CFM of a stock 4.0 HO?

[xjtrailrider]

Does anyone know the answer, I'm looking at in-line filtration systems for my snorkel and I don't want to choke it down any.

The filter I'm looking at has a CFM rating of 575. Its made by Spectre.

 

[WB9YZU]

I found a CFM calc. At 80% volumetric effeciency, you'd be looking at maybe 400cfm at 5500.

What restriction at 575 CFM? I'd go with something a bit more to make sure you're covered. I did a filter changeup on my XJ once. I used K&N filter for a newer Accord. It had a 3" attachment point. Fuel milage around town was same, at speed, the gas milage dropped measurably. Changed it back to the stock box and picked up the milage again.

Ron

 

[xjtrailrider]

Here is the in-line filter I'm looking at;http://www.spectreperformance.com/#CATALOG.9833

I was wrong, the CFM rating is 450.

I want to delete the air box and connect this filter in-line between my snorkel and the TB.

 

[hubs97xj]

Is that the same filter they use in their cowl intake for the Renix models?

 

[xjtrailrider]

Is that the same filter they use in their cowl intake for the Renix models?

I have no idea, I just happened to see this filter used on Hot Rod TV today and it got the wheels turning.

I did a calculation on CFM for the 4.0 based on a 5300rpm WOT and a 70% VE it looks like I need 372CFM to let it breath.

It looks like that filter will get the job done but I sent in a e-mail to Spectre's tech support to make sure.

 

[xjtrailrider]

Ok, here is the e-mail I got from Spectre today;

I can fix the water tight issue, LOL!

We actually use the 9833 in our Jeep TJ kit and the intake kit flows 20% better than the stock intake assembly. As long as your engine in the Cherokee is stock, it will flow plenty of air for engine. The inlet and outlet are both long enough to clamp on 3” couplers. As far as being water tight, we have not tested the filter like this and are not able to make any guarantees. I hope this is the information that you needed.

 

[Dr. Dyno]

We actually use the 9833 in our Jeep TJ kit and the intake kit flows 20% better than the stock intake assembly.

That's fine as long as the filter's clean. Once it collects some dirt, the airflow will be reduced enough to cause some restriction.

 

[xjtrailrider]

That's fine as long as the filter's clean. Once it collects some dirt, the airflow will be reduced enough to cause some restriction.

Agreed, this is true for any filter. This filter is washable much like a K&N so it will get regular/routine maintenance.

This filter is going into my trail rig which is more pampered than any of my DD's. I give this rig a pre/post trail run inspection every time I take it out.

Its on order so when it comes in expect a write up on the "Spectre in-line 4" filter and ARB Safari Snorkel".

 

[hubs97xj]

And there are also larger filter assemblies, should it be insufficient- be interested to see how this works out for ya. I'm wondering if the TJ kit can be easily fitted to an XJ as well.

 

[ehall]

The paper Wix filter is 320 CFM (link)

Make sure to keep us updated on progress this could be interesting.

 

[Boostwerks.com]

FWIW...

The torque curve is the best real world representation of VE you can get. With that said, your peak VE occurs right off of idle. What does this mean? The highest amount of air moved through the engine is NOT around redline like the VE calc tells you.

With that being said, I'm sure that filter will be fine. Obviously the bigger the better though.

 

[badron]

If the flow of the filter element IS measured at all and not just estimated. Then also what MUST be stated is at what pressure drop said CFM was taken. All filters offer some resistance. So one man may rate a filter at just say 300 cfm at 1/2 inch drop across the filer. A other man may rate same filer at 475 CFM but at 1 and 1/2 inch drop across the filter.
Becouse MAN seldom give at what drop they use. Comparing filter CFM numbers from different MAN is a bit of a joke at times. But just using your eyes and head you can generally tell when your getting BS.
Next week we shall discuss the JOKE of a rating system know as "amp wattage output"

 

[lazyxj]

That's fine as long as the filter's clean. Once it collects some dirt, the airflow will be reduced enough to cause some restriction.

For any off-road vehicle, installing an air filter restriction indicator, to show when the filter needs servicing or replacement, is a good idea.

http://www.cleggind.com/postal_tech/filterminder.htm
http://www.knfilters.com/filterminder.htm
http://www.donaldson.com/en/engine/support/datalibrary/053979.pdf

 

[xjtrailrider]

I got the filter tube in today and installed it. I have a couple of issues to work out tomorrow with the CCV inlet and then i will do a write up. The filter tube fits perfectly and i was able to remove about 3' of 3" hose from my original air box set-up. Plus i gained enough space where the original air box was that I can add a Yellow Top for the winch.


Here is a sneak preview.

 

[ehall]

notice any difference?

 

[xjtrailrider]

notice any difference?

I'll drive it tomorrow, still gotta work out the CCV connection.