4.6is Vs. 4.8is......... Has anyone else noticed......
 

Hey guys,

I have an 03 4.6is and I was looking at a buddies 05 4.8is and realized that it doesn't have the same fan shroud and fan assembly in front of the radiator. It looks like the air flow to the 4.8is engine is greatly improved. Does anyone know anything else regarding this upgrade from the 4.6 to the 4.8? Is it possible to modify the 4.6 to the 4.8 set up???

Thanks,

Todd B

Why even bother unless your daily commute is through death valley.

Actually, I spend a fair amount of time in Palm Springs, CA 110+ June to mid September and better airflow is always good thing as well...............

I can't see the other pic :dunno:

I was being facetious. Unless the 00-03 design provides inadequate cooling (which it doesn't), this won't be anything more than a waste of money. If you are having cooling problems, fix the root cause instead of bandaging them by swapping other parts.

Actually with my set up the cooler the better, currently running Vortech SC and no room for inter-cooler. Something was clearly changed and improved on 4.8is front end set up (fan & shroud delete). I'm just searching to find out why the change and what it accomplished. Thanks for the input.

Todd B

Those things are to keep from supercooling. The N62 V8 is very very different from the M62. Valvetronic + Doppel Vanos vs Non-Vanos and single throttle. The best thing you can do is get a Zionsville radiator upgrade...dont bother changing the front fan shroud.

I noticed the BMW fan delete when I was checking out a friend's new 5 series. It just made me feel that my X is old but technically all is good since I replaced my radiator with a new one about a month or so ago.

Ironically I need to fix the fan since it seems slower than usual.

E55,

Tell me more........... what is super-cooling never heard that term. Is the radiator you suggested a larger capacity what improvements over OEM.

Thanks for info,

Todd B

bigfish..Vortech SC huh? How much boost are you running? You don't need an intercooler or anything else for that matter unless you're running too much boost..

Do you have a puller fan behind the radiator?

PT

That's the issue.......... I'm right at the edge of what the OEM cooling system can handle. At this point I'm running 8.5lbs boost, we have cut pulley once from the previous set up and I'm happy with HP increase. Two issues have come up.... one is cooling on hot days and the other is the torque converter/tranny under heavy load throws codes now and then.

I have looked at a water methanol set up however, not sure that is route I want to go plus then it adds to HP issue with torque and tranny.

I'm interested in every option available even those that don't seem obvious...

Todd B

JV,

No I didn't think their was enough room........... Have you see one set up that way?

Todd B

My 4.8 has one behind the radiator, electronically controlled (not attached to a pulley). Mine's stock so I assume all the N62's are the same. BMW has a habit of using different setups on various models depending on engine and chassis combinations. For instance, E36 M3's have fans both in front of and behind the radiator.

It may be that 4.6's simply have a pusher fan instead of a puller? I've never looked under the hood of one to compare. :dunno:

Whatever you do will put further load on almost every system. One thing you can do is try to get the thermostat to open sooner. If you can accomplish that then you can add a toggle switch for the pusher fan so you can turn it on manually when you want some extra cooling.

The other thing I’d look at is an oil sump and larger cooler. Getting that oil cooled down fast will reduce the water cooling system load and might get you some cooler temps.

Cleaner,

Good points... I have been in contact with Dinan about an high volume oil cooler and and additional tranny cooler. They seem to have bigger things on their plate right now.

Thanks,

Todd B

fans............
 

JV,

My 4.6 has two fans, one smaller up front pushing and a larger one attached to motor pulling. It seems that the 4.8 was able to do away with front fan pushing. My 4.6s has a goofy fan shroud with little ports in it, looks like something of Mr. Magoo's car. It looks very restrictive in comparison to 4.8, My observation is that do to some change of 4.8 radiator cooling set up that air is moving more efficiently through the motor. My questions is what was that change and what did it accomplish?

Thanks for your input,

Todd B

Hey Todd,

From my experience, there doesn't seem to be an easily explicable rhyme or reason why each car comes from the factory the way it does. The front fan is usually an auxilary unit that's activated by the a/c since it's attached to the condenser.

I can't tell from the blur in the picture but those ports look to be cooling flaps. Zionsville Autosport offers the same feature on some of their radiators - basically they just open up at speed to increase flow. The different routing may not be more efficient, it may just be out of necessity to accomodate room for everything since the motors are different. (Although i've never looked under a 4.6 hood to compare so that may or may not be the case) Perhaps it may have something to do with the 4.8 bumper having larger openings? Again, just hypothesizing..

Turning to Dinan probably isn't the wisest financial decision. You could certainly have a sweet Ron Davis radiator custom made for the same $, if not LESS that would probably be a better solution to your needs. You could also probably delete both fans and add an electric one from Spal similar to the 4.8. (I've done this to my M3) This would free up some space behind the bumper to add an additional/larger oil and/or tranny cooler as suggested above.

JV,

Thanks for the ideas, I just checked out Zions website.

Todd B

I think you may have a point...A couple years ago when i was on the market, i compared the 4.8is to my 4.6is and did notice that the 4.8is bumper had larger air-intake ducts than the 4.6is.

The electric fans speed is controlled by the DME. It will spin slower if the cooling need is lower. Keep in mind BMWs run a few degrees warmer than other cars on purpose.

Weasel, could you elaborate on the purpose of running warmer? Just curious. :dunno: