Just brought a MD321S turbo and i am going to fit once i actually get a chance, but i have a question, i have a standard exhaust manifold on the car, i have fitted injectors (unknown cc but Simon said they are over 550cc) decat up and down pipe, downpipe is 3" with 3" center section which reduces to 2.5" as i wanted the prodrive back box and Walbro fuel pump forged engine etc...

My question is will this be ok to run with the MD321S?

Or is it not safe to run that turbo with stock exhaust manifold. I want around the 450BHP mark. Is this possible on my setup with stock manifold?

Anybody know what the stock manifolds are good for?

 

you can run 450bhp with stock manifold. however the md321s will be on limits at 450bhp

 

You had better find out what injectors you have as 550's won't flow enough for 450. AFAIK..

 

Thanks bud. It made 457bhp on previous car and I think Simon said that was not quite near peak.. Don't know if it helps but think the turbo may be a billet.

They were sold to me as 550cc but when Simon mapped the car he said there were bigger than 550cc.. So fingers crossed I suppose.

 

Hi Tyler

MD321S can be laggy on yours,S is more suited for 2.5L and not sure if this turbo can be converted to Billet,speak with Mark@Lateral Performance about the conversion

About the headers they should be OKish for 400-450bhp,above 400bhp I would go with 2/3 bolt headers like are RCM,Lateral Performance etc

Jura

 

Hi Jura, thanks for that it came on full boost at 4200rpm on a 2003 blob and he was sold the turbo as a billet but i have no clue on how to check. Money is so tight at the moment

 

Hi Tyler

4200 RPM on the 2003 STI seems OK,but on yours you can't expect full boost at those RPM just due 2003 STI running AVCS

You will see how you get on,but hopefully will be awesome turbo on yours

What heads you are running ?

Jura

 

Ow yeah I forgot they had AVCS.. I'm running v3 sti heads. When I spoke to Simon he reckoned that I should be on full boost at 4200rpm... Just don't know whether to go ahead and do this now.. :-(

 

Hi Tyler

I'm pretty sure you should be OK,but not sure if you will able to make 450bhp

2.5" exhaust can be restrictive and yes some guys has run 2.5" at 450bhp without the issue,but usually people swapping 2.5" exhaust for 3.0"

Standard headers at this level,not sure,hard to say,seen only few cars has run them at this level,but usually on OE Twin scroll headers which flow enough above 500bhp

Tubular headers or any good aftermarket headers can be best bet at this level,but I've seen few guys run ported headers at 450bhp without the issue,some has been unable to make above 400bhp

Jura

 

Thanks Jura, think i will take a chance and see what i get.

Knowing my luck prob will get 370bhp or something silly like that only 20bhp more than what i have now.. lol

 

So, you're expecting another 100bhp from just the turbo swap? Mmm.....

JohnD

 

If i changed the Exhaust manifold and back box i would like to think so, if the injectors dont max out, but knowing my luck they will anyway. But as i am not changing the back box and manifold have no idea what i will get.