62mm throttle body

[Duan]

From what I understand the ID of a throttle body on a TJ 4.0 is 60 mm. For a better engine output a 62 mm throttle body is suggested must I buy the bigger one or can a engineering workshop modify it to 62 mm. What are the pros and cons of a bigger throttle body. Thanks.

 

[Stinger]

I have seen a ton of threads and post on this subject and with the spacer. From what I can understand that until and unless your have head work done or a stroker, this mod is useless. Back when I had a 4.0 liter I put a spacer on it and noticed absolutely no difference in MPG or seat of the pants power. Just noticed my wallet being lighter.

 

[Chris]

I have seen a ton of threads and post on this subject and with the spacer. From what I can understand that until and unless your have head work done or a stroker, this mod is useless. Back when I had a 4.0 liter I put a spacer on it and noticed absolutely no difference in MPG or seat of the pants power. Just noticed my wallet being lighter.

X2 to this, it's 100% accurate.

Your stock throttle body as I understand it can be machined to 62mm.

 

[LJRubiconGuy]

Don't waste your money. Unless you have head work (among other things) you won't get any benefit from a larger throttle body, I promise.

 

[Jerry Bransford]

Don't waste your $$$ on a larger throttle body. The factory throttle body can easily flow more air than the engine can consume at wide open throttle and redline rpms.

Especially don't waste your $$$ on a throttle body spacer. Spacers can help when installed under carburetors and first generation throttle bodies that have a fuel injector in them but not modern air-only throttle bodies. Despite what the ad claims.

 

[Chris]

Especially don't waste your $$$ on a throttle body spacer. Spacers can help when installed under carburetors and first generation throttle bodies that have a fuel injector in them but not modern air-only throttle bodies. Despite what the ad claims.

This has to be one of the biggest pieces of misinformation out there, that a throttle body spacer will give you power gained on a modern vehicle.

May as well just throw in one of those 'electric' superchargers, LOL.

 

[Duan]

Thanks for your inputs it saved me extra money and work, I will then only go for branches and a free flow system.

 

[Chris]

If you have the money to spend and you want to get a bit more power out of you're TJ a good option is a stroker engine.

If you're down on power from bigger tires re-gearing it will give you back some of the power you lost from the bigger tires.

 

[StG58]

Duan, the only way to make more HP is to burn more fuel and air mixture. The only way to reasonably get more fuel and air into the Jeep engine is with a Turbo- or Supercharger. Barring that, it gets really expensive to get a Jeep engine to actually generate more HP and torque. Stroker engines, head and valve train work, cams and then all of the intake and exhaust modifications to make that stuff actually work. Even nitrous doesn't work well off road. Also consider that every time we try to increase the output of these engines, we decrease the reliability and longevity.

Go for a good tune up and fresh oil and filters. That is the most reasonable bang for the buck.

 

[StG58]

There is another way. A darker and more dangerous way. It involves leaving the path of Jeep righteousness and going to the dark side. You may become an outcast of the Jeep clan and have to wander the hills alone. Children will shriek and run, women will avert their faces and men will talk behind their hands as you pass.

That way is the V-8 swap.

 

[Chris]

I'm totally up for a V8 swap... Sounds fun! Just ask @Stinger or @Wildman

 

[Stinger]

 

[StG58]

I know what you mean. I'm working up a build sheet for that very thing. The cost is actually pretty reasonable for what you get out of it. What would kill me is the down time. All the research that I've done says that the best way is to do a frame off restoration type build and use a GM engine and transmission. Increased power and possibly gas mileage would be really hard to argue with.

 

[Chris]

All the research that I've done says that the best way is to do a frame off restoration type build and use a GM engine and transmission. Increased power and possibly gas mileage would be really hard to argue with.

I wouldn't bother doing it unless I removed the tub from the frame. That would make things quite a bit easier so then you could see what you were dealing with.

You can imagine that a V8 under the hood of a TJ would be a lot of fun!

 

[Stinger]

No replacement for displacement!

 

[StG58]

My V-8 Vega was a hoot. I imagine that a V-8 TJ would be similar. The only down side was that after a good pass where the rear tires hooked up, the doors were really hard to open. Like use both feet to kick them open hard to open. The engine torque would twist the body out of shape and jam them shut. Never came up with a fix for that before blowing the engine all over the street. Missed a shift and that's all she wrote.

Wish I still had that one. It might teach the rice rockets a thing or two.

 

[StG58]

No replacement for displacement!

That is the truth right there. The older small blocks could go over 400 cid and 400 hp reliably. The newer generation that would work well in the TJ can go over 383 cid and the torque and HP are in the stupid range.

Another saying is "Injection is nice, but I'd rather be blown". Despite the rude reference, it's the truth.

 

[Stinger]

Doors? On a Jeep? No problem! The sheet metal directly under both my doors on the tub is a bit distorted.

 

[StG58]

Funny, that's right where the torque from the engine get transferred to the frame. Who would have guessed! I have wondered what bends on a TJ with a V-8. Do you get much wheel hop?

 

[Stinger]

No wheel hop at all I suspect the metal got tweaked during the tub removal. Didn't have enough attachment points. Now here is a Throttle Body!