Engine fans.
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,307
Likes: 1
From: Milford Haven Pembrokeshire
Engine fans.
Couple of quick questions.
On my 81 350 and my friends 71 454 ( new fan clutches looking pretty ) just how much bhp is used to turn a Vette fan.
Because, standing there with the hood up - it feels like about 30 bhp at 2,000 revs.
Any accurate figures ????????
Next point, Daves 454 - lotsa new parts including headers, and it accelerates like it has about 180bhp - not the 400 quoted for his engine as is. Now, I know its way outa tune carb wise, but anyone tell me the 0-60mph time for a 1971 454 auto - otherwise standard ??
Cheers,
Hugo.
On my 81 350 and my friends 71 454 ( new fan clutches looking pretty ) just how much bhp is used to turn a Vette fan.
Because, standing there with the hood up - it feels like about 30 bhp at 2,000 revs.
Any accurate figures ????????
Next point, Daves 454 - lotsa new parts including headers, and it accelerates like it has about 180bhp - not the 400 quoted for his engine as is. Now, I know its way outa tune carb wise, but anyone tell me the 0-60mph time for a 1971 454 auto - otherwise standard ??
Cheers,
Hugo.
Drifting
Joined: Nov 2002
Posts: 1,665
Likes: 1
From: Ontario
First, 'they' say you gain between 5 and 10 horsepower when you replace your belt driven clutch fan with an electric one.
Second, don't know the 0-60 time you are asking for but there were two different big block engines available that year, the LS5 (365hp) and the LS6 (425hp). These links may help you identify which one...
http://www.netvettes.com/1971.html
http://www.stingray.nu/tips/tech.htm
Second, don't know the 0-60 time you are asking for but there were two different big block engines available that year, the LS5 (365hp) and the LS6 (425hp). These links may help you identify which one...
http://www.netvettes.com/1971.html
http://www.stingray.nu/tips/tech.htm
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,307
Likes: 1
From: Milford Haven Pembrokeshire
Melting Slicks
Joined: Dec 2000
Posts: 2,041
Likes: 0
From: Wichita, KS
Originally Posted by hensen1954
You expected anything less?When I put electric fans on my 350 I noticed that the engine did seem to rev faster and that the fan noise was greatly reduced. With the engine off and the fans running I can feel a vibration throughout the car in addition to hearing the fans.
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,307
Likes: 1
From: Milford Haven Pembrokeshire
did you find it any better on performance or gas consumption.
I changed my big block Cobra to electic fans, many years ago, and more recently the E Type Jag.
The Vette fan is much bigger than either.
The previous owner put a Kenlowe on the BMW732i, and I noticed I only need it when stuck in traffic on a hot day.
Anyway, most of my driving is done fast on the open road - very fast sometimes..............
I changed my big block Cobra to electic fans, many years ago, and more recently the E Type Jag.
The Vette fan is much bigger than either.
The previous owner put a Kenlowe on the BMW732i, and I noticed I only need it when stuck in traffic on a hot day.
Anyway, most of my driving is done fast on the open road - very fast sometimes..............
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
I don't think it takes more than a couple of hp to turn a fan. I suggest you find an electric 2 hp motor, grab a hold of the front pulley very hard, and the have someone turn the motor on. You'll get an idea of what force 2 hp is like. One of the advantages of a clutch on the fan is that at crusing speed there is suffcient air flow through the radiator and the fan is not needed.
There is no free lunch with an electric fan. Once it kicks on, the alternator is reguired to put out more power. It then puts a strain on the engine and uses some of the hp of the engine to produce the power.
There is no free lunch with an electric fan. Once it kicks on, the alternator is reguired to put out more power. It then puts a strain on the engine and uses some of the hp of the engine to produce the power.
Race Director
Joined: Sep 1999
Posts: 11,358
Likes: 379
From: Plano TX
Non-clutched fans (rigidly mounted to the w-pump) can draw over 20 hp. A clutch fan is typically around 10 hp at high rpm.
Electric fans are a good thing for several reasons:
Max output regardless of engine speed. You need the cooling most going slow in traffic, where an engine driven fan gives you the least airflow.
Only runs when needed (as long as you have it thermostatically controlled).
Less power draw even when running. The big fans use 25A... at 14V that is only 350W. 1 hp = 738W so about 0.5 hp. Add in some losses in conversions (alternator) and you're still looking at less than a 1 hp draw on the engine.
Electric fans are a good thing for several reasons:
Max output regardless of engine speed. You need the cooling most going slow in traffic, where an engine driven fan gives you the least airflow.
Only runs when needed (as long as you have it thermostatically controlled).
Less power draw even when running. The big fans use 25A... at 14V that is only 350W. 1 hp = 738W so about 0.5 hp. Add in some losses in conversions (alternator) and you're still looking at less than a 1 hp draw on the engine.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
I have posted this before but:
Car Craft test, May 2000 issue, page 50-51.
No fan=496 hp
thermal clutch fan 487 hp
HD thermal clutch fan=476 hp
non-thermal clutch fan=485 hp
plastic flex fan 460 hp
HiPerf flex fan 476 hp
lo Profile flex fan=466 hp
6-blade rigid=449 hp
electric fan=494 hp
4-blade rigid=473hp
Car Craft test, May 2000 issue, page 50-51.
No fan=496 hp
thermal clutch fan 487 hp
HD thermal clutch fan=476 hp
non-thermal clutch fan=485 hp
plastic flex fan 460 hp
HiPerf flex fan 476 hp
lo Profile flex fan=466 hp
6-blade rigid=449 hp
electric fan=494 hp
4-blade rigid=473hp
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Racer
Joined: Feb 2000
Posts: 394
Likes: 0
From: Evans GA
I'm more worried about engine temperature then I am about a little bit of horsepower loss... on my '73 I have dual electric fans and a clutch fan... what good does a few more horsepower do you if the engine overheats?
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,307
Likes: 1
From: Milford Haven Pembrokeshire
Thanks - at last accurate figures.
And now I can tell the world - just around the corner from my garage is the big green wheelie bin for my brothers hotel - do you think he will notice a C3 fan hiding in there somewhere.
Cos these figures echo those of the Kenlowe fan people.
So, its roller everything, cold air everything and electric everything
Look out Porche - we're coming to get you..............
And now I can tell the world - just around the corner from my garage is the big green wheelie bin for my brothers hotel - do you think he will notice a C3 fan hiding in there somewhere.
Cos these figures echo those of the Kenlowe fan people.
So, its roller everything, cold air everything and electric everything
Look out Porche - we're coming to get you..............