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I think I read on another forum someone who had this done and they said they felt a bit lighter in the right hip pocket...yeah, that was it, lighter in the pocket.
 

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What I am trying to say is that without a complete update of the "system" that just improving one part will not help - ie. one would need to improve air getting into the engine, through the engine and out of the engine. I think, from what I have read, you would be better off investing in a Superchip to tweak your engine tune, than all the rest of the stuff.
 

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Best bang for the buck as for as performance goes in my opinion is regearing the differentials, especially if you have an automatic.

There isn't a whole lot to be gained out of the 3.8L except for supercharging.

Flashpaq will get a little more power, but will give noticable improvement in throttle response, which is of course difficult to actually measure, but it's been accepted as one of those it feels better improvements.

There have actually been reports of decreased performance by the addition of some mods that were supposed to improve. I think that had a lot to do with bad combinations. The one that stands out most in my mind was substantially reduced torque with certain headers combined with something else. I just know I don't feel the need to spend money on something that makes an already marginal engine even worse.

Regearing will run about $1,200 -$1,300 and fixes most of what is wrong and is not detrimental.
 

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This is the sum total of my thoughts on why regearing is the best way to get better performance out of the 3.8: (Each section came out of different sessions of sitting and thinking:idea:; once in a while, I just sit, though.:shhh:)

Regearing doesn't ADD power. It allows the engine to put out more of its available horse power.
An engine turning 2200 rpm can make more hp than the same engine turning 1100 rpm.
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Another way to look at it:

V6
Automatic in 3rd (1:1)
6 speed in 5th (1:1)
If rear axle = 2:1
You get 6 power strokes per tire revolution.
Change the rear axle to 4:1,
You get 12 power strokes per tire revolution, which feels like a bigger engine. You would go up the hill slower, (at the same rpm), but you could haul a larger load up that hill.
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This may be over simplified, but regearing may in fact be nearly equal to going from a 3.8 V6 to a 5.0 V8.
V6 to V8 = a 33.33% gain in the number of engine power strokes for a given distance traveled.
4.10 to 5.46 (not an available ratio, but ok for this illustration) = a 33.33% gain in the number of engine power strokes for the same distance traveled.
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I did some figuring, using the hp/torque charts at the Hypertech site. Those charts show numbers at the wheels.
These are with O/D off for simplicity, because the 4.7L chart, rpm scale didn't go low enough.

3.8L: 31" tires, 4.10 gears, 70 mph, = 3111 rpm @ 107 hp + 188 ft/lbs.
4.7L: 31" tires, 4.10 gears, 70 mph, = 3111 rpm @ 129 hp + 219 ft/lbs.
3.8L: 31" tires, 4.88 gears, 70 mph, = 3702 rpm @ 135 hp + 195 ft/lbs.

This is very unscientific, but, as you can see, regearing can be very similar to going to a V8.
 

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For $136 you can put a 08 Viper TB on there pretty much plug and play. Air intake adapter and a line elbow is all thats required. Puts you from a 58mm bore to a 74mm. Of course running a programmable tuner will help you reap the most benefit from this. This will work better then any polishing.
Personally, up here in the cold I found a great benefit in running 91 octane rather then 87. Better performance and gas mileage..
 

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For $136 you can put a 08 Viper TB on there pretty much plug and play. Air intake adapter and a line elbow is all thats required. Puts you from a 58mm bore to a 74mm. Of course running a programmable tuner will help you reap the most benefit from this. This will work better then any polishing.
Personally, up here in the cold I found a great benefit in running 91 octane rather then 87. Better performance and gas mileage..
Any dyno data showing the results of this? For some reason I am skeptical of the benefit of this.
 

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like the title says... Has anyone tried to port and polish their TB? Or do you know anyone that has and what was the result? Similar to this How to Port and Polish Throttle Body | eHow.com

I guess we dont have MAF so sorry about that.
You had me worried there - I thought that the silly Ford MAF idea had caught on at ChryCo and replaced the speed/density setup!

"Port and polish" should really be restricted to head ports and possibly intake runners. You're not going to get anything out of doing the TB - and if you screw up and open the bore up, you're going to have to get a new butterfly to fit (and probably take it in to have the bore trued so the butterfly works.) The ECU will pitch a b**** if the throttle valve can't close all the way - idle air is supposed to go just about entirely through the IAC passage.

As far as perceived performance benefits - they're right, you'll note an increase in pep from having a lighter wallet. Putting on a bored throttle body doesn't even improve performance - it improves part-throttle response, but doesn't actually do anything for power output. Ergo, the old "butt dyno" gets confused. (The OEM throttle body is perfectly capable of supporting airflow for even a mid-grade stroker - say, 285ci or so - without any trouble.)

Leave it alone, and put your nickels in a jar until you have enough to get a CAI kit - that will have more effect.
 

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Prob is the factory air system works good enough that even a aftermarket CAI really has no benefit.

Here is a lengthy discussion on the Viper Throttle body. VIPER THROTTLE BODIES FOR JK's - JkOwners.com - The Community for Jeep JK 4x4 Owners Dyno tests are likely to come shortly as there are many folks switching over. It must be noted that a programmer and proper tune must be used to get full benefit of the TB otherwise the factory ECU will control it as stock and only increased throttle response will be noticed.

The Supercharger is still by far the best performance increase.
 

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I just read through seven pages of b.s. which was mostly guys arguing and not one dyno chart, horsepower figure, torque number, or anything tangible showing the benefit of that throttle body was posted. Furthermore, that us the same throttle body used on a Commander as well as another unsexy vehicle. Using the Viper name makes it sell better, but it's the same damn throttle body on more mundane vehicles.

Repeatedly what was said in summation is buy it because it is better and when asked why, the answer was repeatedly it just is. Granted $136 isn't a lot if money for an upgrade these days, but at least a better answer should be given than what has been. They might as well have said paint your jeep pink because it will make it more powerful. Just do it because it's a fact and we don't need to prove anything. BTW we are having a sale on pink paint. The color is Viper Pink, which we all know Vipers have the fastest colors.

You know, I really want to believe this will help, but seven pages of asking for numbers and none being provided sounds like b.s. to me.
 

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Well, I just bought one... Like ya said, $140 is pretty cheap - that and the $50 in 3" intake parts falls into my 'experimental' budget for next year.

The programmer is another $300 - I'm kicking that around as I type... Been wanting one since I bought the Jeep just to take out the throttle lag.

I've got a bunch of data from some timed runs up Floyd Hill here in CO... Things like time to point, rpm at point, speed at point, air temp, etc. While it won't be a true dyno, I can probably state with some certainty if the ECU in the JK understands that there is more air available and therefore more fuel is needed - and therefore more power is being made.

The thing I worry about is the ECU not figuring out the 16mm bigger hole and running the engine lean.

If I get the tuner I'll have to do a few runs with just the TB, and then the tuner just to see which is making what difference.

And, if it doesn't work, putting the old TB back on isn't exactly 'hard'. :)
 

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Funny thing is, I was reading about this and posting in this thread while at the dealer getting the brake recall done. That is all I wanted done. The service manager comes up to me later and tells me my throttle body has a lot of carbon build up and needs to be cleaned. I have no idea why they would be messing with my throttle body, but whatever. I ask him how much to have it taken care of. He says $107. Now I am thinking I could buy a lbrand new larger one for only $20 more. Needless to say I told him no and that I would do it myself instead.
 

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Funny thing is, I was reading about this and posting in this thread while at the dealer getting the brake recall done. That is all I wanted done. The service manager comes up to me later and tells me my throttle body has a lot of carbon build up and needs to be cleaned. I have no idea why they would be messing with my throttle body, but whatever. I ask him how much to have it taken care of. He says $107. Now I am thinking I could buy a lbrand new larger one for only $20 more. Needless to say I told him no and that I would do it myself instead.
Excelent question as why they were in there when you were in for the recall.
I too had carbon build up on the back side of the butterfly valve found inside the throttle body. They also said it would cost something like that, so I had the mechanic show me how they would go about cleaning it, and then took it home and did it myself. Little Seafoam, no problem all clean.
 

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If any mechanic tries to charge you for a throttle body cleaning.. just wind up and kick him in the sack.

10 minutes, a buddy and a bottle of TB cleaner and you saved yourself a few $$$
 

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:popCorn:
 

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Why are you getting carbon buildup inside the throttle body? I wonder if this could be related to the common bad PCV valve, or the magic dissappearing oil issue?
I've never seen carbon buildup there, at least not to any degree that I ever questioned.
Did they also want to change your headlight fluid from indancescent to halogen?

:)
 

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The new TB from Mopar Supercenter came in today - fortunately they packed it well because the outer package looks like something that tried to cross enemy lines in WWII... The box inside the box was still in one piece though - hopefully the explosive forces involved in getting the package here didn't break anything in the TB itself.

But, yeah, that's a big hole - about a 1/4 inch wider than a soda can...


For the OP, the TB is plastic - dunno how much porting and/or polishing you could do to it.

My new Diablo Sport programmer should be in either today or tomorrow (it was ordered the same day as the TB). Once that gets here, the fiddling will commence. :thumbsup:
 

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Well, it's been over a month and no updates to this thread. How has the the TB done? Any reports on "before and after" the Diablo programmer? How about with and without a CAI (using the stock box instead)?

Inquiring minds want to know :popCorn:
 
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