Hello,
I’m having a pretty severe over heating issue with my carafter I installed a GReddy turbo kit but before we get into that, I think Ishould share some details about the car. It is a 2004 6 speed Touring package. I bought the car from a dealership in 2009 and used it as a fair weatherdaily driver until 2013 when a friend of mine took me to an HPDE at which pointI started upgrading / modding the car for track duty. The most recent mod was the addition of aGReddy turbo kit about 6 months ago.
During normal street driving, the water temp stays at 180*For below at all times. Oil temp staysabout the same as water temp.
I have the overheating problem during HPDE’s (30 minutesessions on track). I have run 2 HPDE’ssince the install was completed, 1 at Memphis International Raceway and theother at Barber Motorsports Park. Inorder to keep water temp at 220*F, I was shifting at 7000 RPM and only using ľ throttle. If I ran harder than that, water temp wouldvery quickly climb to 235*F where I would run easy laps to get the temp backdown. I’m sure water temp would havekept climbing above 235*F if I kept running hard. One interesting observation is that oil tempdid not go over 220*F even when water temp was 235*F.
I did run one session hard where I got focused on traffic andstopped paying attention to the gauges for several laps and water temp peakedat 260*F that session. Oil temp didn’tgo over 220*F even when the water temp was that high.
Prior to the turbo install, I could run the car flat out allday long and not have any overheating issues. My lap times slowed down 8 – 10 seconds per lap after the turbo installbecause I have to run the car easier now. That isn’t what I had in mind when I went the turbo route.
So, I’d like to hear from other turbo track guys how you overcameany overheating issues you might have encountered.
Current cooling system upgrades:
Koyo radiator
RE-medy water pump and 170* thermostat
RX8Performance cooling fan relays
Upcoming cooling upgrades– why I think it will help:
Louvered hood similar to Singular Motorsports kit – pull hotair out of engine bay and produce low pressure zone behind radiator to promoteair flow through the radiator
Relocate battery to the trunk – unclutter the area behindthe radiator for better air flow
Relocate the intercooler to a higher position – intercooler inits current mounting location is choking off air flow to the front side of theradiator

 

There are several threads on this subject so you might want to take a look at those. The remedy pump and thermostat are useless but probably not hurting unless your pump is failing (my Remedy pump failed within 20k so it is worth removing it and checking it out). The cooling fan relay kit is also useless. But you have to think of the system as a whole. I also recommend the FAL fan upgrade but that won't really help while on the track unless you use a fan controller to run them all the time.

 

That and replace your ECT sensor.... maybe it's just pooched. Also are you sure it stays at 180F during all normal driving conditions? That's where mine sits during highway driving but stop and go traffic it climbs to that 190-195 range.

 

Along with whats been said above, do you have the under tray for the radiator? And, is your AC condenser still in front of the radiator or have you removed that as well?

 

@ 9k:
I always wondered how effective the fan relay kit was. I’ve looked at your FAL fan install threadbefore but it’s been a while. I’m tryingto remember if you mounted the fans straight to the radiator or if you havethem on a shroud? And you’re moving 5000+/- CFM of air too, right? I’ll searchfor the thread and re-read it if you can’t remember off hand. The reason I ask is I have a Mishimoto fanshroud that I could mount big fans to. Myremedy water pump is less than 500 miles old although it could still be comingapart. It wouldn’t hurt to check itout. I installed it after the MIR eventin preparation for the Barber track event. I’ve read about the big race radiators from Ron Davis and theothers. I had decent water temps beforethe turbo so I feel like I had a decent cooling setup. That’s why I went to air flow through theradiator first but I might have to reconsider.
@ RotaryMachine:
That’s a good point about the ECT sensor. I have a ProSport water temp gauge on mydash. It has been within +/- 2 degrees tomy Cobb AP when I compared them in the past but I haven’t done thatlately. I’ll do another comparisontonight. I usually run 170* when I ammoving and climb to 180* in stop/go traffic.
@ DAT2RTR:
My undertray and duct work is complete and pretty wellsealed up. Yes, I do still have the AC condenserbut it is spaced off the front of the radiator about ľ”. I’m still stuck between nice daily driver anddedicated track car but I’m leaning more towards dedicated track car everyday.
Thanks for the input so far, I appreciate it.

 

You're getting raised temps while moving, so sounds like clean airflow is not hitting your radiator.

Post a pic of the intercooler placement. You want to have about a 3" space below your IC, above your undertray for the cool air to run through to your radiator.

You also should have the foam installed around the radiator so air is forced through the radiator rather than around the sides of it.

At the location where you cut the side of the under tray plastic to let the IC pipes through, how much gap is there for air to leak out? There should be minimal gap between the cut holes and the IC piping so no air can leak out there.

 

The FAL fans really help at low speeds and idle to drop temps quickly. My guess is that your Koyo is just not up to the task and that could be due to corrosion in the system or clogging. When I removed my AC condenser to clean it when I installed the new radiator, it was nasty.

If you are certain the water pump, etc are working as they should and you have done a coolant system pressure test then I would look into flushing the system. You can also install a secondary radiator or upgrade to a better dual core radiator. My inter-cooler is in the normal Greddy location and I have a large secondary oil cooler that is center mounted behind that and I don't have overheating issues. But I have secondary radiator, I run Evans water less coolant, and my turbo is on its own coolant circuit with a separate heat exchanger and reservoir.

 

Oh and relocating the battery is a great idea as well, mainly for battery life though.

 

Hey Jimmy,

I'll get the pictures and measurements you asked for tomorrow and post them up. I don't have the foam around the radiator anymore but I did seal everything off with sheet metal. I'll take pictures of that too.

Good call on the corrosion 9k. The Koyo radiator was one of the very first changes I made on my car when I got it back in '09. I'm sure you remember the infamous plastic nipples that broke off....

Pics coming soon.

 

I forgot to mention my AC condenser is pretty nasty too. I can see through it but there are a bunch of tiny pebbles stuck between the fins in the bottom 1/3 or so. That's not helping the situation any.

 

I attached some pictures of the front of my car. The first couple are generic front end shots. The third shows the gap between the undertray and bottom of the intercooler at 2 3/8". And the last picture shows the sheet metal ducting I used in place of the foam. The picture only shows the bottom passenger corner but the entire perimeter of the radiator is sealed off as shown. It is kind of hard to differentiate the sheet metal from the plastic so I circled it in red. I didn't get any decent pictures of the IC piping going through the plastic but there are some gaps around the piping.


It looks like the next thing I need to do is relocate the intercooler higher up. I'll start on that this weekend and post pictures of the progress Monday.

 

Getting the IC higher and clearing out the pebbles will help some but I have a feeling you will still have issues . Very few people have actually run track days with turbo kits installed (and reported back here with results) so there is limited relevant information .
I only recently got my setup working well at the track :
*stock radiator
*stock fans set to come on early
*all foam in place and bottom foam held in place with brace (This helped heaps) .
*All plastic around pipework cut for minimum clearance on plastic ducting.
*Intercooler bottom sitting level with upper lip (hope that makes sense)
*Running an additional radiator (actually an oil cooler) instead of the second oil cooler

That last one probably doesn't help you much but I note you mention that oil temps were kept well under control .My oil temps are fine too -with one cooler. I have long believed that a second rad. is more beneficial than a second oil cooler ......

 

off topic: Next time you're at Barber let me know so I can come spectate. if it's next year I'll join you... 2 boosted rx-8s on track should be fun

 

Looks like the IC placement is as good as it can be. Some more ideas:

• Remove AC condenser if that's an option for you.
• If not, space out the top of the AC condenser from the radiator with 1" spacers. OD did this and it helped his track temps. He was supercharged so you may not see the same improvements with your IC.
• Replace the radiator (again!). Did you get the 36mm core Koyo? OEM radiator is 26mm from memory. A dual pass version would help. This may need to be custom made.
• Vented hood or spacers at rear of OEM hood to lift it 1" higher than stock (not sure if your track rules allow this). If you're running air out the top of the engine bay using one of these methods you'll want to remove the intake undertray and ideally relocate the battery to free up the airflow behind the radiator. The air in the intake piping can get quite hot if you remove this intake undertray so if you're sitting stationary and idling for periods of time you'll want to put some insulation around the intake pipes (MAF tube and pre-TB tube).

 

A normally aspirated RX8 will overheat on the track even with the other mods so adding an undersized turbo to the mix and an intercooler partially blocking flow to the already undersize radiator while also kicking out hot air in front of it too is only compounding the issue.

.

 

Hey Brettus, what water temp do you normally see during track events?


Using my third picture as a reference, do you mean how my intercooler is slightly below the nose?

 

Yeah, that would be great. It'll probably be early next year before I head back to Barber. I live about 20 minutes from the road course in Memphis so I'll do all my testing there. Once I have this problem beat, Barber here I come.


Here's a link to a video from my last trip down there. My little sister's fiancé went with me. The video is shot from the hood of his car.

 

My Koyo is the 36mm core. I have been working on a vented hood the past couple weeks. I just got the louver panels back from powder coat last night and the hood is going to the body shop for paint in the next few days. I think the hood will help, although I have a feeling it won't totally solve the problem.

 

I have logged up to 225F but managed to improve on that to 210 last outing just by holding the lower foam in place (it was blowing out of the way previously)

Basically you need to leave that entire bottom opening with unobstructed flow to the radiator .

 

Are these the RX-8 specific vents?

 

No, those louver panels aren't from Singular Motorsports. I duplicated their basic design but modeled the louvers to follow the accent lines in the hood closer. A friend of mine has a small CNC plasma table. He cut the louver panels out for me. And my brother has a vinyl plotter. He made a cut template for me. I have a bunch more pictures of the louver project if anyone would like to see them.

 

Nice job

 

awesome job on the hood

 

That hood looks sick! Wouldn't it be a problem when it rains?

Regarding your overheating issue, I don't have any experience with turboed cars but even stock RX-8s overheat at the track in hot weather. My car is stock and I've had my fair share of overheating.

If I were you, I'd get 3000 CFM FAL fans and run them on full speed all the time. Yes, despite what most people say, that helps even at speed, not just when idling.

From the pics of your radiator, it appears that you've sealed around the sides and bottom pretty well. Did you seal the area on top of the radiator? It should be easier to reach it from inside of the engine bay.

Removing the AC condenser will help a lot. If you need AC, you can also mount it flat on the undertray. One guy on the club did it and noticed a 15-20F drop in temps. I can't remember the name of the thread now. A search should pull it up if you're interested in doing it

If all else fails, run the heater on full, put the windows down and point the vents towards the Windows. The heater core acts as a secondary radiator. It should drop the temps pretty quickly. Sure, it'll suck, but it's better than buying a new engine :P This is not a solution, but it should help when it's an emergency

Let us know what the temps are with the new hood. Good luck

 

Thanks for all the compliments on the hood, I appreciatethem all.

I don’t think there will be any negative effects from thelouvers in the rain. If there are any, I’llreport back.


I had an idea about the AC condenser last night. Before my next HPDE, I am going to have theAC system evacuated but leave everything in place. If the changes keep water temp in check, allis good and I’ll be able to keep the AC. If water temp is still high, I can remove the AC condenser at the trackwithout releasing refrigerant. Then I’llbe able to see how much the AC condenser effects temp. Ideally, I want to be able to keep theAC.


I am working on the battery relocation and intercoolerrelocation at the moment. Pics to comeshortly.


On a side note, I was planning on building an elaborate rearshock tower brace and incorporating a battery box into the brace for solidmounting of the battery. Whileresearching shock tower braces, I found this thread which leads me to believethat shock tower braces on our cars are just added weight. Anyone care to chime in on this?


https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/mazdaspeed-strut-tower-bar-135910/