I was thinking of using two smaller radiators and two fans and ducting not only the intake but the exhaust through the fenders.

This would allow more usable trunk space....

Try it, take lots of pictures of how you are doing it. When it is done, test it out real good, drive in some heavy traffic, stop and go, and drive up some steep hills or up to the mountains and let us know how it works. I thought about all different kinds of ways to do it, when it was all said and done, the only way to go is a Renegade system. Thats just my opinion though.

IMHO, we need more people thinking "outside the box" and trying out new ideas. There's a lot of hear-say that is passed around. Do it Roger.

I'm not clear on where exactly you're thinking of placing the radiators. Care to modify a picture?

Roger,

This is what I plan for my V6 conversion to save the trunk space. I don't know if it will work for a V8...

If you use finned tubing you get about 170 sq in per ft of tubing cooling surface.
That will pulls alot of heat out before and after the radiators.

are you thinking the rear fender wells for the radiators?

Hmm, I hadn't thought of the rear fender wells but that's an interesting proposition.

I don't have the rear flares to duct from. Did you have some thoughts on that? Draw air from where?

No I was thinking almost exactly what Felix's pic shows. Only from the existing light openings in front bumper.

You guys are great for bouncing ideas by.

Finned tubing?? Who would have thunk it?

Any and all ideas are greatly appreciated..

ok, this is a very lame pic but i kinda' shows what i'm thinking...

if you were going to use two small radiators why not attached them to the rear engine lid w/ a fan underneath?

I think you could use some modified fab like Scott T. did on his suby conversion to draw air upwards then thru the fans onto the radiator and out the lid grills. kindof a scoop?

wouldn't that draw air from around the headers/engine area??? pre-heated air trying to "cool" the radiator water?

QUOTE (rogergrubb @ May 30 2005, 02:23 AM)

ok, this is a very lame pic but i kinda' shows what i'm thinking...

Oh Jeesus! Did Joe Ricard ask for a diagram?


M

QUOTE (rogergrubb @ May 29 2005, 10:37 PM)

wouldn't that draw air from around the headers/engine area??? pre-heated air trying to "cool" the radiator water?

Probably some.

But, everyone told Scott T. his way wouldn't work and he drove it cross country with no problems. He did some fabrication to draw air from under the car into his radiator which fit in front of his subaru engine. why couldn't you do it in a similar fashion and draw the air up further?

I'm just throwing some alternatives. The Renegade system is proven and works great. But, you loose the trunk and have to cut the wheel wells.

i was thinking out loud.

very interesting on that Subaru idea.....

so he ducted from underneath the car for the fresh air source?


as you all know, having the radiators up front allow for the ram effect at cruising speed. no fans.

was the subaru setup for "no fans" operation at cruising speed?

QUOTE (joe buckle @ May 29 2005, 10:45 PM)

QUOTE (rogergrubb @ May 29 2005, 10:37 PM) wouldn't that draw air from around the headers/engine area???  pre-heated air trying to "cool" the radiator water? Probably some. But, everyone told Scott T. his way wouldn't work and he drove it cross country with no problems. He did some fabrication to draw air from under the car into his radiator which fit in front of his subaru engine. why couldn't you do it in a similar fashion and draw the air up further? I'm just throwing some alternatives. The Renegade system is proven and works great. But, you loose the trunk and have to cut the wheel wells. i was thinking out loud.

all of the front radiator solutions i've seen so far are sooo intrusive.

i think the aluminum ducting would work and it would look cool. i just want to impress the tough crowds at the next IHOP breakfast......

QUOTE (rogergrubb @ May 29 2005, 10:52 PM)

very interesting on that Subaru idea..... so he ducted from underneath the car for the fresh air source? as you all know, having the radiators up front allow for the ram effect at cruising speed. no fans. was the subaru setup for "no fans" operation at cruising speed?

it's Scott Thatcher. look up his posts. i'm sure he has put some pictures of it up here. i don't remember if he had a fan or not

What about 2x what Felix has there, that... new thing...

One on each side? Make sure you cage the crap out of the inside of the wheel house... you don't want her paddling a rock through yonder..


M

QUOTE (redshift @ May 29 2005, 11:00 PM)

What about 2x what Felix has there, that... new thing... One on each side? Make sure you cage the crap out of the inside of the wheel house... you don't want her paddling a rock through yonder.. M

yea', i'm wondering how the boxster protects it's radiators...

i'm thinking more towards the inner fenders for the exhaust. just ducted in.

NOT inline of a potentially fatal thrown rock.

Oh I was totally thinking the same kind of thing... but I couldn't think of an elegant way to carry it on out the side, and away from the brakes..




M

exhaust hot air like this???

The only thing I could think of would look silly on a teener... a BMW 507 type exit, or God help us... gills.. I mean there isn't enough room, width wise, to pull a 935 trick..

No, no... and NO!


M

Roger,

There's been discussion about this many times before, I don't have the links right now. Besides the front common trunk configuration I know of no other successful solutions in the 914. The problem as you've noted is air flow.

Toyopet developed one for a 911 housed under a large turbo tail.

I've seen a large oil cooler mounted between the tail lights, large air to air intercoolers in the rear trunk but these wont exchange enough heat to cool a V8.

If you read the jaide link you'll see they layed their radiator low enough to still package the spare tire and tools. Prior to that they tried to mount twin vw radiators in the engine bay sides but abandoned that design for the conventional front mount.

If you had large enough side scoops and AIR type flares you may be able to mount radiators at the intake.

When I first built my V8 20 years ago, a guy followed and stopped me because he knew I had converted it. He claimed he successfully mounted a radiator in the engine lid with several fans in his 914 before he sold it.

With newer technology and materials you have a better chance of developing a new system that works. An electric pump and speed controller will give you flow control. The finned tube idea may work if you made the rockers the heat exhanger. Just remember you need to find the "right" heat exchange rate, volume of liquid, and air management. Of course you would have to make it look good too...

QUOTE (rogergrubb @ May 29 2005, 10:09 PM)

I was thinking almost exactly what Felix's pic shows. Only from the existing light openings in front bumper.

I was trying to convince Bill P to use these opening on JLO but he decided to cut the nice chrome bumper's center for the Renegade rad...

not sure if it would be large enough but they make double and triple pass AL radiators for the jeep cherokee. the dimensions are like 10x30. The shrouding would be more like the gt oil cooler, bottom exit and most of your trunk would be available...

Roger,

I've done it with oil coolers and it works well.
and there are some other vintage 914 race cars out there that have also done it with oil.

you will have to give up the headlights entirely, so it my not be workable for a street car.

here is a pic:

and exit:

Brant,

I always love seeing that work! What are the dimensions of the heat exchangers? If I use the Boxster rads, I will surely need to cut the longitudinal bracing...

they are the twin pass models.

14 3/4 by 9 1/4 by 3

Here is the link:fluidyne

Here's something to keep in mind if you decide to run 2 rads. If possible, you should plumb the rads in parallel rather than in series. A parallel approach will be a bit more difficult to fabricate, because you'll need two Y-connections, but it will cool better than will a series setup. This is because thermal systems transfer heat more efficiently with greater delta-T (difference in temperature). If you plumb two rads in parallel, the coolant entering each rad will be at engine-out temp; however, if you plumb both rads in series, then only the first rad will have coolant entering at engine-out temp. Because the second rad will have a lower delta-T (difference between coolant temp and air temp), it will be less efficient at further removing thermal energy from the coolant.

To get an intuitive sense of this, consider the following thought experiment -- you have a quart of water at 70'F and the assignment to heat it to 100'F in the least amount of time possible. Which will be the fastest method: by placing the water on a 100'F hot-plate, or by placing the water on a 200'F hot-plate? (If you chose the first option, then I'd suggest you stick with air-cooled engines...)

The other advantage to running the rads in parallel is that such a setup will have approximately 1/4 the flow resistance of a series setup.

Damn, this is such good information. =-)

I was at Blockbuster tonight waiting in line and noticed this.... The new Lotus Exige. Check out the hood..... Wow.

Hey Andyrew...... wadda' U think?

QUOTE (davesprinkle @ May 30 2005, 08:00 PM)

Here's something to keep in mind if you decide to run 2 rads. If possible, you should plumb the rads in parallel rather than in series. A parallel approach will be a bit more difficult to fabricate, because you'll need two Y-connections, but it will cool better than will a series setup. This is because thermal systems transfer heat more efficiently with greater delta-T (difference in temperature). If you plumb two rads in parallel, the coolant entering each rad will be at engine-out temp; however, if you plumb both rads in series, then only the first rad will have coolant entering at engine-out temp. Because the second rad will have a lower delta-T (difference between coolant temp and air temp), it will be less efficient at further removing thermal energy from the coolant. To get an intuitive sense of this, consider the following thought experiment -- you have a quart of water at 70'F and the assignment to heat it to 100'F in the least amount of time possible. Which will be the fastest method: by placing the water on a 100'F hot-plate, or by placing the water on a 200'F hot-plate? (If you chose the first option, then I'd suggest you stick with air-cooled engines...) The other advantage to running the rads in parallel is that such a setup will have approximately 1/4 the flow resistance of a series setup.

Dave,

Good points, we used to do this with thermoelectric heat exchanger designs. Personally I'm just trying to adapt existing technology, not reinvent it. I need to get more details on the Boxster system...

hello guys, i have been too busy to get on here for a few days and i missed this thread

to cool a v8 with out loosing the front trunk might be difficult but the 2 ways i might try it are

a 2 radiator set up... a gt oil cooler and an engine bay radiator under the engine lid, i would make the front one the primary or first one

or i would just lay radiator flat on the floor with a reverse scoop to pull air out under the car and a opening on the front to get air in

my opinion on doing to radiators would be to make the in series.. doing a parallel set up would work better but it would be very difficult to get it balanced

and in my car i have 2 fans on the radiator i can shut one off on the highway and the temp stays good, i might be able to shut both off but i only have control of one off them from inside the car

A really clean cooling setup towards the rear would be ideal but I haven't seen anything I would like...

Anyone ever seen anything, keeping the radiator in th rear half of the car, that is well engineered??????????? Practical?

An oil cooler is definately going to be installed. That, again, is another subjective topic as to the best location/solution. I'm lovin' the oil cooling solution that Brant did.

Roger,

just my opinion....
but the rear idea really screws with the weight distribution and it also doesn't have the benefit of efficiency like a front cooler does....

frontal air being rammed through, just has to be more efficient I would think?

brant

Tell that to Scott Thacher...

I think making a center mounted rad work (as Scott has) is the best of all possible setups. No long coolant lines, far fewer problems with bleeding, both trunks are retained, and the weight is still more or less centered within the wheelbase.

Making this work with a V8 would be a big challenge, not only due to lack of space in the engine bay for rads, but also the cooling requirements. A V6 would also have space problems.

A rotary MIGHT be able to do this, as long as you don't go gaga with tuning the engine (no turbo). You'd need more rad area than with the Soob, but from Scott's photos, there looks to be room for a much bigger rad than he used. With some clever ducting, you might even be able to exploit the chimney effect.

An inline four would have a lot more space to stick rads in the engine bay, perhaps running them more or less flat next to the engine with cool air ducted from below.

I wonder if scott has played with a set of corner balancing scales though...........


brant

What hasn't been brought up here to use alternative radiator designs is what can be done to reduce the heat losses from the engine. You can get by with a smaller or less-efficient cooling system if you can make the engine more efficient and get more waste heat out through the exhaust gases rather than the water jacket. Frictional losses can be lowered by using moly coatings on bearings and crank/rod journals and using roller lifters and rockers. Heat loss from combustion can be lowered by reflective barrier coatings on the piston, valves, and head. There are also some thermal dispersant coatings that could improve heat transfer from the block to surrounding air. A couple years ago I thought these coatings were mostly snake oil, but I had some of this done to my 350 and I think it made a big difference. Here are some technical articles by Tech Line Coatings that discusses some of the things that can be done. A recent edition of Performance Engine magazine (engine rebuilder/machine shop trade mag) also had a good article on these coatings.

QUOTE (lapuwali @ May 31 2005, 12:19 PM)

Tell that to Scott Thacher... I think making a center mounted rad work (as Scott has) is the best of all possible setups.  No long coolant lines, far fewer problems with bleeding, both trunks are retained, and the weight is still more or less centered within the wheelbase.   Making this work with a V8 would be a big challenge, not only due to lack of space in the engine bay for rads, but also the cooling requirements.  A V6 would also have space problems. A rotary MIGHT be able to do this, as long as you don't go gaga with tuning the engine (no turbo).  You'd need more rad area than with the Soob, but from Scott's photos, there looks to be room for a much bigger rad than he used.  With some clever ducting, you might even be able to exploit the chimney effect. An inline four would have a lot more space to stick rads in the engine bay, perhaps running them more or less flat next to the engine with cool air ducted from below.

Do you have a link to his radiator pictures???

Im not afraid of "clever ducting". The racers do it all the time....

QUOTE (brant @ May 31 2005, 12:50 PM)

I wonder if scott has played with a set of corner balancing scales though........... brant

no i have not, but why, the suby engine weighs less than a complete type 4. the radiator weighs about 20 lbs full of water, heck the whole cooling system only takes about 1.7 gallons. water which weighs about 8.5 lbs pergallon thats only 13 lbs or so of water.

the big difference in weight is no engine shelf, no cooling tin, etc. my engine bar weighs a bit less than a stock bar, my whole exhaust is probably 5 lbs ( if not 10) lighter than a stock type 4 HE and muffler set up

edit for roger: roger click here for a link to my pics of the radiator

Scott,

I think I should have look before I lept.
or read my comments before I hit send.

What I was getting at is balance.
not totals but balance.

even a -4 is rear heavy and needs all the weight moved forward that possibly can for a track car.

I guess I'm just thinking from the mindset that even If I could reduce the total weight, I would want to move as much of it as possible to the front of the car.

plus I played with 3 different oil cooler set ups on my old race car before I learned my lesson about having direct frontal air and clean cooler exit on an undersized and barely adequate cooler (needed maximum efficiency)

So I guess I'm saying that for maximum efficiency and optimum weight distribution, I still think frontal coolers have an advantage theoretically.

I hope that you don't take any offense to my comments, and I assure you that none was meant.

brant

Theoretically, a front mounted cooler would have some advantage, if only because more high-pressure air is available. However, if the airflow is adequate to keep things cool, then it's adequate. No more airflow required, and any more is wasted.

As for balance, the 20-25lbs of rad and water in Scott's setup are roughly where the fan housing resides on the Type IV, or the front pair of cylinders are on a Six, so I'd be willing to bet the balance is just as good as it is with those engines. Theoretically speaking, keeping the weight centered near the middle of the wheelbase (which this would do), will help some aspects of handling.

QUOTE (lapuwali @ May 31 2005, 02:53 PM)

Theoretically, a front mounted cooler would have some advantage, if only because more high-pressure air is available. However, if the airflow is adequate to keep things cool, then it's adequate. No more airflow required, and any more is wasted. As for balance, the 20-25lbs of rad and water in Scott's setup are roughly where the fan housing resides on the Type IV, or the front pair of cylinders are on a Six, so I'd be willing to bet the balance is just as good as it is with those engines. Theoretically speaking, keeping the weight centered near the middle of the wheelbase (which this would do), will help some aspects of handling.

On a set of corner scales, you will find that putting a person in the cockpit is not forward enough to shift the front to rear percentages as much as optimum. (I think the foot well would be near optimum, for trying to shift polar weight)

the center of the car is around the drivers butt, and not the engine bay. I'm guessing that the stock jack point is rear of the car's balance point to compensate for the rear bias of a stock car.

I fully believe that scotts set up could be lighter than stock and thus his car has better rear balance than stock....... but wouldn't a car be even more balanced and lighter by using the smallest most effiecient size as possible and putting all of the weight forward for balance purposes?

that was more my point than anything negative about Scott's car

Here is a quick scetch of what i'll be doing for my eg33 conversion (flat 6 3.3 liters subaru engine). my drawing talents still need refining
i don't know if it'll fit a V8. but it's just my idea, and if you guys think it won't work please chime in.
Nick
p.s./no highjack intended: Scott, i really really could need those scoop pics, if available, pleaaase (i've looked up all your porscharu posts and couldn't find any pic of it)

sorry for the high jack but i am going to post a few pics for nick here on the scoop

I think you'll find once you have all the bits in place that you won't be able to angle the rad all that much from vertical. The firewall angles back, and the trailing edge of the engine lid is about 2/3rds of the way back along the engine, not at the nose of the engine.

If anything, it would probably be easier to angle the rad back, opposite what you've drawn. However, I don't think you'd gain much airflow from this. Having a scoop below that directs air into an enclosed area on one side of the rad (using the scooped-out area of the firewall) will generate the pressure you need to force air through the rad. You can leave the other side of the rad open, dumping into the engine bay. However, more ducting that directed the air upwards would provide some amount of chimney effect, as the hot air would want to rise out of the duct, lowering the pressure in the duct, creating a stronger pressure differential across the rad.

next

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QUOTE (lapuwali @ May 31 2005, 02:37 PM)

However, I don't think you'd gain much airflow from this. Having a scoop below that directs air into an enclosed area on one side of the rad (using the scooped-out area of the firewall) will generate the pressure you need to force air through the rad. You can leave the other side of the rad open, dumping into the engine bay.

exactly what i did, i have the radiator vertical and i use the dish in the firewall to get the air as far up as possible. i think have the fans not running, just sitting there is a very large restriction, thats why i have them running all of the time.

nick ( hyrdra ) i think you would have more luck mounting the radiator on the engine lid, with the lid being a gt style lid. then use a scoop to send air in to the engine bay at speed. i dont thing unless you move the engine back ( renagade style ) you will have enough room.

Thanks for the pics scott
I guess the radiator's angle in the drawing isn't accurate, but the top section is to force the air out the engine lid, since you would want the coolest air possible for the engine air intake....
edit: scott, i'll be using the subaru gearbox, which alone, will give me an extra 5 inches clearance, plus i'm fabricating mounts that will give even more room for the radiator.

QUOTE (Hydra @ May 31 2005, 02:48 PM)

Thanks for the pics scott I guess the radiator's angle in the drawing isn't accurate, but the top section is to force the air out the engine lid, since you would want the coolest air possible for the engine air intake....

True, but you can duct air to the airbox from the wheel well a lot easier than you can duct all of the rad air out of the engine bay.

Scott, now that you know the system works, you might try removing one of the fans and run it that way for a bit to see how the temps go. You might only need one fan at low speeds, and you've already determined you don't need both at speed.

Mounting the rad completely above the engine has some promise. Is there enough vertical clearance above the intake stuff for that?

i did try to one fan at first and the temp would climb to about 200 if i was in stop and go traffic. unless it is night time and cool out i just run both fans. also there is about 4 inches of sapce to the ran tray so figure 7 to the lid it self.

nick you can only probably go back about 3 inches in my car till the engine would hit the rear trunk