Road Race Ducting Brainstorm

[kamikazeredneck]

What is really going to SUCK is trying to route all the lines in and out of the ducting. IC pipe, intake pipe, oil feed line, oil return line, o2 sensor. Sounds like a massive cluster F&!k to me. Also all those items move since they bolt to the engine while the ducting will be static. WAY over complicated and not worth your time. IMO

Kevin

My exact same thought. It seems like everyone is trying to make this so complicated that it will not be worth the extra effort IMO. Even with my turbo needing air all I'm going to do is make a second duct from the side of the radiator to flow air in the general direction of the turbo because as all the pieces attached to the engine move, you wouldn't be able to make the ducting move with it. I know that most people run almost solid motor mounts but still these pieces need to have some flex. Also I think we are overlooking one the most important parts which is removal of the ducting for servicing of components. In a racing situation this is one of the most important things because if you break something you don't want to take apart the whole front end just to change a radiator hose, turbo, o2 sensor, blown t-clamp, etc. Racing teams spend a lot of engineering time finding ways not just to make a part work but how to mount it and remove it easily and quickly if there is a situation that calls for it. This is just all in my opinion and I'm not trying to hurt anyone's feelings or say that someone's idea is stupid, but I just am trying to share some of my experience with this issue as I am currently working on the same thing with my car.

 

[greengoblin]

It's a stupid idea. There I said it.

I can't even imagine how fun it would be to get your hands down in there to button things up. Much less on race day with the car at operating temp AND IN A HURRY.

 

[AngelOfPassion]

Thank you. These are the things I need to hear from you guys. That's why I want to brainstorm. While the cooling effenciency could be better. It would be a pain if something down there broke during race day.

I guess I can stick more to something like Beau did. I'm still just a little worried about the heat in the engine bay that would build up.

I guess I could put one main vent that is sealed to the radiator and maybe a couple smaller vents that could vent out ambient temps in the bay...

 

[greengoblin]

Did you talk to Beau about his under hood temps? He is a data kinda guy. You might have nothing to worry about at all.

 

[AngelOfPassion]

I've sent him a PM with some of the concerns that are mentioned here and a link to this thread. I'm just waiting for a response.

 

[96ETT]

I think some of you are thinking about this the wrong way. The coolant system does remove the heat from the engine, so making that system more efficient will not some how make under the hood hotter. The radiative heat component given off by engines is significantly less than what the coolant absorbs. If it were the other way around they would just be air cooled. I would follow the picture that was posted and use a blanket type insulation on the exhaust parts and call it a day.

 

[AngelOfPassion]

Thanks for the input. That is pretty much where this is heading. I'm thinking of trying to mimick Beau's setup and then adding something like this:

DIY Cold Air Intake

I am going to try and chat with Beau though to see if he has any negative effects from it first though.

 

[greengoblin]

I talked to Beau today (text). He said he would come look at the thread when he has some time.


Kevin

 

[AngelOfPassion]

Thanks bro! That is helpful!

Side note: I checked out those chassis braces that you recommended. I may pick some up from you in the future when I get the car on the track more.

 

[eclipsegsx1736]

Geez, you guys are making me feel special! It's just a radiator duct

I agree with most of the posts in here about routing of radiator exhaust. Good aerodynamics on a racecar should help prevent pressure build-up under the car, or even work to reduce this pressure and create a vacuum (such as diffusers or "tunnels"). Reducing pressure underneath the car will reduce lift. On that same note, increasing pressure on the top side of the car will also reduce lift (downforce).

Ideal aerodynamics for a road-race car would reduce drag and increase downforce. Creating an effective radiator duct that not only evacuates all the radiator's exhaust air but also actively extracts it from the radiator by creating a low pressure around the vent would reduce lift as it prevents air pressure from building up under the engine bay as it normally would, but it also can increase downforce and reduce drag at the front of the vehicle, as it helps reduce air pressure at the nose of the car.

Regarding incorporating the turbo/exhaust manifold into the duct, I definitely considered that as a way of reducing ambient engine bay heat when I was initially planning the design of the duct, but one of the main aspects of my design was a fully sealed duct (tightly sealed with weatherstripping) and I couldn't think of a good way to do this with the turbo assembly involved.

As far as engine bay heat, I haven't had a problem with that yet, but I've definitely considered it. I also haven't ran the car as hard as it's being built to run, as the car is still being built for competition. You'll notice in the pictures in my thread that the radiator and duct are offset to the passenger side, leaving a gap of about 6" between the radiator and the edge of the radiator support/FMIC on the driver side. This was originally done because of the wastegate setup on the car, the width of the Scirocco radiator, and the fact that the hood "bump" gets in the way, but it also had the side effect of creating extra airflow room on the driver side. I've considered putting a duct that directs air from that portion of the FMIC/radiator support up and into the engine bay to promote airflow, and then adding extraction louvers near the back of the hood. Airflow over the hood could help to pull air out of these louvers, and cool air supply would come from this section of the front radiator support area. This would be the only air inlet supply once the radiator is sealed and the full front splitter/undertray is complete.

Also, I don't have any hard data on typical engine bay ambient temperatures for what's considered "normal". It was just never something I datalogged. I can put temperature strips all over the engine bay (and I already have) but without knowing what's normal for a car like this with more conventional engine bay airflow, I'm not sure how useful that information will be. I do have another GSX that I occasionally road race that has all factory cooler locations, no hood duct/vent and no special ducting, so I've thought of putting the same stickers in the same locations to give a rough "baseline". Here's an example of the temperature strips you can use. The nice thing about them is they "record" the peak value so you don't have to worry about the engine bay cooling down by the time you pull into the pits:

Temperature Label

In the next coming months, I'll have the car back out at the track with the boost turned up and should have a better idea of how the engine bay temperatures are, although I'm really not worried about it from my experience thus far.

Let me know if you guys have any questions! All in all, I've had great results from the ducting I created, and this is really only the first iteration of the design. Eventually I'm planning on doing a new from-scratch tubular front radiator/bumper support so I can design and position everything from scratch. This should allow for more optimal placement of the radiator and allow a better and more smoothly shaped duct to be created to improve cooling. I also need a better, stronger mounting point for my splitter design as the front radiator support isn't very good for how heavy and thick it is.

Beau

 

[AngelOfPassion]

Wow that is a lot of good info. Thanks Beau. I'm glad to see that we weren't the only ones to consider including the turbo in the airflow path.

I really do think that your duct design would help reduce lift. I am thinking I am going to make a similiar design to yours.

When it comes down to it, the engine bay heat is really only going to effect IAT's, the turbo itself, the alternator, and maybe the power steering. Those are the only things I can see being negatively effected by it. I plan to combat this a little by sealing the intake filter off from the rest of the bay and giving it its own air supply from the stock side mount hole below it. As far as everything else, it should be able to take the possible few degree increase without too much trouble.

What is making you consider the full undertray? Just the lift that is created by having it open?

 

[eclipsegsx1736]

Wow that is a lot of good info. Thanks Beau. I'm glad to see that we weren't the only ones to consider including the turbo in the airflow path.

I really do think that your duct design would help reduce lift. I am thinking I am going to make a similiar design to yours.

When it comes down to it, the engine bay heat is really only going to effect IAT's, the turbo itself, the alternator, and maybe the power steering. Those are the only things I can see being negatively effected by it. I plan to combat this a little by sealing the intake filter off from the rest of the bay and giving it its own air supply from the stock side mount hole below it. As far as everything else, it should be able to take the possible few degree increase without too much trouble.

What is making you consider the full undertray? Just the lift that is created by having it open?

Yeah, the way I see it there aren't too many components that should be adversely affected by an increase in ambient engine bay temperature (if there even is one). The IATs shouldn't be affected much since the FMIC will remain unchanged, and you can use good heat insulation on the charge piping leading up to the intake manifold. The turbo is cooled with water and oil (each with their own coolers of course, out of affected part of the engine bay). Same story with the power steering. The alternator and other ignition components such as the igniter and coil packs could suffer if they get too hot, but I haven't had any issues yet.

The cold-air intake is definitely a good idea, and I have yet to make a nice one, but it's definitely on the list.

In the "Street" classes in Time Attack, you're only allowed to add an undertray fore of the front axle centreline and aft of the rear wheel centreline, so a front splitter/undertray is definitely allowed, but not a FULL car undertray. The splitter of course helps to keep more air on top of the car and can increase downforce. A diffuser can be integrated into the front splitter to promote a vacuum under the front of the car and further increase downforce. The full engine bay undertray also helps to prevent air getting up into the engine bay area and all of its rough/uneven surfaces which can promote turbulence.

This is all theory, of course, without a wind tunnel. Often, though, it does pay to learn/steal from designs of high-level motorsport race cars who have spent tons of money in the wind tunnel. They usually have a pretty good idea of what they're doing.

Eventually, my front bumper/splitter will be similar to the picture below, with the large front dive planes and diffuser integrated into the front splitter. This setup creates a lot of front downforce, but also a lot of drag. This works well for a Time Attack car though, as power is essentially unrestricted. In a class with power restrictions, you have to be more careful with your downforce vs. drag balance as the increase in drag can really hurt you on larger tracks with lots of high speed sections/straightaways.

You must be logged in to view this image or video.

Beau

 

[jdsoza]

This is one awesome thread. why not turn your spare wheel well into a housing for a rear mounted radiator? Use the factory pump to get water back there and a remote mounted pump to get it back up to the front of the car. If the piping or hoses are external this will aid in cooling as well. There is the added weight of coolant and water and extra lines and piping, but you could build this into a rear diffuser and aid in downforce. I have seen supras, 240SX's, RX7's and tons of other rwd cars and even a few evos and sti's. I dont have money much less i had to sell my shell, but im tempted in trying this. This way you could seal the front, keep thew engine bay cooler and cleaner, and leave room for an effective intercooler system.

 

[eclipsegsx1736]

This is one awesome thread. why not turn your spare wheel well into a housing for a rear mounted radiator? Use the factory pump to get water back there and a remote mounted pump to get it back up to the front of the car. If the piping or hoses are external this will aid in cooling as well. There is the added weight of coolant and water and extra lines and piping, but you could build this into a rear diffuser and aid in downforce. I have seen supras, 240SX's, RX7's and tons of other rwd cars and even a few evos and sti's. I dont have money much less i had to sell my shell, but im tempted in trying this. This way you could seal the front, keep thew engine bay cooler and cleaner, and leave room for an effective intercooler system.

I've toyed with the idea too, but from what I've seen rear mounted radiators are hard to pull off effectively. The hardest part is getting enough airflow through the core. You need a high pressure zone to force air through a radiator core, and the highest pressure zone is at the front nose of the car.

There are not many (if any) high pressure zones near the back. In order to effectively place inlets at the rear top/sides of the car, you'd need a good airflow model of your exact car to ensure that the ducts get placed in the correct area.

I've seen some race cars (the GST Motorsports Impreza L Time Attack car comes to mind) who tried to pull off a rear mounted radiator and even with a ton of ducts and inlets, still had issues with cooling capacity. They also had to add some pretty large ducts on the sides of the car, which increase frontal area and hugely add to the total drag of the car. A well made, centre mounted inlet at the front of the nose is about as ideal as you can get, from an airflow standpoint, as no increase in frontal area is made and the pressure is so high there.

It is true that there is a weight distribution advantage, but the total weight of the vehicle would certainly increase from a rear mounted radiator from all the extra water in the system and also plumbing, and while correcting weight distribution has its advantages in handling, total weight not only negatively affects handling but also acceleration and braking.

Just my $0.02.

Beau

 

[AngelOfPassion]

Hey Beau,

In your crafting paper mock up how did you measure where the vent would contact the hood? IE: how tall to make the vent sides?

 

[eclipsegsx1736]

Hey Beau,

In your crafting paper mock up how did you measure where the vent would contact the hood? IE: how tall to make the vent sides?

If I remember correctly, I built all the sides up past where they needed to be, and slowly cut down a portion of it as it would come in contact with the hood as I closed it with a droplight underneath. Eventually when the hood was within an inch or less of closing completely, I marked the section of hood to cut out using paint and made the cut in the hood. Once the hood was cut, fitting the duct the rest of the way was pretty easy!

Beau

 

[jdsoza]

thanks for the reply, i got what you're saying and it makes sense. I have a question, on a track car, is going with a half size radiator like the civic radiators a bad idea? Im talking about a road race/time attack. I know the engine can get heated when racing at long periods of time, but i was also thinking using proper cooling methods like a smaller radiator but have a decent oil cooler as well. Im trying to think of an efficient system myself. I know dentsport built their radiator into the rear diffuser, and vents on the side windows through the trunk feed it as well as incoming air from under the car. I just dont know if we have the room for something like that.

 

[eclipsegsx1736]

thanks for the reply, i got what you're saying and it makes sense. I have a question, on a track car, is going with a half size radiator like the civic radiators a bad idea? Im talking about a road race/time attack. I know the engine can get heated when racing at long periods of time, but i was also thinking using proper cooling methods like a smaller radiator but have a decent oil cooler as well. Im trying to think of an efficient system myself. I know dentsport built their radiator into the rear diffuser, and vents on the side windows through the trunk feed it as well as incoming air from under the car. I just dont know if we have the room for something like that.

Making a "civic" style half-size radiator work on a road-race car is going to be tough. In order to get the same cooling capacity over a smaller area, you have to accelerate the air to a higher speed. This can be done with some fancy ducting, but accelerating inlet air with a venturi style shape but this is hard to do correctly and can cause drag and higher pressure at the front of the car. It's just easier to have a radiator with a bigger area and take advantage of it with good ducting. That said, I'm using an AFCO Scirocco radiator which is smaller area wise than factory and have had no issues, although the radiator is twice as thick and is a double-pass.

Oil coolers really are a requirement for any car that's going to be driven on a road course, but a piston engine (unlike a rotary) put a vast majority of its heat into the water opposed to the oil, so a massive oil cooler isn't going to do you any good. In fact, it's just important (if not more important) to get the oil hot quickly. Oil temperatures are often overlooked as part of the warmup process. I won't go past about 4500 RPM on the warmup lap until oil temps are at least 180F. Put a huge cooler on the car and this will only delay the warmup of the oil.

Beau

 

[96ETT]

Also hotter oil means less friction in the engine and therefore more power. So the cooler should only be sized so that oil temps are kept at a normal level while racing. You arent really trying to cool the oil, your just trying to keep it from getting hotter than it was designed for or too hot that it losses film thickness in the bearings.

 

[TSiAWD666]

Delays the warmup if there's no oil thermostat. Don't our oil filter housings have built-in thermostats?

 

[shampoo]

Some great info on cooling in here.

I'm keeping an eye on this thread.

I had no idea having an oil cooler could actually be bad for our cars.

Thanks!

 

[eclipsegsx1736]

Delays the warmup if there's no oil thermostat. Don't our oil filter housings have built-in thermostats?

They do, but some amount of oil is always run through the cooler even when below the 180F thermostat temperature to prevent temperature shock, and a large cooler core will make the oil take much longer to warm up. There just isn't enough heat put into the oil on our cars unless you're under heavy boost and the turbo is nice and hot.

 

[eclipsegsx1736]

Some great info on cooling in here.

I'm keeping an eye on this thread.

I had no idea having an oil cooler could actually be bad for our cars.

Thanks!

Definitely a GOOD thing to have an oil cooler, it's just bad if the oil cooler is so large it prevents the oil temps from getting hot enough before you drive the car hard! As stated above, the oil cooler's job is only to keep the oil at its ideal operating temperature and prevent it from getting overly hot.

The same could be said for a radiator and a water system, but it's very rare that you find a DSM that's over-cooled on the water side, so typically it's a case of the more the better!

 

[ed1380]

Speaking of oil cooling. What's the cheapest oil thermostat available? The cheapest I've found that isn't for a transmission is $80+

 

[eclipsegsx1736]

Speaking of oil cooling. What's the cheapest oil thermostat available? The cheapest I've found that isn't for a transmission is $80+

All the factory oil filter housings designed for external air-oil coolers ('90 6-bolt, Evo III, Evo 8/9) have a built-in thermostat. As far as I know, they're all set to right around 180F.