Installing a 4.0L Throttle Body on a 2.5L Jeep Engine 

I never thought of it's usefulness at elevation. Very interesting

@@JeepSheepTV indeed makes a difference with elevation. like a turbo, operates different under barometric pressure.

Omg thank you😊

Did y’all figure out how to reduce the blow by? 4:17

I certainly believe that you are right. I have cleaned out the vent on the top of the crank case that has a hose going to the air box (it was completely clogged). That helped a ton! I am hoping to do a budget rebuild on the engine this winter which will involve lots of cleaning. Stay tuned for that!

Jeep Sheep TV any questions feel free to email me @ annaleejean2017@gmail.com if I don't know the answer I certainly know someone who does

@@dallaskelley7395 I have some family members with a lot of experience in engine rebuilding but I would love to talk with you more about other modifications and common issues. Thanks for commenting!

I always assumed that was blowby from leaky valves and age since my air hose and elbow was clear. Worth a shot for the price of a gasket and a little time

Cool! Thanks

Wasn't the 2.5 actually based on and shared parts with an OLDER straight 6

@@maverickricardo4478 The 2.5L four was made first and a cousin to the AMC 199/232/258 inline six. Cash-strapped AMC made a more efficient design of what they already had for market. The 4.0L six blew everything new away in late 1986 when it came out: watch the movie "The Goonies" for proof! ;]

@@slant6guy No disrespect... why spell fake that way?

I thought spacers were useless on dry intakes?

What is the optimal spacer size between the TB and the manifold? And why does that make a difference? I have seen a lot of guys that have done it, but I've never heard what the advantage is. Thank, in advance!

@heatmizer-jim6762 Just adds velocity to intake. Not a major mod, but combined it helps

I did a video on that! And I agree! Probably my favorite mod so far and at a great price!

Does this work for a 94 2.5l Manuel trans??

@@issacayala4254 yup

@@issacayala4254 if your air meter is on the intake or throttle body then yes.

What do you mean by mounting it to the firewall? Jeep sheep i tried to find your video but couldnt.

Normally I would agree with you but since installation the 4.0L TB has developed pock marks as well.

Is it from debris getting caught under the air connector making the pits over time? It’s not really a hard metal

He does... That appears to be a "drop-in" K&N filter (at 3:13 ).

K$N is poop compared to some paper filters. Alot of particles still.get thru on K&N filters

Would not recommend a K&N as they let too much crap through. The 2.5 air box is the same size as the 4.0 including the element. No need to upgrade.

Seems to be a common problem, I have heard many people with the same complaint. I'm contacting corporate!

What size tires?

Jeep Sheep TV 33x12.50x15 BFG’s 4:10 gears

@@socalRooster have you changed your speedometer gear? If not you might actually be going 65. When I switched to 4.11s my top speed dropped from 80 to 75 but I get there faster and maintain that speed easier. When I could hit 80 if the wind blew just a little bit I would drop to 70. Keep in mind that I have electric fans, 4.0 throttle body, ported intake manifold, 4 hole injectors, a header, and a remanufactured engine. All if which I have or will have videos for lol.

Mine does on a good day? 2.5L/Manual?

My 88' 2.5l 4speed 2wd with 4.10s comanche lowered 3" with 235/60/15 tops at 107 if you wind it up

That's an interesting theory. I'll look into that!

Fascinating, I replaced my engine with a long block. It was the same cost as the machine work I would need to rebuild. The new engine sounds much better lol

Lol I used to think that this engine was the 2.4l and the earlier pre 90s version was the 2.5l. I have since learned that the late model year TJs came with an over head cam 4cyl and that was the 2.4l. Anyway....

Yes they did make one. Research

Good to know! To be clear, did you say that you do have upgraded exhaust or not?

@@JeepSheepTV Haven't touched the exhaust yet.

@@amorag59 gotcha, it does kinda sound like the backfire could be in part due to restrictive exhaust? Or maybe timing? If you figure it out let me Know, this is a good learning moment!

@@JeepSheepTV Also worth mentioning I think my choice of injectors was an oversight on my part. I noticed a youtuber swapping to 4 hole and their "tuning" consisted of switching their year of 4.0L injectors (they had a 4.0) until it ran in closed loop (and more or less stoic). I didn't really check mine haha, but I'm sure it's running rich, my injectors are 96-98 meant for a 4.0 (~23 lb/hr) which I'm sure is much more than my 2.5L needs, I just need to find info on what the 2.5 is supposed to flow and where to find 4 holes at that flow. I could see this being a part of the backfire problem.

@@amorag59 19lbs for them.

Oh no! What problems were you having? I haven't had issue with mine but that doesn't mean problems can't happen. I'm very curious.

It really depends on the wind. I've had days where I couldn't get over 65 based on wind direction. Also depends a lot on your tire size and gearing. Check out my YJ performance playlist. Look first at the IAT sensor video and throttle cable video.

Fascinating! Do you have any idea why the corrosion is accelerated in that Area?

Jeep Sheep TV I seen what causes it in one of my college textbooks but I don’t remember what exactly does it, I do know that it’s a sort of wear on metals, I’ll look in my book to see if I can find the answer for you.

Thanks for the comment! I did not know that (obviously). I'll be more careful with what brushes I use next time.

MY 2.5 LITER ENG HAS ALOT OF BLOW BY. I WILL TRY YOUR SUGGESTION.

I guess I’m just lucky my 2.5 has no blow by. I cleaned the valve cover so I know it’s breathing but barely any oil.

I need to get one of those and supercharge it... sounds fun

This doesn't really increase power (except maybe a little at wide open throttle) but it does increase throttle response. If you are talking about carbs then that's a very different scenario as the carburetor controls fuel flow as well and one for a 2.5L will be tuned very differently than one for a 4.0

FYI, they have done some investigation into roller rocker arms moving up from a 1:15:1 to 1:16:1 giving .030 more lift (duration) which acts to get more air and exhaust out of the stock cam (a 1:17:1) will greatly increase air and exhaust .060 more open and duration. However, the 1:17:1 you will be modifying your valve cover and can only use the non-adjustable roller lifters, may be altering the stud lengths to get them all the way down to come back a half turn (hopefully can get them -o-ed to back off that half turn (my luck so far is everything I read and try to carry out has had a glitch (accept for the body wrap carbon fiber fenders went well), the lifters hit. Someone did a lot of engineering for this bolt on mode. I'm in the middle of this now, I read a lot from the race engine builders, seems that TB spacer hasn't added to the top end of (interstate speeds) but they all said its better throttle response.

@@rubyclay5543 yes, ultimately changing angle or length of a rocker, will slightly mpdify opening a valve as well, same effect as cam

31's, 4.11 gears, 70-80 was hard to come by but not impossible. I put on a supercharger, and now both are much easier!

cleaner instead of dirty. less work on his part

It's a good theory but a year later the 4.0L TB had pock marks as well. Still not sure why.

@@JeepSheepTV Interesting. Looked like casting marks to me. Let us know if you ever find out.

Fascinating, looks like you are right. However the brass brush didn't leave any visible scratches and worked well for removing gunk when my nylon brush did not.

@@JeepSheepTV kool kool

That's why people use brass knuckles and not aluminum knuckles..

True but machine time vs a $10 junkyard part. Either way you have to take the sensors off.

It still increases throttle response since you are letting in more air at less throttle. I assume when porting the manifold matters is in scenarios closer to wide open throttle. Porting probably helps everywhere, but I have no data to support it. I ported mine later on, if that helps...

It really just changes your throttle response. For better mpg I would start with just cleaning everything, especially your valve cover. For more power upgrades, I would start by moving the IAT, I have videos on both of those things, and a few about superchargeing too.

@JeepSheepTV it's been a while since I cleaned everything. Also I watched your SC series, dad and I are planning on turboing mine. Also thanks for making yj and 4 cylinder content. As a high schooler with a kinda rare first vehicle and engine it's nice seeing a channel with this much support for the platform.

The 2.5L is an incredibly reliable engine in whatever vehicle it's in. It's just not very fast.

@@JeepSheepTV Got it......thanks again

@@carloscartaya9932 still have the cherokee?

That's pretty normal for cold start. After it has been running for a while it should idle at a lower rpm around 800-1000

@@JeepSheepTV so you are saying that is normal, it is just so different than my other jeeps I have owned,

@@serf3469 if I am understanding what you are saying correctly, yes, high idle at cold start is normal. Unless it lasts for a really long time, that could be a vac leak or something else but if it's just at cold start you should be fine.

So you are saying that you have a 4.0L throttle body with the 2.5L sensors on it? Did I read that correct?

@@JeepSheepTV I have 2.5 engine with the 4.0 throttle body installed, but the shop didn't switch the sensors. So the 4.0 sensors are still on after install.

@@beavers7979 I believe that the idle air control valve has a different pin-out on the 4.0L than the 2.5L I'm not sure how they could have even hooked it up. Does it idle?

@@JeepSheepTV i installed 4 hole injectors, cold air intake, iridium plugs, header, exhaust system, and the throttle body. Pick it up, drove 10 minutes down the road and over heated bad! They had to tow it in and found that the head gasket may have blown. Out of all the parts they put on, the only thing the shop didn't do right was putting the 2.5 throttle sensors/plugs on the 4.0 throttle body. Just wondering if that would cause the head gasket to blow

@@beavers7979 You see, the 2 sensors that are present are idle air control and throttle position. If the throttle position sensor feeds incorrect info to the computer you could have a lean mixture resulting in more heat but the values should be the same from 4.0 to 2.5. The only thing that would be really different is the idle air control but outside of idle that shouldn't have affected the engine temps either. None of your mods should have any affect on you head gasket unless it was it was already about to blow and the marginal increase in power is what set it over the edge. Unfortunately I don't think you have a case. I would be more worried about the engine cooling system ( fans, water pump, thermostat, etc.)

Do you mean the intake manifold? If so, I did that and created a video about it!

As far as I know, if it's a 4.0 in the Grand Chrokee then it should work. Fun fact those use the same style fuse panel as the YJs. Keep that in mind if you lose your cover and can't find another one.

Keep in mind that mine is lifted, with larger tires. However, if you are looking for a jeep for the first time get a 6cyl, I love my 4cyl and you can have a ton of fun with one but jeep made a killer straight 6 and that engine is a major part of the jeep culture so I would get one of those. But if you do get a 4cyl... join our little band of misfits and I'll see you back on this channel.

@@JeepSheepTV Yeah I know about the 4.0. I'm considering the 4 cylinder because it's rare and in the older trucks. It's probably more AMC than Chrysler. Also have an '88 4.0 with leather on my radar.

@@VinylToVideo My 01 Deville does 30-33 mpg

Yup, look at the video post date. Gotta start somewhere. I used to have a hard time remembering names and numbers when on camera, it was really frustrating.

@@JeepSheepTV my dumbass never paid attention to that. So this modification increases throttle response slightly. Did you ever port the intake to more closely match the 4.0L throttle body?

Yes I did, there is a video about it. But basically a Dremel some carbide burr cutting tool thingys and just shape it till it feels "right". The science here is vague but the idea is to reduce turbulence.

I used the 2.5L TPS. Not sure if it matters

Re-gear, basic maintenance, clean everything, move the IAT sensor, supercharge it.

Is it the ticking noise? That's the lifters, unfortunately it's normal. Some have tried some lifter additives in the oil. I've found it's happier if you let it rev a little more while driving. Like let it hit 5k every once in a while to get oil in there.

@@JeepSheepTV thank you thank you I love your videos man they’ve helped me out quite a bit with my Jeep and my girlfriends. After all the 2.5 is the 4.0 with two cylinders loped off. Keep up the great work man

Spacers work on a series of fluid flow principles that depend highly on the geometry of the manifold, head, and a whole bunch of other variables. Basically, they provide different results for different engines. There was a dyno test done that you can find online saying it gives about 5hp for this engine. Some spacers are priced way too high for 5hp in my opinion but that part is up to you.

@@JeepSheepTV thanks a lot!

@@JeepSheepTV I just bought a jet throttle body spacer for 12 bucks on Amazon.

I went to a pick yourself junk yard and pulled it off of an XJ. The same throttle body was used on just about all the jeeps with 4.0L fuel injected engines. They are very easy to find.

They are also on Dodges.....thats why I'm here, my lil 2.5l Dakota needs alil more power lmao

I think that grinding the intake manifold will make a difference. In fact I plan to make a video later of me having that done. The wider opening of the TB gets instantly choked down by the smaller diameter opening in the manifold. If there are any gains from this modification, grinding the manifold would provide gains for the same reasons

@@JeepSheepTV nice! I'll wait to watch your video first! Ha Thanks for this video, very detailed and easy to follow along! Subscribed! i still have to swap out the fan with an electric one, among other projects first. I have the tb already though.

@@richconrad4554 Awesome! Thanks for the comment! I am working on an E-fans video right now where I will include some wiring diagrams that have worked well for me.

@@JeepSheepTV nice, I'll wait to do that video as well! Haha i posted a link to this video in wrangler forums, hope it helps others out too!

@@richconrad4554 Oh wow! Keep doing that! I'll have you to thank if I get a ton of views.

Maybe not as you need the functionality of the current TB

@@JeepSheepTV how about an 89?

That is true if the intake manifold is the weakest link, if the throttle body is the weakest link then replacing it will help flow. I honestly don't know and the hp gains if any are so small its impossible to tell. I did port the manifold later on just in case. :)

@@JeepSheepTV after you ported it did you notice any difference?

Lol 22k views and you are the first person to say something! I could not for the life of me remember what it was called.

Lmao I was just looking through the comments and I was like how did nobody catch onto that yet! I’m working on a customers TJ right now and I’m gonna try and convince him to do this swap. Nice video!

@@dylanrowan6626 I recommend it, it's crazy cheap to do and new shiny parts are usually a good thing! I recommend boring the manifold as well (I have a video for that) it's also easy lol

Swapping the throttle body and difference in response and power?

@@dylanrowan6626 I personally have no hard data but there was a dyno study done that showed 5hp gained.

The 4.0 and 2.5 have different bellhousings. The 2.5 shares a bellhousing with GM v6's and such

It's custom made. If you really need one send an email to jeepsheeptv@gmail.com and maybe we can work something out

That's a great video suggestion. I'll do that. Mine is just a generic fan I bought on Amazon. I can explain the wiring in the video.

@@JeepSheepTV did it help the HP at all ....also this the best vid on the TB upgrade on you tube ...it is the only one so it the best ...good job dude

@@kennethlindahl9206 Not sure if you are asking about the fans or the TB but if either helped with HP it would be in the single digits. Unfortunately with gains that low it's hard to tell without a dyno. According to what I know of physics, either mod couldn't have hurt though. Thanks again for the comment and compliment! I'm hoping to make more videos and to improve them all the time, so check back for more!

@@JeepSheepTV subbed and watching 94 XJ 4\11 gears in a 8.25 behind a 5 speed..... good shape except paint

@@kennethlindahl9206 Thanks! And that sounds like a beast

Yea, and somehow I've never gotten that good since this video... some strange kind of irony.

33" mud tires

Change the gears or go back down to 29s

No clue, completely different engine architecture. Check the diameter of the TB on the 2.4L for some reason I think it already is larger, similar to the 4.0 TB

thanks for the reaction and for you time and for the answer, i will this check out, i have a one question about the eatonm62, is it possible to install in my car jeep Liberty ( cherokee ) 2.4L 4 bangs handly, sorry for my bad english and greatings from Europe Netherlands l👋👋👋

@@recepgokkaya6602 I'm sure it's possible. I believe that engine had a turbo option in the dodge Neon so there might be an easier way to turbo it. Either way that means there could be an ECU out there that knows how to handle boost. Sadly I know very little about that engine.

The idea is similar but I can't imagine it would accept a TB off of a 4.0L

@@JeepSheepTV I’ll do some research

Petal down, shift late, no wind

@@JeepSheepTV do you have a lift or bigger tires on your jeep? Or is it all stock

@@tylerlipscomb4878 I currently have a 1.5" spring lift and 2" body lift with 31" tires

@@JeepSheepTV I'm running 31's and 4inch rough country and my 2.5 is a complete dog. Did you re gear yours?

4.88 gears

Lol yea...

So the 4.0 throttle body got the pock marks after 4 months of use so I don't think it's the casing... hmmm

@@JeepSheepTV The little engine was cheaply cast aluminum. The 4.0 was cleaned up on a lathe. Or do I have it backward?

@@neshobanakni what I am saying is that they were most likely made from the same process. The 2.5l had pock marks on it after years of use. The 4.0l gained pock marks after a few months of use. So something from my engine is causing the marks not the manufacturing of the throttle bodies themselves.

@@JeepSheepTV You are likely correct.

@@neshobanakni The only real question that remains is, what is causing it?