My 3.3L Subie Conversion Thread, Got me some 914rubber stuff Options

[914forme]

Electric water pump I am using and Andrew is using is the only pump we have. It actually reduces the flow rate to optimize the engine ability to transfer the heat to the coolant. Yes sometimes things can move to fast or be to big for the combination of systems you have working out.

I see this argument a lot on the forums amd I can't for the life of me make sense of it from a heat transfer perspective, maybe someone can help me understand what im missing.

The radiator is in essence a heat sink with forced convective flow through the fins. For a given radiator set up the heat transferred from the radiator to the air depends on only two things, air velocity (and the associated Reynolds and prandtl numbers), and temperature differential between the radiator and the cooling air.

If you are pumping faster, the temperature drop across the radiator will be less, but the volume of coolant cooled will be greater, and since the radiator temperature will be increased on average, the heat transferred out of the system should be greater. This should result in more efficient cooling, and should continue to improve with increased flow with diminishing returns infinitely.

Can anyone poke any holes in this?

I'm with you. Was wondering the same thing. Could higher volume place some air in the system? Or turbidity that impedes flow? (IMG:style_emoticons/default/confused24.gif)

You are spot on in your engineering text book knowledge.

Issue is with the EG33 (maybe others)is that pump actually stops pumping as it creates suction cavitation. Once it cavities, it no longer pumps the coolant thus spiking temperatures in the engine. So I still think my design and understanding of the system is spot on.

Solutions increase inlet hose size 2" was the preferred size in testing. And remove the thermostat. My systems solves the cavitation issue by not being tied to engine RPM. And thus eliminates the need for a larger volume for the inlet hose. And with this system I am able to remove the thermostat as the pump controller will optimize the coolant movement based on temperature.

Other solutions, increase the pressure the system produces. Higher pressure cap. Change coolant to a none water based coolant might also work, but never tested that one.

It must be a know issue with Subaru pumps as killer B makes a modified water pump / thermostat housing to fix the issue. Or maybe to sell more product (IMG:style_emoticons/default/confused24.gif)

[ThePaintedMan]

My systems solves the cavitation issue by not being tied to engine RPM. And thus eliminates the need for a larger volume for the inlet hose. And with this system I am able to remove the thermostat as the pump controller will optimize the coolant movement based on temperature.

So Stephen, the question is, do you also still run the stock pump with a piggybacked electric pump? Or did you figure out a way to gut the stock pump? Since it is driven off the timing belt, that pulley must remain in the loop.

[914forme]

My systems solves the cavitation issue by not being tied to engine RPM. And thus eliminates the need for a larger volume for the inlet hose. And with this system I am able to remove the thermostat as the pump controller will optimize the coolant movement based on temperature.

So Stephen, the question is, do you also still run the stock pump with a piggybacked electric pump? Or did you figure out a way to gut the stock pump? Since it is driven off the timing belt, that pulley must remain in the loop.

Gut the pump, you just cut the impellers off the pump. I keep the pump face so the bearing still has a thrust to it, generalization of the process. We will see how well t works over the long haul.

[mgp4591]

My systems solves the cavitation issue by not being tied to engine RPM. And thus eliminates the need for a larger volume for the inlet hose. And with this system I am able to remove the thermostat as the pump controller will optimize the coolant movement based on temperature.

So Stephen, the question is, do you also still run the stock pump with a piggybacked electric pump? Or did you figure out a way to gut the stock pump? Since it is driven off the timing belt, that pulley must remain in the loop.

Gut the pump, you just cut the impellers off the pump. I keep the pump face so the bearing still has a thrust to it, generalization of the process. We will see how well t works over the long haul.

Okay...since the stock pump works well and just needs more fluid at higher engine speeds, doesn't the electric pump only come on when needed? So in case the pusher pump fails (I know electric pumps NEVER fail...) you can still have the stock pump to get you through...?
And sorry for the hijack - this is an interesting subject and inquiring minds want to know!
Your build is always on my mind and I've already copied a bunch of your ideas and methods - the car sounds right on the money!

[Chris914n6]

Electric water pump I am using and Andrew is using is the only pump we have. It actually reduces the flow rate to optimize the engine ability to transfer the heat to the coolant. Yes sometimes things can move to fast or be to big for the combination of systems you have working out.

I see this argument a lot on the forums amd I can't for the life of me make sense of it from a heat transfer perspective, maybe someone can help me understand what im missing.

The radiator is in essence a heat sink with forced convective flow through the fins. For a given radiator set up the heat transferred from the radiator to the air depends on only two things, air velocity (and the associated Reynolds and prandtl numbers), and temperature differential between the radiator and the cooling air.

If you are pumping faster, the temperature drop across the radiator will be less, but the volume of coolant cooled will be greater, and since the radiator temperature will be increased on average, the heat transferred out of the system should be greater. This should result in more efficient cooling, and should continue to improve with increased flow with diminishing returns infinitely.

Can anyone poke any holes in this?

Easily (IMG:style_emoticons/default/biggrin.gif)

If the engine is adding 50F and the radiator is only cooling 30F because of the high flow then you get heat creep.
The stock water pump should be designed to deliver the best cooling and consistent temp for the engine concerning flow volume.

I don't know the subie well enough to discuss captivation theories and I didn't read back too many pages so that's all I got to offer today (IMG:style_emoticons/default/smile.gif)

[914forme]

Okay...since the stock pump works well and just needs more fluid at higher engine speeds, doesn't the electric pump only come on when needed? So in case the pusher pump fails (I know electric pumps NEVER fail...) you can still have the stock pump to get you through...?
And sorry for the hijack - this is an interesting subject and inquiring minds want to know!
Your build is always on my mind and I've already copied a bunch of your ideas and methods - the car sounds right on the money!

It's not an airplane, if I started thinking like that, I would run it like a datacenter.

Twin EG33s (IMG:style_emoticons/default/happy11.gif) (IMG:style_emoticons/default/idea.gif)

[motoTrooper]

Hey Chris, I hope all is well in your corner of this mad world. So any updates? You mentioned talk of console fabrication... You've earned a rest from the posts with the last video but that was months ago! The autumn leaves are turning and make for lovely acceleration videos at golden hour.

[Chris H.]

Well I do have a few small updates. Haven't started on the interior yet. Been very busy lately but wanted to get the engine sorted before it was time to put it away.

Just wanted to go through the idle-affecting stuff one more time. First, I was able to get my intake to sit normally by slightly trimming the rubber snorkel part. I didn't document it but will post the pics from where I borrowed the idea. I DID NOT trim as much off as it shows in these pics. I cut about a mm beyond the stock thicker clamps. This person was converting a Vanagon, and apparently there is even less space there than a flipped-intake 914.

From The Samba site thread titled 3.3 Subaru SVX/Vanagon Syncro Conversion:



Reminder my trim was not that drastic. See below for my pics.

Then I also shaved a little off the lip of the throttle body so that the snorkel would slide further on to it. Again, not my photo.



Here's how it looks back on the car (finally my pics):





Fits very well and the clamps are holding it tightly. No doubt there was some air getting in before with it twisted up on the passenger side like it was. I also found that the throttle position sensor was probably bad. I'll post a video of how to check that later tonight. Very easy.

[motoTrooper]

Hey Chris, had a quick question - I just got a 2004 WRX trans for the build and I've been reading about the conversion to front wheel drive for mid-engine use. Is there any reason why after modding the center diff you couldn't just re-use the rear cover and block off the driveshaft hole? Or does a flat plate serve a purpose other than being lighter and 2.5" shorter? Thanks and happy holiday wishes!
-Christopher (IMG:style_emoticons/default/santa_smiley.gif)

[Chris H.]

Christopher,

Well, I'm not really an expert, but I suppose it's possible as long as all of the gears and stuff were removed from that end and you completely plugged the hole. It would require a lot more fluid.

Here's a pic of the removed parts:



In the case of the 914 that extra few inches is pretty important. The trans would be very close if not touching the rear apron with that piece on. It's so easy to make a cover from an aluminum piece I'd recommend you do that. Always nice to save some room and weight if you can.

[mgp4591]

Plus the center diff is worth some cash on Ebay, so why not cash in and save some weight in the process?

[rnellums]

I guess the question is why not use a block off plate? I just spec'd them out and am having a few cut if you want one.

[Chris H.]

^^^ Take Ross up this! I think you'll have more options for your cable mechanism with no tail on the trans too. Can't really visualize how it will fit in there.

[rnellums]

^^^ Take Ross up this! I think you'll have more options for your cable mechanism with no tail on the trans too. Can't really visualize how it will fit in there.

I'm coming up with a solution on that front too! (IMG:style_emoticons/default/smile.gif)

[motoTrooper]

Ok guys so (don't laugh too hard at me) but my question if more about aesthetics.
(IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/lol-2.gif)
Anyway, the styling on the Lancia in the rear gives it a very exposed undercarriage and the bottom half of the rearend of the Subaru transaxle will be fairly visible. Ala Ferrari 288GTO:
https://goo.gl/images/QCPvKl
The flat plate is all flatty and plain but for the bolts whereas the stock rear cover has cool contours and structure. But if the drive shaft opening is cut flush with the rest of the structure and plugged it's ~2.5" inches longer than the plate. When I get the assembly located in the engine bay I'll decide then which way I'm going but I was initially curious about possibilities. If I'm showing the world what's under my skirt I'd like it to be interesting at least!

Also, I'm way too close to the beginning of this stuff but thanks for the offer Ross! I miss Colorado still, winters and all.

[motoTrooper]

Here's a shot of the Scorpion for reference:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i1111.photobucket.com-19774-1481650057.1.jpg)

See the jacking point structure just left of center? The bottom of it is flush with the floor of the car and will be removed and replaced with Subie transaxle butt (centered between the suspension points though)

[914forme]

Subaru Gears



Bremar



Of course seeing these should give you the idea you can do hat ever you want. Machine a pattern in, weld some stuff on, or laser engrave a picture if you want. Sky is the limit here. Biggest issue is really space.

Of course the 288GTO is just (IMG:style_emoticons/default/wub.gif)

[BIGKAT_83]

Chris are these the ECU connecters at the engine side for a EG33?



Merry Christmas (IMG:style_emoticons/default/santa_smiley.gif)

[Chris H.]

Yes they are Bob! I see you found that ECU too (IMG:style_emoticons/default/biggrin.gif) . I'll send you something for all that. You can't give everything away! Really appreciate you digging it all up.

BTW all Bob might be selling his flared orange car. He's putting a 6 speed Boxster trans in it first but it'll be ready next year. It has a 383 in it that runs perfectly. I'm kind of a wimp in the passenger seat but that one is a real neck snapper even with the 901 in it. The interior is tan with a neat high bolstered drivers seat. He is re-doing the flares with steel ones and then will paint it. If you get to him beforehand you can choose your own color. If I had the room I would have (tried to at least) bought it a while ago. Just throwing it out there early for anyone looking for a V8 car.

[mgp4591]

Yes they are Bob! I see you found that ECU too (IMG:style_emoticons/default/biggrin.gif) . I'll send you something for all that. You can't give everything away! Really appreciate you digging it all up.

BTW all Bob might be selling his flared orange car. He's putting a 6 speed Boxster trans in it first but it'll be ready next year. It has a 383 in it that runs perfectly. I'm kind of a wimp in the passenger seat but that one is a real neck snapper even with the 901 in it. The interior is tan with a neat high bolstered drivers seat. He is re-doing the flares with steel ones and then will paint it. If you get to him beforehand you can choose your own color. If I had the room I would have (tried to at least) bought it a while ago. Just throwing it out there early for anyone looking for a V8 car.

I'll have to see that one next time I'm out... (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/rolleyes.gif)