285 whp! - Page 7

shotgunslade · #91 02-26-2008, 11:22 AM

This overheating behavior is completely consistent with my own experience at the track. 15 or 20 minutes into the session, water temperature starts climbing. When you slow down to pit, temperature spikes toward the red zone. If you park it then, it will go up into red, so I typically drive it around the infield slowly in 3rd gear, until it calms down. During this period I will see occasional spikes in temperature that slowly return to normal, which I assume may be air pockets passing the temperature sensor. After it settles down and I shut it down, I will see that the coolant in the overflow tank is very high and that it may have pushed some out into the engine bay. After it has cooled down and I pop the radiator cap, I will see that the coolant level has dropped in the radiator.

It boiled over the first time I saw this, right after my tranny transplant, when I shut it down immediately after pitting.

Normally on the track, I observe a 7200 rpm red line. When it starts to warm up I will drop that to 6400.

Originally YT thought I had a leaking head gasket, but I had no other symptoms.

Also have consistently had PS problems, leaking O-rings, and a totally hemorrhaging PS pump. On second track day had the PS return line split and spill all PS fluid onto pit pavement. Kitty litter time.

How do you purge air from the system?

I'm afraid the problem is only going to get worse with my Tomyx snorkus and new CAI.

sicksubie · #92 02-26-2008, 11:25 AM

What are the details on the PS pump you are using now and how did you quicken the steering ratio?

sicksubie · #93 02-26-2008, 11:26 AM

And I am getting the same oil blown into the intake as you mentioned as well. I have a catch can but it is not hooked up right now. See what improvements are made with that functioning properly.

RallyBob · #94 02-26-2008, 11:42 AM

Quote:

Originally Posted by shotgunslade

How do you purge air from the system?

Once in the pits, the car is jacked up very high in front. After cooling down a bit, the radiator cap gets removed and the vehicle is restarted. A tall funnel is fitted to the filler neck, and coolant is poured in. Once back up to temp, the thermostat opens, the coolant level drops, and more is added until it is full again, A column of coolant/water is kept in the tall funnel, the column of pressure here is high enough to overcome the system pressure w/o the cap fitted. About 5 minutes of running are all that's needed, then the radiator cap is refitted.

A 24 psi cap will be tested next track day, to see if that helps. Maybe a bigger oil cooler too.

Bob

RallyBob · #95 02-26-2008, 11:48 AM

Quote:

Originally Posted by sicksubie

What are the details on the PS pump you are using now and how did you quicken the steering ratio?

It's a KRC aftermarket pump. Commonly used in circle track cars. Funny thing is, it looks like the typical OEM Japanese PS pumps out there. Almost a direct fit. His is the steel version, an aluminum one weighs half as much but costs more. The Subaru pulley was apparently a direct fit. The new reservoir has greater capacity, and the return lines are now -10AN. Foamed-up, overheated fluid does not return easily, so a larger return line is needed to avoid stalling the pump due to cavitated fluid not returning. The cooler helps a lot as well.

The quickener is a Howe 'Stealth' 2:1 quickener. It's fitted within the stock steering column (welding required). Most of the rally guys have been doing this for years.

Bob

RallyBob · #96 02-26-2008, 12:01 PM

No one has posted any racing pics yet, but one guy that was in Jack's race group has a video from Saturday's race.

As it's a standing start, Jack got quite a jump on a lot of the cars. At approximately 37 seconds in, the Impreza comes into view passing the Corvette driver on the right side of the screen. He holds him off fairly well until the car starts to overheat.

Bob

SVXRide · #97 02-26-2008, 12:03 PM

Quote:

Originally Posted by RallyBob

It's a KRC aftermarket pump. Commonly used in circle track cars. Funny thing is, it looks like the typical OEM Japanese PS pumps out there. Almost a direct fit. His is the steel version, an aluminum one weighs half as much but costs more. The Subaru pulley was apparently a direct fit. The new reservoir has greater capacity, and the return lines are now -10AN. Foamed-up, overheated fluid does not return easily, so a larger return line is needed to avoid stalling the pump due to cavitated fluid not returning. The cooler helps a lot as well.

The quickener is a Howe 'Stealth' 2:1 quickener. It's fitted within the stock steering column (welding required). Most of the rally guys have been doing this for years.

Bob

Bob,
Very cool! Can you provide pics of both installed in the car. I'm very interested in both additions.
-Bill

RallyBob · #98 02-26-2008, 12:11 PM

Quote:

Originally Posted by SVXRide

Bob,
Very cool! Can you provide pics of both installed in the car. I'm very interested in both additions.
-Bill

Since I already spent the money on a new video camera battery/charger/tapes last week, I'll try to do one better and get some video of the car. Under the hood, under the chassis (on a lift), and maybe some of the car running.

Bob

AndrewR · #99 02-26-2008, 12:12 PM

Bunch of STi boys up here who do track are having similar overheating issues, and have all found head gasket issues.

I know it is a different engine, but very similar symptoms. They would run cool on the street, but when pushing on the track, overheat.

HTH

longassname · #**100** 02-26-2008, 01:05 PM

I'm a little suprised you haven't replaced the thermostat with a restrictor plate. I'd use a restrictor plate and kick the fans on full blast at 180 degress F.

TomsSVX · #**101** 02-26-2008, 01:35 PM

I was going to mention Dan's hot experiences at the track as well but he already chimed in. Have you guys thought of the cooling capacity that the wrx radiator you are using has?? Maybe its about time to go to a bigger all aluminum rad?? Good luck with it anyways

Tom

Trevor · #**102** 02-26-2008, 04:18 PM

Quote:

Originally Posted by RallyBob

Stock shortblock, it's never even been taken apart!

So, no coatings to anything...not the head, valves or pistons.

Bob

Good going Bob.

The above does not surprise me on several counts.

P.S. Congratulations you are on the right track in all respects and are blazing a trail.

shotgunslade · #**103** 02-26-2008, 05:30 PM

I don't think radiator size has anything to do with it. I think there is some section of the block that has insufficient adjacent water flow to prevent local overheating. When you are really running the engine hard, even though the radiator may have sufficient capacity to reject the total heat output of the engine, that section overheats, and causes localized boiling of the coolant. That is why the temperature needle stays OK, until suddenly it starts rising toward the red. As long as the temperature sensor is surrounded by liquid coolant, it registers the correct temperature. When the steam bubble passes it, it goes over the top. The steam bubble also forces coolant out into the overflow tank. Even so, the average temperature of the coolant as a whole is not excessive. Hence the weird behavior. Temperature starts rising, goes from normal to red in maybe 20 seconds. a short time later, drops back to normal. As I'm slowly driving around the infield roads, cooling down after a track session, I might experience this behavior 2 or 3 times. In between, coolant temperature registers normal.

Same behavior might be exhibited by a head gasket leak out on the track, but probably not as I'm cruising the infield roads at 1100 rpm in third.

Nomake Wan · #**104** 02-26-2008, 05:41 PM

Funny... this behavior sounds just like the behavior my car exhibits when I'm climbing a steep grade in 2nd with the throttle fully open. Or when I'm otherwise pushing the car hard, staying above 4k RPMs for long periods.

Well crap.

RallyBob · #**105** 02-26-2008, 06:28 PM

Quote:

Originally Posted by AndrewR

Bunch of STi boys up here who do track are having similar overheating issues, and have all found head gasket issues.

I know it is a different engine, but very similar symptoms. They would run cool on the street, but when pushing on the track, overheat.

HTH

I'm very familiar with the STI head gasket issues, as I've seen it on a lot of other race cars. Those tend to be more 'violent', for lack of a better word. In other words they push the coolant out suddenly, and the temp spikes suddenly, thanks to combustion pressures/boost being transferred to the cooling system.

With the EG33, we're seeing a gradual buildup of temperature (and presumably coolant pressure), and then the eventual letting go of the pressure cap, so the coolant overflows into the catch can.

I used to crew on a mini-stock circle track car, and we had tons of cooling issues. We tried slowing the water pump speed by 35%, deleting the thermostat and adding a restrictor, installing a huge aluminum radiator, etc. All helped a bit, but none solved the issue. The eventual fix was a change from the OEM 13 psi cap to a 24 psi Stant racing cap. Never overheated after that!

I'm hoping this problem may be as simple as a good radiator cap.

Bob