need for speed

[ryansmaid]

I'm looking to squeeze a bit more speed off the line from my 4.0L YJ automatic. It runs great, it just doesn't have quite the get up and go that I'd like. I was thinking a set of headers or maybe new exhaust, any suggestions?:?|

 

[TerryMason]

What year YJ? Does it have a carb?

 

[jeepster357]

Not sure what your fuel supply set up is but I sure preach the gospel of after market cold air intakes and throttle body spacers. Its not gonna win you a drag race but on my manual trans it has reduced the amount of downshifting on steep grades and given me a little more zip while passing on the highway.

 

[Bounty__Hunter]

Do you have stock size tires? If larger than stock, regearing the axles to lower gears will be the number one improvement to off-line driveability.

If you're YJ is a '91+, I'd recommend a 62mm throttle body (like the ones I sell). They greatly increase airflow to the engine and it removes the taper beneath the throttle plate that restricts airflow for the first 1/4" of throttle movement. Throttle response is increased dramatically.

 

[dave123]

I agree with bounty hunter. gears best bang for the buck

 

[ryansmaid]

It's a 93, fuel injected, w/31 inch mudders. I hadn't thought of the TBS, I'll go that route first. Thanks

 

[Bounty__Hunter]

The 62mm TB will do more for you than a spacer, but the 62mm TB and a 62mm spacer would be even better. I know somebody that sells both, pretty cheap

Also consider injectors from a mid '90s Ford v8, either Mustang or Crown Vic.

Then there's the Livewire kit from Performance Distributors for a hotter ignition system, plugs gapped at .065".

 

[97teejay]

bounty hunter

Does a 97 4.0 have a 62mm throttle body? Just curious if i could beneifit from that.

thanks

 

[Bounty__Hunter]

I believe the stock 4.0L TB is only 55mm, with a restrictive taper beneath the throttle plate.

Here's a pic comparing my 62mm TB to a stock 55mm TB.

 

[ryansmaid]

Bounty__Hunter

Do you have a website I can peruse where you sell this stuff?

 

[Bounty__Hunter]

No website, just me, either sites like this one or on Ebay.

Nothin really to peruse but 62mm TB's and the occasional 62mm spacer.

 

[mrmopar02]

A turbo can fix anything :shades:

 

[Jeep Junkie]

Bounty Hunter,

what would be your suggestion for the 4 banger.. I have 92,wrangler fuel injected
besides dropping in a v8 !!!

 

[Bounty__Hunter]

My suggestion would be to regear the axles to match any increase in tire height, and add performance mods as your budget allows. My 2.5L is fun to drive, very responsive and holds its own.

 

[tom_TJ_performance]

i can sell you a 68mm throttle body. i am a distributor for one of my sponsors. F&B Throttle Bodies

 

[tom_TJ_performance]

cheaper than buying direct:shades:

 

[ryansmaid]

I had to do an unexpected rebuild on the motor about a month ago and went ahead while I had the whole thing pulled out and put on a set of banks headers and the 62mm TB and spacer and I got exactly what I was looking for. Throttle response improved dramatically with that combo, I couldn't be happier. Now if I could just afford the cool air intake and exhaust...might have to shoot off a letter to Santa.