UK Lakester build G/GL

[Rex Schimmer]

John,
One of the things I suggest for cooling systems is to use a 3 way thermostat. I suggest using the mid 80s BMW 320 I unit. I happen to have one in my hand right now and the MFG/PN is: Vernet V2020-71. The advantage of the 3 way configuration is that as the engine is warming up the water in the engine is constantly circulated through the engine until the thermostat temp is reached and then coolant from the cooling tank is allowed to flow to the engine. As opposed to a normal thermostat that simple restricts or stops any water from circulating through the engine until it opens at it's rated temp. Many (most?) of the standard 2 way thermostats have a small hole in them to allow some circulation until they open. I am a big supporter of using a thermostat as they give much better engine temp control than no thermostat or some type of orifice.

Rex

[kiwi belly tank]

I don't believe I've ever seen a production engine equipped with a mechanical pump that didn't have a bypass built into the system allowing coolant to circulate prior the thermostat opening allowing valve seat cooling during warm up & preventing pump cavitation. A thermostat (restriction) in the system allows the pump to create block pressure, not to be confused with cooling system pressure, to help the heat transfer from the engine to the fluid. This is why in many situations you will see an engine run hotter without a thermostat or restriction. Most heavy engines actually have two thermostats at different temps to cope with the extreme range of conditions. I have truckers ask me to remove the thermostats because they're running hot but that only makes the problem worse. It's simple enough to hook up a pressure gauge to the engine to check if the pump is making block pressure.
I believe the automotive three way thermostat is used in conjunction with a twin core radiator where it uses one section for cold climates & both for hot. The double pass radiator is a different animal again.
  Sid.   

[ggl205]

Hopefully you have been reading a lot of other build diaries and ingesting all the cooling information out there.  We never used a thermostat until we ran a Busa motor and in a rush, didn't take it out... our cooling improved dramatically... I strongly recommend running one.  In a lakester the best you can hope for is water in a tank that stays close to ambient before you run.  We warm up until the water out hose is hot and then let the motor heat soak. We have a 5 gallon water tank... so far it has been enough but we are close to needing more.... and yes, I think I'm leaving room for a couple more gallons in the future...

Or maybe a radiator in your 5 gallon tank? We ran a pressurized ten gallon tank in the first lakester and always worried about over pressurizing that tank. This restricted pressure to 7 psi and would have liked to up that pressure to around 15 psi. This was accomplished in the new car with a radiator in the tank.

John

[Lemming Motors]

Many thanks for the thoughts and explanations over the last few days. I have been searching the forum for other related threads and noodling - which doesnt get anything built but its surprising how much noodling can be achieved doing 5 hours canoe training each weekend. I get that time back aftert he race at Easter.

The Honda engine has coolant hoses and bypasses in all directions and that has been part of the 'joy' trying to work out the flow. The water pump has several takeoff points and the one to the rad incorporates the stat. I have now figured out that it has something that runs over to the oil filter - a by pass that flows back into (or out of) the block next to the oil filter. I dont know if that is a permanent circulation or just part of warm up to bring the oil to engine temp, or possibly a really crude cooler as engine oil runs hotter than engine water (I think?); I want to add an oil cooler rad - if nothing else to increase the volume and a bit of passive cooling.

The other rad connection (back of the inlet manifold) has a pipe that runs to the pump as well and I am assuming that is the 'block' circulation during warm up until the stat opens.

I am of a mind to remove the mechanical water pump and control the flow through the rad / tank solution with an engine temp sensor controller combo whilst retaining the stat as well. That idea might need a smaller pump to effect the cold start circulation as, without the mechanical pump that will not flow. Maybe a bypass pump that has a reverse relay on a temp sender - turn off at 80oC (or whatever the stat opening temp is) and let the main pump circulation kick in.

[Stainless1]

Keep it simple.... you don't know it yet but you are running out of room to put stuff 
You are not running 500 miles.... well maybe over 10 years.... oil cooler not necessary
 

[Lemming Motors]

Keep it simple.... you don't know it yet but you are running out of room to put stuff

Thank you. Your timing is perfect; this weekend I started to properly worry about room. It works beautifully in my head and sketched out but with everything bespoke some things just bite you when you look the other way for just a moment. Up to know I have been lalala about some of the reality rear of the firewall. I just mocked up some rearward chassis rails and ....... one looks suspiciously like it will run straight through the stock oil filter which will be messy when I fire her up so if I can lose the (proposed) sandwich plate for the oil cooler and only have the one for a remote oil filter takeoff you may have just solved two problems in one message which is most opportune. 

[tauruck]

Running out of room?.
I don't know how the Belly Tank guys do it!!!!.
Lakester too!!!!.

You first look at your chassis and think "EASY".
My liner is near 40' and I am clearly out of space.
Packaging is the toughest part and like I was taught, Tack before, weld later.

[ronnieroadster]

John when I began building my race car using the drop tank as a body I realized I was now joining an elite group of builders who discovered the LESS is MORE theory.  That being LESS space available and lots MORE stuff to add. Oh the fun of it all plus many nights of lost sleep thinking where oh where to put everything.   

[tauruck]

John when I began building my race car using the drop tank as a body I realized I was now joining an elite group of builders who discovered the LESS is MORE theory.  That being LESS space available and lots MORE stuff to add. Oh the fun of it all plus many nights of lost sleep thinking where oh where to put everything.   

And when you do sleep, Nightmares!!!!.

[kiwi belly tank]

With engine electronics you'll need an alternator so include the stock water pump if you can, cheap & simple.
  Sid.

[Lemming Motors]

Hi Sid
My thinking with the electric water pump and a controller was that the water could continue to circulate after the engine was shut down. I am assuming that several minutes at wide open throttle is a lot of heat sink and it could take some time for the circulating water to catch up with it.

Now that the water pump pulley is redundant (on paper at earlky stage), and there is potentialy two or three hp gained from the exercise, the next question would be; do you need an alternator and could you therefore save another one or two hp (data from the interweb so its probably dodgy). Each engine situation will differ but I guess you could reasonably say no belts and pulleys is worth a few ponies on a n/a 2 litre four cylinder.

The engine electrical requirements become a consideration - if I split them into three categories;
1. ECU / spark / injectors / sensors 2. Water and fuel pumps and 3. starting
then I would reasonably assume (and that is the trouble - for assume substitute the word guess) that;

1. could easily be dealt with with a moderate sized battery fully charged - I have no idea how much an ECU would draw over say 5 minutes for 4 injectors and 4 coils,
2. will require more amp minutes so a larger / second battery, and
3. from an umbilical off the push vehicle (or one of those booster packs the car dealers use) cross wired to battery 2. in case of a stall.

All this assumes two batteries will fit and an easily accessbible takeoff point for charging; solar would be readily available with a gennie / battery charger if quick turnaround is required.

The most obvious counter arguement is complication and the need for charging is a pain so a secondary water pump to support engine circulation after shut down using the primary water pump and alternator is much simpler.

Counter arguements (or support for the total loss electrics approach) gratefuly received before I commit to engine water pump surgery.

John

[RidgeRunner]

     No expert here, to which anybody who has seen my pit performances can attest   That said, here's my 2 cents:

     Quick shut downs on engines that have been running full speed under load can lead to internal engine hot spots potentially leading to longer term issues.  Metal, especially aluminum, likes to move with temperature changes and doesn't always expand or contract at the same rate in all places at once or always return to the same exact dimensions when the cycle(s) is(are) completed.  One of the reasons we put an electric water pump on my buddy's lakester was for a more gradual cool down to help prevent that just in case.

      Electronics, especially ECU's and injectors, like a constant full voltage for efficient operation.  I know some seem to sneak by with constant loss systems but we run an alternator, feel the small loss in driving HP is well worth the increased efficiency in component operation which also leads to easier and more consistent system calibration and tuning.

                   Ed

[Stainless1]

I would keep it as simple as possible...  If you want water circulation after shutdown then you will need an electric pump... we do not do a "hot chop shutdown" any more... we used to to make plug reading viable, but that came with a lot of other problems.  The very small valve stems used on 4 valve engines tend to wilt a little making compression and leak down checks fail... yes they straighten when they warm up so the failures move from cylinder to cylinder.  We let the motor idle until the car rolls to a stop.  Keep the water pump.

Total loss electric... we used to do that too... but a lot of ECUs require a minimum of 12v to operate.  Making strong spark at sustained high RPMs uses more power than you think.  Keep the alternator.
My current ECU keeps track of voltage in... the Hayabusa alternator does not keep up... I think the algorithm in the regulator turns output down at higher RPM... something I will be investigating.  But back to you... 2 large batteries take up a lot of room... I already mentioned you don't have a much of that as you think a 20 ft car would.  Start looking at the volume you need for systems....
Don't overly complicate your already complicated endeavor 

[manta22]

Stainless;

I've wondered about this for a while... a total loss electric system usually loses voltage as current is drained from the battery but that doesn't have to happen. If a buck/boost regulator is inserted into the line from the battery it will maintain 12V output until the battery is totally exhausted. In fact, you could adjust its output to be 12V, 14V, 16V, or whatever you wanted. Has anyone ever used one?

Regards, Neil  Tucson, AZ

[Lemming Motors]

Thanks guys, as always I am enjoying the discussion - its always educational. I think driving the alternator off the propshaft is quite common on race cars - it therefore runs at lower revs so it continues to produce an output - doesnt work sitting idling on the start line though.....

To be hoenst, at this stage, I can probably house an extra battery easier (add length) than I can fit the alternator (add width) but its early days.

I am starting to wonder if 40' Liners are more about packaging than aero (which was my naive observer assumption) .....