Dyno Testing Bolt-ons On The 4.0

Jezza

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I recently purchased a 1997 TJ (4.0 32RH) for some projects I am working on. I am planning to do some tuning sessions on it to get some base files for my tuning business. As part of that process I am going to be on the dyno in a number of different configurations with different mods. As a part of this process I will be able to get dyno data from a range of different engine mods. This is a list of the mods and configurations I am planning on testing.

Dyno 1 - Stock Un-modified
Dyno 2 - Stock With Tune-up Done (Plugs, Wires, Cap, Rotor, Clean Injectors, Filers)
Dyno 3 - Add Windstar Filter
Dyno 4 - Locked Up Fan Clutch
Dyno 5 - E-Fan
Dyno 6 - HP Tuners Tune, All Further Mods Will Have Tunes Optimized For The Mod
Dyno 7 - Add Header
Dyno 8 - Add Bored Throttle Body
Dyno 9 - Add Exhaust
Dyno 10 - Add Headgasket, Milled Head and Cam

If there are any other modifications that anyone would like to see, let me know. I don't want to spend lots of money on this testing, so things like the Edelbrock head and roller rockers I'm not planning on testing, unless someone is willing to donate them. ;)

Also, if there are any specific methods of testing that I should consider feel free to mention them as well. I won't be able to do it all in one day, so there may be some temperature differences and such. I think overall it will still give a good overview of whether or not these mods are worthwhile, as well as giving me data for base tune files.

20240525_144201.jpg
 
Following, thanks for sharing. Wheel dyno? Wouldn’t an engine dyno be a better measure since it doesn’t involve the TC or clutch effects?
 
Chassis or engine dyno?
Different tire sizes if dyno is rollers?

Chassis dyno. It's a Dynojet 248 big roller. It's extremely accurate as it uses mass and acceleration vs the new stuff that has user inputs and adjustable constants. When I dyno the turbo kit installs we do locally it will back up runs within 1-2 hp from run to run.

The TJ has stock tires no lift. I'm not sure how much tire I can even fit. It certainly won't fit the 37s off the LJ. Maybe someone locally to North Dallas has a set of 33s I could try.
 
Following, thanks for sharing. Wheel dyno? Wouldn’t an engine dyno be a better measure since it doesn’t involve the TC or clutch effects?

Yes and no. Engine dyno would probably show a more clear picture of the differences in modifications. The engine dyno doesn't do a good job when it comes to real world conditions like engine bay heat, losses from drive components and accessories.
 
How many miles? Wonder if a timing chain should be included in that tune up?

Maybe a leakdown test just to establish baseline numbers for science?

-Mac

Mummbleeee248...

Timing chain will be installed with the cam.

Good idea on the leakdown, I will also do a compression before dyno and after the head/cam swap.
 
Have you picked a cam yet? Head gasket thickness?

Well I'm a Comp and Cometic dealer so I was looking at doing a Comp 68-501-5 and a 0.027" thick Cometic for the gasket. That would bump it from around 8.8:1 to 9.2:1 or so and move the quench from 0.072" to 0.048". I'm also planning to cut the head 0.010"-0.015" which should give me another 3 tenths or so of compression to almost 9.5:1. With that cam and the gasket it will have a dynamic of 8.14-8.4:1 or so at my 600ft altitude. However I'm open to suggestions. The cam specs...

Advertised Intake Duration242
Advertised Exhaust Duration246
Intake Duration at .050 Inch Lift197
Exhaust Duration at .050 Inch Lift201
Intake Valve Lift0.450
Exhaust Valve Lift0.450
Lobe Separation108
 
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Well I'm a Comp and Cometic dealer so I was looking at doing a Comp 68-501-5 and a 0.027" thick Cometic for the gasket. That would bump it from around 8.8:1 to 9.2:1 or so and move the quench from 0.072" to 0.048". I'm also planning to cut the head 0.010"-0.015" which should give me another 3 tenths or so of compression to almost 9.5:1. With that cam and the gasket it will have a dynamic of 8.14-8.4:1 or so at my 600ft altitude. However I'm open to suggestions. The cam specs...

Advertised Intake Duration242
Advertised Exhaust Duration246
Intake Duration at .050 Inch Lift197
Exhaust Duration at .050 Inch Lift201
Intake Valve Lift0.450
Exhaust Valve Lift0.450
Lobe Separation108

That would be a very interesting test. I'm excited to see this.
 
I'll suggest using the same type of filter when doing intake/filter stuff, i.e. a K&N filter for each or a standard brand X paper filter for each, just keep them the same. Also, hood shut if possible.

If you're pulling the head, any plans to change rocker ratio?
 
Well I'm a Comp and Cometic dealer so I was looking at doing a Comp 68-501-5 and a 0.027" thick Cometic for the gasket. That would bump it from around 8.8:1 to 9.2:1 or so and move the quench from 0.072" to 0.048". I'm also planning to cut the head 0.010"-0.015" which should give me another 3 tenths or so of compression to almost 9.5:1. With that cam and the gasket it will have a dynamic of 8.14-8.4:1 or so at my 600ft altitude. However I'm open to suggestions. The cam specs...

Advertised Intake Duration242
Advertised Exhaust Duration246
Intake Duration at .050 Inch Lift197
Exhaust Duration at .050 Inch Lift201
Intake Valve Lift0.450
Exhaust Valve Lift0.450
Lobe Separation108

That cam is not good for fuel injection, want 112 or higher Lsa, less messes with the low rpm idle quality. I ran the crane 753901 in mine, if you look at all of the fuel injection motors, they are very wide compared to carburetor engines. Also consider high lift, short duration, increased torque at low rpm.
 
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That cam is not good for fuel injection, want 112 or higher Lsa, less messes with the low rpm idle quality. I ran the crane 753901 in mine, if you look at all of the fuel injection motors, they are very wide compared to carburetor engines. Also consider high lift, short duration, increased torque at low rpm.

https://www.compcams.com/xtreme-4x4-197-201-hydraulic-cam-for-jeep-40l-1964-98-cpg.html

Overlap is the problem with factory EFI. With such small duration I don't think there will be an issue.
 
https://www.compcams.com/xtreme-4x4-197-201-hydraulic-cam-for-jeep-40l-1964-98-cpg.html

Overlap is the problem with factory EFI. With such small duration I don't think there will be an issue.

Optimism, look at all of the modern cams, 112-116 Lsa, ford Chevy and hemi cams are all very high, and comp cams are 💩, I have replaced 2 wiped out ones, they are just soft and lobe profiles just don’t perform like other cam companies. They just advertise more so the sell more. I would be in the .480 lift intake and up to .485 on the exhaust with a short duration, accelerated lift and slower decent profile.
 
If they were still in business, this was a great cam that didn’t need to reprogram the pcm, ran 3 in different motors, a 258 with the carter carb and one in a 4.0, and the last one was in my 4.7 stroker. It just worked across all power levels.

IMG_9436.png
 
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Optimism, look at all of the modern cams, 112-116 Lsa, ford Chevy and hemi cams are all very high, and comp cams are 💩, I have replaced 2 wiped out ones, they are just soft and lobe profiles just don’t perform like other cam companies. They just advertise more so the sell more. I would be in the .480 lift intake and up to .485 on the exhaust with a short duration, accelerated lift and slower decent profile.

Any other currently available cam you would recommend? I was also looking at this one:

https://www.howardscams.com/hydraul...-1995-american-motors-199-258-40l-1000-4400-0

I am trying to stay budget-ish. Meaning I don't really want to go changing valve springs and rockers etc.. That being said I think 0.450" valve lift is about max.

There is also this Crower as well:

https://crower.com/camshafts/amc/19...pet/amc-hydraulic-flat-tappet-camshaft-4.html
 
I recently purchased a 1997 TJ (4.0 32RH) for some projects I am working on. I am planning to do some tuning sessions on it to get some base files for my tuning business. As part of that process I am going to be on the dyno in a number of different configurations with different mods. As a part of this process I will be able to get dyno data from a range of different engine mods. This is a list of the mods and configurations I am planning on testing.

Dyno 1 - Stock Un-modified
Dyno 2 - Stock With Tune-up Done (Plugs, Wires, Cap, Rotor, Clean Injectors, Filers)
Dyno 3 - Add Windstar Filter
Dyno 4 - Locked Up Fan Clutch
Dyno 5 - E-Fan
Dyno 6 - HP Tuners Tune, All Further Mods Will Have Tunes Optimized For The Mod
Dyno 7 - Add Header
Dyno 8 - Add Bored Throttle Body
Dyno 9 - Add Exhaust
Dyno 10 - Add Headgasket, Milled Head and Cam

If there are any other modifications that anyone would like to see, let me know. I don't want to spend lots of money on this testing, so things like the Edelbrock head and roller rockers I'm not planning on testing, unless someone is willing to donate them. ;)

Also, if there are any specific methods of testing that I should consider feel free to mention them as well. I won't be able to do it all in one day, so there may be some temperature differences and such. I think overall it will still give a good overview of whether or not these mods are worthwhile, as well as giving me data for base tune files.

View attachment 531522

Looking for things to prove/disprove? Would exhaust in order of progression be a good test before tuning? Maybe a multi hole injector test? But I am curious about doing an all conventional oil to a full synthetic Redline through the engine, x case, diff change would be a measurable attribute?
 
Here is what my 4.0 has:

Hesco AL head milled to get me to just under 10:1 compression ratio. Hesco pushrods, Hesco H264 cam, Harlan Sharp roller rocker kit with Hi perf valve springs, late model manifold swap and load tuned on a Dastec dyno using a Unichip. Didn't get 40HP... more like 27. Did see a nice gain was in torque - picked up an additional 35 lb/ft. These numbers are all at the rear wheels on 35" tires and 4:56 gears so figure about a 30% loss rate to get at gross crank numbers.