Sorry if this is a dumb ? but does the fc down pipe from raceing beat even get you anywhere remotly close in a fb?

Where talking turbo here

 

Fits just fine,as does the stock downpipe/precat.

The 2.5" steel one fit up perfectly and allowed easy fabrication of the rest of the system.The 3" stainless one required a little heat at the lower bend to get her flush and parallel to the floorpan.....nothing big.

 

I'll let PercentSevenC answer that.

Edit: nevermind, Steve got here first.

 

Steve, what flywheel setup is that?

 

Cool i bought a stock s4 turbo and mani tonight for my project gonna put that spare 12a i have to good use. gonna mock up my setup on that and possiably run it on that one before i blow my good motor!!! what do i need to do to the stock s4 mani just slot the holes out a little

 

You need to make an adapter/extension to go from the 12A exhaust ports to the 13B turbo mani. There have been several writeups about this. Basically you buy a 12A and a 13B header flange, then join them together with short pieces of heavy wall tubing. This wil give it the needed strength and push the turbo and mani out far enough to clear the intake, whether it be a carbed 12A or a 13B SE.

 

are the stockers good mani or would i be better off getting a tubular one? I have the stocker or will have it shortly. Thanks for the help!!!

 

The stock manifold will work fine. The problem is getting the clearace between the intake and the turbo. Therefore the need to space it out. If you are using a S-4 or S-5 turbo on a 12A spaced out liked this, the downpipe will need two inches cut out of the middle, and slightly reclocked. If you use as is, it will bottom out on the ground.

 

so should i get a 12a flange a 13b flange and make some 2 inch runners between the two flanges. And then bolt onto turbo mani then block. understand about downpipe. Couldnt you just heat it up and bend it???

Also check out my thread on the car for any input you can give me about this build. It will be documented for all to see. WE really need a master thread on the 12a turbo conversion. I mean there is tons and tons of info on this site, I mean tons for all the new guys. But a Master build record would be sweet and maybe i can help with that.

 

 

Jeff,thats my old OS Giken clutch and flywheel.Its a multi disc unit that was major overkill for my setup.It was an awesome clutch,but a little too grabby for me.I could drive it easily with the stereo off,but it stalled out sometimes because of the lack of mass.The clutch is small because there are multiple discs and spacers,like a motorcycle clutch.Paid 400 bucks,sold it for 400 bucks a couple years later.

The stock S4 exhaust manifold is quite poorly designed and prone to cracking.They can still make good HP,but they are built around the switching valve and its ability to help spoolup by redircting the exhaust into the direct contact scroll at low RPMS.The merging manifold design eats up exhaust noise and it clears the 1st gen idler arm better,but the switching valve cant be retained in a 1st gen swap and the wastegate of the S4 is woefully small.
The S5 is basically the same turbo,but it has a far better,split runner exhaust manifold,not unlike a header on an N/A engine.Its design is more compact and designed for simple low rpm spoolup ability,unlike the S4 which needs an active valve to modulate exhaust flow to get the same results.The S5 turbo also has twice the wastegate volume and a freer flowing turbine housing.The S5 unit is a direct bolt on to an S4 engine but requires a boost controller to obtain pressures more than the 5psi the wastegate spring is set for.The S4 can make its stock 6-7psi maximum simply because it boostcreeps a little even in stock form.The switching valve allows for 6-7 lbs at lower rpms,then when it opens up, the turbo lets down to about 5psi under the wastegate spring's control.The S5 use a factory boost control solenoid to maintain even boost levels and hit a maximum of 8psi without any outside control valves or flow regulators.

 

That seems like one of the worst thought desighns mazda could have used. way more headache than it worth. the s4 design anyway. Still dosnt cut in stone if a custom tubular would be the way to go or not. Money is always a issue with these projects so i am not gonna say it isnt. But when it comes to the parts that matter the mose ie: fuel turbos and the mani itself i will not go cheap. This is all gonna be done on a mock up engine i have on a stand so i can pick and choose diffrent routes if needed. Problem is where i live there isnt anyone around except v8 guys and ricers with there sticker powered hondas. If anyone is in my neck of the woods i engourge them to get ahold of me. beers and lunch on me for some good old fashion planing. I would liek this to be added to my other thread about the car itself. What i am trying to do here is acquire all the knoledge and pros and cons of others that have been here before me. No flameing just cold hard facts about this porcess. Like i said we ned a thread about the 12a turbo. Sure is it easier to drop the 13bt i am sure it is. But thats not what i want to do and not wha ti want to hear. This is old school style gettin er done As always everyones help and opinons are more than welcome.

 

Would something like this work without adding the extra runners. I am sure this one is a pil of ****. Just wondering if these can just be slotted to work the 12a

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