Dyno Testing Bolt-ons On The 4.0

[Woodrow]

This is the Holley throttle body sized difference from stock, the gasket is the oversized diameter.

View attachment 626006

When I installed my stroker, I used a 62 mm BBK throttlebody instead of stock which was maybe 6 mm less in diameter? The BBK unit matched the opening in the stock manifold so that made me feel good but no idea whether it makes a difference. So, I’m looking forward to @Jezza ’s data (although it won’t directly correlate because presumably the 4.0 needs less air than a 4.6).

Well AI seems to alighn with my memory. I recall that you can get .9% increase for every 10 degree drop. Ai is giving it a full 1%. Either way with an optimistic 30 degree drop in IAT with a CAI on a 125Hp base line that would be 128.75hp with the mod.

I always thought you can see both sides of the argument that it there is gain to be realized and eh not really I notice nothing. That is not a bing swing in numbers. I enjoy the tinkering and I will chase single digit % gains because you get a few of those added together and it starts to creep into double digits .

But to your thought on intercooler is that I think is a net zero gain. If you can get ambient CAI what value does the intercooler offer other than friction loss with the additional intake plumbing?Vs a boost situation where you have a highly elevated tempature from compression that intercooler adds value.. That assumes you are using an air to air VS some sort of icebox system on the NA.

I thought about it more after I posted and came up with the same. Maybe methanol injection would be helpful for a NA motor?

Random additional thought I have wondered if the multi hole injectors value of atomization is not the better distribution of fuel but the finer spray it is actually cooling the air too

I have those in my stroker as well and I couldn’t tell you. I think @Jezza was going to test those too?

 

[Wildman]

When I installed my stroker, I used a 62 mm BBK throttlebody instead of stock which was maybe 6 mm less in diameter? The BBK unit matched the opening in the stock manifold so that made me feel good but no idea whether it makes a difference. So, I’m looking forward to @Jezza ’s data (although it won’t directly correlate because presumably the 4.0 needs less air than a 4.6).

Because of the better flowing heads I put on the Hemi I got a larger throttle body also. Have no clue if it helps or not... One day I do want to get it on a dyno.

I thought about it more after I posted and came up with the same. Maybe methanol injection would be helpful for a NA motor?

I don't know if it would or not. I know it's used on forced induction... But anytime you can cool the air charge theoretically it's supposed to increase the HP & TQ. Old school drag racers used to use dry ice to cool the intake air...

I have those in my stroker as well and I couldn’t tell you. I think @Jezza was going to test those too?

It's another one of this things that has been debunked all the time as not helping any so it's going to be interesting to see.

 

[Jezza]

I have those in my stroker as well and I couldn’t tell you. I think @Jezza was going to test those too?

I do have a set of 4 hole injectors. Should be in episode 4 after this next one with the Windstar setup.

 

[MikeE024]

I thought about it more after I posted and came up with the same. Maybe methanol injection would be helpful for a NA motor?

Water/meth injection will change your air/fuel ratio and make things run rich unless you tune it. And then you’ll need to ensure you don’t run out of juice or you’ll run too lean. Thats a lot of money and effort for a gain that can probably be achieved by simply getting more ambient air to the intake.

 

[Woodrow]

Water/meth injection will change your air/fuel ratio and make things run rich unless you tune it. And then you’ll need to ensure you don’t run out of juice or you’ll run too lean. Thats a lot of money and effort for a gain that can probably be achieved by simply getting more ambient air to the intake.

That certainly makes sense. This is all an interesting mental exercise. I'm not considering any of this stuff, except maybe a tune at some point. My 4.6 has been reliable with good power on the street and trail. Honestly, going to 5.13 gears has been the biggest performance enhancer.

 

[ColoJeep]

Honestly, going to 5.13 gears has been the biggest performance enhancer.

Gears are what made T-2 IRS buses awesome offroad , factory 5.38's

 

[Woodrow]

Gears are what made T-2 IRS buses awesome offroad , factory 5.38's

I had to look that one up. I work with a guy who has a bus he’s fixing up. Didn’t know there was an off-roading community for them. Although, now that I think about it, I think I saw a MORR video where they recovered one with a broken shaft or something.

 

[astjp2]

Consider breaking up the videos into 20 minutes, hour long is hard to go through in one chunk.

 

[JustDandee]

I do have a set of 4 hole injectors. Should be in episode 4 after this next one with the Windstar setup.

Local guy/shop to me that ran his product 4 &12 hole test on dyno day. Dont know if that might assist on how you tackle that but sharing.

 

[Jezza]

Consider breaking up the videos into 20 minutes, hour long is hard to go through in one chunk.

Yeah, I got a bit long winded on this one. The future videos will be shorter. Ya think watching it is bad, try dealing with the editing.

 

[Jezza]

Local guy/shop to me that ran his product 4 &12 hole test on dyno day. Dont know if that might assist on how you tackle that but sharing.

Wow, interesting results. I have a set of the 4 hole injectors. Maybe I can get them to send me a set of 12 hole at some point. I think the most interesting take away here is they made almost idential power gains with the cold air intake that I made on my other Jeep.

 

[Steel City 06]

I run the 12-hole injectors. I was under the assumption they were supposed to be the same flow as stock but I ended up having to cut down all of the fuel tables to 75% of their original values in order to have reasonable fuel trims.

Not sure if it was just the set I got that was different, but figured I'd note it.

They work very well, but I installed them along with some other work (such as the Windstar intake) so I can't definitively say that they actually do anything. Startup seems to be smoother, as does cold operation. (I did also increase my cranking spark advance for a faster start.)

 

[Steel City 06]

Also another thing I run is the V10 Viper coil, specifically the K-fab suspension one, along with cheap low-resistance spark plug wires intended for a TJ with distributor.

 

[astjp2]

Wow, interesting results. I have a set of the 4 hole injectors. Maybe I can get them to send me a set of 12 hole at some point. I think the most interesting take away here is they made almost idential power gains with the cold air intake that I made on my other Jeep.

I didn’t have time to watch the entire video, what did the 4 hole injectors change?

 

[ColoJeep]

Yes, the newest video is up and it was a shock for me. I didn't expect those results. I am working on getting the footage for the next episode, which is going to be the Windstar cowl intake.

I was surprised that the difference is in the margin of error . I guess Rambler motors are like honey badgers and don't care.

 

[BlueC]

(although it won’t directly correlate because presumably the 4.0 needs less air than a 4.6)

The way I understand it, fuel/air demands are power dependent, not displacement dependent, if that makes sense. Theoretically, a 3.0L and a 6.0L engine making roughly the same power should require similar amounts of fuel/air. A 4.0L that makes more power than your 4.6L should require more air. If a throttle body can efficiently flow enough air for a given power, switching to a larger TB show have no meaningful effect, maybe just flow a little better at the top end of the RPM range where nobody drives, at least not for long.

 

[Woodrow]

The way I understand it, fuel/air demands are power dependent, not displacement dependent, if that makes sense. Theoretically, a 3.0L and a 6.0L engine making roughly the same power should require similar amounts of fuel/air. A 4.0L that makes more power than your 4.6L should require more air. If a throttle body can efficiently flow enough air for a given power, switching to a larger TB show have no meaningful effect, maybe just flow a little better at the top end of the RPM range where nobody drives, at least not for long.

That absolutely makes sense. In my case, the 4.6 stroker is making about 25% more HP and TQ than my prior 4.0 (not bad with only a 15% displacement bump). I think the extra 10% likely comes from a more aggressive cam and larger injectors because the the tune/ECM are still stock. Although the stock 4.0 is not supposed to be restricted by the stock air box or throttle body size (@Jezza's work will likely confirm or deny that), I wonder if my stroker actually benefits from the larger 62mm throttle body or is restricted by the stock air box (which I would probably keep because its a good design to protect against water ingestion in stream crossings).

 

[BlueC]

I wonder if my stroker actually benefits from the larger 62mm throttle body or is restricted by the stock air box

What is the i.d. of the piping in front of the throttle body? If smaller, which I assume it is, it is a potential choke point, but then the question is at what point in the RPM/power range does it begin choking the intake.

I'll guess that the stock intake setup is capable of flowing the needed air for a stock-ish engine, but I'll also bet the intake air source (heated under hood air) is detrimental, and that a cowl intake sucking ambient air is better. It would be interesting to see a stock box sucking heated under hood air vs ambient.

 

[Rickyd]

I don't have an dyno,but i definitely gained power at higher rpms with the windstar cowl setup on my stroker.

 

[Steel City 06]

What about a 70mm throttle body?
https://www.newcomerracing.com/store/p76/70mm_"Wide_Mouth"_Throttle_Body.html#/