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-   -   87 325IS doesn't like track...? (http://www.bimmerfest.com/forums/showthread.php?t=655656)

Ben T 11-02-2012 12:23 PM

87 325IS doesn't like track...?
 
Hey guys! I own a 1987 325IS and I finally lost my SOLO 2 "virginity". :D The car ran great and I love the sport, but the car was running hotter then expected. I have a good friend who knows these cars inside out, and I remember he had once said that the temp sensor usually never reaches the center unless your really pushing it, and mine had been at the three-quarters mark or farther... The car has plenty of coolent, and the only other thing I can think of about that race was that I was deffinitely pushing the car (5500-6000 rpm in second gear) but I didn't think the car would have such a reaction. oh, and the car has close to 250000 miles on it. Thanks for any help you guys can offer!

markseven 11-02-2012 12:54 PM

Quote:

Originally Posted by Ben T (Post 7172119)
Hey guys! I own a 1987 325IS and I finally lost my SOLO 2 "virginity". :D The car ran great and I love the sport, but the car was running hotter then expected. I have a good friend who knows these cars inside out, and I remember he had once said that the temp sensor usually never reaches the center unless your really pushing it, and mine had been at the three-quarters mark or farther... The car has plenty of coolent, and the only other thing I can think of about that race was that I was deffinitely pushing the car (5500-6000 rpm in second gear) but I didn't think the car would have such a reaction. oh, and the car has close to 250000 miles on it. Thanks for any help you guys can offer!

Fan clutch maybe.

downhiller 11-02-2012 07:33 PM

put in a lower temp t.stat and do an electric fan conversion. if youre gunna race it, do a dual fan setup, one push one pull both offset from the other. probably 2 12" fans. use one for low and the other for a high.

markseven 11-02-2012 08:08 PM

Quote:

Originally Posted by downhiller (Post 7172751)
put in a lower temp t.stat and do an electric fan conversion. if youre gunna race it, do a dual fan setup, one push one pull both offset from the other. probably 2 12" fans. use one for low and the other for a high.

That is a band aid. A stock setup in proper working order will handle track duty.

BMWFatherFigure 11-02-2012 09:11 PM

New larger radiator and use only genuine coolant. Change the sender for the gauge.

markseven 11-02-2012 09:32 PM

Quote:

Originally Posted by BMWFatherFigure (Post 7172890)
New larger radiator and use only genuine coolant. Change the sender for the gauge.

Band-aid

downhiller 11-03-2012 09:50 AM

Quote:

Originally Posted by markseven (Post 7172797)
That is a band aid. A stock setup in proper working order will handle track duty.

i notice a slight increase in temp when i ran mine hard and my fan clutch was fine, with a new water pump and a 60/20/20 mix of water/coolant/redline wetter water. did the fan delete and ran the aux fan on high and temp never went over half way between 1/4 to 1/2 way.

plus doing the electric conversion will help free up some power, along with an ac delete.

7pilot 11-04-2012 03:00 AM

With certain types of bad Head gaskets, the coolant temps stay normal when the car is operating in the street, and even when driven enthusiastically on the street.
However, when the engine is exposed to sustained high loads and RPMs, the cylinder nearest the weak spot in the gasket pumps air through the bad spot and into the coolant circuit, causing coolant temps to spike. When the engine cools off, the coolant may leak into the cylinder.

The coolant system should be pressure checked, and a leak down test performed on the cylinders.
Until these items are judged healthy, any work on the cooling system may be a band aid until the engine is again in a sustained high load state.

m

downhiller 11-04-2012 03:21 PM

Quote:

Originally Posted by 7pilot (Post 7174589)
With certain types of bad Head gaskets, the coolant temps stay normal when the car is operating in the street, and even when driven enthusiastically on the street.
However, when the engine is exposed to sustained high loads and RPMs, the cylinder nearest the weak spot in the gasket pumps air through the bad spot and into the coolant circuit, causing coolant temps to spike. When the engine cools off, the coolant may leak into the cylinder.

The coolant system should be pressure checked, and a leak down test performed on the cylinders.
Until these items are judged healthy, any work on the cooling system may be a band aid until the engine is again in a sustained high load state.

m

:nono: a bad hg is a bad hg. the only difference between a normally operated engine verses the same one being raced, is its at higher rpms more often. however, its still within the manufacture specs on combustion pressure. so if a hg is leaking while racing, its gunna leak driving around on the streets as soon as it gets to op temp.

theres 2 main ways a hg can fail, which either leaks all the time, or only leaks when the cooling system gets to pressure. not if your driving down the street vs racing.

7pilot 11-05-2012 06:01 AM

Quote:

Originally Posted by downhiller (Post 7175489)
:nono: a bad hg is a bad hg. the only difference between a normally operated engine verses the same one being raced, is its at higher rpms more often. however, its still within the manufacture specs on combustion pressure. so if a hg is leaking while racing, its gunna leak driving around on the streets as soon as it gets to op temp.

theres 2 main ways a hg can fail, which either leaks all the time, or only leaks when the cooling system gets to pressure. not if your driving down the street vs racing.

I only offer suggestions based on experience.
Yours appears to be limited.
A casual "slap a couple of fans on it" is not much help, is it?
Read up a little more on the effect of rising temps on dissimilar materials that are bolted together.

m

downhiller 11-05-2012 05:11 PM

Quote:

Originally Posted by 7pilot (Post 7176361)
I only offer suggestions based on experience.
Yours appears to be limited.
A casual "slap a couple of fans on it" is not much help, is it?
Read up a little more on the effect of rising temps on dissimilar materials that are bolted together.

m

i mainly raced drags, so thats where the fans come from. but i never once had a problem from running a single stage fan or the stock when i decided to run the track. even on autox runs i just didnt turn the fan on. sorry my experience is limited cause my car was working just fine with my band aids.

BMWFatherFigure 11-05-2012 06:43 PM

I would not call a larger radiator 'band aid' either. Change the temp sensor. My road cars sit at exactly half not matter how hot outside with or without air con running. Once a sender has been cooked they are unlikely to be as accurate.

markseven 11-06-2012 02:36 PM

Quote:

Originally Posted by BMWFatherFigure (Post 7177792)
I would not call a larger radiator 'band aid' either.

Basically you are saying that the stock cooling system, even in good working condition, is not suitable for autocross duty, correct?

BMWFatherFigure 11-06-2012 04:52 PM

Yes. Regard my suggestion as 'overkill' maybe, BUT NOT 'band aid'

markseven 11-06-2012 04:58 PM

Quote:

Originally Posted by BMWFatherFigure (Post 7179908)
Yes. Regard my suggestion as 'overkill' maybe, BUT NOT 'band aid'

You are probably one of two people that feel the M20's cooling system cannot keep up with the demands of an autocross. All two minutes of it. At less than 60 miles an hour.

OP, a bigger radiator is addressing the symptom, not the problem.

markseven 11-06-2012 05:11 PM

Quote:

Originally Posted by markseven (Post 7179916)
You are probably one of two people that feel the M20's cooling system cannot keep up with the demands of an autocross. All two minutes of it. At less than 60 miles an hour.

OP, a bigger radiator is addressing the symptom, not the problem.

Didn't mean for this to be mean :)

downhiller 11-06-2012 05:15 PM

what about a bad pressure cap? if it doesnt hold the pressure as well, lower coolant pressure, higher temp.

BMWFatherFigure 11-06-2012 06:01 PM

OK, I refer to the BMWCCA / Bentley publication 'BMW Enthusiast's Companion' page 81. Inter alia 'substandard radiators from Behr Radiator of Mahwah, New Jersey.' Also 'BMW radiators are too small in capacity and a constant source of grief to owners.'
Ben T wants to race, high rpm (horsepower / heat). Although he has not quantified the higher gauge reading or changed the sender he thinks the engine is running too hot. By all means change the water pump, thermostat, radiator cap and hoses but for his application I believe a larger radiator is prudent.
Having crewed for a race team in Western Australia (it gets hot here) we ran oversize radiators compared with the same engine in road use without problems. Also from his OP his gauge is not behaving normally - change sender.

Nick323 11-07-2012 12:02 AM

Running your car cooler
 
I will take you a bet that if you run a mildly modified 325 E30 over 100 mph (pleny of airflow) for over 20 minutes, you will see it overheating !
Of course this is in our balmy temperatures where it hardly drops under 100 F in summer :eek:
Anybody who builds cooling systems knows that you wan more liquid capacity in the radiator :thumbup:
If possibile increase the frontal surface area, but try not to add another core.
Thicker can block airflow :(
But this is hadly of refference for somebody racing short distances in a cool climate :dunno:

BMWFatherFigure 11-07-2012 04:05 PM

So Ben T is from Alberta. Does he even need a radiator? If he is having overheating problems (according to his iffy gauge) then he needs a cooling system overhaul. If he is going that far and the radiator is proving to be inadequate AND he is going racing fit a larger one. Its not rocket science.

_Ethrty-Andy_ 11-07-2012 08:19 PM

stock cooling system in 100% order will be fine, but if you want to run cooler and add safegaurds which are of course recommended for a dedicated track car seeing sustained high RPM, then upgrades may be required

Ben T 11-07-2012 08:30 PM

So far a great help guys! Thanks so much! I forgot to mention that I have already replaced some of the hoses and the water pump, temp sensor and the fluid. If it makes any difference (which I'm not sure if it would) I also have added in a sports chip in the car. The head gasket I beleive is fine, as we checked it, but that was over 3000 kms ago... cylinder pressures are all normal too, they were checked at tops 1000 kms ago. Raiator has crossed my mind as a source of the issue, but more because it looks relatively old and (knowing the previous owner) not very well cared for. After the drive shaft replacement, the radiator is likely the next thing to get checked by next summer. After all, overheating in Alberta during the winter? :rofl: on a side topic, does anyone also have any ideas on places to get a driveshaft redone or where to just purchase a whole new one entirely?

Nick323 11-08-2012 12:08 AM

Coolant ramblings
 
I have just started thinking (which is not a good thing) ;)
The temperature gauge measures the temperature after the Thermostat going to the radiator on my 323 :(
On most cards the Temperature is measured before the Thermostat, on the engine side.

Now in your arctic conditions you could have the content in the radiator freeze up causing the car to overheat. I'm sure you know that better than me.

Maybe the cold outside air is keeping your temperature gauge up ?
I had this on Buick V6 motors that needed a long cycle of hot-cold-hot-cold before stabilising on our -5 C winter mornings. This was with a very quick responding gauge & I would think the MotoMeter gauge would be a lot more dampened, showing you tempertaures that are not current

The thermostat is also responsible for keeping the water circulation at a constant rate !
You can get the water overheating in the head & block if you run certain engines without thermostats, as the water circulates too quickly to absorb & transmit the heat.

I have been suffering with heat related issues for most of the past 19 years and realised it is not einfach...

markseven 12-03-2012 08:09 AM

Quote:

Originally Posted by BMWFatherFigure (Post 7182298)
So Ben T is from Alberta. Does he even need a radiator? If he is having overheating problems (according to his iffy gauge) then he needs a cooling system overhaul. If he is going that far and the radiator is proving to be inadequate AND he is going racing fit a larger one. Its not rocket science.

This full version of this pic has been on my desktop for months. I just now realized that it may be revealing for this thread, the focal point being the M10-size radiator. The car on the right made upward of 320hp.

http://markseven.net/bmw/E30_M3_12_bimmerfest.jpg


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