Building a 10,000 rpm NA engine.

[oab_au]

Originally Posted by Dessertrunner

You Win Harvey,

before we do anything we will run the test your way to get a base line number. Bazza is sorting out the oil heater in his sump tanks as we do need it to be some sort of reaistic temp. I will see if I can rough up some thing to drive the pump electric motor. Not sure I want to screw with compressed air in a tank with oil.
Tony

OK I see the point there.
You could go lower on the pressure, a regulated 30psi will still give the info, that we can work out the higher pressure flow from there. The main thing is to have a 'constant flow at a constant pressure'.

Using heated oil is not necessary, as it will change the flow, as the metal mass cools it, as it goes through the engine, the flow won't be constant.

You have that little mill working overtime.

Harvey.

[Dessertrunner]

Originally Posted by oab_au

OK I see the point there.
You could go lower on the pressure, a regulated 30psi will still give the info, that we can work out the higher pressure flow from there. The main thing is to have a 'constant flow at a constant pressure'.

Using heated oil is not necessary, as it will change the flow, as the metal mass cools it, as it goes through the engine, the flow won't be constant.

You have that little mill working overtime.

Harvey.

Yes the mill is flat out,
I want to use the pump as well so I can check it does what Bill Dailey says. What flow at what revs etc. Simple to drive it electric.

I have to set up a engine to do more flow working on cooling as well so I will do the oil tests at the same time.

Tony

[Dessertrunner]

Harvey did you read the artical in Race Engine Tec page 18,
Its all about a Puma Parrallel Twin engine in a bit. I have just scaned it bit it looks pretty interesting.
This is a link to the engine so everyone can see what we are talking about.

http://www.mtceng.com/home/puma-engi...-press-release

this is the mag that has the artical

http://www.epi-eng.com/epi_general_i...technology.htm

Tony

[oab_au]

Originally Posted by Dessertrunner

Harvey did you read the artical in Race Engine Tec page 18,
Its all about a Puma Parrallel Twin engine in a bit. I have just scaned it bit it looks pretty interesting.
This is a link to the engine so everyone can see what we are talking about.

http://www.mtceng.com/home/puma-engi...-press-release

this is the mag that has the artical

http://www.epi-eng.com/epi_general_i...technology.htm

Tony

A great little 'Nitro gobbling' power plant.

I could see you milling one up on the mill.

The 1300cc version, is around the same as our cylinder, 75mm stroke. Didn't say what the boost was but a cylinder pressure of 900bar, was impressive.
Apart from the extreme strength of the engine, it was designed to breath, four valves all 42mm, 11mm lift 280* cams, at 110* centers. So the timing is
Inop. 30* clos 70* --- Exop 70* clos 30*.
So the tune was mild, but when you use a blower to force the air in, then substitute the air for Nitro methane, guess you don't need much tune.

Harvey.

Their earlier 4 cylinder engine had one inlet and two exhausts.

[Dessertrunner]

Its a confusing name, parrellel twin, from one of the photes it looks like it has twin exhausts as you suggested.
Tony

[oab_au]

Originally Posted by Dessertrunner

Its a confusing name, parrellel twin, from one of the photes it looks like it has twin exhausts as you suggested.
Tony

That one is a parallel twin, just like the Triumph/BSA parallel twins of old, that the Senior members would have 'vibrating memories' of.

The engine to look at is the Ford V6 turbo that RYE is building to replace the V8 for the Daytona 500. (August issue) Two versions, 3.5lt and 3.2lt. which are along the same lines as our development. It is restricted to 1.7bar boost, so they have developed the breathing to get the torque, adding the boost to that. They don't use high rpms, running the 5000 to 7000 rpm range.

Harvey.

[Dessertrunner]

Sorry to everyone with out access to this mag Race Engine Tech,

Harvey on page 26 top box of the August issue it says the rules limit the engine to 7,500 rpm. Also as I understand it we are talking about a turbo engine not NA so I am not sure why you think it best to run the engine at 7,500 rpm.
In the Jun/July issue it has a story about the development of a motor for the V8 super cars (Australian version of NASCAR). What's interesting is that the torque curve page 62 is flat from 5,800 to 7,500 rpm which is impressive and they have again rev limited the engine to 7,500 rpm due to the rules.

In every case the engine have been pulled back by rules not by the engine developer. I would like to understand why you want to us to pull the revs back or develop maxium power down lower. I want the motor revs to go higher if I could get it to run at 12,000 rpm I would do it. Untill the race rules pulled these guys back they were going as hard as they could to move the revs up to get more power with a NA engine.

I need to understand why you think its better to pull revs back, when I do the maths it just doesn't make sense a 3.3l engine will be lucky to get more torque then 350 nm, (please jump in if you think we can get a higher torque number)
If this torque is developed at 7,000rpm we will get 256kw
if the same torque is developed at 10,000rpm we get 366kw
if I develop the same torque at 12,000rpm we get 439kw.

I am happy for you to show me why I am on the wrong parth with higher revs, we need to be going higher not lower. This point has been buging me for a while so I would like to get some sort of understanding about were you thinking is. I accept that we will need to try to get some sort of flat torque curver to make it all work but that is a seperate issue. We don't need to start the project assuming that a flat torque curver is impossiable.

Please don't take it that I am having a go at you I am only trying to understand were you head is at.

Tony

[Dessertrunner]

Okay Pic time, here is the latest photos, Bazza got his crank machined so its ready for the new drive sprocket. I have to go away for 10 days but when I get back we should be able to finish it and install it on Bazza car for a test run.

[Dessertrunner]

New info,
As part of this project Bazza and I have recently been disussing the cooling system and the logic of the position of the thermostate. Tom a couple of years back was instant that it needed to go up the top of the engine to function correctly which I now agree with. As a result of my trip accross the Simpson Desert I felt that a 10,000 rpm engine will need further changes to the cooling system.
Yesterday I read a aritical on the V8 Super cars and they claim that the maxium performance of there engine is when it operates with coolant at 71c and the oil is at 110c, this agrees with what I saw in a Nissan GTR that engine operated at 75C.
For those that don't know my car runs coolant tempreture guages in outlet of the radiator and the back of both heads. On my recent trip I had the thermostate installed in the normal position on the water pump. I was concerned that in the early morning the engine would not warm up and damage to it would occur. What I found was that the range of temp in the head varied between 75C and 105C which is 30C variation. I had assumed up to this point that the 75C would occur when the radiator temp was low. This proved to be incorrect, the engine temp was effected by the load & revs the engine was doing not the radiator return temp.

So this doesn't make sense
Why did this occur?????
and how the hell will I get the engine to run at a consitant 71C when it can't run cold on a cold morning???

This got me thinking, whats going on------ so started to develop a excel spread sheet to try and explain this issue, its a sort of simulator. In the short time I have been working on it I can see that its possiable to overheat the engine even when the radiator is cold. In fact the colder the radiator the bigger the problem.
I plan to prove mathmaticialy that I can boil a SVX when the radiator is cold.

So what does this mean to the other guys, well given what I have learned you can all drag the old Supercharger out and dust off the cobwebs because I am sure that they will run correctly when we sort this issue out. I am happy to go into detail as to why they will now work as opposed to before.

Tony

[icingdeath88]

Originally Posted by Dessertrunner

I am happy to go into detail as to why they will now work as opposed to before.

Yes, please explain.

[Dessertrunner]

Okay I will explain, given that the model is not finished it maybe a bit more difficult to understand.
In simple terms if we ignore the fact that the pump was cavitiating and just for the minute deal with the temp of the coolant going throught the block.

Currently the temp of the coolant flowing into the engine throught the thermostate is based on the sum of the tempreture from the return pipes (small pipes into the side of the pump). The stat opens at 78c so as soon as two much cool water from the radiator comes throught it it will close and stop flow. In simple terms if the engine return coolant throught the small pipe is at 90c and the radiator return coolant is at 66C the state will just open (90 + 66)/2)=78. Now it doesn't matter what reves the engine is doing because half the coolant will come from the radiator and half from the engine. The key factor that determines the amount f coolant in the system is the quantity in the return pipes going into the side of the water pump.

THe amount of cooling aviable to the engine is the flow now aviable times the differencial in the 78 block inlet temp to 90 block outlet.

Why is this a issue to the SC well when you increase the power of the engine such as happened with the kit there is no change in the ability of the cooling sytem to deal with it. Harvey made the point years ago that the engines were doing bearings due to denonation, I agree.

In short engine runnig to hot, oil to hot, air being forced in is to hot means it all turns bad real quick.

Hope that explains it, it is real difficult to get your head around but if the thermosate is in the cooling system is uneffected by revs. Infact given what we know of cavitiaty higher revs mean bad news.

Tony

[SVXRide]

Tony,

Dug up this old figure of the coolant flow path (reflects the initial phase of what YT did with Dan's car). If I follow your explanation correctly, doesn't it make the case for having the thermostat moved to the return line into the radiator, as YT proposed?
Thanks!

okay, the site is killing me. The link to the pic is http://www.subaru-svx.net/photopost/...php?photo=1910



Bill

[Dessertrunner]

Bill you are 100% correct, with the thermostate opening and closing based on the actual coolant temp out of the block the amount of coolant in the system is unlimited. Also the opeation temp of the engine will be close to the 78c the design required.
Tony

[bazza]

Originally Posted by Dessertrunner

Currently the temp of the coolant flowing into the engine throught the thermostate is based on the sum of the tempreture from the return pipes (small pipes into the side of the pump). The stat opens at 78c so as soon as two much cool water from the radiator comes throught it it will close and stop flow. In simple terms if the engine return coolant throught the small pipe is at 90c and the radiator return coolant is at 66C the state will just open (90 + 66)/2)=78. Now it doesn't matter what reves the engine is doing because half the coolant will come from the radiator and half from the engine. The key factor that determines the amount f coolant in the system is the quantity in the return pipes going into the side of the water pump.

More analysis needs to be done on the thermostat because it doesn't open like a solenoid in a split second. It takes a while to open and close. Therefore it may be far less sensitive to cold radiator water - ie it opens, then by the time it's starting to close it might be trying to open then it's trying to close - end result is it will find a "mean" position which will be dependant on how hard the engine is working and ambient temps.

Also as I said, Subaru's and most other road cars are designed to run hot - far better fuel economy. During combustion fuel + air need to reach the temperature of combustion and a hot engine means less energy (fuel) is used in doing so. However the GTR R35 and V8 supercars are interested in power 1st... fuel economy... far less.

To make this simulator work we really need to understand what the pump is doing when radiator feed is closed. Due to lack of supply (from small return suction lines) it's most likely not pumping anywhere near it's capability. I see this all time playing with my pool pump setup. It can be blocked up somewhat, reducing flow quite a bit before cavitation kicks in.

Also the thermostat might open and provide 75% of the actual flow... it's just going to be very hard to get the simulation accurate IMO.

[Dessertrunner]

Originally Posted by bazza

Also the thermostat might open and provide 75% of the actual flow... it's just going to be very hard to get the simulation accurate IMO.

Its not possiable to get 75% of pump flow unless the radiator is above 78C, sorry to be the bear of bad news but the amount the stat lets through is directly related to the amount coming round the side pipes and its temp.

Agree with everthing else you said.
Tony