Dyno Testing Bolt-ons On The 4.0

NashvilleTJ said:

Man, you must have some powerful headlights - my SPAL draws something like 40 amps at full blast…

Click to expand...

Fwiw, Steel’s comment also matches up with the real-life test result I shared in post #106 (the draw was 9.3A).

This amount of draw is easy to simulate for testing.

Steel City 06 said:

Applies for many different kinds of fans, including push or pull and axial or centrifugal.

Click to expand...

It also applies to centrifugal pumps!

I actually use these principles at work fairly regularly. One of our products with a pump has a live reading of flow rate without a flow meter, because I did a least-squares polynomial regression fit on the pump curve and combined it with affinity laws to calculate flow as a function of speed and head (pressure rose across pump).

For fans it's better to use power instead of pressure because the pressures are so small that the accuracy required would drive the cost of instrumentation beyond commercial viability.

freedom_in_4low said:

It also applies to centrifugal pumps!

I actually use these principles at work fairly regularly. One of our products with a pump has a live reading of flow rate without a flow meter, because I did a least-squares polynomial regression fit on the pump curve and combined it with affinity laws to calculate flow as a function of speed and head (pressure rose across pump).

For fans it's better to use power instead of pressure because the pressures are so small that the accuracy required would drive the cost of instrumentation beyond commercial viability.

Click to expand...

One mill I worked at struggled to balance pressures in a veneer dryer after one of the fans lost a blade and the quickly-sourced replacement had a different pitch, so they didn't know how to set it. I used clear plastic tubing and a little water and made a manometer to get it set right until matching blades could be found.

I'll be interested to see how the cam performs. I'm replacing the cam in my Jeep in the next couple weeks or so due to my OPDA tearing up the gears. I'm torn between a Comp cam or just sticking with the OEM cam. Unfortunately, I'll probably be done with my cam before the testing is done here. But I'm still looking forward to it.

Any updates? Interested in several of the mods

Which mods?

Jezza said:

I just finished editing the first video this morning. I released a CJ2 video today. The first bolt-on video will go up next Saturday.

Click to expand...

will you link it here, please?

Jezza said:

Just intro and baselines for this one. Which mods are you interested in?

Click to expand...

Start simple, oversized throttle body, cold air from the cowl, lockout hubs?

Jezza said:

Just intro and baselines for this one. Which mods are you interested in?

Click to expand...

Since we're quickly jumping into summer heat, I'm interested in the effects of the cowl (Windstar) intake, which I think is early on your test list order. I've noticed my Jeep seems to pull timing pretty hard, at least that's my best guess as to what's happening, when ambient temps get above 90F. I'm interest to see what info you can pull from the dyno, intake temps and power figs, especially if you will do a few heat-soaked, hood shut runs stock vs cowl.

Oh and maybe an edelbrock aluminum head, once the mods get more in depth

BlueC said:

Since we're quickly jumping into summer heat, I'm interested in the effects of the cowl (Windstar) intake, which I think is early on your test list order. I've noticed my Jeep seems to pull timing pretty hard, at least that's my best guess as to what's happening, when ambient temps get above 90F. I'm interest to see what info you can pull from the dyno, intake temps and power figs, especially if you will do a few heat-soaked, hood shut runs stock vs cowl.

Click to expand...

My anecdotal experience is it helped a LOT with allowing the engine to keep more advanced timing, even with the tune I previously had.

Here's the caveat though: it may be extremely difficult to get this to show on a dyno, unless the dyno is able to take very long full-power pulls.

In my experience, the gain largely occurs after having sat at full throttle for some time. In the normal setup, you have full power immediately, with maybe 10 seconds for the timing to start retarding, with it noticeably retarding after about 30 seconds to a minute in. The Windstar intake did not appreciably change the initial power level for me. However, it did allow that power level to be sustained indefinitely, and it is extremely noticeable when holding full throttle for 2-3 minutes.

The gain also seems to be largely independent of the engine RPMs as well. At 2,000 or at 5,000 RPM and full throttle, I would always get that sluggish feeling after a couple minutes. Now it does not happen much at all, except for very low RPMs (1500 or less), but it's seldom you'd want to hold full throttle at those low RPMs for more than a minute anyways.

Also of note, I suspect in my case power enrichment as programmed in the PCM does not really provide much of a gain if at all, and is instead there to prevent detonation. My tune keeps it out of PE except for when my pedal is absolutely to the floor, and I try to keep the pedal out of that condition (usually closer to 95% throttle) until pinging sets in. (Then the pedal is floored or I just downshift.)

Makes climbing the hills around here a lot faster for sure.

astjp2 said:

Start simple, oversized throttle body, cold air from the cowl......

Click to expand...

Jerry has already proved beyond the shadow of a doubt these do nothing. Because he talked to a guy this one time. #science

SkylinesSuck said:

Jerry has already proved beyond the shadow of a doubt these do nothing. Because he talked to a guy this one time. #science

Click to expand...

If Jerry had numbers to back it…and it did make a difference on my stroker, but I don’t remember how much, it was almost 20 years ago

Steel City 06 said:

My anecdotal experience is it helped a LOT with allowing the engine to keep more advanced timing, even with the tune I previously had.

Click to expand...

I notice my issues driving the highways at temps at or above 90F. In cooler weather, I have no problems running 70mph and average around 15 mpg. At or above 90, I can maintain 70, but it's a struggle, and my mileage drops to 11-12 mpg. I'm assuming my computer is pulling timing due to intake air temps, so I'm curious if I should go through the trouble of doing a cowl intake setup to get ambient air in there. Did you happen to monitor your before and after intake temps?

BlueC said:

I notice my issues driving the highways at temps at or above 90F. In cooler weather, I have no problems running 70mph and average around 15 mpg. At or above 90, I can maintain 70, but it's a struggle, and my mileage drops to 11-12 mpg. I'm assuming my computer is pulling timing due to intake air temps, so I'm curious if I should go through the trouble of doing a cowl intake setup to get ambient air in there. Did you happen to monitor your before and after intake temps?

Click to expand...

I did monitor it, but not enough to prove beyond a doubt. (I don't have much data from before the cowl intake was installed.)

Edit: saw you meant intake temps, not timing specifically. Yes, my intake temps dropped dramatically. Normally it varies between 15-50°F over ambient; now I'm consistently closer to 5-15° over ambient.

I also have a tune that makes the timing less likely to be pulled in the first place, and also advanced it across the board. Immediately before/after the install, I had the same time, but then modified it a bit more to take advantage of the new setup.

I did notice after install pretty quickly that my total fuel trims kept showing close to the same at the low-RPM and low-throttle range, but then were +6-9% in the peak power range, namely full throttle and about 4500-5200 RPM. Installing an exhaust header and having both intake and exhaust headers coated with low-emissivity ceramic coat bring that top end total fuel trim to about +9-12%.

So that did indicate to me that there might indeed be more air making it into the cylinders.

With my specific setup there's also one heck of an intake drone at 2,200-2,400 RPM and full throttle, and short term fuel trims go +5-8% positive there. So I probably inadvertently created a torque peak there via intake resonance. Very helpful when cruising at 65-70 mph in 6th gear.