Topic: 4.0 throttle body question..like or dislike

[kenandtj]

i went to a local salvage yard yesterday and i found a tb for sale they wanted 75.00 for it.i know i can find them cheaper but my real question is do they really make a difference? i have read a lot of things saying they dont really do anything.....but then i find some that say do it it's worth it.. whats the opinion round here? thanks

[chrisfranklin]

I use a 62mm TB which is slightly larger than the 4.0 version.  I don't think the 62mm or 4.0TB hurt performance on a 2.5 and they probably help slightly at mid-rpms and WOT.  I don't have any real, immediate reference though since I made the change a while back.   

[Bounty Hunter]

They are worth it, but you want to ensure your intake manifold opening is as large as the TB, and throw on an airtube and conical K&M filter to get the most benefit from the larger TB.

[kenandtj]

i do have the intake and that it self was a huge improvement....makes alot more noise, but still more performance. so worth it....any one else? i sold my brush guard so i am thinking of doing this or shocks next, so any help would be great...my next investment is going to be the jet chip----hopfully!

[SKI BOY]

I have the 4.0 tb with tbs and noticed a decent increase in both take off speed & highway top end. Shop around on ebay you usually can pick them up for $40-50 on a good day.

[gomi]

I thought it was a noticable difference, but $75 is too much.

[GreenBayjeeper]

I got my TB from a salvage yard in town for $25-30 dollars.  Coupled with the TB spacer from eBay ($10-20?) it was well worth the money.

[dunklervogel]

I got my TB from a salvage yard in town for $25-30 dollars.  Coupled with the TB spacer from eBay ($10-20?) it was well worth the money.

x2

[wrangler387]

I didn't notice much of a gain with my TB/Spacer/ported intake plenum with a AEM conical filter/aluminum tube.  Then again i barely ever REV the motor up high, so maybe thats why i didn't notice much of a difference. But once i put a header/2.5" exhaust on it definately made a difference. I wouldn't spend $75 on it thats for sure.

[Jeffy]

Unless your air tube setup is long and routed to an actual cold air source, all you're doing is sucking in warm engine heat which will drop power.  So choose your CIA's carefully.   1+1=-2 in this case.

[wrangler387]

There is basically no difference in inlets temps between a "ram style" intake and the stock set-up (i didn't notice temp changes when i switched to the ram style from my stock set-up with a WIX filter). I didnt see much of a gain from the intake, i did the 4.0/spacer/intake plenum portmatch first, and didn't notice anything, so i then did the "ram" style intake hoping maybe that would help some, but i still noticed barely anything. The jeep already has decenly hot intake temps just because of the fact that the intake/exhaust flow right by each other on the head.

[neale_rs]

I´m also getting ready to do this swap.  Does anyone know of a dyno test of the 4.0 TB upgrade? 

My concern is that the extra throttle response is simply due to a larger air opening per peddal travel distance, making one think there is more power but it may be just a touchier throttle.  Has anyone felt the throttle was harder to control off road, making you feel like you need a hand throttle?

[kenandtj]

I´m also getting ready to do this swap.  Does anyone know of a dyno test of the 4.0 TB upgrade? 

My concern is that the extra throttle response is simply due to a larger air opening per peddal travel distance, making one think there is more power but it may be just a touchier throttle.  Has anyone felt the throttle was harder to control off road, making you feel like you need a hand throttle?

i would be very interested in that test. You guys are a great source of info.Thanks to everyone that answered..ken

[Jeffy]

I´m also getting ready to do this swap.  Does anyone know of a dyno test of the 4.0 TB upgrade? 

My concern is that the extra throttle response is simply due to a larger air opening per peddal travel distance, making one think there is more power but it may be just a touchier throttle.  Has anyone felt the throttle was harder to control off road, making you feel like you need a hand throttle?

Well, I'm able to lug my engine below 500rpm and not have it die.  It's a lot easier to catch when it is hinting of dying, though.  Offroad, the smoother throttle is great when having to start from a dead stop on an obstacle.   You're not jjumping on the throttle as much.  The other thing is at higher RPM's the engine is smothered a bit.  But then if all you did was put a 4.0L TB on an otherwise stock Jeep, you'll probably see a decrease in performance.

As for a dyno print out, I doubt anyone has one.  Dyno numbers change from dyno to dyno also.  BUT I do know the person how told me about this swap, did test his on a emission tester which showed air flow.    He lives in CO where the air is thin and from his tests, he said his engine was breathing at sea-level.

[jfrabat]

I got my 4.0L TB from a salvage yarfd for about $30, and a TBS (62mm) from eBay for something similar to that (dont remember exactly how much it was).  When I installed both, the idle RPM's would not come down from 1,500, so after a couple of days of this (I figured that the computer had not adjusted before that), I took off the TB and left only the spacer.  Maybe my TB had some problems (I used the sensors from my 2.5L TB, so I know it was not that).  In any case, for me, it did not work.  And I would not advise you to pay $75 for that, as they can be found cheaper on eBay or by looking in a salvage yard.

By the way, JP had an article about the performance gains of putting a ram air type intake.  Check it out at:
http://www.jpmagazine.com/techarticles/engine/154_0706_jeep_wrangler_tj_intake_dyno/index.html

Felipe