c00lduke

Any tips on shops producing exhaust manifolds for 20Bs? Through familiar names and searching I've found many that either no longer produce them and/or haven't responded to inquires about their availability.

hsmidy

Would depend on what the vehicle is that the 20b is in, not a whole heap of 20b's running around so for a shop its not going to be a big money maker for them to have manifolds laying around.
I'm pretty sure ebay will have something for ya though.

c00lduke

Sorry, forgot my old sig isn't there anymore. It's an FD.

Ebay is full of the CX Racing manifolds which I've gotten the impression from reviews for other applications that it's the 2014 version of the OBX manifold from years past.

patman

iTrader: (3)

Wow, that's a surprise. I didn't realize there was an ebay 20B manifold.

I personally have nothing against ebay manifolds, but you will notice that there are no pictures on their auction of one in a car. Since everyone uses a little bit different mounting solution, I'm not sure how you would know if it would fit or not?

hsmidy

Just giving the guy an option, they aren't really an off the shelf unit.

custom is pretty much the norm for any application

Troclo

The only problem I find with this is that the turbo seems to lean outwards…there is only
about 2-3mm between my turbo and whats left of the car I havnt grinded down to make room for it!

http://www.ebay.com/itm/Thick-Turbo-Manifold-11-Gauge-T4-RX2-RX3-RX7-RX-7-20B-3-Rotor-60mm-12-PSI-WG-/380508077492?pt=Motors_Car_Truck_Parts_Accessories&hash=item58980c7db4&vxp=mtr
Its a good price though, I paid 1200 USD for mine at Defined Autoworks, it took 6-8 month to arrive and needed a supporting weld and having the flange grinded flat as it was crooked, and the of course my car had to be cut to pieces to fit the turbo, which is actually
a pretty small one as 20B builds go.

I think I would buy the ebay one and have it remanufactured if it don't fit!

Monsterbox

iTrader: (6)

I used it. Piping is nicely sized. Turbo sat too high so we cut the runners off in the same spot and reconnected with additional piping in new angle. Manifold to engine flange is perfect and super thick. T4 flange needs to be decked. Welds are not very pretty, but look solid with full penetration. It looks like it was machine welded and then someone laid another bead over the machine welds with a tig.

Piping is 2 3/8 not the advertised 2.25od

Holes align perfectly on motor flange, t4 flange needs a few of the holes retapped if you like threaded flanges.

felix_is_alive

i am not sure , but i honestly think that T4`s are too small for a good 3 rotor , i mean dont get me wrong it works , and i am running a T4 myself , but the small hints i get .....
i run a T76 netics . with a a/r 1.32 on hotside , and it seems , or at least i have a feeling it might be slightly choked , i used to run a 3 inch exhaust but was having backpressure issues , 4' solved that real quick .
however i still think/feel that it could use a larger turbo ....this is of course a full gut feeling ,adn i cant prove this in any way , but i think it could make more power with a slightly larger frame turbo

Monsterbox

iTrader: (6)

How much power were you going for when you ran into backpressure issues with 3" exhaust?

felix_is_alive

I didn`t really go for backpressure at all , i wanted as open an exhaust as i could .
i ran a full 3 inch exhaust , it ran ok , but i was noticing my EGT`s would stay up and take a long time to go down

as soon as i switched to 4 inch (full but with a 4 inch resonator in between) the EGT`s started to "act normal" again , as in they would go down quicker , plus i felt an immediate surge in power

only thing with 4 inches is that its ALWAYS loud ....ALWAYS .....

WJM ROTARIES

On my 20b I use a 4" engine pipe then split system in to a twin 2 1/2 system flows well and keeps noise down as well

felix_is_alive

yeah that should work too

Monsterbox

iTrader: (6)

I'm running a 4" dp that transitions into a 3" flange to 3" midpipe/catback. I wonder if the 4" dp will be enough to keep EGT in check. I didn't really think 4" was necessary for my immediate power goals (650-700rwhp) but I guess we'll see. Good info, thanks for the input.

felix_is_alive

Keep us posted
For me, the 3" just didn’t work, and I don't think I was close to 700 back then, let is know

Monsterbox

iTrader: (6)

I was just checking out your setup from your signature link. Magnificent! How much power do you make now?

felix_is_alive

Last time I went to the dyno my gearbox exploded around the 500 mark, I just recently swapped my injectors for ID units, and I'm going for another run on a dyno to see what will happen, I would like to keep it around the 600/650, since mine is a straight street car,

jozeyrx7

iTrader: (2)

i got a 5"er
straight through, was in an rx8 and most likely going in an rx3 or something
borgwarner t6
tial v60 wastey

im gonna learn a bit about tig welding stuff like this and do most of the frame and mounts work myself just as a hobby
skill you cant buy but you'll have them forever, think about doing it yourself, good miller tigs are over $6k but a new everlast 255ext will have more than everthing you need for under $3k which is close to what a good ss or ti exhaust setup will cost

hsmidy

I hope you have got some serious port work to help support that turbo Jozey, 5inch might be a bit of a stretch in an rx3

jozeyrx7

iTrader: (2)

Yeh this 20b was bridgeported, but I didn't think the turbo-back exhaust could be too big? And why does it matter what kind of car this is in as long as I have a strong enough driveline, frame, brakes etc.. at 500rwhp this is a mild 20b rx3 setup compared to the 1000hp rx3 club and they pretty much have no exhaust. I do appreciate your help and would just like to know the reason behind your comment. Cherrs

hsmidy

What I was referring to was space. as in are you going to have enough space in your engine bay/under your car to run a 5 inch exhaust without having to worry about it being too close to the ground.

I suppose with yours being LHD you don't have to try and dodge a steering box.

Don't get me wrong I think putting a big power plant in a small framed car is a great idea, I wasn't having a go about your plan...just how practical 5inch would be.