Apollo Racer Build Thread, Numeric 981 Shifter Upgrade Options

[rnellums]

I had a bit of an epiphany tonight. I'm not sure how important/unimportant it may be, but its at least something to thing about.

I have been thinking for a while about removing/bypassing the heater core tubes that are still on my engine as I don't have a heater core.

Now, the first issue with removing the tubes entirely is that they are critical to proper thermostat operation (as they provide an additional return path for coolant until the thermostat opens and allows coolant to move through the radiator).

Since the tubes seem a necessary evil I, and many others, bypass the heater core using a 5/8" hose loop.

Here's the issue: the radiator and heater core act like resistors in parallel in an electric system, and the water pump is the applied voltage. You always have the same voltage drop across the resistors, but the current flowing through each resistor varies based on the resistance of each path.

By eliminating the heater core and replacing it with a large-diameter bypass you are creating a path with much less resistance to flow than was originally intended by Subaru, which diverts flow from the radiator and instead cycles it back into the engine.

I can calculate what the flow resistance of the bypass is, but the hard thing is that I don't have a way to quantify what the flow resistance of the heater core and radiator are.

Ideally I would size the coolant bypass to a flow resistance that provides the same coolant flow rates as stock.

[mgp4591]

Would running a T from the heater inlet and outlet into the main coolant hoses respectively balance out the system effectively enough to solve this? It may not provide the "resistance" you may calculate but it could provide enough overall balance to negate your issues...

[914forme]

You could add a heater core out back, if you wanted to duplicate flow and resistance. That being said it seems that the heater cores might reduce the flow it would be pretty easy to figure out. It will be based on the diameter of the core tubes. They should be pretty free flowing though. But you would never know with out doing a test and figuring out what the flow rate is between the two systems. I know on the EG33 the coolant pump flows a huge amount and it is actually restricted by the Tstat and water inlet sizing.

Also I see what your saying from the diagram, but lets look at it this way, it will only heat up until the T-stat opens, it will marginally add reheated water back into the system, and well it has worked for a bunch of people not including us. 818 guys bypass it, even some Subaru people by pass the heater core. Don't try and over think this thing, It is not an issue. Many a thousand of miles has been run on the bypass systems.


borrowed from Small Car

[914GTSTI]

Could the water at the TB be for anti-icing and then maybe emissions ?

[mgp4591]

Could the water at the TB be for anti-icing and then maybe emissions ?

From what I've seen it's mainly for emissions- it helps the tb heat up with the rest of the engine and keeps the fuel delivery balanced with engine warm up. That's why when they go bad you'll hear the rpms rise then drop, rise then drop over and over. The tb doesn't know that the engine is warmed up to operating temp until the O2 sensor tells it it's getting too much fuel. The newer engines may have more controls that make the older systems antiquated but I'm not bypassing my tb on my EG33...

[Andyrew]

borrowed from Small Car

Downloaded and saved.. Awesome diagram.

[914forme]

Could the water at the TB be for anti-icing and then maybe emissions ?

From what I've seen it's mainly for emissions- it helps the tb heat up with the rest of the engine and keeps the fuel delivery balanced with engine warm up. That's why when they go bad you'll hear the rpms rise then drop, rise then drop over and over. The tb doesn't know that the engine is warmed up to operating temp until the O2 sensor tells it it's getting too much fuel. The newer engines may have more controls that make the older systems antiquated but I'm not bypassing my tb on my EG33...

It is emission related but only for this reason. When the engine is cold it produces lots of water vapor, that conduces again in cold areas. Since you have a PVC system on these engines that systems vapors gets re-interduced back into the intake track. This contains the same mix of crap that condenses elsewhere. And since it is going through a Venturi it will tend to cool the vapors and they can form crystals that can potentially freeze up the TB. That is the emission side of this equation.

The other side is if you live in cold climates the same effect can cause icing in the same way.

BTW, the TB is not a smart device, it might house a sensor or two, like TPS, and maybe an intake temp sensor, but beyond that it does noting. It has one function, help you maintain control of the engine. Gas engines control the entry of air into the engine, it is one of the three requirements for ignition process. Modren Diesel engines don't even have a TB, its all done via fuel. Some do have an a shutdown plate that blocks the intake track. This is because they can run on, off oil introduced into the intake. Newer TB units also have a stepper for drive-by-wire systems. Solves the packaging issue of a cable connected your TB. That is also there to help control the engine, but it allows the engineer to manipulate the system also easier, so things like traction control become much easier when the computer can control all inputs and out put functions. IT is a wonderful thing, and can be used for much good in our world. Emissions, fuel economy, stability and traction control, and the list goes on one on...
All good things, for the average driver. With out this stuff, would anybody in the general public be able to drive a Dodge Hellcat off the dealer lot. (IMG:style_emoticons/default/confused24.gif) So since I share the road with these lack of control "great drivers" I'm glad theirs and engineer on the other side keeping them close to being in control. (IMG:style_emoticons/default/beerchug.gif)

The hunting your explaining is a leak, and can come from the TB shaft, most likely from another source though. TB shafts can't be ruled out though. Replacing the TB, means you have replaced other items, or secured them and maybe solved the leak.

Hope that cleared some stuff up, and then made it about clear as mud. (IMG:style_emoticons/default/confused24.gif)

[rnellums]

I've been finishing up the exhaust system. Just need to add some hangers at the end of the mufflers.



Also, does anyone notice anything different about my backup engine?

[bandjoey]

It's red? (IMG:style_emoticons/default/biggrin.gif)

[rnellums]

Hah, funny! I meant the one in the middle of the frame (IMG:style_emoticons/default/smile.gif) my backup subaru engine!

[A&P Mech]

Nice job! How much fab is going to be required to do the same thing on Apollo?

[914forme]

3.0 or 3.6 oh please say its an R (IMG:style_emoticons/default/drooley.gif) Okay no plastic manifold not an R Im so (IMG:style_emoticons/default/confused24.gif)

[rnellums]

3.0 or 3.6 oh please say its an R (IMG:style_emoticons/default/drooley.gif) Okay no plastic manifold not an R Im so (IMG:style_emoticons/default/confused24.gif)

Well it's just the plain old EZ30D, but this engine I'm particular is my test mule (I have another EZ30D in the car already). And what I'm playing with at the moment is flipping the manifold so that I don't have to cut into the trunk and can run a stock air cleaner!

So far the modifications have been:

• grind/cut alternation mounting boss of of block
• remove and reroute heater core bypass
• modify head breather tube to move rearward
• remove egr and block off
• modify/reroute intake manifold wiring harness
• remove fuel line mounting boss on side of intake
• relocate alternator

I'll add more bullets and photos as I polish it up and get it rolling

[914forme]

(IMG:style_emoticons/default/poke.gif) EG33 is a lot easier to flip the manifolds on. (IMG:style_emoticons/default/beerchug.gif)

[rnellums]

I pulled the engine and transmission today to install some upgrades!

I swear it looks better out than in!

[majkos]

(IMG:style_emoticons/default/popcorn[1].gif)

(IMG:style_emoticons/default/smoke.gif)

(IMG:style_emoticons/default/beer3.gif)

Looking good. (IMG:style_emoticons/default/aktion035.gif)

[3d914]

OOh Yeh! (IMG:style_emoticons/default/aktion035.gif)

[914GTSTI]

I see you have the heat on ? LOL

Looks like the EZ water in and water out are on the top ? Or 2 in at the top ?

Randy

[rnellums]

I see you have the heat on ? LOL

Looks like the EZ water in and water out are on the top ? Or 2 in at the top ?

Randy

Heat on? Hell yeah! Its been a bit too cold for garage work here recently, but I want to forge ahead anyways!

The EZ30 actually has two outlets on top and one inlet on the bottom by the thermostat. Kinda weird huh?

In other news I installed Spoke's new front turn signals today and dropped my headers off to get ceramic coated!

I have also renovated my clutch actuator (switched from #10 allthread to wound cable) and painted a few things.

I installed a new starter cable and re-routed the heater core return to delete the throttle body heater and also fit around my new exhaust.

It looks like my manifold flip project IS NOT going to work. No clearance for the alternator, it would require ~2" of spacers underneath the manifold. I'm thinking that next winter I may go through and build my own manifold from mandrel bends. I'm sure it won't be as well tuned as the stock (or tuned at all), but I'm willing to lose a bit of power to have an un-cut trunk.

This weekend (when its nice) i'm going to do an engine bay deep clean and weld on some suspension ear stiffeners I got from Chris at Tangerine. How critical is it that I anneal the area after welding?

Also on the to do list is organizing and fixturing the wiring loom in the trunk.

[Amenson]

Do you have a non blurry overhead picture....this is the money shot!