Throtle body performance

[jeremyswrangler]

Does anyone have a bored out throtle body on their inline six? I was wondering how well they increase performance. Do we need a ECM chip or anything ? Thanks!!:confused:

[My1stJeep]

I have a 4.0L bored out TB on my 4 banger and it works great.

I got mine from someone who had it on his 6, liked it, but was going to move up to the larger bored out Rubicon Express TB for a bit more performance. My reccommendation would be get the RE bored out TB.

[Y2K-XJ]

There should be no other mods needed, unless you go with a extremely large bore then your dealing with the need for more fuel.

that can be overcome by getting bigger injectors..

I've also heard that the engine looses low end power but gains in the high end..

Thats the problem Im finding with my project car. Im building a 82 nissan 280ZX Turbo.
I want a bigger TB but it will make the turbo kick in later and I will loose low end power.
Thats no good in a vehicle that really needs low end grunt ya know.....

OK so my answer is You will probably be fine to just bolt it on and go!
dont get too technical............

[My1stJeep]

Why would it make it kick in later? With more fuel pumping into it the RPMs should increase quicker, thus engaging the turbo sooner. I am not much of a Turbo guy, so I may be way off here, just thinking logically so I am sure I am missing some info on the Turbo that makes this happen.

As far as a TJ with no turbo I have seen gains in both low end power and top end with the larger TB on mine. I have not had it on dyno to know actual numbers, but can feel it pull harder from right off the line through the whole RPM range. Along with the bored out TB I have a high flow exhaust, cat and muffler, K&N mounted directly to the TB, the TB spacer and Performance Distributors coil/8.8mm wires/cap and rotor. Seems to do real well, can run upwards of 80 mph if I wanted, but with my gearing that pushes the RPM's higher than I want to run for a sustained distance.

[Linda]

Dumb question and maybe a little off topic:
Why aren't the new 4-cyl TJs equipped with the SRT-4 engine?

[My1stJeep]

Good question, I haven't looked it up, but I am sure they are better, what are the numbers for that engine (HP and torque/at what RPM's?)?

[DsrtJeeper]

I can warrant a bored TB on a 4 banger for obvious reasons. I do not advise it on a six though. The narrowing of the TB on the intake end is done for a reason from the factory. It's to control the rush of air which causes quicker throttle response. When you are trying to crawl through a very technical section; imagine the Jeep jumping forward instead of slowly finessing it through. Bored out Tb's cause a quicker throttle response along with quicker revs. This isn't as much of an issue with autos as it is with sticks. Jeep built an excellent engine with their six and I wouldn't mess with a thing. Altering your power band in a crawler is not where it's at.

If you're looking for more power on the highway; try a turbo or supercharger that won't effect your crawling rpm's. The 4.0 makes 80% of it's power just off idle. It doesn't get much better than that. ;)

[Linda]

Hmmm.. It looks like DC might be doing that.

http://www.hotrod.com/techarticles/engine/113_0309_srt/

"...This story may also be of interest to those without an SRT-4, as the 2.4L was introduced in '94 in the Stratus, Cirrus, and the minivans, and it still appears in those applications. The base 2.4L is also current in the PT Cruiser, and it's called Power Tech in the new Jeep Wrangler SE and Liberty. The Jeep applications mean that rear-drive bellhousings are available for the 2.4..."

The SRT-4 is a 2.4-liter dual overhead cam 4-cylinder 16-valve Intercooled high-output Turbo engine produces 230 horsepower at 5,300 RPM and 250 pounds-feet of torque from 2,400 to 4,400 RPM

[Y2K-XJ]

Why would it make it kick in later? With more fuel pumping into it the RPMs should increase quicker, thus engaging the turbo sooner. I am not much of a Turbo guy, so I may be way off here, just thinking logically so I am sure I am missing some info on the Turbo that makes this happen.


If your running bigger injectors or higher pressure Yes your right, more fuel and more air = quicker spool up.

But if I just slap a bigger TB on my turbo motor without fuel mods all Im getting is more air thus making a dog off the line, until the turbo kicks in and tells the ECU to give more fuel.

I found a really cool graph that showed all this. let me see if I can find it.

[jeremyswrangler]

Thank you for the advice!!

[My1stJeep]

Rob,

Would love to see that chart if you can find it, always love to learn new stuff!!!!

[SavageSun4x4]

The SRT-4 is a 2.4-liter dual overhead cam 4-cylinder 16-valve Intercooled high-output Turbo engine produces 230 horsepower at 5,300 RPM and 250 pounds-feet of torque from 2,400 to 4,400 RPM

With rpm in the top end of the thing, this is a place where gearing can make all the difference. Drop in a Atlas 5.0/6.0 transfer case and a 4+ low gear in the tranny with some 4.10 cogs in the rear and watch out!

[Y2K-XJ]

Rob,

Would love to see that chart if you can find it, always love to learn new stuff!!!!


I've searched all over and I'll be damned if I cant find it again.

It was on HybridZ.com somewhere (its a really friggin big forum)....
it had Flow rates, fuel injector size and TB info

It was all from a question of someone asking how much Porting and polishing really accomplished....

its a needle in a haystack now....

Ill keep trying. It was a really good read...