throttle body size

[StroktWJ]

What size throttle body do you guys think I should go with? I'm running the stock 00 throttle body on a 4.6L? *choke..choke..*

I have a set of 26lbs injectors from a Marauder laying around i'm going to throw in and planned on installing a larger TB at the same time.

I was planning on boring my throttle body housing out and buying a new blade. Also I have the ability to machine a TB spacer if needed.

[gradon]

You can bore it to 62 or 63mm max. You'll notice a nice increase in throttle response as well as top-end power if you have the stock 60mm tb that necks down to 55 or 56mm. Some people just open up the bottom half to 60mm and use the same blade, but I feel our strokers could make use of even a 70mm tb. It would be nice to see at what point the manifold becomes the restriction when at WOT a bigger tb makes no difference.

[SilverXJ]

63mm from strokedjeep.com

[Biggrnjeep97]

I bored the lip off the bottom of my stock TB, so it still used the stock throttle plate. I liked the little gains it gave. I didnt notice a whole bunch o' power up top but i did want to keep the stock-ish bore so the throttle wasnt too twitchy offroad.
-Will

[Cheromaniac]

I think a 62mm TB is a good compromise in terms of performance and tip-in throttle response on a mild 4.6 stroker. The throttle response from my modified Mustang 65mm TB is absolutely razor sharp making it huge fun to drive on the street, but it can sometimes make the engine jerky when trying to crawl at less than 10mph on a very light throttle.

[Dmondeac]

Well I just bought a TB off a 2001 Dakota and my new Lunati cam just showed up so I guess I will see if the 68mm TB is better than the 62mm Turbo City unit that I am currently running. However, the cam swap might taint my evaluation slighly.

[Biggrnjeep97]

Well I just bought a TB off a 2001 Dakota and my new Lunati cam just showed up so I guess I will see if the 68mm TB is better than the 62mm Turbo City unit that I am currently running. However, the cam swap might taint my evaluation slighly.

FWIW, I just read your reply and decided to measure my '01 intake manifold bore. Its 61.8mm. My opinion is you wont see a topend gain off your 68mm, just a snappier throttle, until you match the throttle body to the opening in your intake. When i find time, Ill bore my intake and postup how it goes.
-Will

[Dmondeac]

I agree, without boring the intake it won't help much, but I am going to enlarge the manifold when I install my new cam.

[Biggrnjeep97]

I bored my intake last night out to 68mm with a 30* chamfer on the bottom side. It turned out real well, IMO. I see no problem with boring it further, like 73mm+, if someone really feels the urge to put a monster TB on one.
-Will

[Dmondeac]

Have you run the engine yet? just curious how it idles and accerates?

[aaronkeiser]

I'm running the 63mm TB from Leigh performance and my throttle is sensitive as hell! Plus its got a granny low 4 speed. It's nothing i haven't been able to learn but every time a new person drives my jeep they are all over the place with the brake-throttle-and gas

[Biggrnjeep97]

Have you run the engine yet? just curious how it idles and accerates?

No my 4.0 has blown up and my engine builder is slower than molasses, uphill, in winter....so im waiting on him. If you send me an intake I can bore it out to whatever size you want.

I'm running the 63mm TB from Leigh performance and my throttle is sensitive as hell! Plus its got a granny low 4 speed. It's nothing i haven't been able to learn but every time a new person drives my jeep they are all over the place with the brake-throttle-and gas

This is my biggest fear with running a bigger TB. Twitchy throttle = broken Axle shafts. I have, however, replaced my AX-15 with a TF727 so maybe the TC will smooth out any jerky throttle inputs.
-Will

[Dmondeac]

I might take you up on that offer in a couple of weeks. I have a heavy travel schedule and then it on to the cam swap and TB upgrade.

[SilverXJ]

I'm running the 63mm TB from Leigh performance and my throttle is sensitive as hell! Plus its got a granny low 4 speed. It's nothing i haven't been able to learn but every time a new person drives my jeep they are all over the place with the brake-throttle-and gas

x2 I have the same throttle body and every comments on how responsive it is. I think any larger would be overkill.

[Dmondeac]

Looks like it will take a bit of fabrication to get the Dakota TB to work on the XJ manifold. Seems the cables (throttle, cruise, & trans) and mounting are not the same.