12-hole Injectors + TB Port & Polish - JeepForum.com
 
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post #1 of 13 Old 06-16-2019, 01:39 PM Thread Starter
MrBaz
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12-hole Injectors + TB Port & Polish

INJECTORS
The factory injectors on the '04 WJ 4.7HO are 2-hole injectors. Feel free to search YouTube to see how poorly these atomize fuel.
Factory Injectors:




I tried the Bosch 12-hole injectors (280156161) but had issues with them being unbalanced - ie: not flow-matched. I had 3 normal cylinders, and 5 rich cylinders. I blame this on the vendor.
Bosch 12-hole injectors:



Sent those back and ordered the Denso 12-hole injectors (12582704). These came from a vendor with a better warranty, posted specs (265CC, flow-matched to within 2%, etc.). Put these in and had no problem after putting the PCM into fast-learn.
Denso injectors:



Compared to factory:


TB Port & Polish
Factory TB has big flat faces. These flat surfaces = turbulence. Turbulence = reduced air velocity. Reduced air velocity = restricted airflow.
Note the rough as-cast surface.


A measurement from the back of the TB shows it to be machined out to 68mm.

If you don't believe me, it is stamped right on the throttle plate.


The front clearly is not. It is more like ~66mm.


You can see the 'step' clearly.



PSA: Clean your IAC valve.


Sorry, I didn't take pictures of the process. It was tedious and annoying. I wanted to see how far I could get with just hand tools. I was going to polish everything to a mirror shine, but I was running out of time and was not satisfied with the end result. I'm going to find access to a lathe and just take it to 70mm and machine a new throttle plate.
Note the flare. This eliminates those flat faces and will facilitate airflow into the TB.


There is only a tiny step left.



2004 WJ, 4.7HO, 2 cats, magnaflow
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post #2 of 13 Old 06-16-2019, 10:29 PM
Reaper3-1A
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I was actually planning this on my standard 4.7L along with an 08+ Intake, some H.O cams, and modifying a Chevy throttle body once i found the right one (I have a couple in mind) rather than porting the little 'ol 68Mil stocker. Question: Did you get the Denso's from online or from a local vendor?

If its online i was wondering if you can link them so i can get a set. I picked some of these exact same Denso 704's up from a couple junkyard Saturn'd and Pontiac's with the 2.4L Ecotec motors but idk if i can get a set new or refurbished for cheaper or the same to just flow balance the ones i have then i'd rather have the new ones instead.

~Reaper
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post #3 of 13 Old 06-17-2019, 07:23 AM Thread Starter
MrBaz
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Quote:
Originally Posted by Reaper3-1A View Post
I was actually planning this on my standard 4.7L along with an 08+ Intake, some H.O cams, and modifying a Chevy throttle body once i found the right one (I have a couple in mind) rather than porting the little 'ol 68Mil stocker. Question: Did you get the Denso's from online or from a local vendor?

If its online i was wondering if you can link them so i can get a set. I picked some of these exact same Denso 704's up from a couple junkyard Saturn'd and Pontiac's with the 2.4L Ecotec motors but idk if i can get a set new or refurbished for cheaper or the same to just flow balance the ones i have then i'd rather have the new ones instead.
I purchased the Denso's from a company off eBay. They specialize in reman injectors.

2004 WJ, 4.7HO, 2 cats, magnaflow
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post #4 of 13 Old 06-17-2019, 09:12 AM
sdg3205
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Quote:
Originally Posted by MrBaz View Post
I purchased the Denso's from a company off eBay. They specialize in reman injectors.


I just installed these as well. Worked well.
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post #5 of 13 Old 06-17-2019, 04:28 PM
Reaper3-1A
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Nice, ill give this a shot on ebay and get some quote to flow balance the ones i already have. Nice to see other people doing 4.7L upgrades

Sent from my SM-N960U1 using Tapatalk

~Reaper
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post #6 of 13 Old 06-19-2019, 07:43 AM
Heeps_R_Us
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What kind of benefit would I see going from my factory 4 hole injectors to the 12 hole injectors?
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post #7 of 13 Old 06-19-2019, 08:24 AM
torchd
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Quote:
Originally Posted by Heeps_R_Us View Post
What kind of benefit would I see going from my factory 4 hole injectors to the 12 hole injectors?
Better atomization of the fuel, and maybe 1 mpg increase

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post #8 of 13 Old 06-19-2019, 08:30 AM
Frambo
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Originally Posted by Heeps_R_Us View Post
What kind of benefit would I see going from my factory 4 hole injectors to the 12 hole injectors?
Was just going to ask this myself
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post #9 of 13 Old 06-19-2019, 09:41 PM
97Mule
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Using a vacuum gauge for a driving tool will also provide more mpg! Better atomization of the fuel... maybe so, but it still is a port injection engine. The fuel still has to travel into the intake port before it gets to the combustion chamber. I can see it cleaning the intake valve better! But what do i know!


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post #10 of 13 Old 06-20-2019, 02:56 AM
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post #11 of 13 Old 07-01-2019, 10:59 AM
sdg3205
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12-hole Injectors + TB Port & Polish

After a few weeks I can add a few notes.

The injectors seem to break even. MPG cruising at constant speeds is considerably better but accelerating seems to consume more than previously. I still havenít run a whole tank yet to see what sort of total mileage Iím getting, but Iím not seeing the big gains some people claim to see.

I think if youíre a highway driver youíll be quite happy but around town may disappoint.
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post #12 of 13 Old 07-01-2019, 04:25 PM
Frambo
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Originally Posted by sdg3205 View Post
After a few weeks I can add a few notes.

The injectors seem to break even. MPG cruising at constant speeds is considerably better but accelerating seems to consume more than previously. I still havenít run a whole tank yet to see what sort of total mileage Iím getting, but Iím not seeing the big gains some people claim to see.

I think if youíre a highway driver youíll be quite happy but around town may disappoint.
And apart from economy, are there any performance improvements?
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post #13 of 13 Old 07-01-2019, 05:09 PM
sdg3205
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Hard to tell because I did so many things all at once. I think the better throttle response is likely from the 70mm TB ; when you think about it, when the throttle plate opens the same amount as previously itís now sucking in more air.
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