We are building a track car for endurance racing in Lemons/Chump Car series from a 74 914-4 1.8/carb converted. Rules state we have to spend no more than $500 on the car minus the safety equipment (seat, cage, tires, wheels, brakes, etc..)

I am thinking of leaving off the 914 cooling system and much of the engine tins and running a electric fan to cool the motor. The fans are cheap $70 for 2100 CFM fan and I can also use some big ducting to cool motor at speed. Elec is free (no night racing) right and no HP drain. Just loosing the 50lbs of fan/ducting on the front of the motor seems worth it.

I would build a shroud and use some of the existing tins push air across the jugs and heads. I would relocate the alternator above the oil fill/breather and run it off the small AC pulley that was behind the fan. Would love to buy a DTM or Fat 911 conversion kit but not allowed in budget.

I was wondering what the peanut gallery thinks of this.

Is this going to give me cooling issues?
Will ALT function from smaller pulley?

Thanks!

Plus the motor looks much cooler without all the ducting, heat exchanges and tins.
Click to view attachmentClick to view attachment

There's this pesky little thing called "Physics" that disagrees with your statement above.

Unless you have an extra battery that can power the fan for 24 hours without an alternator to recharge it.
As soon as an alternator is used to generate the electricity to run the fan, it ain't "free" no more.


I have seen electric fans work OK on AX cars where you usually run for less than two minutes.
I would be very nervous using an electric fan for a 24 hour run.

Plus, the ducting and sheetmetal on a T4 is also used to separate the hot air under the car from the cooler intake air.
Removing the tin will rob you of HP since you're sucking in hotter intake air.

I'm no Andy, and I don't have the experience that most of these guys do but we're planning on entering Chumpcar this season too. I think if you remove all of the cooling that VW/Porsche worked so tirelessly to design, you might as well your car and don't even bother trailering it to the track. Worry less about going fast and more about safety, then reliability. Besides, I've already done a Chumpcar race in a well-prepared, FAST Mustang and even a stripped down 914 isn't going to have a chance in the world. I would suggest you do as we do - build the car for reliability and have fun, get some experience then come back with a different engine (Suby, V8, whatever) once you are comfortable with how the race and car works.

So we race off road as well with a Type I motor but have some friends in another class that race with a Type IV motor. I thought the Fat kit converts over to what is basically a 911 style fan and Alt. So if we built something like this with a electric fan being fed from air ducts cut through the roof. Oh and also an external oil cooler.


In our Off/Road racing we are running 6-9 hours at a time like the typical Lemons racing (only one race a year is 24hrs and we prob won't enter that one).

I guess I am better off with where it is and blocking off all the heater stuff and use the fan over the heads/jugs.

Do we need all the other engine tins/metal work tho? Can I cut the end of the main top tins (over the pistons and heads) so that we can check/adjust valves without removing the engine.

And I hear ya ThePaintedMan, I am already thinking of a Type 1, subi, or some other conversion.

I agree. The benefits you're looking for don't exist and you're adding more risk of unreliability in exchange for dubious benefits. Bad tradeoff in a racecar.

But it sounds like you've decided to go this direction and you just wanted us to pat you on the back.

Give it a go and report back. We learn from success as much as failure. And I mean that in an honestly respectful way. Try it out, and let us know what you find so we can all learn.

If you go without a fan based cooling system you'll need two 6" ducts from the front of the car to the engine compartment. I don't think there's another way to supply enough pressurized air to the heads/cylinders for road racing, or you'll cook the engine.
Electric fans would probably be sufficient for cooling around the paddock.
Click to view attachment

The Little Spec Book rates the stock coaxial fan at 800 liters/sec at 4600 rpm which is 1695 cubic_feet_per_minute - so you're in the ballpark on airflow.

But - how many amps does it take to make 2100 cfm, and Watts (pardon the pun...) that in HP ?

Keeping in mind that there are coupling loses in the alternator drive the coaxial fan doesn't have. The alternator will run with any size pulley, and it's a common racer's trick to run them with small(er) pulleys on high-revving engines. But it's gotta rev fast enough to make the power you need (plus stuff like ignition, fuel pump, cool suits? Helmet blowers? ...).

You may be able to pick up some airflow efficiency with an external oil cooler, at some cost in drag. And weight, due to the hoses and fittings, although the tradeoff is you can move the weight to where it helps you. And the downside is more risk of damage due to contact or debris.

The upside of the coaxial fan is it only draws power (roughly) proportional to your need for cooling.

That would be good if CFM was the important measure of a fan's ability to push air through the cooling fins of the engine.
Electric fans designed for moving air volume typically don't produce much head pressure, and stall easily when backpressure increases.

Yup - I agree.
However, I believe the engine-mounted coaxial fan also stalls at high revs - not coincidentally when backpressure reaches 'some point.'

It'd take a dyno setup or more CFD than I have access to in order to measure or model what 'some point' is. But I believe this is one of the several reasons 'some number' of vanes are removed from the fan for high-rev operation. And I'd expect you'd consider that number more than a little proprietary, so I won't ask ;-)

But I do know that 935's completely removed all the upper cylinder fins and improved cooling as a result...

Guess the admin role and 16K in posts means you have seen it all and type people pretty quick. I was actually asking since I have the motor torn down and deciding if going a different route is worth it. The benefits I see (still haven't been convinced they aren't there) are worth exploring so exploring.

1. Room to work on the motor in the car. From experience I assume we will be dealing with oil pumps failing, valve adjustment, Ign/electrical issues so room around the motor without removing it would be huge.

2. If the belt to run Alt takes 5HP to run from the motor and a fan (5LB of spinning mass + air resistance) takes another 3HP, wouldn't getting that 3HP back since I have to run ALT to keep batt charged for coil regardless of the elec fan or not.

3. Stock air shroud is 40-50lbs with all that heater hardware maybe more. Putting the air box back on may be only adding 30lbs back so maybe I close up the heater ports and use it with stock fan

#1 is probably most important to us in the long run.


Fan is 8-9 amps so should be plenty left over to charge batt and power coil. I was thinking of external oil cooler in back window or below mesh above motor. May plumb it further if we can get more air to it.

Adding to the e-fan we would put ducting into the motor for additional airflow at speed tho not sure how to run this with the fan, into same fan opening?

Removing the cylinder head tins won't gain you any additional accessibility for valve adjustments, however, removing the tin around the exhaust pipes, as you have already have done, will.

I don't think you'll have a problem with the oil pump, but if keeping the stock fan housing arrangement, an oil pump replacement would typically require an engine drop.

Try this experiment: With the engine you already have out, reinstall the fan housing and remove the front engine crossbar/mount to see if you have enough clearance to remove the pump.

If that works, when the engine is in the car (and if the pump needs replaced), jack the engine up, remove the rear shift rod and engine crossbar and perform the change-out

Do it. Prove us wrong. I love to learn.

And there really is no sarcasm there. I'll never build an electric fan cooled Type 4, so people like you are the ones who will teach me something.

Its not that anyone wants to see you fail, trust me. Its just that these engines have now been around for 40+ years and everyone from Porsche and Volkswagen engineers to weekend racers have explored most other options, and usually with a larger budget than those of us trying to make it through a Chumpcar/Le Mons race. Racer Chris is a great example of someone who has already learned it all the hard way but has developed reliable, high quality alternatives for the rest of us. If he hasn't come up with an electric setup, I don't know who would have.

Personally, again, as another Chumpcar hopeful, I think that keeping it simple is the way to go. I've seen multiple aircooled cars run these races with good success using the stock cooling setups (plus maybe an external oil cooler). Two Beetles ran Sebring last year, and one of them ran the whole race on the same engine. I don't know what the rules say for Le Mons, but in Chumpcar, if you're betting on getting the car in without any penalties as a bone-stock car, they will allow all 914s. Again, assuming its bone stock. Adding an electric fan will mean that your car then has to go through the Average Internet Value (AIV) process and the burden will be upon you to prove that there are 10, running 914s across the country that are worth $500 or less. At that point, any additional engineering you do to the car will be assessed based on its value. Thats why we've decided to run the car as close to stock as possible and just have fun.

But as McMark said, no one has made it work yet, so you guys might be the first. Give it a shot!

Jake, Chris, AJRS, and others did a lot of work on overhead fan and electric fan cooling.

it is much more complicated that just dumping the air onto the motor

you have to try and keep the temperature consistent across all 4 of the cylinders and heads. So the duct work under your electric/overhead fan is the truly important part

this was tested on the dyno extensively
I have seen electric cooled 914's
they work for short sprint races

the AJRS ones were total loss systems and running no alternator, or a transmission driven alternator.

the oil pump won't fail
and you probably won't be touching the valves hot

the front shroud is magnesium... all of the duct work together is probably closer to 20lbs total.

I run a 914 race car without the chassis side shelves
but its a sprint car

brant

I've run tests on 4 different cooling systems.
Head pressure increased somewhat linearly with RPM.
Even at 5000 rpm there was no evidence of cavitation on any of the systems.
I'm sure an electric fan that draws less than 10 amps is incapable of producing even half the head pressure of the 4 most popular mechanical blower systems - Stock, 911 style (FAT), Type 1 (DTM), Horizontal (Tangerine).

The level of air pressure required to cool the engine is roughly equivalent to air speeds of 60-90 mph.
You would need efficient ducting with the same crossection as the top of the heads & cylinders to rely on vehicle velocity to provide the necessary pressure for cooling.

Chris Hamilton's Dad (and company) have been running a fan cooled 914 for years, but it only runs autox's.

Maybe Chris will jump on this posting and tell us his experience.

Removing the side tin and engine shelves won't adversely affect engine temp through a long race - as long as the car is in motion most of the time.
However,this won't make topside access much better for parts swapping or valve adjustments. Its still easier to work from below on most engine maintenance.
It does improve visibility however.

I agree.

the shelf only seperates the rising heat from the headers when the car is sitting still.

probably its biggest effect is that the fan now has access to a tiny bit warmer under motor air, and road dust with the front chassis shelf removed.

This is getting way more complicated that I expected and I trust you guys know what your talking about. I realize the oil/engine cooling is all we have going for these motors so not ready to risk it since we won't have ability to truly test before the race. Just thought the T1 in our O/R racecar is simple and thought I could replicate that with the T4 motor.

So forgetting the e-fan option, what I am hearing it's not advisable to alter any of the engine tins to add additional cooling as that will effect pressure across the cyl/heads?



I hope to remove some of the shelves and tins. I think I will still do this to keep us from having more work at the track if(when) we have issues and need to drop the motor.

Is this a decent solution for external oil cooler?
Sandwich Oil Cooler Adapter
We are already over budget (see my parts for sale in FS forum...) so I am looking for a cheap solution for external oil cooler.

So RC, you run this car with no fan at all, just the 6" ducting?
What sort of racing? We are looking at 6-8 hours per day over two days. This was more in line with what I was hoping to accomplish (ducting for cooling at speed and e-fan for pit/warmup.

With rules around the engine and fuel compartments being sealed off from driver, we would have to weld in sheet-metal around the ducting through the drivers compartment if we wanted the inlet at the front like you have here but that may be worth it. I was just wondering what sort of racing you do with this car and the motor/head/oil temp issues you have seen.

The sandwich adapter you pictured will work fine. I use a high pressure sealant (Loctite 518) to on the o-ring since the manufacturing on the cheap ones isn't all that great. Oh and don't overtorque the center bolt or the filter. Just good-n-tight.

Here's a pic of my engine compartment.

Click to view attachment

The horizontal cooling system is something I developed and have used since 1998.
The fan and the duct are both necessary to control the head temps on my race engines, which produce up to 180 hp.
I mostly race in the SCCA F Production class. Displacement is limited to 1832cc. Races are up to 45 miles.

Why would you need sheet metal around the duct if the duct is metal and the bulkheads are sealed where the tube goes through?
IMO you would need two of those ducts, or the equivalent, if you want to have even a chance with the electric fans.

The rules state engine and gas tank need to be completely sealed off from driver. Not sure if 6" dryer venting is legal. May crush in a wreck and allow fuel into dvr compartment.

That isn't dryer venting.
Its a heavy weight aluminum high temperature duct for fumes from McMaster-Carr.
A ten foot piece costs more than $125.
It is a very durable product with enough flexibility to route it smoothly through the car.
SCCA regs are at least as stringent as Chumpcar.

I would say moreso. Chumpcar initially based their tech rulebook on the Le Mons model, but now appears to follow SCCA pretty closely. However, SCCA is still a little more stringent in some areas. If Chris' setup is allowed in SCCA, I doubt you would have a problem with the Le Mons judges. However, its ALWAYS worthwhile contacting someone from the series to verify things before you begin major modifications. Although, Le Mons values each part more closely than Chumpcar as well - that $125 tubing might put you guys over, but I guess they still do the whole credit for parts sold thing. I dunno. This is getting increasingly complicated. Our route: build the car, get the safety stuff out of the way, do a track day and run the piss out of it. If there is any major flaws that need to be corrected, they'll show up then. The rest of it will show up during the race

I'd worry about cooling the brakes and leave the engine cooling stock ,maybe an oil cooler with a fan on it....my friend ran it in an Alfa and said the brakes went away quick...those are really. Fun events with great looking,funny ideas but be careful !! I think it's just a matter of time before there's a fatal accident ...

There already has been one actually. I can't remember it if was Le Mons or Chumpcar, but apparently the driver had a massive heart attack. Very sad, but it was not contact or collision related.

Endurace racing an aircooled car comes down to a couple of things - cooling, cooling and a bit more cooling.

Last year we had a burned out 911 running in ChumpCar and controlling the heat was the main issue - after 14 hard hours of racing we found a couple of rocker shafts walked due to cam tower expansion. This, along with other failed seals / leaks put us on the trailer.

Keep in mind, this was a rich running 2.4 with the 911 11 blade fan and an external cooler - it still had problems keeping up - we think we needed to have the external oil cooler in a better position

Regards,
Andrew M

Hi Andrew,
I think we met on the Chumpcar forum regarding cages. Thanks for your input on this one. So you guys had problems with head temps, oil temps, or both? I wonder if running a smaller motor, like our 1.7 will make it easier to cool? I assume we have less of a chance of rocker shafts walking with a one piece head on the Type 4 motor as well. Either way, we'll definitely have a backup engine.

Cooling, gotcha...
Yep, I understand that. We run 7+ hours at a time in the Texas heat in our off road car. Cooling is key; 8-9 quarts of oil, a T1 fan and open engine compartment and we still run around 200* if it's hot out.

We have decided to go with the stock cooling system with some minor mods to close off heater channels and get as much air to the motor and oil cooler as possible. We are cutting some of the tins to make it easier to get the motor in/out and work on valve train if needed.

Working on some ducting for the rear deck lid but the pricey stuff won't fly. We are truly doing this legit, paid 600 for the car (+ extra parts) and selling off stuff to get us down to $500 or under to add performance upgrades.

So by purchasing the parts we have for sale you could be helping put a 14 on the podium of some crap can racing series truly solidifying it's rightful place in racing history. http://www.914world.com/bbs2/index.php?showtopic=202397

I don't know where you stand with your cooling issue but we raced F production with one 7 inch aluminum tube from front to the original fan with shroud ( of course a 1980-83 Vanagon fan shroud is probably a little better) with engine tins and had no trouble with CHTs. I do have a fiberglass engine shroud with an electric fan we used successfully for autocross but I doubt it would be good for a 24 hour event. I'll try to post a picture tomorrow.
You would probably benefit significantly from an oil cooler. You could probably run a couple non-braided lines through the side pod, run it inside around the wheelwell with a metal cover and then up into the front trunk. You definitely don't want those hot oil lines to break and cause oil to get on the driver but being in the side pod would keep it out of the driver's compartment. I will donate an oil cooler if you could use it.
I'll also post some pictures of some homemade plates we made to run cooling hoses from the front to the brake rotors. I don't know how much they help but we did not have any significant brake fade. Buying some really good pads, particularly fronts, would be a good idea. We use Carbotech X10 but probably X8 would be adequate. They are a little pricey but maybe you could work a deal with them (i.e., advertisement).


Milt