Topic: 2.5l ITB's

[Steve97tj]

Has anyone ever ran an independent throttle body set up on one of these motors?

Been reading about turbo'ing my TJ's 2.5 for the past few years and although i like the idea i'm not sure if i'm 100% sold on it yet. ITB's provide a quick throttle response, flat torque curve. I don't really know much about them but from what i can figure, ITB's with a megasquirt set up would yield you a pretty fun little motor.

[Jeffy]

I've never seen one but I love ITB's.  I think you'd have to build an adapter from scratch which would be the hard part.  Then you have to be able to sync the TB's which was always a pain with carbs.  Not sure about EFI though.

[sharpxmen]

this engine is not a high rpm one and you're also limited on the cam profile with the lifters, i doubt you'll see a lot of improvement over a large t/b and a good porting job (which you would have to do anyway with the itb setup).

[Steve97tj]

Ya kind of reading into it it seem'd like it wouldnt be very all that great because of the head. I still think you'd get some gains from it and sound cool as hell but would be expensive, unless you had done several before.

Honda guy's use the gsxr 750 itb's with a cut up intake manifold to keep it on the cheap as well as some type of standalone.

[sharpxmen]

we're talking an motorcycle engine that goes to 15k rpm and overhead cams, not the same thing, you'll never run that at 2 to 3000 rpm. It can be done but i don't see the point honestly unless you spend tons on pistons and connecting rods, a roller cam, roller rockers not to mention a custom ECU so you can spin it at 7000 rpm or over to get something out of it.

[Jeffy]

Well, for what it's worth,  people have put the GSXR ITB's on Suzuki Samurai engine for a while.

<a href="http://www.youtube.com/v/5lFe8jEHon4" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/v/5lFe8jEHon4</a>

[grumpygy]

Wouoldn't they end up with more HP if they just used the whole GSXR engine.

[Jeffy]

Wouoldn't they end up with more HP if they just used the whole GSXR engine.

GSXR engines have made their way into 4 wheels before.  Although I think they all use a chain drive.

[grumpygy]

GSXR engines have made their way into 4 wheels before.  Although I think they all use a chain drive.

Chain drive from Transsmission to transfer and then Normal from there.  Does not seem that had.  Be a Busa would make it fly.

[sharpxmen]

Chain drive from Transsmission to transfer and then Normal from there.  Does not seem that had.  Be a Busa would make it fly.

i think you'd burn the clutch, there are also a few other things that are wrong with that setup (i'm talking about the motorcycle engine/transmission in a 4x4 vehicle).

EDIT: as far as the chain to t-case since the bike engine/gearbox is 1 unit i can't see it done if you install it under the hood, be better off to go with a driveshaft between them so it's the same rotational axis (install the engine longitudinally).

that's only for assembly concept but still not suitable no matter how many ponies it makes (too much weight and rotational mass compared to a motorcycle), if the AX5 couldn't take it i doubt the transmission from a bike will not to mention the lack of torque at low rpm - the max torque for the GSXR 1000 is 80ftlb but that is at 8000 rpm, at 3000 rpm is about 40ftlb and can't tell you below that since graph i was looking at starts after 2500 rpm. Compare that to our 2.5L which makes about 120ftlb at 1500 rpm and maxes out at 140 to 150 depending on the year at around 3000 and it still struggles to get going. the Jeep 4.0L I6 makes 235ftlb at 3200 rpm.