Questions need some help.

[JEEP_cannible]

I'd like alittle more power from my 4.0.I was thinking about a larger throttle body.I saw were Meanlemon's has bored throttle body's for sale. I was also looking into the spacers they sell.Anyone use either or have suggestions on whats better. I know we used to use the spacers a lot,but they didn't help much on the top end or didn't seem to help much. When fly'n through the desert sometimes its hard to tell. It really seemed to help the 2.5,but any gain in HP would have helped there.On the 4.0's I really didn't notice much of a gain.I did notice that different injectors made a big difference on the power band's. Any Idea's ?

[89 MJ]

How much money do you have to stick into power adders?

[Pete M]

what gear ratio are you running? 

[JEEP_cannible]

89 MJ I really have a fresh motor so not interested in boring,and stroking it for now. Supercharging it goes against my,(religion) not allowed in offroad racing unless stock equipped most cases.  I also have an HO 4.0 sitting in the wings should I need it.

Pete I haven't had a chance to read the tags,and or check yet.I would guess they are a normal range,because it gets great gas mileage for a 30 year old truck.Yet low enough to pull stumps in first gear,2wd. I haven't had to use 4 low in a year,after replacing the tires,(31 x10.5's on it now). 

[Pete M]

if it's a 4.0/stick and you're rockin' the 3.07s, that's definitely part of the problem   

[DirtyComanche]

TB spacers are mostly a myth.

 

A larger TB or bored one might gain a little power, combined with a better intake and filter.

 

For injectors everyone says to use the Volvo 746s on the Renix.  I have them on one and Ford 710s on another.  Neither vehicle is comparable to the other, besides both having Renix 4.0s, so I can't comment beyond they both run better than they did with old cruddy and leaking stock injectors.

[JMO413]

Meanlemons throttle body is noticable at higher RPM for sure. He does good work!

[Minuit]

I'd be very interested in some before/after dyno results for these bored TBs.

[kryptronic]

My opinion: Skip the spacer, nothing to gain there.  Bored throttle body, 4 hole injectors, use a good header for the exhaust and a high flow cat.  Use the HO block with the 7120 head casting.  Should do 210 to 220 horsepower and very good low end torque with this combo as long as spark is good and all else is in tip top shape.  Make use of it all with lower gearing as Pete suggested.

[MJXJjeepguy]

15 hours ago, Pete M said:

if it's a 4.0/stick and you're rockin' the 3.07s, that's definitely part of the problem   

Yup  friend of mine had 2000 wrangler 4.0 with 5 speed had 3.73 gears with 33s it feel like u drive 4.88 it huge different, also easiest to upgrade ur jeep if ur jeep is manual u can find both axle out of auto with 3.55 it should be good with your 31s. 

[JEEP_cannible]

Thanks for the help guys.I have a cold air intake It's the first thing I did to all my Jeep's.I have all the parts to upgrade the motor,but this one is fresh an runs great.I need to check the rear end's like Pete suggested.Someone has done some work on them,but not sure what the gearing is.The rear has a leak at the rubber plug so that has to be addressed.I was thinking about up grading to 4 wheel disk's since I have the parts.I'm sure I will know more about the gears when I start digging around in there.Thanks again for the help,and now I have some idea's to work with.