Originally Posted by c5racr1

update on the V09?

Originally Posted by X25

Backgroud: It depends on many factors, from local temps, to track configurations, to driving style, but in my neck of woods (Pacific Northwest), my '23 C8 Z51 has been running pretty hot (coolant around 240 degrees F) even when I ran it at temps as low as 75 degrees F. The car loses substantial power at those levels, and you start 'losing' : ) Thanks to our community discussions, it was discovered that export cars sent to 'hot' countries actually get shipped from the factory with an additional auxiliary radiator on the driver side rear pod location. Looks like GM decided us Americans don't need it, and they replaced the radiator with a plastic grill for our market. This is my attempt to add it back.

What you need:

• Sockets / Tips: 7, 8, 10, 13, 14EP, T15.
• 2 x 6ft heater hose (available at local auto stores).
• 8 x clamps for 5/8" hose.
• 2 x heater hose elbow
• OEM AUX radiator 23429489
• OEM AUX radiator front duct 23428551

WARNING: This car platform (mid engine C8) is very hard to work on, and this project was also pretty demanding, even for simple steps. You are forewarned. If you follow, you're also doing it at your own risk. If you make mistakes, you can cause harm to your car, others, or yourself.

1. Open hood and trunk, and disconnect the battery..
Since we're messing with a fan, and will need to unplug things to open up space, it makes sense to get the battery disconnected. Before doing that, though, make sure you open the trunk.

2. Put the car on the lift/jacks and remove driver rear side wheel/tire.

Next up, remove the wheel liner. It is held in place by 2 plastic retainers, many T15, and a few 7mm bolts at the bottom,

3. Remove the fake radiator.

Our cars already come with everything we'd need to install the radiator, including mounts, fan, etc. All we need to do is to remove the fake unit : P


How it looks with the fan removed.


You have to remove the bottom mount to be able to remove the fake radiator. It is held in place by 3 x 10mm bolts. The third one is not easy to see, but it's there.


They're out!


... just look at the huge opening that will feed the radiator...


4. Assemble and install the aux radiator.

Assemble the radiator along with the ducting. You can also reuse the ducting of the fake radiator, but it doesn't have that air baffle in front of it; your choice. I reused the plastic retainers (screws) of the fake radiator as well.


Next up, install the fan onto the assembly. The radiator core took about 800 ml of coolant. Make your concoction per your desires (I did 30%), and fill it as much as you can to reduce air in the system.


Attach the hoses and put clamps on them. Now we have an octopus.


Finally, you can also move these fuel overfill dump line retainers, but I was not able to really reach there during reinstall, so it was not necessary for me.


I used 2 of these hoses from local O'Reilly's.


Now reinstall time. First align top pin with its hole, and then push the assembly up.


Then comes the hard part. Due to small clearances, I struggled to properly reinstall the bottom mount for a while. Later, I sprayed a bit of WD-40 to the holes, which made it much easier and 'possible' for me to align everything and start putting 3 x 10 mm bolts back in. Good luck!

5. Route and connect the hoses,
We'll soon remove a hose, and it made quite a bit of mess when I removed it. I think the best way to handle it is still just removing the line and putting a bucket in preparation, since it will make refill and getting airs out easier (compared to complete drain). It's your choice!



The OEM setup uses the top opening for routing the hoses towards the engine. This puts the hoses pretty close to the headers, and I don't think it's the best idea, though I understand why they did it that way (packaging constraints). In my case, I realized I can route the lines far far away from the header by making a small modification. That bracket I'm pointing at needs to go, so that you can bundle the lines with that big harness and safely tuck it under the wheel liner. It is held in place by one plastic retainer, and a few small zip ties. Second pic shows it removed.


Look at that; nice and bundled! You can then route the hoses towards the engine from (behind) where the brake hard line connection is.
At this point, temporarily install the wheel liner back to confirm that the lines are tucked behind it safely, and are not close to the tires, etc, or making any bumps on the liner. Don't skip this step.


V09 splices into the oil cooler's input line as show in the pic above. We need to remove the soft part of the line (1) in this pic. The direction of flow is from the top connection (coming from the engine) to the bottom (oil cooler).


Easier said than done. This was the hardest part of the project for me. The clamps were facing away on both ends, and they're different size! The bottom one is 7mm, and the top is 8mm. I was able to reach the top one using a swivel head 1/4" ratchet, but the bottom one was not easily accessible. I ended up forcing the clamp to turn a bit with a long screw driver, after which I had a small access to slowly loosen it with a long flat head. Good luck!!!


It looks like this when removed.


Create this by using hose elbows. After doing this, I had to cut down the length of the one for the hard line hose coming from the top, since it would not clear the engine mount. The bottom one has space, so a bit longer hose is OK. Keep in mind, these will need to move a little as the engine rocks back and forth.


Sorry for the dark pic. Here they are installed. To make it much easier on you, lace the inside of the hoses with coolant before trying to put them on. If the hoses are dry, they will get progressively harder to push forward, and you might get stuck (I did on one of them).


Now comes the routing part. As you can see from the pic above, the top radiator port rear of the car needs to plug into the oil cooler core side (bottom connection), and the port to the front of the car needs to plug into the hose coming from the engine (top).


Here's a pic with the bottom (oil cooler) side connected to the hose already, and the one coming from the top pending.

6. Leak checks, reassembly.

• First refill coolant. Don't worry about overfilling, since the engine can easily dump it if it's really too much. Keep refilling until it can no longer take any more, and there are no more bubbles.
• Cranking the engine: With your left food on brake, and right foot 100% throttle (not any less!!!!), hit the start button. It will just crank the engine, but will not start it. This way, you can run the water pump a bit and let the coolant move around. I recommend cranking twice for 15 seconds, 1 minute apart to let the starter cool down.
• Check for leaks: If you see any, fix it.
• Top up, and start the engine: With the coolant fill plug open, let the engine idle, and check for leaks. Top up the coolant if it gets lower. Now put the plug back in so we can let the engine safely come to high temps (150+ degrees F); blip the throttle to 2K, and then 3K for a short while, a few times. Shut the engine down, and if it's below 200 degrees F, slowly, and carefully open up the full plug to check on the level. Top it up (overfill), and you're done!

Reassembly time! Start with the liner.


Don't tighten the bottom bolts before every bolt is in its hole. Otherwise, it's easy to misalign.


Tired of 14EP? You can switch to any flanged M8x25-1.5 bolt like I did.

7. DONE! Time to test drive.
Now it's time for a test drive. You should check the coolant level often for the next few drives as the car bumps its air pockets out.

8. Optional: Inline thermostat.
If you'd like the new radiator to not aid in cooling below certain temps, you can source an inline flow thermostat with a bypass (i.e. ~90% of the coolant would be returned back and not hit the radiator, while 10% would hit the radiator to keep system pressurized).

I hope this helps : )

Originally Posted by Nabush

Hey Ozer,

I was initially planning to attend ORP one day next week end, but I decided to wait for cooler weather...

I think I will come 09/30 or 10/01 and maybe one last time mid October.

I don't have new R7 like you to try my PB but cooler weather should be better anyway. Still curious to see if you will be able to be as fast as the C7 with your C8.

My bet : C7 is faster Looking at your first time with the C8 car definitely lack power, straight line speeds were really slow ? DCT and mid engine layout only helps at low speed and dig it looks like .. I will probably try the CR-S as well on one of my set of 18's they look promising. Probably next year

Originally Posted by combatninja

Hilarious that everything is there but the rad is a fake blank. This is the sort of stuff that you uncover when ripping apart a $60K mid engined sports car. They have to cut every corner to deliver it at the MSRP.

Originally Posted by X25

Temps dropped a bit; take a look at the forecast. Indeed, the car was off pace compared to C7, but I suppose that's a bit expected? It was also running pretty hot, so I'm sure I was losing power from that, too. We'll see if the temps stay much lower this time with the radiator. I'm also an OK driver, not the best; there'll be some time left on the table : )

I decided to not bring in the new R7s. It's not the most ideal temps, and these tires are way too expensive to waste in non-ideal conditions. I might do the 295 / 315 experiment when it's cooler next month.

Originally Posted by Nabush

If I recall your best time with the Z51 C7 Stingray was low 1min50's on R7 scrubs. Do you think you can beat that with the C8 ? Knowing that you did not run new R7 on the C7 Stingray (is it right ?)

On my end, even if temps are dropping for next week end, since this is the release of Starfield (early release 09/01) I think I prefer spending some time on my PC

Originally Posted by X25

It should definitely beat C7 Z51's time. We'll see..



Finally organized the tires. There are too many tires to go through, and I have this many on the other side of the garage as well now that I've invested in CR-S tires. Here's hoping everything works out and I can get to use the car more.


Here's the 335/30/18 CR-S next to 345/30/19 RRs (both unmounted).


The driver side pod looks identical to the passenger side now; I love it. This is quite a bit of cooling capacity, and I am very much hopeful that it will make a huge difference. Thinking of it, this should be a must step for anyone doing forced induction, too, considering the cooling challenges.


I'm still waiting on my ST47s. The 18mm rear fitment now has an ETA of about 7 days, but there's no ETA on front fitment. Anyway, fearing I might run into issues,I ordered a set of EBC SR21s front/rear as a backup.



https://www.amazon.com/gp/product/B0...0?ie=UTF8&th=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I have been communicating with Derale regarding their (25719) fluid control thermostat. They said it should work just fine for the coolant application as well; great! This will be perfect, since it will let the system bypass at 90% rate when the engine is not hot enough, yet use the radiator for 100% of the flow when it exceeds 180 degrees F.

If I understand the OEM system correctly, GM has a permanent bypass (a parallel circuit), at least on the passenger side, and uses an inline thermostat to cut the flow to the radiator when the temps are low. This simplifies the design, but pretty much means that even when you have temps running very high, most of the coolant flows through the bypass that never shuts. It probably doesn't matter too much as long as enough amount of fluid hits the radiator as well, but it's clearly not as optimal.

Originally Posted by Nabush

That's a lot of $$ in tires !

Question about R7 vs RR. Which one lasts longer are far as cycles ?
With R7 scrubs which were looking like new, I had the feeling last time they were loosing grip after my second day (8-10 cycles). I know the RR is slower but how do they cycles vs R7 ?
​​​​​

Originally Posted by Driv200

Remind me: what are CR-S tires?

I just got Falkens for track set.

Originally Posted by Driv200

Remind me: what are CR-S tires?

I just got Falkens for track set.

Originally Posted by J5isalive

The Nankang CRS is essentially an A052. very similar characteristics. They run very similar lap times, heat up quickly, etc. Their life is similar to all the Super-200 tires.

Originally Posted by J5isalive

The Nankang CRS is essentially an A052. very similar characteristics. They run very similar lap times, heat up quickly, etc. Their life is similar to all the Super-200 tires.

Originally Posted by PRE-Z06

The CR1 (v1) acts like the A052, but the CRS (v2) needs warming up like a Rival S, 3R or R7.

Originally Posted by Nabush

Yeah the CR1/CR-S V1 were pretty terrible as far as wear, like the A052... All my buddies were using them in AutoX (or A052) in 2021-2022

Looks like the V2 is way better in that regard. One of my buddies with a Cayman GT4 981 (2017) was able to do 5-6 days with the new CR-S earlier this year (May/June)