Well, this has been in the works for quite a while now.. Finally getting to work on it.

I'm working with a local shop called Boost Flow Technologies on a custom RB20 intake manifold. The manifold is built and were trying to work on the finishing touches.

I have some questions and I would be very greatful to you guys for any help you can give me.

First off... Here's the manifold.. (sorry for the picture quality... camera phone)

Here's the engine bay currently..

Here are my questions...

1.) Vacuum ports in the manifold itself... We are planning to mount the AAC on the top of the manifold between cylanders 5 and 6. We are going to mount another vacuum port on the right side of the manifold opposite of cylander 6 runner. That vacuum port is going to this vacuum manifold... http://cgi.ebay.com/ebaymotors...QrdZ1From the vacuum manifold were planning to run the other necessary vacuum lines.. brake booster, fuel pressure regulator, boost gauge, the tubes on top of the valve covers.

Q - What other ports or vacuum lines should I remember to run? We can throw more onto the manifold itself if needed (Should we do that for the brake booster since that's a big line?)

2.) Coolant lines... The stock intake manifold and lower runners have a maze of lines and channels for coolant. We cut off the lower runners on a spare intake manifold and welded them to the new manifold to preserve the coolant passages. I have some questions though on how to route new coolant lines... what's necessary and what can be blocked and negated.

There's a line on the lower runners that runs parallel to the fuel rail. On the end of that line it cuts to the right and a small tube runs toward the fender, then up to the top of the intake manifold where the bleeder screw is located. Then that line exits the bleeder on the manifold and heads directly to the throttle body. From the other side of the throttle body it runs back down to the block.

Q - Can we get away with eliminating the run to the bleeder and then to the throttle body? Can we just run a line from the exit on the runner before the bleeder straight back to the block after the throttle body? Obviously the bleeder is there for a reason... but how would you build some sort of bleeder onto a custom manifold? Is there another way to bleed the coolant system of any air bubbles if you get rid of this bleeder screw? What's the point of running coolant to the throttle body??? Is this necessary?

3.) Battery relocation. In order to run the cold side piping up from the FMIC, we have to move the battery to the trunk. I got a kit from Summitt Racing... install is pretty self explanatory. But I ran into one question. Q - The old ground wire from the battery runs to the base of the battery tray and connects to the metal on the wheel well. Then it runs out of that same point and goes to the engine block. Does the engine block need to be grounded to the chassis? Or can I just remove that ground wire entirely? I don't know if going to the block is just an additional insurance ground for the battery, or if the block actually needs to have some grounding?

4.) What the heck is this thing... Is it for the closed loop cold start system??I'm referring to the metal piece toward the top of the picture... not the AAC. It's got a black electrical plug on one end and two vacuum ports on either side... not sure if it's measuring the intake air temp, or actually controlling the air intake during startup cold loop...?What is it? Where does it go?

Thanks so much for any advice you can give me. Hopefully I don't sound like too much of a noob for asking them.. .
Modified by Eikon at 10:51 AM 6/15/2006

#4 is the air regulator. It allows the motor to idle at a higher rpm during start up. After a few seconds it closes somewhat to allow normal idle rpm. One the rb25 it's under the intake manifold, maybe the same for the rb20.

Thanks eh?.

I was at least on the right track I guess. Now my question is... do I need that for the future? If I get rid of it, will it be really hard to start the car?Actually it already is hard to start the car... but that's a fuel pressure issue I think.

Anybody else have answers for me on the vacuum, coolant, or grounding questions????

Please!!

Eikon wrote: Should we do that for the brake booster since that's a big line?

Brake booster is a good one. Plug the remainder of the ports you don't use and you can always re-open them if you forget something.

Eikon wrote: Can we get away with eliminating the run to the bleeder and then to the throttle body? Can we just run a line from the exit on the runner before the bleeder straight back to the block after the throttle body?

I can't really picture this in my head as to what you are talking about. If you have some sort of diagram or something you could post or mock up, that would help. On the RB26, there are coolant lines running through the intake manifold for all the runners. This might be the same on the RB20. You'll need these because the engine runs pretty hot.

Eikon wrote: Obviously the bleeder is there for a reason... but how would you build some sort of bleeder onto a custom manifold?

It would be possible. You'd just have to drill and tap a hole in one of the highest locations in one of the water jackets somewhere.

Eikon wrote:Is there another way to bleed the coolant system of any air bubbles if you get rid of this bleeder screw?

Yes. I have a pressure bleeder that essentially sucks all the air out of the system and then fills it with coolant. It eliminates the need to bleed the coolant. It's this one:http://www.eastwoodco.com/jump...ODUCT

Eikon wrote: What's the point of running coolant to the throttle body??? Is this necessary?

Car manufacturers do this to prevent frost/ice buildup on the butterfly. If you aren't going to drive the car in the winter, no need to have coolant running to the TB.

Eikon wrote:The old ground wire from the battery runs to the base of the battery tray and connects to the metal on the wheel well. Then it runs out of that same point and goes to the engine block. Does the engine block need to be grounded to the chassis? Or can I just remove that ground wire entirely?

They do this to ensure that the engine is properly grounded. Otherwise, the only tie the engine has to ground is through the motor mounts. What I've done in the past is run a ground wire from a trunk mounted battery to the engine bay and tie it into the factory grounding points. You are running a power line anyway so just pull another ground wire along with it.

You could obviously get away without running another wire, but getting good grounds is important.

^-- You rock! Thanks for all the input.

I think I'm pretty much settled on the coolant system and the electrical. I'm going to get one of those pressure bleeders and drop the manifold bleeder and the throttle body tubing. Rather than running the tube from front to back, I'll just plug both ends... no sense running coolant down a tube for no reason. That will simplify things. I'll hook that ground wire back up from the block to the engine bay, and great idea on running a ground back up the front just to be safe.

Here's my plan for vacuum lines into and out of the manifold... 1. Large port for the brake booster2. The AAC assembly3. small port from idle controller4. small port from blowoff valve 5. small port to vacuum manifold for other stuff (fuel pressure reg, boost gauge, etc..)

questions.. Can you think of ports that I'm missing?Is it OK for the idle controller to go into the vacuum manifold, or does it need to be a direct link?

ive never needed to bleed a coolant system through a bleed valve.. *shrug* seems like you could probably delete it.

I didnt run a ground wire to the front of the car for my trunk mount. theres no thicker gauge wire than the frame rails/body... so i just used that. run a ground wire from the battery to a good spot.. i used rear strut tower bolt.. some ppl use seat belt or something, make sure its sanded good to expose the metal.

i would ground the block b/c i believe your knock sensors and oil press senders rely on this ground. on the stock setup, there is a ground for the head and block separately.

do you need a port for your wastegate actuator/boost controller on the plenum? or do you plan on having a port pre-TB for that?

Eikon wrote:Is it OK for the idle controller to go into the vacuum manifold, or does it need to be a direct link?

Your IACV is essentially a bypass for the throttle body so that your engine can breathe with the TB closed. For it to work, it needs a line running to a spot before the TB.

gawdzilla wrote:theres no thicker gauge wire than the frame rails/body... so i just used that.

True, but there is no better ground than the negative terminal on the battery.

Grounding the motor is a good thing. When I grounded mine was about the time my seatbelts and speedometer starting magically working lol.

gawdzilla wrote:
do you need a port for your wastegate actuator/boost controller on the plenum? or do you plan on having a port pre-TB for that?

Thanks for all the input gawdzilla.

You bring up a point that I'm a little confused on. I beleive there is a port on the wastegate that goes to the hot side intercooler piping. Pre intercooler and pre TB. I don't have a boost controller hooked up at all yet. I was thinking the boost controller could port off the vacuum manifold. (which is basically an extension of the plenum)

kjlindgr wrote:Your IACV is essentially a bypass for the throttle body so that your engine can breathe with the TB closed. For it to work, it needs a line running to a spot before the TB.

Yeah.. the source of air will be pre TB, but I'm wondering if it's ok to run other side into the vacuum manifold or if it would be more effective to run it into the plunum directly.

The vacuum manifold should maintain the exact pressure dynamics as the plenum itself. But, I've never used it, so I'm a little nervous about the effectiveness of it all. In theory it's a great idea... run a tube from the plenum to another small open area. The tube should allow pressure to transfer exacly the same way to the ports on the vacuum manifold as they would on the plenum. I'm just not sure if it works as well in practice as it does in theory.

You could run the IACV to either the plenum or the manifold. It might be easier, fabrication wise, to put a flange on the plenum versus making a flange for the IACV that converts to a barbed hose fitting to plumb it to the manifold. Just something to consider.

Eikon wrote:I beleive there is a port on the wastegate that goes to the hot side intercooler piping. Pre intercooler and pre TB. I don't have a boost controller hooked up at all yet. I was thinking the boost controller could port off the vacuum manifold. (which is basically an extension of the plenum)

boost controller goes in series with the wastegate port and pressure/vac source. source -> bc -> w/g. you can either move your whole w/g control to your vacuum manifold, or leave it where iit is stock and just put your BC there. really its up to you. only difference is you will run slightly more boost if you move it to the cold side into your vac manifold cuz there is some pressure drop across the IC.

your w/g will just be triggered by "plenum psi" instead of "compressor outlet psi". really there is not much of a diff. the 26's w/g source is on the plenum and there is a line that wraps all the way around the back of the block, then splits in 2 and feeds both w/gs.

1. I would mount the iacv directly to the manifold and on the bottom for cleanliness and minimal hosing.

2. I think you are still missing one nipple that should go to the pcv valve

3. Water lines on the outside of the motor are simply there to direct coolant flow through accessories, ie heater core, tb, oil cooler, turbo etc... If you just follow the path of the coolant, you can choose which accessories you don't want coolant running through.

4. I would leave the bleed screw if possible, It makes bleeding the motor 100x times easier. with the bleed screw, you can purge the air out of the block without having to wait for the thermostat to open.

5. The more grounding points you have the better....

AND finally when designing a manifold you need to visualize how all the vac lines and other things will route once everything is installed. You have a fpr and pcv valve right by the front of the manifold, why not put two nipples right there. The brake booster is in the rear so put a nipple in the back. The Iacv valve need a large tb bypass hose from the intercooler pipe. Imagine what it would look like with a large hose running from the top of the manifold all the way to the cold pipe... Yes it would easier to adjust the iacv if it were on top but honestly after its adjusted you will never touch it again.

-Bluefire

Bluefire wrote:1. I would mount the iacv directly to the manifold and on the bottom for cleanliness and minimal hosing.

2. I think you are still missing one nipple that should go to the pcv valve

3. Water lines on the outside of the motor are simply there to direct coolant flow through accessories, ie heater core, tb, oil cooler, turbo etc... If you just follow the path of the coolant, you can choose which accessories you don't want coolant running through.

4. I would leave the bleed screw if possible, It makes bleeding the motor 100x times easier. with the bleed screw, you can purge the air out of the block without having to wait for the thermostat to open.

5. The more grounding points you have the better....

AND finally when designing a manifold you need to visualize how all the vac lines and other things will route once everything is installed. You have a fpr and pcv valve right by the front of the manifold, why not put two nipples right there. The brake booster is in the rear so put a nipple in the back. The Iacv valve need a large tb bypass hose from the intercooler pipe. Imagine what it would look like with a large hose running from the top of the manifold all the way to the cold pipe... Yes it would easier to adjust the iacv if it were on top but honestly after its adjusted you will never touch it again.

-Bluefire

Thanks for the great input Bluefire!

We are going to try to get the AAC and the IACV port mounted on the bottom near the back. We'll run a port from the cold side piping pre TB then T it to supply both units.

PCV... That's the crankcase velntilation right? In other words the vacuum to pull excess oil out of the valve covers? It's an area that I'm pretty noobish on. Can I run the pcv system off the vacuum manifold? I will have a ton of expansion ports there to use. Where is the PCV valve itself? anybody have a picture? Is it built into the stock manifold? This is why I love NICO... I wouldn't have even thought about that.. I'm a moron.

I think we are going to get rid of the coolant lines to the throttle body and the bleeder as well. Karl posted that link about the electronic bleeder that he has. I'll pick one of those up someday... or perhaps Karl will be nice enough to help me out with the one he already has.

Hopefully Ross will have some free time and he and I can pound this thing out.. It would be nice to have my car back soon.

I will def. post pics when it's done and report back on the succes of it. Or... if i run into snags, I will ask for more help.

Thanks a ton to everyone who gave advice!!!

The pcv valve would be the plastic nipple coming off the cam cover. I don't think you'll want this line headed to the vaccuum manifold since it will then sucking in oily air. Best way would be too have that line is to tap it directly to the manifold and close to the runners.

-Bluefire

I'm confused.

I thought the PCV valve itself was a suction based valve that pulls the excess oil out of the crankcase, but seperates the oil and sends it to the catch can. It doesn't really let oil into the port and then into the intake manifold itself? I would think oil in the manifold itself would be bad.

isn't that what a catch can is for...

^ no, theres 2 sides to the crankcase venting system in the factory setup. the pcv valve pulls in air when your motor is under vacuum. when you're boosting (where almost all of your blowby comes from), the PCV valve is shut and the blowby goes the other way into your intact tract, pre-turbo. this is where you want to put a closed catch can as a filter.

another alternative is to cap the pcv valve and intact tract and just run open breather filters.

thanks gawdzilla..

I'm starting to catch on.. thought I'm a bit slow.

So under vacuum... low rpms... the plenum does suck in some of the oil that comes off the top of the valve covers. So the intake does actually take in a little bit of oil, though not much at all... and that oil would eventually make it into the combustion chamber and not be a big deal.

under boost (which is when there is much greater likely hood of oil needing to be filter out of the valve covers) that air get's pushed out the other direction to the catch can.

I have been looking for pictures to help.. Are you saying I can run two of these little breathers and call it a day? Is it important to get that oil out of the valve covers? The breathers won't allow it to get out?

Will this have any effect on how the engine runs? I've noticed that the idle changes a bit if I unscew the oil cap... but, I don't know if it's better or worse...

I need to do more homework on this whole thing... Why do you get excess oil in the valve covers? Does airflow into or out of the valve covers have any effect on the combustion chamber and how the engine runs?

Sorry for all the questions. I tried to search on it... but there isn't much out there.

The pcv valve and breather are solely there to vent pressure created in the crankcase. Also when venting this pressure you will inherently vent oil vapors created by all the moving parts splashing oil. Now instead of running a catch can, that would periodically have to be emptied, manufacturers route these vents back into the intake to be burned in combustion.

And to answer your other question it has been proven that sucking out pressure during vaccuum can definitely help with power. But how much power really depends on the car. I believe some motors even have separate vac pumps to suck the pressure out of the head...

Bluefire wrote:And to answer your other question it has been proven that sucking out pressure during vaccuum can definitely help with power. But how much power really depends on the car. I believe some motors even have separate vac pumps to suck the pressure out of the head...

i hope you all know that oil vapors routed back into the intake lowers your fuel octane grade. that's why there's the purpose for the oil-catch-can. when it come down to it, you can just leave the vent on the valve cover open if you want--it's the emission regulation that the manufacture are forced to route it back into the intake track.

I thought the catch can was on the other side of the track.

From what was discussed above, it's a two way system.

On vacuum the oil vapors go into the plenum. On boost the oil vapors go to the catch can.

Is this correct?

Eikon wrote:I thought the catch can was on the other side of the track.

From what was discussed above, it's a two way system.

On vacuum the oil vapors go into the plenum. On boost the oil vapors go to the catch can.

Is this correct?

No...there's no boost nor vacumm present in your valve covers.The main reason to run a catch can is to prevent oil from entering your intake as well as everything on the way including the intercooler. The advantage of a catch can breather combo over just a breather, is that hot oil does not get sprayed all over your engine. Less oil in your intake means less chance for detonation. This set up also eliminates back pressure from the head created by blow by gasses. have you looked inside the stock turbo's compressor housing? all the oil gunk you see in there is result from blow by oil vapors, you dont want that in your new turbo nor your intercooler. the catch can prevent that.

i recommend you guys to connect your catch can like this on mine:

It's almost done!

(Sorry again for the terrible camera phone quality)

It's crazy how much time this takes.. Thought we'd be done weeks ago. But, the RB's cooling system is so complicated. It's taking a really long time to get all the hoses and connections right.

Anyhow.. Still need to weld up the cold side pipes, extend the wires for the throttle body sensors, get some longer fuel lines to run underneath the manifold vs. over the top. Run an air line from pre-TB to a "T", then to the IACV and AAC, get a catch can and lines for the PCV, get a power grid for the front battery connection, reinstall the blowoff valve, and finally mount a bracket for the throttle cable. Should be able to knock those out on Sunday.

I can't wait.

Seth my man....I went out there this afternoon and got the cold side all cut up, made a bracket for the throttle cable, and got a hose on that last section of coolant routing.

I don't know if Rooster is going out there tomorrow morning but everything else is minor. Shouldn't take long on Sunday.

Sweet!! Can't wait to fire it up.

you guys rock!