eclipsegsx1736
Supporting VIP
- 1,599
- 39
- Nov 11, 2003
-
Los Angeles,
California
See this thread HERE for a preliminary discussion on this topic and idea.
Being involved in motorsport for the past few years has taught me an unbelievable amount about race car design, and still when I talk to engineers I feel like I was just born yesterday. It really is incredible what goes into REAL race cars. When I say this I mean Formula 1, ACO Le Mans/ALMS, WRC, etc. Racing where every team brings a unique solution to the problem of, "How can I make this death trap with 4 wheels go as fast as possible without breaking and still be within the rulebook?"
It has also made me realise what an uphill battle I'm facing trying to get a street-car to go around a race track quickly. They just weren't made to do it. No, not even a Porsche GT3 RS. If the GT3 (which, for a street car, is quite amazing) was truly made for going around a track quickly and NO other reason, it would look like a P1 Le Mans car. Because it would be a P1 car. A GT3 is just a 911 (which is just a VW beetle, but that's another story
) with some "racing stuff" bolted onto it. Wings, wider bodywork/tires, bracing, better engine, etc. It's not purpose-built.
My point is, even with the above knowledge, I'm modifying/racing my car because 1) I already started modifying it for road racing before I learned the above, and 2) because I'm already so close to finishing, and I love the feeling of accomplishment and return on investment (time and money).
ANYWAY, on to the project! My idea for a ducted radiator set-up was taken from seeing this done on the Ford GT, and many GT race cars such as team Rahal Letterman's GT2 BMW's from the ALMS series:
My goal was this: to force 100% of the air entering the front inlet fascia to flow through the intercooler, through the radiator, and up out through the hood. This would involve sealing the FMIC inlet side to the bumper, the FMIC outlet side to the radiator inlet side, and finally the radiator outlet side to the hood.
This isn't very hard on cars such as RX-7s or Corvettes which have longitudinally mounted engines and huge belt-driven fans and radiator shrouds. The engines in these cars are shoved as far aft as possible, often part of the engine running under the firewall, with the transmission next to the driver. On front-wheel drive platforms, though (a GSX is a front-drive platform with a rear diff and drive shaft jammed up the transmission's ass), this is more difficult. The engine centreline is usually forward of the front axle, very much the case on our cars. This leads to very-less-than-ideal handling characteristics due to the huge front weight bias, but that's another story for another time. On top of this, add a large turbocharger assembly hanging off the side of the engine towards the front, and the 2g's stubby front nose, and there is almost no room between the factory radiator location and the turbocharger assembly.
Because of this "problem", and because I don't have the time or money to mount the engine lower and farther backward, I knew I would have to move the radiator forward as much as possible. Initially I wanted to just completely rip out the entire front radiator support subframe and have a tubular one made in its place. It could still house mounting points for the headlights and nose, but would give me the freedom to mount a radiator at any angle or location I wanted (within the confines of the front nose, of course). I wanted to mount the radiator at an angle, with the top kicked forward as much as possible to make the ducting easier and flow better, and to reduce the angle which the air would have to turn as it exits the rad and makes its way up to the hood.
A custom tubular front end would be quite expensive, due to the amount of measuring, testing, and fabrication involved to have it still fit within the OEM front nose. So the other day I removed the radiator (still mounted in the factory location) and made some measurements. I realised if I mounted the radiator around where the factory A/C condenser is located, possibly at a slight forward angle, I should have enough room to make the exit duct.
I saw several people on the ECMLink forums switching to the AFCO Scirocco radiator and mounting it in this location to allow larger turbo setups to fit in the factory location and not interfere with the radiator. It looked like a good unit, it's significantly shorter and narrower, but almost 3x as thick as the OEM core, and still much larger than the half-size radiators found on some drag cars. It's also a dual-pass core, with the inlet and outlet mounted on the passenger side of the car, making radiator hose routing easy. I made a cardboard model of the core for measurements, and sure enough, it looked like the perfect unit.
I was considering having a custom core made my Ron Davis, but the AFCO Scirocco unit seemed like it would work and it would be half the price of a custom core. HERE is the link for the AFCO unit.
With the Scirocco rad in-hand, and the front end of the car disassembled, I tried to find the best location for the core. I quickly discovered that mounting it at an angle would be very hard. The nose is just too short, and I couldn't mount it lower since the lower rad support bar interferes. Any further back and the bottom of the rad is too close to the bottom of the turbo assembly.
After eliminating the hood-latch (I have hood pins anyway) and removing the vertical support bar on the rad support (not a structurally critical piece, it only serves as a mounting point for the hood latch bracket and the power steering loop), I had made enough room for the radiator. This is where it ended up:
As you can see in the pictures it is mounted almost 3 inches forward of the factory location. The reason for the offset mounting position is 1) to allow the radiator exit duct to clear the wastegate assembly, 2) avoid having the duct enter the area of the hood "bump" molding, as I will be using an OEM style carbon fibre hood for this for the time being, and 3) to allow mounting of a cooler next to the radiator in the open area (I will be running a pump and trans cooler for my manual trans), or to allow this empty area to be used for engine bay airflow.
Next, I made brackets for a single straight-blade SPAL fan:
Front nose mounted, radiator hoses hooked up (I was able to use both of my existing hoses with no modification, what a nice surprise!):
I drove the car like this for a few days, and like everyone else I have read about on the Link forums, I noticed an improvement in cooling with this radiator, and remember this is with absolutely no ducting yet whatsoever. I saw on average 5*F cooler temperatures, and this was a 10*F higher day than when I took readings with the factory radiator.
Next, I made a rough model of the radiator exit duct:
The mode was made using 16ga art paper, and as you can see in the pictures it is deformed slightly especially at the hood flange but it will serve as a rough estimate to make into sheet aluminium. There is still work to be done on this rough model, but it was getting late and this is where I stopped for now.
There is still lots to be done, next I will finalise the paper model and cut the hood to fit the model. Once I am happy with the design I will make or have it made into (most likely) aluminum. Ideally I will eventually have it molded into fibreglass but that isn't critical. Once that's done I'll figure out how to secure it to the car. As the car will be used for road racing, the ducting setup will have to withstand speeds of up to 150 mph, and will no-doubt be creating some front downforce, so the bracing for the duct will have to be sturdy. I'm looking at using quick-release mounts for it so I can quickly remove it for maintenance/inspection of the turbocharger area but haven't figured that bit out yet.
Any ideas for mounting points and/or quick-release hardware? I may use Dzus fasteners.
Anyone know of some good weatherstrip-like material that I can use to line the edge of the ducts to seal them against the various components? It would have to provide a somewhat air-tight seal, and also withstand high temperatures (say, 500F).
I'm sure I missed 75% of the thoughts, ideas and info that went into this and left out a bunch of stuff by accident, but I'd love to hear any questions, comments and suggestions on this project!
Beau
Being involved in motorsport for the past few years has taught me an unbelievable amount about race car design, and still when I talk to engineers I feel like I was just born yesterday. It really is incredible what goes into REAL race cars. When I say this I mean Formula 1, ACO Le Mans/ALMS, WRC, etc. Racing where every team brings a unique solution to the problem of, "How can I make this death trap with 4 wheels go as fast as possible without breaking and still be within the rulebook?"
It has also made me realise what an uphill battle I'm facing trying to get a street-car to go around a race track quickly. They just weren't made to do it. No, not even a Porsche GT3 RS. If the GT3 (which, for a street car, is quite amazing) was truly made for going around a track quickly and NO other reason, it would look like a P1 Le Mans car. Because it would be a P1 car. A GT3 is just a 911 (which is just a VW beetle, but that's another story
) with some "racing stuff" bolted onto it. Wings, wider bodywork/tires, bracing, better engine, etc. It's not purpose-built.My point is, even with the above knowledge, I'm modifying/racing my car because 1) I already started modifying it for road racing before I learned the above, and 2) because I'm already so close to finishing, and I love the feeling of accomplishment and return on investment (time and money).
ANYWAY, on to the project! My idea for a ducted radiator set-up was taken from seeing this done on the Ford GT, and many GT race cars such as team Rahal Letterman's GT2 BMW's from the ALMS series:
You must be logged in to view this image or video.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
My goal was this: to force 100% of the air entering the front inlet fascia to flow through the intercooler, through the radiator, and up out through the hood. This would involve sealing the FMIC inlet side to the bumper, the FMIC outlet side to the radiator inlet side, and finally the radiator outlet side to the hood.
This isn't very hard on cars such as RX-7s or Corvettes which have longitudinally mounted engines and huge belt-driven fans and radiator shrouds. The engines in these cars are shoved as far aft as possible, often part of the engine running under the firewall, with the transmission next to the driver. On front-wheel drive platforms, though (a GSX is a front-drive platform with a rear diff and drive shaft jammed up the transmission's ass), this is more difficult. The engine centreline is usually forward of the front axle, very much the case on our cars. This leads to very-less-than-ideal handling characteristics due to the huge front weight bias, but that's another story for another time. On top of this, add a large turbocharger assembly hanging off the side of the engine towards the front, and the 2g's stubby front nose, and there is almost no room between the factory radiator location and the turbocharger assembly.
Because of this "problem", and because I don't have the time or money to mount the engine lower and farther backward, I knew I would have to move the radiator forward as much as possible. Initially I wanted to just completely rip out the entire front radiator support subframe and have a tubular one made in its place. It could still house mounting points for the headlights and nose, but would give me the freedom to mount a radiator at any angle or location I wanted (within the confines of the front nose, of course). I wanted to mount the radiator at an angle, with the top kicked forward as much as possible to make the ducting easier and flow better, and to reduce the angle which the air would have to turn as it exits the rad and makes its way up to the hood.
A custom tubular front end would be quite expensive, due to the amount of measuring, testing, and fabrication involved to have it still fit within the OEM front nose. So the other day I removed the radiator (still mounted in the factory location) and made some measurements. I realised if I mounted the radiator around where the factory A/C condenser is located, possibly at a slight forward angle, I should have enough room to make the exit duct.
I saw several people on the ECMLink forums switching to the AFCO Scirocco radiator and mounting it in this location to allow larger turbo setups to fit in the factory location and not interfere with the radiator. It looked like a good unit, it's significantly shorter and narrower, but almost 3x as thick as the OEM core, and still much larger than the half-size radiators found on some drag cars. It's also a dual-pass core, with the inlet and outlet mounted on the passenger side of the car, making radiator hose routing easy. I made a cardboard model of the core for measurements, and sure enough, it looked like the perfect unit.
I was considering having a custom core made my Ron Davis, but the AFCO Scirocco unit seemed like it would work and it would be half the price of a custom core. HERE is the link for the AFCO unit.
With the Scirocco rad in-hand, and the front end of the car disassembled, I tried to find the best location for the core. I quickly discovered that mounting it at an angle would be very hard. The nose is just too short, and I couldn't mount it lower since the lower rad support bar interferes. Any further back and the bottom of the rad is too close to the bottom of the turbo assembly.
After eliminating the hood-latch (I have hood pins anyway) and removing the vertical support bar on the rad support (not a structurally critical piece, it only serves as a mounting point for the hood latch bracket and the power steering loop), I had made enough room for the radiator. This is where it ended up:
You must be logged in to view this image or video.
You must be logged in to view this image or video.
As you can see in the pictures it is mounted almost 3 inches forward of the factory location. The reason for the offset mounting position is 1) to allow the radiator exit duct to clear the wastegate assembly, 2) avoid having the duct enter the area of the hood "bump" molding, as I will be using an OEM style carbon fibre hood for this for the time being, and 3) to allow mounting of a cooler next to the radiator in the open area (I will be running a pump and trans cooler for my manual trans), or to allow this empty area to be used for engine bay airflow.
Next, I made brackets for a single straight-blade SPAL fan:
You must be logged in to view this image or video.
Front nose mounted, radiator hoses hooked up (I was able to use both of my existing hoses with no modification, what a nice surprise!):
You must be logged in to view this image or video.
You must be logged in to view this image or video.
I drove the car like this for a few days, and like everyone else I have read about on the Link forums, I noticed an improvement in cooling with this radiator, and remember this is with absolutely no ducting yet whatsoever. I saw on average 5*F cooler temperatures, and this was a 10*F higher day than when I took readings with the factory radiator.
Next, I made a rough model of the radiator exit duct:
You must be logged in to view this image or video.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
The mode was made using 16ga art paper, and as you can see in the pictures it is deformed slightly especially at the hood flange but it will serve as a rough estimate to make into sheet aluminium. There is still work to be done on this rough model, but it was getting late and this is where I stopped for now.
There is still lots to be done, next I will finalise the paper model and cut the hood to fit the model. Once I am happy with the design I will make or have it made into (most likely) aluminum. Ideally I will eventually have it molded into fibreglass but that isn't critical. Once that's done I'll figure out how to secure it to the car. As the car will be used for road racing, the ducting setup will have to withstand speeds of up to 150 mph, and will no-doubt be creating some front downforce, so the bracing for the duct will have to be sturdy. I'm looking at using quick-release mounts for it so I can quickly remove it for maintenance/inspection of the turbocharger area but haven't figured that bit out yet.
Any ideas for mounting points and/or quick-release hardware? I may use Dzus fasteners.
Anyone know of some good weatherstrip-like material that I can use to line the edge of the ducts to seal them against the various components? It would have to provide a somewhat air-tight seal, and also withstand high temperatures (say, 500F).
I'm sure I missed 75% of the thoughts, ideas and info that went into this and left out a bunch of stuff by accident, but I'd love to hear any questions, comments and suggestions on this project!
Beau
Last edited:
Works well!
. Also waiting for results
!
. 
