DD's Z3 supercharger evolution

markrnorton · 11-16-2009, 01:43 PM

Guys

been reading this forum alot, usually use one in the UK, but not many people used F/I on there M44's here. This is a very good forum for info and development it seems.

Been developing my Z3 for about 6 months now, done the DASC conversion and trying to evolve it into something just a bit more.

The car has run hot for a while, not causing a problem, but hot. I put this down to the 2" exhaust i had on it.

I am currently re-building the pipe in 2.5" stainless, here's an early pic of the downpipe

i have also mocked up the rest of the system , including a race CAT. run the car up at the weekend and now it seems there is defo problem with the cooling. system is getting hot on the top hose only, and blowing out the header tank. Bottom hose is cold.

Does any body have any experience of the thermostat or water pump failing ?? , i'm guessing its the thermostat but any help would be appreciated.

spidertri · 11-16-2009, 02:06 PM

Cooling system is the biggest weakness on the M44. T-stat can definitely fail as can the waterpump. Look for the cooling system rebuild thread by Cirrus in the knowledge base.

markrnorton · 11-16-2009, 03:30 PM

Thanks for the quick response. read the thread.

would the M44 benefit from removing the thermostat altogether and having a 'free flowing' cooling system ?

any thoughts ??

projekt EPiK · 11-16-2009, 05:53 PM

depends on your climate. the purpose of the t stat is to maintain the coolant at operating temp. if there is no t stat then the coolant never gets warm and the engine will run rich and it will effect your fuel economy at the very least. on an FI car it will also affect the tune.

projekt EPiK · 11-16-2009, 05:54 PM

fwiw, i would replace both the wp and tstat at the same time. possibly there is a variance in tsat opening temps you can buy.. usually around 160 and 180* F for most cars.

tiFreak · 11-17-2009, 12:38 AM

Quote:

Originally Posted by markrnorton

system is getting hot on the top hose only, and blowing out the header tank. Bottom hose is cold.

I think you're radiator is clogged, coolant can't flow through to the bottom hose so it's not getting hot

projekt EPiK · 11-17-2009, 12:41 AM

that explanation generally means the tstat is not opening and circulating the coolant. in most cases anyway. hot upper hose, burns to the touch, cold lower hose.

MPWR · 11-17-2009, 01:22 AM

If you overheat an M44, you will usually blow the headgasket. Only takes once, and often the head will warp also. These engines are very very intolerant of being overheated. At all costs, avoid running it hot. Period.

Quote:

Originally Posted by markrnorton

would the M44 benefit from removing the thermostat altogether and having a 'free flowing' cooling system ?

No. Like all engines, the M44 is designed to operate in a narrow temperature band, and the thermostat regulates this. Too hot will damage the engine, and too cold will dramatically increase wear. Running without a thermostat is definitely unhealthy.

The thermostat and water pump are both very easy to change on the M44. But before other stuff, you might want to run a compression test to see if you still have a head gasket....

projekt EPiK · 11-17-2009, 02:36 AM

another simple test you can do to look for a BHG is to remove the radiator cap, start the car, and look into the radiator opening for a fine constant stream of bubbles as the cooling system is pressurized by a leak into one or more of the cylinders.. if this is the case you can usually smell exhaust gas in the coolant in the radiator. car doesnt have to be hot for this, just make sure the coolant is topped off.

also, check your oil dipstick, the water from the cooling system will enter the oil thru the leak in the seal between the head and block.. can give the oil a milky look.

markrnorton · 11-18-2009, 09:34 AM

Well i had the thermostat out yesterday, it was locked shut !

so bought and fitted a new one, problem now is the readiator header tank split when it over pressurised.

New radiator need now !!! argghhhhh

denglish318ti · 11-18-2009, 04:35 PM

Like the look of the exhaust! Need to sort out a backbox for mine. Good to hear it was not anything too serious with the coolant system. My water pump bearing went, and the thermostat jammed open, so they are parts that need replacing.

markrnorton · 12-01-2009, 11:49 AM

Finished the downpipe now to a decent level and fitted it

bolted up fine and new lambda fitted to car, just need to fit the wideband sensor now for the datalogger.

working on the sports CAT and back end of the pipework now, getting there, will need a cleanup and need to work up the backbox so its supported firmly.

also getting the larger 2.5" pipework under the axle need close attention as it does reduce ground clearance

denglish318ti · 12-02-2009, 03:41 PM

Looks great! Will the cat be in the same position as standard?

markrnorton · 12-03-2009, 08:20 AM

close to original position, just slightly further back. flows 85% better than standard cat so it should help

macilona · 01-13-2010, 12:54 AM

hello Mark---have you completed this exhaust modification now? What is your assessment of the impact on the engine power/torque--is there a noticeable improvement? I had seen other threads that had mixed reviews of a more free flowing exhaust, with some suggesting that the back pressure of a smaller system actually gives better performance. So curious about your results. Thanks, Mac

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