Mopar Performance Viscous Fan Package

[ykf7b0]

I have an aftermarket flex fan on my 69 road runner and I've been reading horsepower gains are to be had by switching over to the Mopar Performance Viscous Fan Package. I'm thinking of investing in one (P4120758) and getting an aluminum water pump and housing to lose some weight up there as well. Do any of you use this fan? Pro's and Con's are appreciated! Thanks for the replies!

 

[bigmanjbmopar]

I was going to but with an aluminum rad and pump there wasn't enough clearance. guess make sure you take all the measurements first. Flex fan keeps me at 180° all day.

Why do you want to switch, correctness?

 

[ykf7b0]

I want to switch for the potential horsepower gain. It is a street car that is not caged but is a 10 second car on nitrous. The car is "correct" only in appearance with the hood on and has lots of hidden go fast components.

 

[ykf7b0]

Anybody else using the MP viscous fan package with the 5 blade fan?

 

[Meep-Meep]

Not necessarily the MoPar fan but I've used my original Road Runner fan years ago and I tend to seek out a clutch fan for nearly everything I have. The HP gain they speak of is mainly at high RPM, along with the A/C water pump and windage tray. I had all those "tricks" on my 68 RR back in the 80's.

 

[moperformance]

I have an aftermarket flex fan on my 69 road runner and I've been reading horsepower gains are to be had by switching over to the Mopar Performance Viscous Fan Package. I'm thinking of investing in one (P4120758) and getting an aluminum water pump and housing to lose some weight up there as well. Do any of you use this fan? Pro's and Con's are appreciated! Thanks for the replies!

I have had one on my 383 Bee since 04. Rad is 4 core copper w fan shroud and have never had a problem. You could leave it running and walk away from the thing in the middle of Texas in 110 degree day and she never ever got over 190.
Hope this helps!

 

[Rustyiron]

Meep-Meep what would be a good price for the 070 fan clutch?

 

[sixt4driver]

So, is the fan that comes with the MP Viscous Package an aluminum fan?

 

[ykf7b0]

Good question. I have only read that it is lightweight.

 

[Sixer]

Clutch type fan is probably the best system for a street car. The clutch is heat sensing, it will kick the fan on solid when it's needed. Electric fans are nice, but never engineered for big block motors. The heat build up under the hood from exhaust manifolds/headers, blocks, road, brakes can be substantial and electric fans do not address this-they rely solely on coolant temps. Some horsies are not worth the price-good race doesn't necessarily translate to good street. A engine driven fan helps to keep compartment temps down-a good thing. Keeps that firewall cooler too-A/C guys take note. Don't overthink it-if it's street, look to how the original engineers thought-they were the ones that were gonna have to answer for flaws, and as such were cautious in how they set things up. They would have loved to present to marketing increased horsie numbers-but would have been shot when warranty claims started coming in.

 

[uk-maxie]

So, is the fan that comes with the MP Viscous Package an aluminum fan?

No, I'm pretty sure it's steel. It's painted black anyway, and weights quite a bit so my bet is mild steel!

We bought a viscouse fan package a while ago from Mancini's I think it was. That was for correctness and because of its supposed efficiency.

But when we went to fit it, we came to realise that the rad we had was 'thicker' (front to back) than standard, at 3.5" instead of 3", so the whole fan assy would not fit. We also have an ally MP water pump but they are the same size as stock one as far as I know, so our problem was just the rad.

Might be worth checking yours too, before you splash out on the new fan/clutch :head_smack:

 

[hunt2elk]

I have a brand new one I will sell you if interested. I bought it from Summit for my 69 RR. I have had it for a year and just went to install it and found out it doesn't have enough clearance. I did have my radiator redone to a 3 core and must have lost about a 1/2 inch of space.

 

[Bruzilla]

Back in the day you had unclutched metal fans on the engine, then they started using fan clutches to reduce power robbing at higher RPMs. The problem then, and I think still, is that you have a rotating body ahead of the engine, and no matter how well built a multi-component rotating body is it's going to start feeling the effects of centifugal force beginning the first time it's used and starts to wear. As the wear progresses the components of the clutch fan start losing stability and begin imparting some substantial vibration into the engine and into the car, which is never good.

The flex fans were invented to get around the problem with the multiple component rotating body and the unclutched fan by having a fan that has enough angle to cool the engine at low RPM, but reacts to increased centifugal force at higher RPMs by flattening out and reducing wind resistance and drag on the engine, yielding much the same benefits of a clutched fan without the negatives of added weight and vibration.

I would stick with the flex fan.

 

[68rt]

I bought on from Mancini for a 68 b body with the Mopar Performance alumn. water pump housing and had a problem with clearance, fan was way too close to the radiator. The Radiator is a new Glen-Ray which is exact reproduction. I called Glen Ray and they said they heard of this problem and recommended to use a hayden clutch with the mopar fan. I then called Morpar performance and when I told them what car I had, they did infact acknowledged there is fit problem. Beleave it or not, they recommended I use the same clutch that Glen-Ray recommended. Why the %#@&***% doesn't Mopar Performance tell yoiu this in their catalog...Good Luck

 

[Sweet5ltr]

You have to buy a clutch fan off of a jaguar with the same bolt pattern, to be able to run a clutch fan setup with a thicker radiator. I done weeks of research, after measuring my clearance and trying to figure out what may work with my own setup. I'll get the Part # and post it here later today, the fan clutch is still in the box.

 

[68rt]

Thats exactely right, the fan clutch I purchased was in fact for a jaguar....