Dyno Testing Bolt-ons On The 4.0

[srimes]

I made a manometer to measure this on my XJ. Just need some clear tubing, a little water, and go for a drive. Then apply math.

Highway speeds where good for .036 psi. I estimated that'd be about 1/2 hp. Decided it wasn't worth messing with.

Pics are lost and I'm going from memory, but I would have tested cowl pressure vs. stock intake location, which on the XJ is behind the grill right next to the radiator. That's a high-pressure area too, and better than just under the hood like the stock TJ. It'd be worth testing as it should give better improvement than on the XJ.

I'd do it myself at some point but it's a low priority right now. If anyone is interested I'll walk you threw it. Should only need $5-10 of clear soft tubing from the hardware store.

 

[astjp2]

https://metrommp.com/air_cleaner_grommet_made_of_rubber_278_id_312_o_rp_300/

 

[astjp2]

The cowl is a high pressure area.

so how many inches of WC is the high pressure area? String and tape could show air flow with the heater running, actual values of WC will indicate what is the actual pressure.

 

[Jezza]

I shot the 4 hole injector video tonight and the results were much more interesting than I had anticipated

 

[astjp2]

I shot the 4 hole injector video tonight and the results were much more interesting than I had anticipated

slackin on edit'n I see lol

 

[NashvilleTJ]

I shot the 4 hole injector video tonight and the results were much more interesting than I had anticipated

Teeze…

 

[Jezza]

slackin on edit'n I see lol

I feel like I am ahead of schedule. I am trying to get them out and released on Saturday mornings.

 

[Rickyd]

Teeze…

What injectors does a hemi have?

 

[Wildman]

What injectors does a hemi have?

8....of them

I don't think Jeff has stock injectors in his 392.... I've still got stock ones in mine.

 

[NashvilleTJ]

What injectors does a hemi have?

I'd have to go back and look - but I know they have enough holes to give me 8 miles per gallon...

 

[Wildman]

I'd have to go back and look - but I know they have enough holes to give me 8 miles per gallon...

I think that might be partly due to your right foot too...

 

[Wildman]

The stock fuel injectors for a 5.7L Hemi engine typically flow around 300 cc/min (approximately 28.5 lbs/hr at 58 PSI).

Stock Jeep 4.0L inline six-cylinder engines use fuel injectors that typically flow around 24 lb/hr at 39psi.

 

[GoldenGorilla]

Stock Jeep 4.0L inline six-cylinder engines use fuel injectors that typically flow around 24 lb/hr at 39psi.

The stock injectors in the 04 4.0L rated 20.6 lb/hr @ 43.5 psi, but the jeep in these years runs at 4 bar or 58psi which does put them at about 24lb/hr.
https://www.injectorplanet.com/products/bosch-0280158119-chrysler-04861667aa-1

Very detailed thread over at jeepstrokers on various fuel injectors suitable for higher displacement and hp builds.
https://www.jeepstrokers.com/forum/viewtopic.php?t=6709

As with alot of TJ stuff there is a huge amount of variance in all sorts of weird things on a year by year basis. One of them being changes in the injectors, changes in fuel pressure,..

 

[GoldenGorilla]

@Jezza Your CAI and windstar testing has changed my mind on that front, so thanks. The K&N dirt and dust management has always been my biggest concern seeing how much dust we see on the trail and in early days I'd always viewed it as a low roi mod. I'm trying to manage in cabin noise so I'm not going to go the windstar route, but I've ordered one in the traditional location. I'd considered a higer flowing, but non-K&N alternative for the stock filter. I've been doing some light mods on my 04 4.0 with some 1.7 roller rockers, short headers and a 62mm throttle body with an eye on bigger future mods and have been thinking it's a good time to do a dyno run as is. On the street I've seen a notable measurable improvement. Swapping a CAI is pretty quick so I should be able to do both in a session.

On that front one of the annoying lmitations with the tuning on the 4.0 and JTEC+ is the lack of MAF data. I have a pro-link with my HPTuners with my wideband O2 currently routed into it. Does anyone have a good standalone MAF sensor option that can be fed into HPT even if the data is voltage only?

 

[Jezza]

@Jezza Your CAI and windstar testing has changed my mind on that front, so thanks. The K&N dirt and dust management has always been my biggest concern seeing how much dust we see on the trail and in early days I'd always viewed it as a low roi mod. I'm trying to manage in cabin noise so I'm not going to go the windstar route, but I've ordered one in the traditional location. I'd considered a higer flowing, but non-K&N alternative for the stock filter. I've been doing some light mods on my 04 4.0 with some 1.7 roller rockers, short headers and a 62mm throttle body with an eye on bigger future mods and have been thinking it's a good time to do a dyno run as is. On the street I've seen a notable measurable improvement. Swapping a CAI is pretty quick so I should be able to do both in a session.

On that front one of the annoying lmitations with the tuning on the 4.0 and JTEC+ is the lack of MAF data. I have a pro-link with my HPTuners with my wideband O2 currently routed into it. Does anyone have a good standalone MAF sensor option that can be fed into HPT even if the data is voltage only?

That does raise an interesting question. What if just changing the stock panel filter to a higher flow version would eliminate most of the restriction?

 

[Wildman]

The stock injectors in the 04 4.0L rated 20.6 lb/hr @ 43.5 psi, but the jeep in these years runs at 4 bar or 58psi which does put them at about 24lb/hr.
https://www.injectorplanet.com/products/bosch-0280158119-chrysler-04861667aa-1

Very detailed thread over at jeepstrokers on various fuel injectors suitable for higher displacement and hp builds.
https://www.jeepstrokers.com/forum/viewtopic.php?t=6709

As with alot of TJ stuff there is a huge amount of variance in all sorts of weird things on a year by year basis. One of them being changes in the injectors, changes in fuel pressure,..

I was just grabbing the info I could find quickly last night.
I was on the stroker forum when I had the Magnum stroker in my TJ.

Thanks for the additional information.

 

[GoldenGorilla]

That does raise an interesting question. What if just changing the stock panel filter to a higher flow version would eliminate most of the restriction?

It would be easy enough to run the stock box with no filter in it for a run just to get an idea about whether there is potential there. I wouldn't worry about that for a dyno run. I'll make a note to try that when I do it and report back.

 

[Jezza]

I really thought the stockers were 19lb/hr. I thought the 24s were an upgrade for stroker guys. The 4 hole part number that is sold as an upgrade is a 19 iirc.

 

[GoldenGorilla]

I really thought the stockers were 19lb/hr. I thought the 24s were an upgrade for stroker guys. The 4 hole part number that is sold as an upgrade is a 19 iirc.

They kinda are. I think there are a bunch of variations, but most injectors are quoted at 3 bar and alot of the jeep 4.0s run at 4 bar. It looks like the 3bar spec on my 2004 injectors is 20.6 lb/hr. Going to a 24 lb/hr spec at 4 bar is closer to 29 or 30 lb/hr.

On those lines, I'm sure you're thinking about it, but you'll want to drive the jeep a bit on the injectors after the swap so it rebuilds the STFT and LTFT and gives a more accurate representation.

 

[JustDandee]

It would be easy enough to run the stock box with no filter in it for a run just to get an idea about whether there is potential there. I wouldn't worry about that for a dyno run. I'll make a note to try that when I do it and report back.

Note in an earlier post I was showing the straw that crosses over from the stock box to throttle body at 50mm it is for sure smaller inside then it looks. I am thinking Factor in some restrictions are happening there as well.