Topic: 4.0 TB swap

[jonesy]

Just a quick question. I have a 97 TJ with 2.5, I am going to do the swap to a 4.0 TB. Do I need a TB from a TJ or caN it be from a grand cherokee? Anyone know if the years matter? Thanks

[Sidetracked]

Mine is from a xj, A zj will work also. Just make sure it has 4 mounting bolts.

[sharpxmen]

make sure it's the same as your's - some have the MAP on the t/b, not sure if you have it there or not but if you do you'll need one with the vac port and the mounting holes on the t/b

[jonesy]

Thanks guys, Mine does have the MAP sensor on the TB. I didnt realize some had it there and some are on the firewall.I guess i will have to find a different one!

[Torch_Ind]

I couldn't read your thread from your display pic

[sharpxmen]

Thanks guys, Mine does have the MAP sensor on the TB. I didnt realize some had it there and some are on the firewall.I guess i will have to find a different one!

not sure what your budget is but in case is not tight have a look at the garage sale section - i have a TJ 64mm t/b and spacer for sale - see if it's like yours (there's a few pics in there). If that's not the same Bounty Hunter in the vendors section sells the 62mm ones and he might have one that works for you

[AC3tj]

i have the same set up in my jeep and i was thinking of doing the same swap, but from what i have been hearing it doesnt sound like its worth it and i feel like it would kill mpg.
let me know how yours turns out.
has anyone check mpg with this swap done im just curious.

[sharpxmen]

i have the same set up in my jeep and i was thinking of doing the same swap, but from what i have been hearing it doesnt sound like its worth it and i feel like it would kill mpg.
let me know how yours turns out.
has anyone check mpg with this swap done im just curious.

since otherwise it's competing with all the hybrids out there

[AC3tj]

haha no im was just wondering because from the dyno charts i saw it seems that the swap only helps in the higher rpms ( which i rarely reach) so if it killed mpg i didnt think it was worth it. unless im wrong!

[sharpxmen]

haha no im was just wondering because from the dyno charts i saw it seems that the swap only helps in the higher rpms ( which i rarely reach) so if it killed mpg i didnt think it was worth it. unless im wrong!

larger intake and better air intake flow help with the VE (volumetric efficiency), regardless of the rpm the more air you can fill your cylinders with the more fuel you can burn and that's where the extra power would come from (at any rpm as long as you don't run lean). you can always not press the pedal all the way and that will save you gas (so opening the 4.0Lt/b about 90% would be the same as just leaving your stock 2.5 on - just picked this number out of the air, didn't calculated the actual opening to match the old one).

[AC3tj]

well thanks for your input i was thinking that if you went with more air going in  then you would need more gas as well wich would give you more power but also use more gas because to keep the fuel/air ratio the same the amount of gas would have to be incresed which is what i was referring to
 because according to the charts i read it is not a noticable increase in torque for the trouble to do it but i have not done it myself ( this is why i asked, but it seems that you have done this swap so that makes you god on the subject so you tell me the right way)

[sharpxmen]

well thanks for your input i was thinking that if you went with more air going in  then you would need more gas as well wich would give you more power but also use more gas because to keep the fuel/air ratio the same the amount of gas would have to be incresed which is what i was referring to
 because according to the charts i read it is not a noticable increase in torque for the trouble to do it but i have not done it myself ( this is why i asked, but it seems that you have done this swap so that makes you god on the subject so you tell me the right way)

not sure why my reply brushed you the wrong way, i was just answering your question. you can't make more power without more fuel or better efficiency in burning fuel (or bsfc) and in this particular case that won't change.

[AC3tj]

ok so Im interested in doing the swap is there anything i need to do other than swap the new t/b and spacer.

[jonesy]

Just make sure to swap your electrical components from the 2.5 to the 4.0

[Jeffy]

No one reads the FAQ anymore?  http://4bangerjp.com/forums/index.php/topic,8.0.html