Qingdao

iTrader: (3)

Alrighty... this is now a TURBO bridge port engine build thread.



I picked this up for $200 a few hours ago. Even came with a waste gate


And I couldn't wait to bolt it right on; however I seem to be missing some key components.





And before the el cheapo police jump on this thread. I know this is a cruddy Chinky Ching Chong Chinese turbo... If I blows up I DON'T care. Thats why my air filter is gonna be after the turbo.




Now for the Q/A

1) The previous owner of the turbo (I'm assuming) was running water injection. This is a big turbo and I don't really want to run that much boost can I just set the waste gate to dump at 10#s? Or am I stuck with god knows how much boost?

2) Will running boost mess with my vacuum advancers on my distributer?

Mazda RX-7 EFINI TYPE

1) I believe that depends on the spring. I believe the general rule is that the spring is good to about 2-3x it's rating. So a 10lbs spring is good for 30 psi (though I believe that's pushing it). So I think there's a good chance your spring could be okay for 10psi, but i guess, who knows, lol.

2). To the best of my knowledge, you will need to lock your distributor to prevent it from advancing in boost & ultimately murdering your engine.

Qingdao

iTrader: (3)

I think I might muck with my electronic ignition on this thing. I don't wanna mess up my points.


Well I'll just finish the engine and then watch the boost gauge on startup... like a suprize

woodmv

iTrader: (8)

Great thread! Learning lots. Never knew what an S4 or S5 was, but it moved me to look it up.

Yep that turbo looks HUGE. It'll be interesting to see how you make out with it. Good luck, and keep us posted on your progress. In the words of Gunnery Seargent Hartman from Full Metal Jacket, I have been born again hard for these RX-7s and I love to learn as much as I can.

I especially liked seeing the aluminum housing polished up and the front cover. I plan on doing the same but my dremel tools keep wearing out. Must be cheap attachments. What attachment for your drill did you use to polish them, and did you get an answer to your question about what kind of paint you can use on them?

Great job on your build so far - resiliency and determination to get 'er done! Loving it so far.

Mazda RX-7 EFINI TYPE

Oh crap! I didnt read the first page, I thought you were boosting your 12a! lol. In that case, why aren't you using the OEM FC CAS? Though I am using an FC CAS in my 12a turbo build...lol

Qingdao

iTrader: (3)

I used my soft metal cutting bit to remove the large chunks of imperfections. Then 120 sanded, 400 sanded. then mothers polish.

The clear coat hi temp paint plan did not come out as I had hoped... Don't use clear engine paint!!! Its flaky and yelloish. Never again.



@ EFINI : CAS is the fuel managment program?
I'm blowing through my Edelbrock.
HOT... to the distaste of most RX-7 owners.

.

Mazda RX-7 EFINI TYPE

CAS = Crank Angle Sensor. Would have to run it with a standalone or something.

Qingdao

iTrader: (3)

Did a little rust removal... I figured if I'm gonna stack on the power with this thing I might not want any sub par parts of the frame. Strangly this is the only spot of rust on the car. The other side is clean and the rest of the body is clean save a few surface corosion (which I've already sanded and painted). And yeah its a couple of pieces of angle iron I welded in there... whatev... it works.


AND I sold my old 67' Honda CD50 so I've FINALLY got the cash to get those irons from my buddy.

LET THE DRILLING AND DREMELING BEGIN!!!!!

Qingdao

iTrader: (3)

With a little reseach I've learned that brass floats are NOT a good idea... Kind of a face palm moment for me. I've never boosted a carb with brass floats so I guess it never became an issue; although I bet it would look cool if they did get crushed.

Also, the accelerator pump seal on the old Edlebrock needs to be changed out because it doesn't handle boost so well.

Still waiting on my buddy to call back for my irons. I can't wait to start the porting process!!!

Mazda RX-7 EFINI TYPE

When I had my boost prepped IDA I had a plastic float. I had bought a new one also, which also came with a plastic float...but that may be because I requested a boost safe float.

Mazda RX-7 EFINI TYPE

I'm sure Edelbrock has a replacement/upgraded float

Qingdao

iTrader: (3)

Holly does. Close enough


My question is will my fuel pump/regulator (an aftermarket pump that reads "4.5#s") be able to keep up? I doubt it, but I don't know what pump will without pissing off my carb. I've heard of a "rising rate fuel pump" but quick searches on Ebay don't show anything.

EDIT: I think I answered my question...
Is this what I'm after?
http://www.ebay.com/itm/BLOW-THROUGH...565178&vxp=mtr

Qingdao

iTrader: (3)

I found a STEAL today!!!

MOST of an S5 turbo engine for $100

REAL nice rotors. I haven't clearanced the apex grooves yet, but they look real good. They are the nicest I've ever seen in person.

Housings are immaculate.

Irons are ok, but the rear one is F.U.B.A.R. The kid I bought them from didn't know anything about the engine, but it looks like the engine was droped off a 30' cliff clutch first. Thats all right cause I know a local dude who owes me a good iron.




I started drilling... hehe

Qingdao

iTrader: (3)

Came with the stock turbo. Acceptable shaft play


Now... my question is:

HOW much boost does the stock S5 turbo produce? Less than 8#s?

I LOVE the little flap on the turbo to shut off half of it. (twin scrolls?) I dig it. And the dude has another.

Anyways the stock turbo looks much more eazier than the big 'O' turbo.

j9fd3s

iTrader: (3)

the manifold is S4. can't tell about the turbo, if it bolts to that manifold its S4.

the amount of boost it makes depends a lot on the exhaust and intake you have on it, a stock S4 will only run about 6psi, the S5 is like 7, but put a 3" exhaust on it, and the S4 will be closer to 11psi, and the S5 will still stay around 7-8...

Qingdao

iTrader: (3)

So if I quiet it up real good and run two air cleaners (before and after turbo) I can get as low as 6 psi?


Here is the real question.... I read somewhere (possibly miss read) that holly carbs can take 8psi of fuel pressure. If I am only building 6 psi of boost couldn't I blow through and not have to worry about a rising rate regulator? I'm pinching pennies at the moment.

Qingdao

iTrader: (3)

Also, I just did a side by side comparason with my S5/NA rotor... The rotors I got are 100% identical.

Qingdao

iTrader: (3)

ok... I was wrong. They are turbo rotors. They have more dish than the N/A rotors I have I just didn't see it at the time.


Some how I ended up with an S4 exhaust manifold and an S5 turbo... Anyways I went back to the dude's house and he just let me have all of the manifolds and turbos he had. ROCK ON!


At any rate here is the final product porting the midplate

j9fd3s

iTrader: (3)

if you run a stock air cleaner, and a smaller exhaust, then yeah boost will stay low.

the boost is like the total flow vs the amount the turbo can flow vs wastegate flow, so its a little hard to predict.

just to give an example, S4 turbo with just an air filter and cat back can spike to 13psi but settle down to like 6-7psi. put a big exhaust on it, and it won't really flow enough to spike to 13psi, but it'll be running like 9-10psi.

the S5 turbos handle boost much much better.

i have no idea about the holley, but you might be able to do that. since fuel pressure is relatively low, you might have to run larger jets.

Qingdao

iTrader: (3)

I'm polishing my recently aquired S4 turbo and thinking. Where is the air filter element on the turbo FC?

The waste gate boost line on this turbo is right at the turbo.

I guess the cat has to come out of the bag... I am boost preping the blue factory carb hat, and modifying it to fit the Edelbrock. So with a thick air cleaner in the way and the waste gate line before it; I'm guessing the turbo will waste before the carb bowls reach 6 psi.


I guess I'll find out

j9fd3s

iTrader: (3)

stock turbo filters before the turbo, you should too.

woodmv

iTrader: (8)

Awesome! I have a dumb question: Wouldn't having that port so close to the edge of the rotational surface prematurely wear the corner seals? Seems like if they had to travel over an edge they'd wear faster as they swept by the edge of the hole.

Qingdao

iTrader: (3)

BEFORE AND AFTER

I have a TERRIBLE fear of impeller veins entering the engine uninvited.

Hence the filter before (so the impeller won't get hurt) and after so if the viens should leave they won't hurt my engine.


My flow should look like this...

Conic filter-> turbo -> pressure to the waste gate X#s-> piping to air cleaner -> pressure after air cleaner <X#s? -> engine -> back to turbo/waste -> exhaust restricted enough to not spool the SOB so fast -> fire *****...


They ride the little "bridge" along their journey. Side seals are what I'm afraid of snaging... but I've been checking my messurements... it should be fine; however I did push the envelope a bit.

Qingdao

iTrader: (3)

I got to polishing; cause I'm out of funds and got too much time.

So as it sits... my junks is real shinny but doesn't move....


At any rate, I think I will use the engine paint because the housings where polished before (I think) and the owner didn't re-polish them. Without the anodizing from the factory removed in the polish proccess the housings get all pitted. AND once in the car I really don't feel like polishing them. So paint it gets.

Qingdao

iTrader: (3)

Alright so my goals for this car have changed...

No more turbo. I like N/A (at least for this car)
No more bridge port. That **** looks difficult to feed or lazyness on my part. Regardless its gonna eventually be a large streetport.
NO MORE RUST!!!
Also, I'm going blue.






I like the blue.