Building a 10,000 rpm NA engine. - Page 20

icingdeath88 · #**286** 09-10-2012, 02:51 PM

Quote:

Originally Posted by Dessertrunner

So a few of you have down loaded the cooling simulator, have I caused more confusion or does everyone think its totally wrong.
It would be good to get some feed back or discussion going so we can all agree if I am on the right track.
Tony

I am still pretty confused. Having trouble understanding the numbers you're arriving at in relation to the actual mechanical parts.

Dessertrunner · #**287** 09-10-2012, 03:39 PM

Okay the top row is relationship to the current position of the thermostate being in the front of the water pump.
In this example set the RPM to 3,000rpm, radiator at 78 engine at 90

- When you change the rpm the total litre per min that the engine CAN pump goes up this number is the sum of the Radiator lpm & Engine lpm, in this example its 75 radiator plus 25 engine. Giving a total possiable flow of 100 lpm.
- The 25lpm in the "Engine bypass pipe" assumes that the amount of coolant being sent back to the engine throught the small pipes. THsi amount does not change when the pump flow increase due to the fact that it has high pressure lost throught the pipes and that these pipes are taken off after the heads.

What tends to screw with our heads and is hard to come to terms with is that in the example if we look in the "Flow throught engine block" section its a 100 lpm and Kcal square is 1200. Now lower radiator number from 78c to 60. What you now see is that the flow drops to 42lpm and the Kcal down to 500.

This result sends our heads spinning because it doesn't make sense Clearly this is the issue with have with the thermostate on the water pump. It get feed with cold and hot water at the same time there for if the average temp of the twin liquids mixed that opens or closed the thermostate. Its not the temp of the return coolat from the block.

Hope that help start the discussion.
Tony

bazza · #**288** 09-10-2012, 07:31 PM

Subaru Tech Manual:
78-80'C starts to open and is full open at 91'C

9mm thermostat lift
35mm bore

Dessertrunner · #**289** 09-10-2012, 09:05 PM

My computer model had assumed that the thermostate opened fully above 78c. It made the formula's easier. Now Bazza what you show will only make the car worse interms of cooling with current thermostate position.
Tony

Tapani · #**290** 09-12-2012, 05:50 AM

Just a side note after reading the spec for this years 911 Carrera S:

3.8 litres
102.0mm x 77.5 bore x stroke
12.5:1 compression ratio
400hp @7400 rpm
325 lb-ft @ 5600 rpm
direct injection
Vario Cam Plus (timing and lift)
"Resonance intake manifold"

Hard to beat numbers. 116 Nm / litre specific peak torque and still 101 Nm / litre @ 7400 rpm (peak hp revs).

Close to BAT for a production engine of this size today.

Tapani

Dessertrunner · #**291** 09-13-2012, 08:26 PM

Tapani,
The point you make is good, if we could match the torque per litre rate on our engines and move it to 7,500 rpm we would get 270kw. Its a pretty good number.
Tony

Tapani · #**292** 09-13-2012, 09:22 PM

If you shoot for 100Nm/litre @ 7500 rpm you will loose the midrange to some extent. The power band will be narrow, like Harvey has pointed out. That is unless you go the Porsche way and change the concept and target for multiple resonance peaks by variying the basics of the breathing.

I think the SVX engine is well developed for being a 25 years old design as it is and further work towards the current Porsche characteristics needs Porsche resourses.

I am not trying to talk you out of what you are doing, just ramblings from an old man

T

Dessertrunner · #**293** 09-14-2012, 04:38 AM

Tapani,
I agree with every thing you said about trying to match Porsche with all the money their got. It doesn't matter what we do we won't match them, that doesn't mean that we can't improve a 20 year old design and get more power.
There is one big thing in my favour and that is I have no backgroud in engine design or development & I am dyslexic. you might not know but the last point is a type of autism and that means I find soluations to probelms that other never found. I also go into the project saying everything is up for question and nothing can be assumed untill I have proven it to myself.

In the end who cares if I fail it beats wasting time sitting in a pub getting drunk and hell we are all having a great time on this project.
Have a great day.
Tony

Tapani · #**294** 09-14-2012, 07:00 AM

Sounds good :-) !

All the best and good luck, this is very interesting to follow (and occationally comment

) !

Kind regards,

Tapani

SVXRide · #**295** 09-14-2012, 01:03 PM

"In the end who cares if I fail it beats wasting time sitting in a pub getting drunk and hell we are all having a great time on this project." - Tony

I'm going to get this engraved and put up in my garage!!

Bill

icingdeath88 · #**296** 09-14-2012, 03:44 PM

Quote:

Originally Posted by Dessertrunner

In the end who cares if I fail it beats wasting time sitting in a pub getting drunk and hell we are all having a great time on this project.
Have a great day.

You're the man, Tony.

aust92pearl · #**297** 09-14-2012, 06:30 PM

Quote:

Originally Posted by icingdeath88

You're the man, Tony.

+1

23456789

Dessertrunner · #**298** 09-15-2012, 02:57 AM

Thanks guy.

Just ordered some parts to complete the dry sump:-
- Needed a reamer for the drive sprocket for the pump. I need the timing pully and the new drive pully to be in the same line on the crank so I need to ream the alum pully so they will come off easly when we need to remove them.
- Ordered a sandwitch block to fit between the oil filter and the engine block. The aim is to be able to jump into the exiting plumbing of the oil lines. I think for Bazza turbo unit it will be okay this way. When it comes to the 10k unit I will have to build a bigger supply block or go a different way. That will be determined by the oil flow testing.
- Got a tool coming that will make it easier to install the stainless hose into the fittings.

So when all this is done I will hand the unit over to Bazza and he can install it on his car.

Next challange is the cooling pipe on the top of the block. First step will be to get Bazza's sorted so he can race in Oct. I think that the current plan is to use the existing top pipe and increase the size of the cross over pipe between both banks. Then block off the current pipe back at the main header then, install a new pipe that comes from the new inlarged centre pipe. As regards the thermostate it can be built into the pipe or install one on each bank. We have increased its size from 56 mm to 63mm. The unit chose Tridon TT221 (bypass type) or a TT222, the first is aviable in 71, 77 & 82C. Given what we have read in recent articals we need to be able to get better control of the temp to enable a better tune. Each unit quoted takes 12C to fully open, so my guess is that we will be running 71C because it will give 83C fully open.

The cooling for the 10k engine will be tested this way,
Mount the water pump on its own just water in and water out all in a clear plastic pipe. Install electric motor drive and test the pump up to 12,000rpm. It could be that we need to have some sort of restriction of about 30 psi on the up side to simulate the engine block ristance. What we need to do is find out if we have to move the pump if it won't handle the revs. Given Harvey's experiance we need to confirm if this is a problem or not.

Next step will be to install the radiator and see if there are any flow issue sucking from the bottom of the radiator. If there is they need to be corrected with a redsign. What I have mentioned in the past is that we have a new radiator mod that we are going to try on the PWR if it works then you guys in the USA will be able to just go buy the mooded radiator from PWR in the USA. This mod involves the radiator cap being on a pipe that connects to the bottom tank and the current top tank cap is removed. We are trying to get our head around the clearance under the bonnet. There will be a small pipe about 3mm ID that will join the top tank to the cap pipe. This allows the air to escape from the top of the radiator when filling. I have a bit of a plan that I may post when I get a chance. At this point the electirc motor speed controller should tell us the KW consumed.

When all that is sorted we need to reinstall the pump on the block and start testing with the engine block load on the pump. Data we are chasing is KW of power needed, again it needs be at 12k. Pressure with in the respective sections of the cooling system. I expect that we will need to make major changes to reduce the load/pressure and get the KW consumed reduced to a acceptiable level.

Okay one wild idea we have is to contact Gates and find out what load the current timing belt will stand. Then see what stronger belts are aviable but a bit longer then the current belt. Then we will make a steel sleave that slips over the top of the current pump pully and that will reduce the speed of the pump and offer a second advantage in allowing a stronger belt to be used for the engine. At this point we will need to perfect the top pipe design so as it handles the hi flow.

Any way that is were we are heading with this project as I see it it all about oil and cooling when they are fixed we can move on to bigger issues. Equally people who want to improve there cooling can do so with the info we provide.

Have a great day all.

Just had a funny though I wonder what Trevor would be saying about this thread.

Tony

icingdeath88 · #**299** 09-15-2012, 12:48 PM

I have a question, slightly off topic maybe. I was looking at the engine I just got back from the machine shop which is currently assembled to the longblock. On each side of the block, there are 3 outlets for coolant - the one bit one, and two smaller ones. What are the smaller ones for? They are so tiny I can't imagine they flow enough water to make any actual difference in cooling.

Also, am I correct in thinking that the water flows from the water pump out to both sides, first cooling the bottom of the cylinders, then into the heads, and then back to cool the topsides of the cylinders, then up and out to the crossover pipe?

So in the original setup, the thermostat is in front of the water pump, restricting the flow from the radiator until it's warmed up enough to open. During this time, the water pump takes in coolant from a smaller pipe connected to the crossover pipe. This allows the coolant to warm up to operating temp before the radiator starts to cool it.

And what you're proposing is to change this so that the thermostat (or two) is in the crossover pipe? How will you recirculate the water through the water pump before it's warmed up?

Also, instead of having the two sides of the crossover pipe join together, why not just have two separate inlets to the radiator? Seems to me it would be easier/cleaner to weld on a new inlet to the top tank, than to make a Y-pipe that both fits under the intake manifold and has a big enough cross-section to flow the desired amount of water. Basically, just make one pipe that flows water from the right side of the engine to the radiator in roughly the stock location, and another that flows water from the left side of the engine through where the A/C compressor would normally sit, and then to the radiator. You could have your separate T-stats in those pipes as well.

What do you think?

Dessertrunner · #**300** 09-15-2012, 05:39 PM

Quote:

I have a question, slightly off topic maybe. I was looking at the engine I just got back from the machine shop which is currently assembled to the longblock. On each side of the block, there are 3 outlets for coolant - the one bit one, and two smaller ones. What are the smaller ones for? They are so tiny I can't imagine they flow enough water to make any actual difference in cooling

The small holes in the block are to stop air locks.

Quote:

Also, am I correct in thinking that the water flows from the water pump out to both sides, first cooling the bottom of the cylinders, then into the heads, and then back to cool the topsides of the cylinders, then up and out to the crossover pipe?

So in the original setup, the thermostat is in front of the water pump, restricting the flow from the radiator until it's warmed up enough to open. During this time, the water pump takes in coolant from a smaller pipe connected to the crossover pipe. This allows the coolant to warm up to operating temp before the radiator starts to cool it.

Yes

Quote:

And what you're proposing is to change this so that the thermostat (or two) is in the crossover pipe? How will you recirculate the water through the water pump before it's warmed up?

The small pump return pipes are before the thermostate, and not effected unless we decide to ues the bypass type thermostate so that when the thermostate is fully open it shuts the bypass.

Quote:

Also, instead of having the two sides of the crossover pipe join together, why not just have two separate inlets to the radiator? Seems to me it would be easier/cleaner to weld on a new inlet to the top tank, than to make a Y-pipe that both fits under the intake manifold and has a big enough cross-section to flow the desired amount of water. Basically, just make one pipe that flows water from the right side of the engine to the radiator in roughly the stock location, and another that flows water from the left side of the engine through where the A/C compressor would normally sit, and then to the radiator. You could have your separate T-stats in those pipes as well.

yes I agree this would be a better option for the top pipe to have two. the only down side is its a bit complex to get it all in and figured out with the thermostates. Two pipe going into the radiator would be better as well. If it can be done with a single pipe it will be far neater and the same system will be usable on the road cars that run AC units.

Thanks for the input.