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Installed 4.0L TB, 62mm Spacer, High Flow Intake, and bored out intake manifold...

9K views 35 replies 15 participants last post by  accord387 
#1 ·
Hey everyone, I thought I'd share how my intake mods that I did turned out. I installed a 4.0L Throttle Body, 62mm TB Spacer, High Flow Intake, and bored out the intake manifold to match the opening of the spacer. The whole install took about 3 hours, which includes removing all the old stuff too.

Overrall the Jeep seems to drive much better now. The engine runs smoother and sounds like a nice powerful motor thanks to the new high flow intake. It seems to have more power throughout all speeds and maintaining highway momentum has become less of a chore. After installing the spacer my throttle cable was raised up some and made the gas pedal stiffer (for whatever reason). This solved the problem of my touchy gas pedal from before when I would start to buck because I couldn't keep my foot steady (offroad advantage). I also noticed that my gas mileage is starting to improve somewhat, which is even more of a surprise to me because I'm driving like a madman to "test" the new mods. If I mash the gas to the floor the Jeep takes off and has some nice power. On the way to work I was able to get it it up to 75mph + and still had more throttle to work with, but I did have a 15mph tailwind from behind. Coming home from work the Jeep did start to bog down some and I was only able to maintain about 57 with the gas to the floor (the winds were about 18mph gusting to 25mph with the top down, so I wasn't too upset).

All in all I think the install was definitely worth it. With the throttle opened all the way up the Jeep has plenty of power for a daily commute to school and back. The install only cost $130, which includes the tack cloths and dremmel bits. The TB was $35, The spacer was $32, and the intake was only $50.

On a side note; I do not have a high flow exhuast at all, which could be restricting even more power gains. If I find a good deal on a flowmaster or something I may throw that on just to make it complete, but for now its great. I also don't think its a magical cheap solution to run 33s on a 4 banger as a DD. I know some people do it, but the power increase was not significant enough to pull along that much tire. I think regearing to 4.88 is your only real solution to bringing back power.

Happy Jeepin



 
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#3 ·
EABiker said:
You didn't bore that thing out while it was installed on the motor did you? All those aluminum shavings in the intake can potentially cause you to have a bad day!

E
I stuffed it with about 5 tack cloths (one for each split and one in the middle) and thoroughly vaccumed it with a shop vac. Worked out fine and theres been no probelms since.
 
#5 ·
I was considering a homemade intake, but I figured I'd get somethin a little better for the same amount of money off ebay. Ebay is great for performance parts. Just search for "Jeep Intake" or "4.0L Throttle Body Spacer". I'm sure you'll find what you are lookin for, for an excellent price.

The intake is great. It was only $30 I believe and $20 shipping. It sounds cool and it really helps the new throttle body get air faster. The only thing I'm worried about is getting water inside of it...I need to make some kind of splash guard or somethin.
 
#6 ·
micfly83 said:
Ebay is great for performance parts. Just search for "Jeep Intake" or "4.0L Throttle Body Spacer". I'm sure you'll find what you are lookin for, for an excellent price.
Gonna check it out...any chance you remember the seller's ID you bought from?
 
#7 ·
#8 ·
I want to do this to my 95 YJ with the 2.5.
When i go to junkyard, what should i look for? I am only wanting to put on 4.0 throttle body, and spacer. What all do i need, as far as sensors and such? What year 4.0 engine do i want to take it from? Also, what should i be looking to pay for these things?
 
#9 ·
dabomb5756 said:
I want to do this to my 95 YJ with the 2.5.
When i go to junkyard, what should i look for? I am only wanting to put on 4.0 throttle body, and spacer. What all do i need, as far as sensors and such? What year 4.0 engine do i want to take it from? Also, what should i be looking to pay for these things?
I can't really help you hear. I lucked out and got one off JeepsUnlimited.com from another member who was trying to sell his because he rolled his Jeep etc. It was off a 4.0L YJ and he only wanted $35 for it. You can search for car parts over the internet at carparts.com, I think??. And I believe you can use a throttle body off a Cherokee or somethin from the same year, because the engines are the same. I'm sure someone will chime in with the exact details though :D

The sensors are a moot point. I used the 4.0L sensors and so far they have worked fine. It idles correctly sometimes (around 900 rpm) and sometimes it idles at 1500. When I first start her up in the morning in cranks up to 2000, but then readjusts down to the normal idle. I plan to correct this by just swapping out the AIS motors if I feel the need too. I'm going to leave the TPS; so far it has worked fine and I have no need to swap this. If you have a 5spd, your throttle cable should not be an issue either with the addition of a spacer. As stated above my gas pedal is now a little siffer, which I prefer.

As for the year you want the throttle body from; obviously you want one as close to the year you have. I believe any 91 and newer will work, but I would stay away from 97 and over, because they may have done something different with them. But again I'm not positive on this.

I belive when I was searching on the carpart websites the throttle bodies ran about $60 or so. You could easily spend $150 on one, but its not really worth it.
HTH
 
#10 ·
micfly83 said:
There were basically two intakes i had to choose from

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7969511440&category=38634
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7970647012&category=38634

I chose the second one because it looked like the filter was further forward and protected by the fan shroud from water spray from the fan.
Thanks...was just looking at both of those. The first one sits pretty high, was wondering if there'd be any greater protection from water at that height.

dabomb5756 said:
When i go to junkyard, what should i look for? I am only wanting to put on 4.0 throttle body, and spacer. What all do i need, as far as sensors and such? What year 4.0 engine do i want to take it from?
Been told to get a 4.0 TB from the same year as your Wrangler, even if it comes from a Cherokee, the year is the important thing. You'll reuse the sensors off the 2.5 TB. Seems very simple to do and I hope to take care of it once the weather decides if it's spring or still winter.
 
#11 ·
Shinner said:
Thanks...was just looking at both of those. The first one sits pretty high, was wondering if there'd be any greater protection from water at that height.
Thats true, the one I have sits at about the height of my headlight and I wont be going into water that deep to get it sucked in :drool: . After hitten mud holes and I noticed that mud is sprayed all over the inside of the hood. Its basically from it splashing up and hitting the fan and splattering everywhere. The first intake seems like it could get some of this spray vs the other one, which is a little more protected in the area thats in. The first intake looks like it could have a little more of a ''ram" or "higher flow" effect, because theres nothing blocking it and thers not as many curves in the piping.

I'm sure they are both good :thumbsup:
 
#12 ·
I just finished a similar set up, but I built my intake tube out of 3" aluminized exhaust, and some copper couplings jb welded to tube for hoses. Total I spent $105. Luckily the TB I got came with the 90 degree elbow from the TB.

K&N Filter $58.99
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7978176550

TB Spacer $19.85
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7978717138

4.0 TB $26.84
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7977551395



 
#14 ·
micfly83 said:
..........
On a side note; I do not have a high flow exhuast at all, which could be restricting even more power gains. If I find a good deal on a flowmaster or something I may throw that on just to make it complete, but for now its great.
...............
Dynomax has a killer rebate on their ultra flow stainless steel mufflers, I got mine for $13 after rebate, others got theirs for free (after rebate).

http://www.jeepforum.com/forum/showthread.php?t=167800
 
#15 ·
unless you are going to feed it more fuel, and spark, you wont see significant changes with this mod.
it sounds different, but you wont have any "real" gains.
i did it on mine, and even with the larger injectors, i wish i had spent the money elsewhere ;)
 
#16 ·
#17 ·
dabomb5756 said:
yj x, now do any type of mudding or water crossings. See what happens.
Why, what do you think will happen? Suck up some water? I haven't really taken it off road much, but I probably will once my new tires come (33 bfg mt).
 
#19 ·
Well most likely, while driving thru a creek at a spped of over 5 mph, water will splash all over the filter. Then, water can be sucked into the engine. Small amounts of water (Mist) Coming in the intake is not all that bad, it will not kill the engine, but it will run a little worse.

But whenever i do any sort of offroading, i know that the whole inside of my engine compartment is COVERED in mud/water/sand/ whatever. ANd i would not like to have an open element air filter to be covered with water, or mud, or anything for that matter.
 
#20 ·
I've gone mudding with the new intake and all that (signature) and had no problems at all and hit it going a lot faster than 5mph. The filter is right behind the headlight and protected by the fan shrowd so it doesn't really get any direct spray. My engine did run rough at one point but I believe it was from water getting on a spark plug or something...it cleared out within seconds.
 
#21 ·
I haven't had it in the mud or water yet but though others might be interested in these results of the swap:

I started a couple of months ago with a stock 94 YJ, I4, stock tires and wheels with 70k miles. :) New exhaust and cat (also stock) installed by previous owner 6 months ago. It got 18.7 MPG and performed like a peppy little 4 cyl.

I upgraded tires and wheels to 31's. It got 14.8 MPG :( and performed like a mo-ped. ( HWY speeds were tough with any wind or incline)

Wanting the little bit of zip I had back I changed to a 4.0 TB with 1" spacer (no spirals in spacer and no modification to the manifold) and installed a $50 performance intake tube and filter. I'm now getting 17.9 MPG and it's performing like a peppy little 4 cyl. :) Overall a good modification!

I just added some lift shackles and pulled the air tube out of the fuel tank to get 20 gal capacity rather than 15. We'll see how or if that effects the MPG.
 
#22 ·
dabomb5756 said:
Well most likely, while driving thru a creek at a spped of over 5 mph, water will splash all over the filter. Then, water can be sucked into the engine. Small amounts of water (Mist) Coming in the intake is not all that bad, it will not kill the engine, but it will run a little worse.
Maybe it would be worth fabricating a splash guard. It probably wouldn't be too hard to just bolt something to the air box bracket that would protect from splashing.
 
#23 ·
nice clean install, how did you insure that the manifold was 62MM?
 
#24 ·
Shinner said:
Where'd ya get the intake? Homebrew?
i have one KN filter its for a YJ with 6 cyl combine that with the 4.0 TB im also selling and you have an asweome combo

if you interested in both shoot me a PM
 
#25 ·
yj_x said:
Maybe it would be worth fabricating a splash guard. It probably wouldn't be too hard to just bolt something to the air box bracket that would protect from splashing.
He's got the right idea. My K&N intake came with a splash guard. That's the only way to go if you play in water, why risk it.
 
#26 ·
phlex234 said:
nice clean install, how did you insure that the manifold was 62MM?
I took one of the gaskets that came with the spacer and used it as a template to draw a circle. The whole grinding process took about an hour I think with the help of a friend to hold the dremmel in the right position. I probably couldve done it a little better but some girls came over so we kinda got a little careless :drool: . It worked out great though.
 
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