Radiator Placement

[Bugscandrift]

Ok, i am in the middle of a 13B NA 6port swap into the bug, and i am wondering where is a good place to mount the radiator. I dont really want to mount it to the front of the car cause i dont want to have to run ten feet of lines and stress out the waterpump and so on. I saw someone who cut out the luggage area behind the rear seat and flipped it over and put the radiator in there. Just wondering if anyone here has done that. Thats the one i was leaning towards. Because the rotary is so small, i will be able to have it partially in the line of air from the deck lid spacer. This car is mostly used for autocrossing so, driving 20-30 minutes out there, sometimes more and then driving 1.30 hard, driving home. Doesnt spend much time in traffic, but if i happen to stop for a minute, i dont want it to over heat at a stoplight. Sorry for turning this into a novel, but im sure yall understand, this is a big change and its my baby this is happening to, so i have alot to say about the subject. Thanks for any opinions/help.

[Rob]

I started with a rear mount, but decided to change it to a front mount.

Check out my website (in the sig below).



Rob.

[zen]

i'm not sure if it has been thrown out there before, but has anyone tried using 996/986 rads? albeit some of the same placement issues, i would expect the smaller size and split placement might be a slight advantage (cost wouldn't be in most cases).

[volkdent]

Rob,

Like the progress, looking very good.

About those pipes under the car, not such a good idea IMHO. You may want to run them in the channels where the body bolts to the pan or next to the pan under the running boards, but where they are is asking for a big ol headache. If this is just to try things out, please disregard. But if your planning on driving it like this for any length of time, I would seriously reconsider. One odd driveway entrance angle will crimp those guys closed and then you burning up a head before you know it.

Jason

[Steve C]

Hi

The best place for air flow is in the front, a guy on another forum (look for use name Baja Wes on http://forums.aussieveedubbers.com) I visit fitted a V6 Mazda motor to a Baja with the radiator above the trans, he has over heating issues at higher highway speeds.

On my old 1302 I ran 1.5 inch stainless tubes to the front of the car, they followed the chassis bolts under the pan, my car was pretty low and I never had an issue with them hitting the road.

Steve

[ricola]

These are my main and chargecooler radiators.

Unless you have a seriously good reason or a very small engine I woldn't even consider a rear mount radiator. There is NO substitute for natural air flow.

Rich

[Steve C]

Hi

Also having the radiator & cooling fan at the front moves some weight forward, no a bad thing.

Steve

[beetle1303]

I ve seen some watercooled beetles with their rads up front, in real life and many owners are unhappy because his car is running a bit hot or even overheating. This may sound funny but its not only the natural air flow and cold air that is needed. Fitting the rad in front and closing it inside a box is part of the equasion, but remeber that you must provide the rad with enough back spacing in order to allow the hot air to escape ( something many times overlooked). If you make a box big enough just for the rad, trying to lose the less possible space, you will dissrupt the air flow and the rad will not work...

the best thing that comes to my mind would be a rad tilted backwards (top towards the back) with a cover that would be tilted forward. Also try to make a tunnel at the rad entrance going up to the body work. This would improve air velocity and air path thus improving the air flow to the rad. Race cars use a tunnel with a smaller area entrance and gradually the tunnel gets bigger until it reaches the rad. Next you should find a good place for the back tunnel outlet. The best ive seen was a 1303 with vents on its bonnet like a lotus elise/exige.

I would like the Idea of to smaller rads, one on each fender well but with the addition of either louvres or something like that to decrease lift

Sorry for the long reply

Chris

[Panelfantastic]

Rad needs to be up front. I've wasted a lot of time and money tring to get the rear rad to cool. Don't be me.


Jeff-

[Jeza]

You also loose some heat from the pipes if they run under the car, which can aid cooling.

Like Chris says airflow out is often over looked. This is really important, if air can't get out then it ain't going to go in!

[Steve C]

Hi

1303 you bring up some good points. The hot air that has done its work is larger in volume so its needs an easy path to escape.

On my 1302 I only had the stock grilles in the front apron AC front apron and the spent air went over my frame head and onto the road. It gets pretty hot in Sydney during summer (25-40 Celsius) and I never had any issues, the cooling fan only came on after standing in traffic and at around 50 - 60 kph the forward motion was enough to keep enough airflow through the radiator to keep the motor cool.

One mistake I did make was trying to keep the motor to cool with an adjustable fan switch, once I assigned the switching duties to my ECU it all worked great.

I’m not sure what sort bug your building Bugscandrift, perhaps you can let us know so we can offer better advise.

Steve

[volkdent]

In my head I always think of gathering the air into the radiator with ducting, so whatever air is trapped by the ducting HAS TO go through the radiator. Then on the back side, provide a nice open area or vacuum to carry the hot air away. I just ordered my radiator today, 8" tall, 29" wide. I'm hoping that with good ducting and 3 8" fans pulling from behind that it'll be enough.

The proof is in the pudding, so really, ask this guy Zenjoes Rotary Bug to see what worked for him and many like him using the rotary motor. There is also VolksSwap, a related site.

Jason

[Mikey]

For what it's worth. I'm going with a Suby conversion in my Ghia. I'm going with a front mounted radiator. I'm thinking the Ghia will accept it a little better than the bug. I'll make the hole in the body for the horns bigger and route the air from the front grills to the rad. Should be plenty of air. And I know I'll find enough ways to get it out too.

I even had an idea of small air deflecters behind the beam to help deflect the air towards the bottom of the car.

Just my 2cent.

[Jeza]

Once you get your air supply in and out sorted you can improve the effeciency of your radiator by turning it into a double pass radiator.

This uses baffles to force the water throught the radiator twice, ie through half of the radiator first (eg the top then through the other half (eg the bottom).

You may be able to use a smaller opening (like SteveC) or a smaller radiator if your effeciency is good.

[lazylongboarder]

Well, i'm not sure about you guys and i agree whole-heartedly with the natural air and front mount radiators, but how is that the "ONLY" way to do things? How has Porsche with all of their new cars being mid engined and rear engined having the radiators side mounted gone wrong? What about Ferrari, koenigsegg, ford GT, saleen s7, Lambo, renault...?

My attempt on the watercooled beetle will be with a 400 hp (at least for the first time around) 2.0 liter EJ20TT (single turbo conversion), so the motor will produce plenty of heat.I'm not worried about having a side mounted setup. Both will be assisted with big *** fans and scoops like the gallardo, murcielago, and renault, but I don't think the radiator/intercooler will be starved for air a bit.

The only difference between the cars I listed above and our beetles is that the front fender is in the way of the rear quarter panels, with scoops and fans, an aluminum radiator will have no problem cooling a a naturally aspirated 13b. sandrails regularly use 13btt's with smallish aluminum rads' mounted with fans being their primary airflow and don't have problems if mounted properly.

As stated earlier its imperitive that the radiator gets air in AND out.

At a show here in utah I saw a VW TDI motor from a 99' jetta in a baja and he had the radiator mounted on the roof with a "shark fin" style scoop being the only air inle for it and used sheet metal to channel air out of the radiator behind the rear quarter windows...stupid, but he said it doesn't over heat.

Point is, front mount is a great solution, but not the only one. Check out the pics and all of these cars use side mount radiators and intercoolers, including the 605 hp Carrera GT, and 630 hp Enzo... so if you can dream it, do it.