for engine internals. As I don't know precisely what to search for, I never can come up with any good information besides like calculating cylinder volume and compression ratios...