Building a 10,000 rpm NA engine.

[Dessertrunner]

New drafft radiator design,
Still have a few tiding up issues to sort out such as fans and overflow lines but its looking good.
- Okay so why is this radiator different,
- Its overflow pipe and radiator cap are connected to the bottom tank not the top.
- To fill you remove the bung and once full you keep the bug closed.
- If you look closly in the bottom of the radiator cap bug you will see a small 3mm hole into the top on the top radiator tank. This is to remove air that may build up over time.

The reason the cap is connected to the bottom tank is that during hi revs the cap overflow pipe is at vacum which means the radiator sucks coolent in to the system. If it was connected to the top tank it would want to blow coolant out and as the radiator temp rose add to this back pressure of the top tank and the coolant ends up in the overflow tank, The higher the revs the more the problem.

Remember the pdf is 3d so you can click on it and spin it around to look at correctly.

See attached Pdf.

[Dessertrunner]

Second part of the puzzle,
We are using a Tridon TT2029 and Gasket TTG11 as this unit gives us far more temp options. Bazza pointed out to me that it just wasn't going to happen with the other one not low enough temp options. Also this thermostat offers a bypass.
Okay I have figured a way of mounting the unit. This will be sandwich into the cross pipe. If you want single top pipe mount one in the current pipe side. If you want 2 top pipes then mount the same thing on the other side. Design also takes advantage of the bypass ability so it turns the heater off when the engine needs more cooling.

Open to discussions and question. I would also like people to challange my ideas as they may not be right or perfect and with good sensiable debate we could improve the design.

Tony

[bazza]

The radiator is good mate. To optimise I'd change the design to a triangle at the base with a straight outlet opposite the pump inlet. This removes the requirement for the bend and would give a little nicer flow across the radiator.

Will have to get a better understand about the thermostat as I'm not sure where you want to put it? Will this be under the manifold on the cross over pipe so both heads feed this one pipe?

[SVXRide]

Tony,

So if we want to stay with a single pipe at the top of the engine then we'd mount the thermostat housing the same way YT did with Dan's car?

Nice .pdfs!

Bill

[bazza]

Originally Posted by SVXRide

Tony,

So if we want to stay with a single pipe at the top of the engine then we'd mount the thermostat housing the same way YT did with Dan's car?

Nice .pdfs!

Bill

Got a pic of the thermostat housing on Dan's car?

[bazza]

Originally Posted by Dessertrunner

New drafft radiator design,
Still have a few tiding up issues to sort out such as fans and overflow lines but its looking good.
- Okay so why is this radiator different,
- Its overflow pipe and radiator cap are connected to the bottom tank not the top.
- To fill you remove the bung and once full you keep the bug closed.
- If you look closly in the bottom of the radiator cap bug you will see a small 3mm hole into the top on the top radiator tank. This is to remove air that may build up over time.

The reason the cap is connected to the bottom tank is that during hi revs the cap overflow pipe is at vacum which means the radiator sucks coolent in to the system. If it was connected to the top tank it would want to blow coolant out and as the radiator temp rose add to this back pressure of the top tank and the coolant ends up in the overflow tank, The higher the revs the more the problem.

Remember the pdf is 3d so you can click on it and spin it around to look at correctly.

See attached Pdf.

Been thinking about this all avro - are you sure about the cap location? Will it ever see enough pressure to crack in that location? The sole purpose of the cap is to ensure the pressure doesn't get to high as the result of that is hoses blowing off and splitting.

This is what STI did back in the 2002-2005 added a 2nd cap. One cap is on the header tank which has a suction point to the pump. The other point is the top of the radiator. Notice a basic clamp is used on the radiator inlet - these cars dead stock can go and race all day long with decent results, fairly bullet proof as an example of the system working.

[bazza]

Bit more, was researching the Mitsubishi 4G63 engine, far better pump / thermostat design. Pump feeds engine. Thermostat controls head exit temps (is located at other end). However cap on the radiator top. One of these at Superlap WTAC 2012 here in Sydney ran > 1000 odd bhp with only 2.2L, who said peak power was only good for drags ROFL, won the event and clocked a lap time 5 seconds faster than the V8 supercar lap record haha. ( http://www.worldtimeattack.com/index...om-down-under/ )



"NEMO's" 1000 bhp thermostat design, for time attack:


Nemo runs a header tank at back of engine bay, interesting:

http://www.speedhunters.com/2012/02/..._project_nemo/

[Dessertrunner]

Hi all,
Bazza I see the 2 pipes coming from the cap on the STI but I don't understand what is going on so I can't comment as to what they are up to. What some of the people do such as MTR do is put a surge/air tank or what ever they want to call it, but as Brett from MTR told me its just a Band-Aid measure around the problem. At 10k it isn't going to work. With the Evo I will have to try to figure what they have done. Thats real interesting about the EVO.
On the bottom pipe, the challanges are you do have to go left then right into the bottom of the radiator aiming to be near the centre as possiable, when we come from the side we have flow issues. In addiation I have a tappered feed to the pump so there is no sudden coolant flow increase other wise the coolant will airate. Having said all that I accept there maybe a better design but not having the car here its a bit hard. I will play with it when I get home. As to radiator cap its either do it this way or we have to go to cross flow radiator which is not that easy on our road cars. It might sound stupid but I want some of what we develop to be able to apply to be good for road cars.

Top pipe, I had to go catch a boat out the the reef before (tough life, I am on the coast) so I didn't get to explain correctly. So here we go:-
We have chosen a high flow thermostat. What I am to do is were the pipe crosses from one bank to the other cut away the top of the cross over pipe on the side the outlet pipe currently is then weld in the the housing and pipe I designed. I am hoping it will clear under the intake manifold with a bit of final work. When I get home I will start fabricating to make it work.

Will be home in 48 hours then I can post photos of the way I think the top pipe may work.

Tony

[bazza]

As to radiator cap its either do it this way or we have to go to cross flow radiator which is not that easy on our road cars. It might sound stupid but I want some of what we develop to be able to apply to be good for road cars.

This I don't agree with. That HKS EVO was huge power - ran a downflow radiator - same as yours. Both Nemo and HKS had the coolant cap a long way from the radiator via a header tank - nowhere near the suction side. It also goes against the "pressure" issue which I mentioned above. Although test away, happy to be proven wrong as always

To be honest, SVX road cars just need decent thermo fans and the thermostat cover size upgraded - secondary for track work maybe the cross over pipe and thermostat moved etc. Back to the fans, the old SVX fans just like any other Subaru of that period (up until they went a 100% plastic surround) are absolute rubbish compared to the new ones. I recall my old 1992 RS Liberty with 50mm radiator (cross flow radiator) overheated in traffic everynow and then. Same engine transplanted into the 02 STI (30mm downflow radiator) never overheated even in 48'C temps back in 08/09 - both ran front mount intercooler in front of aircon condenser. Only difference was the thermofans really and you could feel it if you stood behind the car when they were on - they're like a hurricane.

Top pipe, I had to go catch a boat out the the reef before (tough life, I am on the coast) so I didn't get to explain correctly. So here we go:-
We have chosen a high flow thermostat. What I am to do is were the pipe crosses from one bank to the other cut away the top of the cross over pipe on the side the outlet pipe currently is then weld in the the housing and pipe I designed. I am hoping it will clear under the intake manifold with a bit of final work. When I get home I will start fabricating to make it work.

Will be home in 48 hours then I can post photos of the way I think the top pipe may work.

Tony

I like the top pipe, think it will work very well.

[Dessertrunner]

To be honest, SVX road cars just need decent thermo fans and the thermostat cover size upgraded - secondary for track work maybe the cross over pipe and thermostat moved etc. Back to the fans, the old SVX fans just like any other Subaru of that period (up until they went a 100% plastic surround) are absolute rubbish compared to the new ones. I recall my old 1992 RS Liberty with 50mm radiator (cross flow radiator) overheated in traffic everynow and then. Same engine transplanted into the 02 STI (30mm downflow radiator) never overheated even in 48'C temps back in 08/09 - both ran front mount intercooler in front of aircon condenser. Only difference was the thermofans really and you could feel it if you stood behind the car when they were on - they're like a hurricane.

I suggest you would best have a look at the way and size of the SVX radiator before you pass comment. Current SVX engine run at 95C on a hot day, rev them up and all the coolant blows out the overflow pipe. The fans on there are good its other issues such as the AC block the total front area of the radiator.
Tony

[bazza]

Originally Posted by Dessertrunner

I suggest you would best have a look at the way and size of the SVX radiator before you pass comment. Current SVX engine run at

95C on a hot day, rev them up and all the coolant blows out the overflow pipe. The fans on there are good its other issues such as the AC block the total

front area of the radiator.
Tony

You've already stated "Below 3k the water was clear, the faster you went the worst it got and at 6k you could have had a milk shake there was so much air" so we upgrade thermostat cover and most of the issues go away. Or are you saying the coolant blows out the overflow pipe with the upgraded thermostat cover? Mine didn't do that after the upgrade and I don't think Matt's did either, maybe I'm missing something here?

Now, the SVX radiator design is near identical to the 02-05 STI radiator and the STI stock radiator and design has been track proven to 8000 rpm / 450 odd bhp and peak hour traffic. What differences do you see that I'm not? A modded STI usually runs a big condenser and then a front mount intercooler in front of that - so airflow is non existent at low kph - thermo fans doing all the work and as I said in traffic no issues. However with the earlier fans - every so often the fans would be 100% yet the engine would overheat after a while. I put it down to just not enough airflow and to much current draw. I once tested this using a hose on the radiator and watched the temps drop after they were not going down with the old fans on.

STI radiator setup



SVX radiator setup



Test the fans for flow and current draw - then test some 02 STI + fans... I wager you'd be shocked - the later model fans are far better.

Recall the assumptions made about the cooling issue which lasted two years... http://www.subaru-svx.net/forum/showthread.php?t=51702

This is why the stock fans shouldn't be assumed to be good. From what I've experienced all early Subaru fans are rubbish. The problem is then compounded for street driving if you're running a thicker than stock radiator - the thermo fans probably aren't good enough to suck air through them and the condenser (and then FMIC in some cases) - so in the end, your pushing **** up hill so to speak, drawing a lot of current and after a while you get past the point of no return where temps just keep climbing until you can get airflow through the system. In the desert the issue would be even worse - sand, dust and bugs in the air con condenser, minimal airflow, very low kph and rpm, big thick radiator. To solve I'd increase the radiator area, decrease the thickness, install some modern low current, high flow fans.

SVX 4 blade design:




RS / WRX 4 blade design:



02STI+ 7 blade design - lighter blades, improved motor:



Further the radiator and cap design and location is on top of the radiator - pressure side on the majority of cars I've researched, including the new R35's. I cannot find one single car with the cap on the suction side.

GTR's.

1000+ hp GTR - note where radiator cap is - R35, note the overflow from the first cap has another cap on it.



1000+ hp GTR - cap on radiator



1000+ hp GTR - R35 - cap in stock position as per the above up top R35, time attack racecar. Close to a million spent IIRC!!

[Tapani]

Originally Posted by bazza

You've already stated "Below 3k the water was clear, the faster you went the worst it got and at 6k you could have had a milk shake there was so much air" so we upgrade thermostat cover and most of the issues go away. Or are you saying the coolant blows out the overflow pipe with the upgraded thermostat cover? Mine didn't do that after the upgrade and I don't think Matt's did either, maybe I'm missing something here?

What have I missed?

My car spat app a pint of coolant on the track days in Sweden a few weeks ago.... the engine temp was ok for most of the time, but did go quite high after one session. It wouldn't get any lower w/o actually driving the car slowly around the area. At this time the (JDM) tranny also went into "a high temp" mode and it found TCC locking even in third ... no warning light, though.

Can you guys point me to the upgraded thermostate housing, please.

Cheers,

Tapani

[bazza]

Originally Posted by Tapani

What have I missed?

My car spat app a pint of coolant on the track days in Sweden a few weeks ago.... the engine temp was ok for most of the time, but did go quite high after one session. It wouldn't get any lower w/o actually driving the car slowly around the area. At this time the (JDM) tranny also went into "a high temp" mode and it found TCC locking even in third ... no warning light, though.

Can you guys point me to the upgraded thermostate housing, please.

Cheers,

Tapani

Tony researched (for about a year) and found that there was major cavitation on the pump due to a restrictive thermostat housing.

Upgrading it to about 2" (50mm) solves the issue which I did after a chat with Tony about a year ago, I never saw the issue but I was proactive and ensured that it would never occur. To upgrade all I did was increase radiator bottom outlet to 46mm ID (ebay Ford F350 radiator) and have a local fabrication shop make a new thermostat cover which was 2" OD.

Recently I did around 65 laps and the water temps were very happy all day, think 92'C was max temp. Revving to 7000 rpm with GT35R turbo etc.

The thread is here - it's over 2 years with a lot of theories.

http://www.subaru-svx.net/forum/show...=51702&page=33

It's still unknown why STI's (with EJ2X's engines) don't have the issue (same size pump) and why the thermostat is only 34mm OD yet the thermostat cover was the thing that solved it upgrading to 50 mm ID.

However what we know now is the thermostat cover solves the issue. Tony and I are now investigating taking the engines to the next level and solving the cross over restriction and the thermostat location.

[bazza]

Found some STI clusters, you might need a new tacho given the plans :P

From JDM Spec GDB C's or late 90's GC8 STI RA's AFAIK.

[Dessertrunner]

The current SVX does 9k I will see if the neddle will read 10k other wise I will have to do as you suggest.
Tony