Most power out of a stock turbo?

[m1tch]

Hey guys, im just wondering what kinda power you can get out of a stock turbo, I know profs FC has a hybrid turbo and thats on 315bhp at the mo, but I was just wondering what is the most power you can get out of a stock turbo if say I street ported the engine, remapped and changed the exhaust again etc

[sadgoth]

depends on the porting and mapping, mid way through the development process I had my bridge port, decat and induction done on the stock ECU and saw 192bhp at the fly (admittedly this was at 3500rpm! it then tailed off very badly) real issue you have is the turbo won\'t take more than 1BAR (prob less) and the interwarmer is a real power limitation

[Prof]

I\'d say theoretically 300 bhp at the fly, but there are some serious issues with getting there - stock intercooler, exhaust, air intake are restrictive, and there is fuel cut programmed into the ECU which comes in at 8.8 psi - that needs to go.  The stock injectors will not take you much beyond 280-300 at stock fuel pressures.
 
I\'d say with 12 psi, induction and exhaust, rewired or replaced fuel pump, chipped ECU or FCD you might get close.  But your intake temps are going to be high, and the engine will be stressed.
 
I made nearly 318 with the hybrid turbo, but at less than 12 psi, still using the stock intercooler, but with fuel pressure slightly lifted and on the stock 550 injectors - there was signs that the injectors were close to their limit, and I wouldn\'t run more than 0.75 bar without being able to retard timing and without a better intercooler.  Street porting will help spool a bigger turbo but is probably wasted on the stocker.

[m1tch]

Hmm so I should make the turbo a hybrid after all the normal mods + safety mods then, which turbo did you use on yours? what turbos would everyone suggest as a basic upgrade?

[Prof]

It\'s a good idea to work out what you plan to do with the car - and have a target in mind for what power you want to make eventually - moving goal posts are never reached
 
For upto about 350 BHP you can use a hybrid turbo - so basically it\'s a larger compressor and intake diameter, keeping the stock outlet diameter, and using the stock hot side.  You need to port the wastegate and ideally change the bearings for 360 degree thrust bearings in the CHRA (centre section) of the turbo.
 
For more than that, you\'ll need to look at bigger turbo\'s, different exhaust manifold and down pipe, an external wastegate, and probably a front or v mount intercooler, or a chargecooler, as the stock intercooler or even an uprated top mount won\'t get you past 400 BHP.
 
You will need to do the injetors and fuel pump for more than 300 as well, and you\'ll be looking at a fuel system redesign for more than 450 BHP (a parallel system).
 
As for the engine, you\'ll need to do more than porting for over 400 BHP, and probably need to start pinching the upper inlet manifold and throttle bodies off an RE or REW engine.
 
A good place to look at for FC tuning stages is FC3SPRO:
 
http://fc3spro.com/TECH/FM2W/power.htm
 
Don\'t forget the suspension and brakes - they need to keep up with any power mods you do.

[Brett]

260 is a realistic target thats easy to achieve on the stock turbo.

[BenLewisMav]

Awesome thread.
Guess i\'m looking at 350hp then?;
Microtech lt-10s, street port, 1000cc secondaries, walbro 255 (running at 5 bar lol! -am fixing it tonight..) T04E Hybrid, 3\'\' stainless exhaust, small fmic + 2.5\'\' custom piping, all emissions + a/c removed, Poss Water/Meth Injection if I get it fitted in time

Plan on getting a GT3540 and a downpipe made, then fitting the stainless T4 manifold and 60mm wastegate I\'ve had lying around fitted, hoping for 450hp after that, anything I should be concerned as being a bottleneck at the kind of power?

[Prof]

I reckon on 360 (300 at the wheels) with a Hybrid turbo, 550 primaries and 800 secondaries, 5psi more fuel pressure, larger top mount intercooler (keeping pipework short), street ported engine, water injection and sprayer, and eManage to control it all.  Probably running just under 1 Bar boost.  Given I managed 318 on 4x550\'s at <0.75 Bar - I reckon the maths stands up to it

[m1tch]

What mods to the stock turbo could I do? Could I change the journal bearings for ball bearings? Im guessing port the wastegate and mod the flapper. What gains if any would I get from polishing and porting the inlet and exhaust sides? Has anyone every tried to fit a VTG turbo to an FC yet?

[Prof]

What mods to the stock turbo could I do? Could I change the journal bearings for ball bearings? Im guessing port the wastegate and mod the flapper. What gains if any would I get from polishing and porting the inlet and exhaust sides? Has anyone every tried to fit a VTG turbo to an FC yet?

Wouldn\'t be worth putting ball bearings in one, but 360 journal bearings is a good move if you\'re going to mod it any further.  Wastegate porting will help a lot with keeping boost creep under control.
 
Not sure on the polishing though - got to be worth a try !

[m1tch]

Is anyone running a VTG turbo or know where I could get my hands on one lol or if indeed it would work on an FC lol

[Prof]

Is anyone running a VTG turbo or know where I could get my hands on one lol or if indeed it would work on an FC lol

We all are !
 
Just realised what you meant by \'VTG\' - Hitachi worked with Mazda to design a turbine and manifold that would supply the exhaust gases to it. The blades are at right angles to the exhaust gases at lower speeds, and hit the curved sections of the blades at higher exhaust speeds (volumes). I\'m not sure if they weren\'t even the first to do this on a turbo.
 
The S4 FC\'s actually have a more complicated manifold with a flapper valve operated at certain rev\'s to open the exhaust path to the other part of the turbine blades, but they did away with the added complexity in the Series 5.