R-X-R

iTrader: (9)

i can always put the stock regulator back. i thought more pressure was better. it a s5 t2. what size restrictor should i use with stock oil pressure?

RotaryEvolution

iTrader: (30)

holley and edelbrock jets are the easiest to find but they are still quite large, i usually just try to find the smallest main jet i can find.

R-X-R

iTrader: (9)

ON MY GT35R I HAVE THIS


IS THAT A OIL RESTRICTOR?

R-X-R

iTrader: (9)

^ anyone?

MrGoodnight

iTrader: (1)

I would make a new thread in the single turbo section.
They would know.

R-X-R

iTrader: (9)

I guess lol

Turblown

iTrader: (12)

It is an internal restrictor, but you still need a .035" external unit...

Aaron Cake

iTrader: (1)

What he said. I asked the local turbo builder about this years ago and they said something like 'if the oil pressure is over 30 PSI at the turbo oil inlet, you need a restrictor".

Cheap and easy way to make one: get a 1/8" NPT male/female adapter and the solder it full. Now drill out the hole to 0.35".

Snaple07

iTrader: (17)

Where is your coolant feed for the turbo coming from...and is the coolant deposit going to the bottom nipple on the water-pump lower neck? The reason why I am asking is that my S5 LIM original coolant feed location is permanently welded (bought off a forum member a while back) so i need a different feed location for my turbo (GT35R). My previous turbo was just oil lubricated and oil cooled, now I went with ball bearing and want it to stay as cool as possible.

Aaron Cake

iTrader: (1)

Coolant feed to the turbo comes from the rear iron nipple.

Originally I clamped a hose to it, though now I have a compression fitting on the nipple to an NPT fitting, which then goes to AN. Coolant then feeds to the back of the water pump housing in the stock return location.

Here's an image from a few years later:

Snaple07

iTrader: (17)

So your coolant feed is coming off of the rear iron (where you had tapped 1/4 NPT) to a 6AN fitting to feed coolant to your turbo and then had the coolant return to top of the water pump (where the BAC coolant return originally was at). I believe the original coolant return on the S4 and S5 turbo was on the bottom of the waterpump. What size drill did you use on the rear housing (coolant feed for your turbo)? and what size drill for the waterpump (coolant return)? I am debating on whether or not I should drill/tap my rear housing and waterpump (my rear iron has the nipple still there but jbwelded shut, waterpump nipple is jbwelded shut as well...and looks horrendous). I already have 4ft of leftover braided fuel line left over and a bunch of 6AN fittings left over from the build. Should I tap them even with the risk of cracking the rear iron and getting fillings in my coolant???

Aaron Cake

iTrader: (1)

That's what I said. Though the rear iron on this engine isn't tapped because the engine was already assembled and I didn't want to risk cracking it. So I just used a compression fitting on the stock nipple.

As it shows in the FSM and training manual (as well as Haynes I believe) the coolant feed to the turbo comes from the rear iron, through the lower intake, into the turbo, and then back out to the lower pipe on the water pump housing.

As they are 1/4" NPT, I just Googled "NPT tap sizes" and found this:
NPT Tap Drill Sizes - Engineer's Handbook

The water pump housing is easy to drill and tap as it's aluminum. And if you screw it up, then just get another.

The rear iron is fairly brittle cast iron. I would only suggest drilling and tapping it if the engine is disassembled and you have enough experience to go slowly. Yes, I have seen them crack. See this video for a demo of the water pump housing and iron tapping process:

Snaple07

iTrader: (17)

As always, thank you for your info and wisdom and I am sorry if I come off as being a derp and being redundant when I repeat what you are saying (this is how I completely understand things and is the best way for me to understand when I write or type information out).

So what you are saying is this right.



My engine is in the car as well and I too am worried that I might crack the rear iron and by the way what size compression fitting did you use on the rear iron?

Even as I type I am debating in my head whether or not I should use a compression fitting or just tap the hole. I might just go full retard and just tap the damn rear housing with a 1/4" NPT tap as you stated in your video.

Now I am not trying to call you out or flame, but when I was researching how to do this, I came across this thread and found that the info was conflicting with your Cosmo Build video post (granted that this thread was from 2008).

https://www.rx7club.com/2nd-generati...es-13b-746285/

On that older forum thread/post you had said to another member, "The small water nipples can be drilled and tapped out to 1/4" NPT, while the rear iron should be drilled and tapped out to 1/2" NPT being VERY CAREFUL not to crack it." But in your Cosmo Build Video you said that you "drilled out the stock coolant feed in the rear iron and am now carefully tapping it for 1/4" NPT"...am I mixing two different nipples on the rear housing up?



Thank You for your help

Snaple07

iTrader: (17)

I went ahead and wiggled/removed the nipple and tapped the rear plate for a coolant feed for my turbo (which answers my question on the previous post) with 1/4" NPT to AN 6 fitting. I also did the same for the waterpump, removed the stock coolant 90degree elbow nipple and tapped it for 1/4" NPT as well (for a coolant return from the turbo). That 90degree elbow was originally for the coolant return from the BAC. I should have done all this when the engine block was outside of the vehicle. LIVE AND LEARN

Aaron Cake

iTrader: (1)

By 1/2" NPT, I was likely referring to the nipple which supplies water to the heater core. And in fact 1/2" NPT is pretty risky. Better would be a straight thread like M16 and then seal it up with a crush washer (probably ened to mill the area flat).

Snaple07

iTrader: (17)

I had figured as much...I didn't quite realize the actual size of the nipple on the top of the rear iron until I actually physically saw the nipple, that is when I realized the hole needed to be drilled 7/16" and tapped 1/4" NPT 18. Your videos were quite helpful and I have been subscribed to your youtube account for quite some time and I have been keeping up with you 1975 Cosmo build for quite some time as well.

Thank You for your help.

Alex052493

Aaron, whats your whole exhaust set up like? i saw vibrant resonator, whta muffler and piping are you using to quiet it down?? i have 13b bridgeport na but its extremely loud. i was wondering if you could help me with the proper set up please!

Aaron Cake

iTrader: (1)

9 year thread necromancy!

So the whole exhaust is something like this:

-3.5" SCH10 downpipe w/recirculated wastegate from turbo to about end of bellhousing area

-3" 304 stainless thick walled tubing midpipe containing Vibrant 1795 (or 1795, I'd have to check) bottle style resonator followed by Vibrant 1142 Ultra Quiet resonator at about the Y pipe location



-Y pipe with fabricated split starting as 3" and splitting to two 2.5" pipes, thick walled stainless 304

-Two dual tip "DTM" style mufflers of imported origin, ordered from Japan way back in the '90s before every company reproduced them. Stainless packed, polished stainless. Think the tips are 2.5"



I've spent a LOT of time pondering and building rotary exhaust to be quiet. And there are a few key factors into it.

First, thick walled stainless for the downpipe. Which means, SCH 10 pipe or similar thickness. That's like 1/8" thick. It takes out all of the resonance, pinging and high pitched bee sounds. Yes, a bit heavier.

Follow up in the midpipe with the bottle style resonator. That doesn't take a lot of sound out of it, but works to further reduce the high frequencies and take the concussive pulses out of the exhaust.

Then the Ultra Quiet style resonator. Note that both these resonators are straight through. You can look directly through them. Impact on flow is negligible. The Ultra Quiet is packed with stainless and is where the majority of sound absorption takes place. it pulls out all the high notes leaving only the lows. Drone happens when standing waves form. The two resonators break up any standing waves. VERY important to place resonators so that they have a fair amount of tubing before and after. This greatly enhances their efficiency.

Dual exhaust. Single exhausts are stupid and very, very difficult to keep quiet while maintaining flow. Seems like Mazda knew what they were doing, eh?

Mufflers should be an offset type. Flow through, but offset. That offset doesn't reduce flow much, but makes an enormous difference in sound. Stainless packed only or if your exhaust temps are not too high, then fibreglass packed will work with reduced life. By the far end of the car, EGTs are much lower. Biggest mufflers you can fit under the car.

And of course, putting a muffler right at the engine in the form of a turbine chops a lot of sound out as well.

For your NA bridgeport, you may find offset mufflers too restrictive and the result may be a decrease in midrange. That's the problem with NA bridgeports. They are extremely sensitive to exhaust backpressure and it is exceedingly challenging to keep them quiet yet keep the flow up.

My suggestion would be to take a similar approach to what I did on my Cosmo for the midsection. Use an Ultra Quiet resonator, follow that up with a straight through MUFFLER, split off into the Y pipe, and place a bottle style resonator in each branch of the Y. Then you can use straight through mufflers and add a set of resonated tips.