external oil cooler

[Brasco]

can't you get them ceramic coated?

[GTG]

I was an ideea but ... hard to find ceramic coating ... Do you have any tip ?

[haz@nocturnal_development]

you tryin to over engineer your setup lol.
ceramic coating is a solution for not bein able to set-up the car correctly.
350cc's are plenty big enuf to boost the t8 to about 25psi.
nitrous kit is just goin to complicate things and unless ya usin it to spool the turbo, which isn't really required, or usin it for strip runs which is not really consistant due to bottle pressure, temps etc.
1.3bar is bout 18psi, plus a 50 shot of gas (which wont actually be 50hp, more like 30hp) or you could just run 18psi plus an extra 5psi (worth bout 7hp for each psi) which will give the same results without the extra cost and hassle
requards the oil cooler, the std volvo water cooled unit is about the same as a front mounted 7 teir cooler so you'll want at least a 10 teir to make it worth while changin. i use the 5gtt sandwich plate and cetre nut, custom braided lines and a 740turbo cooler.
there is also onother solution similar to the volvo set-up. the 5 gtt uses an oil cooler built into the rad so you could use the 5 rad, oil lines and asandwich plate too.
i use halfords 20w50 oil, personally anythin less than 15w is too thin and anthin less than 40 and it falls apart after a hot blast, and once its lost its properties it needs changin.
when i used to use the volvo info centre i had the oil at 100 deg fast drivin but up to 130 after long hard blasts.
BUT, an external cooler will need a thermostat or the oil will take alot longer to get up to temp

[rpruen]

you tryin to over engineer your setup lol.
ceramic coating is a solution for not bein able to set-up the car correctly.

Ceramic coating is required unless you want to modify the piston cooling setup, but only if you plan to use more than 27 psi of boost. The reason being that the combustion chamber is in the piston, and piston heating is a problem at very high power. It gets to the point where the mixture is too rich for the engine to run properly, and you start to hurt power output. The ceramic coating helps to keep the heat in the cylinder, and allows the mixture to be set for beter power. Cooling the oil will help up to a point, but it won't get very far.

I would agree that for lower boost it is possibly not worth ceramic coating. Although it will provide quite a bit of extra saftey net (should something go wrong).

Remember if fitting an oil cooler the oil needs to get hot enough to stop water condensing in the sump (along with nasty acids from the blowby gasses). Idealy the sump temperature should not fall below 95 C while driving on the road 'normaly'. The oil leaving the cooler should be at a resonable temperature, at least 70 C for it to lubricate things properly.

The volvo oil cooler is very efficient, but uses hot water from the engine to cool the oil (and to heat it during warm up). It's a good system for a road car, since it warms the oil quickly from a cold start. The oil leaving the cooler is very staedy in temperature from my datalogging, so the cooler is more than good enough.

If you want to cool the oil more than normal add a small radiator (heater matrix maybe?) to the pipe between the head and cooler. That will cool the water entering the cooler, and result in cooler oil. Simply tape up part of the little radiator to adjust the cooling effect. Not ideal I know, but is cheap and smple to do, and doesn't need much in the way of parts.

Richard

[haz@nocturnal_development]

"Ceramic coating is required unless you want to modify the piston cooling setup, but only if you plan to use more than 27 psi of boost. The reason being that the combustion chamber is in the piston, and piston heating is a problem at very high power. It gets to the point where the mixture is too rich for the engine to run properly, and you start to hurt power output. The ceramic coating helps to keep the heat in the cylinder, and allows the mixture to be set for beter power. Cooling the oil will help up to a point, but it won't get very far. "


or you fit a larger turbo which will be less restrictive and will produce lower charge temps, thus reducing combustion chamber temps along with lower exhaust temps. basically your turbo is too small and your tryin to get too much from it. try lookin at compressor maps, they may shed some light on the subject for ya

[JohnTurbo]

I'd have thought charge temperature would be secondary to fuelling. Not forgetting where all the heat in the engine comes from, if you run more boost, you're spraying in more fuel.

You're saying if the turbo is too small, all the work goes into heat rather than compressing the gas?

I'd wager if you compared the work done on the air by the turbocharger, to the increased chemical energy from the extra fuel, the later would be dominant.

Corrections could also be made with the degree of intercooling of course!

Its certainly important to keep an eye on charge temperature, and to run a suitable turbo charger, but at some point there has to be a limit to the engine's cooling capabilities right?

I personally have no idea where this would come, but assuming an engine is 40% efficient, the dropped 60% is heat almost entirely. Thus if you get 300bhp from a formerly 100bhp engine, you're making 3 times the heat. Or 135kW of heat!!!

[rpruen]

I'd wager if you compared the work done on the air by the turbocharger, to the increased chemical energy from the extra fuel, the later would be dominant.

Corrections could also be made with the degree of intercooling of course!

Its certainly important to keep an eye on charge temperature, and to run a suitable turbo charger, but at some point there has to be a limit to the engine's cooling capabilities right?

I personally have no idea where this would come, but assuming an engine is 40% efficient, the dropped 60% is heat almost entirely. Thus if you get 300bhp from a formerly 100bhp engine, you're making 3 times the heat. Or 135kW of heat!!!

Yes John, you are right.

The thermal loading of the pistons is a factor of power output. Partly because extra energy in the combustion chamber (needed to make more power) gets transfered to the pistons. Throwing in more fuel cools the combustion and reduces the heating, but it also robs power, as cooler gasses expand less, so gives less pressure on the piston.

As the pressure in the cylinder rises (again needed to make more power) the layer of cool gas 'attached' to the inside of the combustion space, is made thinner by being compressed (or may even be scoured from the surface by turbulance). The thinning of this layer increases the heating of the piston / head surface on top of everything else.

The removal of the cool layer of gas is what happes if you get detonation. The exploding mixture removes the cool layer of gas, leading to 1200+ degree burning mixture being in direct contact with the piston / head. This gives rise to local melting of the piston / and / or, head.

The charge temperature has very little effect as things go, it will hurt power production (because it increases the chance of detonation). However if you have no detonation, increasing the charge temperature by 30 degrees results in less power, and lower EGT (because efficency goes down, as the timing needs to be backed off) and that actualy gives you lower temperature transfer to the pistons.

Having datalogging and temperature probes all over the place realy is helpfull.

Richard

[rpruen]

or you fit a larger turbo which will be less restrictive and will produce lower charge temps, thus reducing combustion chamber temps along with lower exhaust temps. basically your turbo is too small and your tryin to get too much from it. try lookin at compressor maps, they may shed some light on the subject for ya

I have looked at compressor maps, and have a plenty big enough turbo. That's the reason I have a supercharger as well, or the turbo does nothing at all until about 4k rpm.

I datalog charge temp, as well as EGT, oil temp (cooler outlet), turbo outlet temp, underbonnet temp, and the infocenter displays sump oil temp. So I have a good idea what is going on.

Please also see my reply to John, that explains some of the things I have found (either by measurement, or by reading up on the subject)

Please stop treating me like an idiot who has no idea, because it is simply not true.

I will be the first to admit I am learning about this, and I'm happy to take on board other peoples ideas, or change my own when presented with some evidence. I like to test things out, and if possible measure them, not accept them blindly.

Richard

[crispy-d]

AhHA! Welcome back Richard - glad to see the car's running! Still a few things to do to perfect it then?

Out of interest, anyone, would cooling the fuel itself, as it's delivered, be of any use? I know some cars here have injector rail coolers, but I've never seen one. Not sure how much difference that would make, but a cooler that actively reduces the temperature of the fuel rail...

Not sure if building a water jacket around the rail would be of any significant benefit, but I don't see why it wouldn't. Unless the cooling effect were to simply be too small to bother with. Or of course there's LPG with a higher octane rating - but then this will naturally run hotter anyway so will most likely cause more heat problems than less!

[rpruen]

AhHA! Welcome back Richard - glad to see the car's running! Still a few things to do to perfect it then?

I'm here for a bit, at least. It seems that I preffer working on cars in my free time than talking about it so much.

I think there are always things to perfect on my car it's sort of an ongoing project. On the whole it's not too bad, though there are a few bits to sort before I can start using the turbo to the full. At the moment there is plenty to do getting the idle and warmup maps sorted, although it's mostly done, just fine tweaking.

Out of interest, anyone, would cooling the fuel itself, as it's delivered, be of any use? I know some cars here have injector rail coolers, but I've never seen one. Not sure how much difference that would make, but a cooler that actively reduces the temperature of the fuel rail...

Not sure if building a water jacket around the rail would be of any significant benefit, but I don't see why it wouldn't. Unless the cooling effect were to simply be too small to bother with. Or of course there's LPG with a higher octane rating - but then this will naturally run hotter anyway so will most likely cause more heat problems than less!

Cooling the fuel isn't that much use from a performace point of view. Although it can help to stop vapor locks and the like when there is very low fuel pressure. Thats only usualy a problem with carbs. Most fuel systems recirculate the fuel back to the tank, and that helps to keep things cool.

LPG if injected as a liquid does cool the charge, it gets cold as it evaporates. I'm not sure how much heat it actualy soaks up, but it will have some sort of detectable effect. I'm not sure if LPG produces a hotter exhaust or not.

Richard

[Ettore Bugatti]

Didn't N2O have some cooling effects? (yeah, Im using NOS to keep the temperature down)

The tip of using a heater matrix is quite old, my dad used to collect to put on his cars as oil coolers.(but that's was 70/80's)

[rpruen]

Didn't N2O have some cooling effects? (yeah, Im using NOS to keep the temperature down)

Yes it does, but it also runs out all too quickly

The tip of using a heater matrix is quite old, my dad used to collect to put on his cars as oil coolers.(but that's was 70/80's)

But in theis case it's even easier. All you need to do is cut one water pipe and insert the heater matrix. No oil plumbing required.

Richard