Dyno Testing Bolt-ons On The 4.0

[freedom_in_4low]

. Did see a nice gain was in torque - picked up an additional 35 lb/ft.

At what rpm?

 

[astjp2]

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

The Howard’s cam. Also 5.7 hemi springs will fit a 4.0 so eBay a set of takeoffs and the beehive style is exactly the correct height for many of the 5.7 hemi with more rate.

 

[astjp2]

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?

I would rather see any difference between true cold air intake vs under the hood with actual numbers of air temps at the throttle body. Air density is air density and hot air is not dense. Others argue that fact but in aviation, hot air is a measurable loss of power.

 

[Brianj5600]

I'm curious if the cowl area is a high pressure area on a Jeep. Driving in the rain there seems to be no air moving at all. I use rain x and the beads don't move at all.

 

[hear]

Maybe someone locally to North Dallas has a set of 33s I could try.

How good do they need to be, and where in North Dallas?

 

[BlueC]

I would rather see any difference between true cold air intake vs under the hood with actual numbers of air temps at the throttle body.

That's why I recommended keeping the hood shut.

 

[BlueC]

@Jezza Test idea for you. I forgot what year Jeep you're working with, but you could run MSD vs good stock coil(s).

 

[Paradiddle]

At what rpm?

Not sure. All work done prior to me owning it, but I will ask my friend. It was his Jeep.

Bottom line is he put almost $5000 into the engine and the gains were decent, but not great. It also has the AEM brute intake and the larger throttle body. Basically almost every "bolt on" mod short of a supercharger or turbo. You can feel it when driving the TJ if you come from a stock one back to back, but it's not anything I would have spent the money on had it been my Jeep from the get go.

 

[Jezza]

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?

I'm not sure there would be enough of a measurable difference on either of those items to quantify. I might have a set of the 4 hole injectors laying around I'll look.

 

[mrblaine]

Not sure. All work done prior to me owning it, but I will ask my friend. It was his Jeep.

Bottom line is he put almost $5000 into the engine and the gains were decent, but not great. It also has the AEM brute intake and the larger throttle body. Basically almost every "bolt on" mod short of a supercharger or turbo. You can feel it when driving the TJ if you come from a stock one back to back, but it's not anything I would have spent the money on had it been my Jeep from the get go.

That depends on the stock one. They vary far too much to be anything other than a mere suggestion.

 

[Jezza]

How good do they need to be, and where in North Dallas?

Able to do 80mph or so a few times, Plano near 75 and Bush.

 

[Jezza]

@Jezza Test idea for you. I forgot what year Jeep you're working with, but you could run MSD vs good stock coil(s).

1997, so it has the single coil and distributor.

 

[Brianj5600]

Not sure. All work done prior to me owning it, but I will ask my friend. It was his Jeep.

Bottom line is he put almost $5000 into the engine and the gains were decent, but not great. It also has the AEM brute intake and the larger throttle body. Basically almost every "bolt on" mod short of a supercharger or turbo. You can feel it when driving the TJ if you come from a stock one back to back, but it's not anything I would have spent the money on had it been my Jeep from the get go.

Who tuned it?

 

[Paradiddle]

That depends on the stock one. They vary far too much to be anything other than a mere suggestion.

Yep. I'm assuming correct gearing and built the same - so same level of "lightness", but yes, it's a crapshoot IMO as far as investing this much into the 4.0. Again - my opinion only.

 

[hear]

so same level of "lightness"

Colin Chapman would be proud.

 

[freedom_in_4low]

Not sure. All work done prior to me owning it, but I will ask my friend. It was his Jeep.

Bottom line is he put almost $5000 into the engine and the gains were decent, but not great. It also has the AEM brute intake and the larger throttle body. Basically almost every "bolt on" mod short of a supercharger or turbo. You can feel it when driving the TJ if you come from a stock one back to back, but it's not anything I would have spent the money on had it been my Jeep from the get go.

i follow. I was just pointing out that it matters. It's probably not hard to squeeze some more torque out of it at 4500rpm but that's not where I want to use it.

 

[Rickyd]

i follow. I was just pointing out that it matters. It's probably not hard to squeeze some more torque out of it at 4500rpm but that's not where I want to use it.

If that's the goal i have one word for you. "stroker"

Well or jezzas turbo kit

 

[Paradiddle]

i follow. I was just pointing out that it matters. It's probably not hard to squeeze some more torque out of it at 4500rpm but that's not where I want to use it.

Robert was no dummy when it comes to building Jeeps and he had it built for JV and to help tow his camp trailer, so I suspect the torque increase was in the typical usable RPM range for crawling.

 

[jwilkinson01]

If that's the goal i have one word for you. "stroker"

Well or jezzas turbo kit

Or both!

 

[ColoJeep]

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.

View attachment 531641

I ran this spec cam in a 350 4 spd. K - 20 , it is a great no B.S. truck cam .