Started my 4.7 Stroker build today.

I have a Chinese aluminum radiator that has been in my rig for about 8 years, but with the Stroker I want to make sure I keep it nice and cool, so before I installed the engine I decided to order a Ron Davis radiator and upgrade, and it just came in today! It is all aluminum and looks really well made. I guess we will see if it was worth it and works well.

Dare I ask how much that cost?

Anak said:

Dare I ask how much that cost?

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I got it without the internal heat exchanger for the tranny, so it was a little less expensive than a Griffin radiator, but more expensive than the Mishimoto! :laugh: Yah it def was not cheap! In all the research I did, there was pretty much a consensus that Ron Davis was one of the best you could buy for performance and cooling. I hadn't really seen any info on people running them in XJ's, but I have an old custom RD in my Early Bronco which keeps my 351W nice and cool. A lot of my Early Bronco buddies, other friends with buggies etc run RD radiators to keep their rigs cool and swear by them. With all the money I had dumped into my stroker build, I didn't want to cut corners on cooling, since across the board I have heard they run hot. I guess as my buddy Cal would say it is a "gratuitous lack of moderation !"

Let us know how it performs with the stroker, particulaly this coming summer.

In fact, you might want to take some good pics now and add it to Cal's radiator comparison thread. I am fairly certain that radiator is not yet represented in that thread.

ETA radiator review link: https://www.naxja.org/forum/showthread.php?t=1150722

Its not. Eric Filar offered me his to compare but it was installed in a car and not worth the effort.

That is one of the best radiators made.

'The intake is a ported 2000 XJ intake, so I believe it is the same intake as the 4.0 WJ intake. The intake has had both the throttle body port as well as the intake port opened up. Since the intake is such a pain in the ass to put on, I don't see myself removing it anytime soon and testing other configs/'

Sorry for the confusion from my terms. And thanks for the picture of the intake. The Power Tech is actually a carb hat and probably includes the airbox. Since you mentioned running with out any thing on the TB and losing power. Also, it would be a good comparison to the Thor intake. I could send you the one I have if it helps.
Yes, agreed removing the intake manifold is a pain, and I would not ask of that. The reference data I look to that is from Hornbrod on CC. His dyno graph showed a 12 hp gain. I remember one from possibly here and also posted on Mall Crawler from Jordan88 of a 27 hp gain. That though included injectors changed and fuel pressure regulator change.
I did a cross calculation from info supplied by Hornbrod as to drive train loss. I calculated that his gain at the flywheel would have been 16 hp. So, I used those to your data and came up with 282 hp.

75SV1 said:

The Power Tech is actually a carb hat and probably includes the airbox.

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Are you talking about the "resonator"?

RCP Phx said:

Are you talking about the "resonator"?

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https://www.allpar.com/threads/the-jeep-grand-cherokee-second-generation-1999-2004-jeep-wj.228758/

Here's a link. It has an assembly picture of the V-8 with a 4.7. The blue box on top of the engine. Not particularly what I'd picture as a carb hat, but if I noted it as an Airbox, it might have a different meaning.

Also, on the intake manifold, the only noted difference between an XJ and the WJ, is that the XJ has 3 bolts to hold on the throttle cable bracket and the WJ has 2. Then again, my 2000 XJ has the WJ type.

That's the resonator, do you have any links to actual documentation?

RCP Phx said:

That's the resonator, do you have any links to actual documentation?

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I'm not sure what info as to documentation? As to the 4.0L resonator, I pick one up at the PnP. I kind of view the letter ones lost power due to the exhaust ports. Then made improvements elsewhere to get back the power.

75SV1 said:

https://www.allpar.com/threads/the-jeep-grand-cherokee-second-generation-1999-2004-jeep-wj.228758/

Here's a link. It has an assembly picture of the V-8 with a 4.7. The blue box on top of the engine. Not particularly what I'd picture as a carb hat, but if I noted it as an Airbox, it might have a different meaning.

Also, on the intake manifold, the only noted difference between an XJ and the WJ, is that the XJ has 3 bolts to hold on the throttle cable bracket and the WJ has 2. Then again, my 2000 XJ has the WJ type.

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Just so you know, Chris sent me info on the drop in power with the intake vs without it. In the data he pulled, even with the hood up, the throttle body with no intake sucked in hotter air, causing a drop in horsepower. So it clearly looks like the impact in performance is not because of restriction of air flow cause by intake type, but directly tied to the temp of the air being pulled into the engine. He sent me the following graph, but I didn't follow up on what each line meant. I assume the line with the substantial drop is the increase in air temp.

bajabronco said:

Just so you know, Chris sent me info on the drop in power with the intake vs without it. In the data he pulled, even with the hood up, the throttle body with no intake sucked in hotter air, causing a drop in horsepower. So it clearly looks like the impact in performance is not because of restriction of air flow cause by intake type, but directly tied to the temp of the air being pulled into the engine. He sent me the following graph, but I didn't follow up on what each line meant. I assume the line with the substantial drop is the increase in air temp.

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To this I was referencing a book "Power With Economy'. It was from the 70-80's. Yeah, dark ages for HP. Anyways, it stated that the airflow would be worse without an air cleaner plate or whatever you want to call it. I had a hard time fitting an improved air cleaner on my '75 Bricklin. I did finally install a Moroso Low profile one. I remember it being mentioned in that book as promoting good flow. I could see the point about sucking in hot air. Some say that is why the K&N types don't add power.

75SV1 said:

I'm not sure what info as to documentation? As to the 4.0L resonator, I pick one up at the PnP. I kind of view the letter ones lost power due to the exhaust ports. Then made improvements elsewhere to get back the power.

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Anything but, "I know a friend who has a friend that has a friend that says this good". Produce documentation or it didn't happen!

RCP Phx said:

Anything but, "I know a friend who has a friend that has a friend that says this good". Produce documentation or it didn't happen!

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http://gojeep.willyshotrod.com/HowtoIntakeManifold1.htm

I swapped in the AEM 50-1220 E85-Compatible High Flow In-Tank Fuel Pump (340lph) last week to solve the fuel flow problem with my dying fuel pump. I was able to get back to Dyno tuning today. The top pull was 229 HP, which we thought might be borderline knocking , so I ended up going with the 227HP tune. The XJ is a lot
of fun to drive even with 37’s it moves!



Final tune I went with



So with the stroker build I gained about 80 rear wheel horse power.

bajabronco said:

I swapped in the AEM 50-1220 E85-Compatible High Flow In-Tank Fuel Pump (340lph) last week to solve the fuel flow problem with my dying fuel pump. I was able to get back to Dyno tuning today. The top pull was 229 HP, which we thought might be borderline knocking , so I ended up going with the 227HP tune. The XJ is a lot
of fun to drive even with 37’s it moves!

Final tune I went with

So with the stroker build I gained about 80 rear wheel horse power.

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That’s awesome. I’d love to see more info like this. The butt dyno always lies.

Here is the dyno data to review, I've included delta hp/tq data as well as some ecu data: intake air temp, coolant temp, injector pulse width, injector duty cycle, vss, measured lambda, commanded lambda, manifold pressure.

I tried to keep coolant and intake air temperatures consistent run to tun since the power numbers vary considerable with engine temps.







- Chris

Now we just need to figure out a real number for powerloss in the drivetrain.

cal said:

Now we just need to figure out a real number for powerloss in the drivetrain.

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Unfortunately the only way to really know is to run a few combinations both on an engine dyno and on the hub dyno.

Just a reminder as to why you need to watch your fuel pressure. This truck had no delivery issues with the stock engine, but once the bigger injectors were installed with the stroker build, the pressure started falling off excessively.