I've got a GT28RS Full-Race setup. This car is build for road racing and currently doing time trials and time attacks.

Normally I run Honda 50/50 in my system, but after a recent radiator replacement, I've added just water with water-wetter.

I had an issue over the weekend of my radiator overflow bottle filling up and, well, overflowing after about 3 hot laps on a 3.4 mile course (~6 minutes). Not only made a traction issue with fluid spilling all over my tires, but also caused an overheating issue with water temps because I had obviously a huge air bubble now in my system. I figured the head gasket is going on me and pushing air into the system when I'm loading the engine. (No coolant in the oil or air bubbles coming out of the overflow tube under idle)

The last time I had water temps problems was when I was trying to run straight water. That was resolved by going back to 50/50. So now that the problem has come up again, I'm beginning to doubt it's just a head gasket. I thought it was weird that I'm having potential head gasket issue at the exact same moment I start running mostly water.

Considering my EGT's are in the 1600 range and my exhaust manifold gets up past 600 just idling (so who know what temps it reaches on track) , which sits about 1" away from the radiator, is it possible that the manifold and turbo are cooking my radiator to the point of causing it to super heat and boil the water to vapor? Thus causing excess pressure and pushing fluid into my overflow.

 

Short answer: No, not likely. We all run our turbos close to the radiator.
Sounds like classic head gasket symptoms to me.

 

Why don't you try putting coolant back in it.

 

road racing is different than street driving. multiple WOT pulls down straights can really push EGT's, if you knew what those were it would help but glowing red manifolds absolutely can boil water. think about how you cook a rabbit over the camp fire, same principle. obviously do a leak down to address any HG issues but you may also consider

1. getting a bigger radiator
2. ceramic coat the manifold and exhaust section of the turbo
3. turbo blanket
4. large oil cooler


if you're using any sort of half rad you're already swimming upstream. the tune, AF and those egt's are a big deal

 

Consider purchasing ATP inconel wrap its pricey but I have never heard a bad review. Its well respected in commercial application and there is a review on S2000 somewhere.

 

Some race groups (like NASA) and tracks themselves require us to run water only. I could sign up and just run laps through an HPDE. But the symptoms don't arise except when I'm on track. The time/effort to setup and go to a track event is taxing. I guess that is where the question came from. To tear down to replace the head gasket is going to open the door for other maintenance items, basically putting me down for 3-5 months. Or if it is possible that the manifold is cooking the radiator, then it would be worth it to shield it and then try get back on track next month. Either way, I need to do a proper leak down first.

Thanks for that. There are not a lot of turbo setup in the Honda road race world. All the turbo experts are usually focused on drag racing. It's hard to get people to understand that I'm at WOT 70% of the time for 20-30 minutes sessions.

1. I've gone up to a dual core full width radiator.
2. Been there and everything has failed:
https://honda-tech.com/forums/forced-induction-16/apology-hpc-full-race-header-ceramic-coating-incident-lots-pics-2094456/
3. I did have the DEI 'titanium' blanket over the turbo, but due to the radiator bust I mentioned before, it got soaked with fluid which eventually turned it into a candle. I've got some cheap fiberglass boot on it now.
4. Oil temps last weekend stayed around 280. Over the summer I see them sneak up to 300. Definitely plan to install a better oil cooler this winter.

Thanks for the recommendation. Will give them a call.

I've gone through several fiberglass wraps and DEI's 'Titanium' wrap. I took a fiberglass blanket (with the aluminum coated backing) and wrapped it like a funnel around the manifold (with a hold in my hood). Was suppose to be good up to 1200 deg. But the backing melted and smoked like crazy. Made a mess too.

 

Bigger Oil Cooler

Switch to E85 for its better cooling

Electric Water Pump (probably best bet)

heat coating/wrapping all turbo parts

the proper shroud and fan combination

 

There is also an alternative for coolant its Evans Coolant. I believe approved for track use. Check it out. but sounds an a lot like heatsoak and/or headgasket issue but start with heatsoak befor tearing down the motor. Also do a leak down test

 

I remember reading up on them a few months ago.

"Evans NPG is the Original Waterless Coolant. NPG is a lifetime coolant. NPG is recommended for racing engines that run on tracks or in series where there is a "NO Ethylene Glycol" rule, and can be used in high performance street vehicles with high flow cooling systems."

They also note: "NPG is NOT recommended for daily drivers or cold weather operation, and may require system modifications to ensure a successful conversion."

System modifications?

 

I've switched some systems over to this coolant. NPG requires you to have less than 4% water in the system. This means you have to find a way to drain your block as complete as possible. Less than 4% is a very small amount, depending on your coolant capacity. You just can't drain and blow it out and refill. It didn't seem to work much different on the vehicles we swapped them over too. Pretty much customer request in these applications. I'd personally look to something else.

 

Evnas sells a solution that you run in the system prior to installing the evans coolant that rids of any water. i used to run this stuff in my old darton sleeved block, works great. i had issues with it running hot and this stuff helped. it wont nessesarily make it run much cooler than coolant/water mixture but it will run cooler than straight water in your system and is suitable for track use which is the key element here. It also has a higher boiling point than water which helps too

 

that's good to know they have a solution to run. They never told me that. lol. It's been awhile though also.

 

seems like you would have to use a coolant flush machine loaded with this stuff

 

Its been a long time but i believe i drain my coolant, flushed the system with water ( i had standard coolant in it) go as much water out as i could. with thermostat out i pressurized one side with air compressor to blow out as much of the water in the block as possible. then flushed with the evans pre fluid. seemed to work for me

 

Sorry if I skipped over it, but what fan and shroud are you running ?

 

Why on earth does it take 3-5 months to change the head gasket? Pull the manifolds and the timing belt. Change the gasket then put it back together again.

 

you can even do it without pulling the intake manifold

 

Why don't you simply fabricate a heat shield out of 1mm thick aluminum around the exhaust manifold? Just weld on a couple a small brackets to your valve cover for stay. Should be pretty easy to fabricate and very efficient against radiant heat. All stock cars equipped with turbos have aluminum heat shields like that. And for the love of god get an oil cooler. Those oil temps are just crazy.

 

Because I can only work on the car during the weekends and probably only every other one for 4-6 hours at best. There are about 6 projects on the list to be done. The manifold, downpipe and hot side of the turbo needs to be sent off again to for another ceramic coat, rings will be replaced, new oil/water pump, oil cooler changed out/rerouted/reinstalled, new plastic around the timing belt and probably some of the wiring cleaned up, coolent lines for the new Tail wastegate run, etc.etc. Just looking at past projects and my work schedule, plus the lack of local shop support, I can see the car being put up for a good 3 months.

Just a couple 14" pusher fans. No shrouds.

I guess that was sorta one of the points of my original question. If radiant heat is an issue, then a heat shield will definitely be added to my project list. It's always been obvious that extra heat was being transferred into the system from the proximity of the manifold to the radiator. But it was assumed the radiator was large enough to dissipate the heat.

 

I run a aluminum half rad in my boosted ef I had be constantly in the red due to how close my rad was to my manifold/down pipe to fix the issue I moved my rad under the front crossmember and dropped 20+ degrees ECT I dont road race but after a quarter mile pull WOT to the top of 4th im just about 190F normal operating temp is 180ish

 

No name brands ? And they're mounted on the front of the radiator correct ? Pick up some good name brand fans with shrouds. Also keep in mind that when a fan is acting as a pusher, its less effeciant, so if you're running no name brands, pick up something a little better.

 

I had this same question with a full size rad in another thread. But if it were true then my buddies time attack evo I would think would run into the same problems.

I think a good turbo blanket and wrapping everything possible would eliminate the exhaust heat factor.

Ducting to the radiator is also important. Considering cutting a cowl in your hood as well.

 

I'll keep this quick and simple, it's your radiator cap!