300-350bhp stock turbo
 

Hey guys
I got a question.

I have 87’ FC TII with S5 turbo

- Ported wastegate

- Removed all emision crap

- premix

- Decat + 2,5” stainless exhaust

- Boost controller

- Fujita air filter

- Aluminium radiator

- 2xOEM oil cooler

- Stock injectors, ECU

- Bosch fuel pump (more flow than 255 Walbro)

- Fuel cut defender

My next mod will be AFR+WB and injectors. My goal is 300-350bhp. I would like to:

-run pump gas (no meth or other)

-stay with stock turbo


Is it possible? What are your recommendations? Rtek or standalone?

turbo would require as a minimum of 54mm-60mm front compressor
( U or V to4b up to 60-1 to4s ...keep in mind only a to4b front cover will fit against the inlet manifold on the stock exhaust manifold .. and that the U and V trim wheels are the limits of what can be hi fi hogged into a stock front cover if that look is required )

and at around 300 rwhp at the limits of even the ported wastegate with a stock turbine wheel and it will spike and run excessive EGTs

your options then turn to making a better turbine wheel fit in the stock turbine housing and the to3 stage 2 stuff ( ta34 ) fits as is with the required lift in flow

another option is the back cut t04 P trim turbine inside a hogged turbine cover . though requires much specialized work


absolutely you will need a standalone that will grow with any future requirements,, recommends the low end adaptronics as best price option that is relatively unfettered with limits

thanks for valuable info! :icon_tup:

and what are the limits of a fully stock turbo?

250 rwhp at 15 psi.. off its compressor map ,,cooking the inlet air..exhaust temps through the roof .. and turbo life limited
( cooking the shaft, the bearings , but especially cracking up the turbine housing and exhaust manifold )

a V trim to4b wheel can be made to fit in the stock ( modified ) compressor cover and the ta34 turbine wheel will fit as is and is lighter with less shrouding than the stock turbine wheel

with the smaller compressor upgrades it wont lose out much to a stock turbine wheel down low but will flow more up top and thus reduces EGTs and boost control issues on a stock wastegate


a turbo built thus will appear stock on the outside

when turning down to 13-14psi and adding FMIC for better inlet air temperature would it be ok for turbine housing and exhaust manifold?

And what about the ECU, what do you recommend? I did a research here and think Apexi PFC would be fine

apexi PFC for FC needs a few tricks or a special unit

.. it is also fairly aged and limited in some of its growth potential
.. notably in the ignition setup
( stuck with wasted spark .. stuck with the reluctor based timing signal and no ability to control its high end drift )
that is before you compare the map definition.. the user definable output and inputs ..the processor speed and other features like engine protection

there is 10 yrs between them .. and one at the end of its potential.. while the other is gaining a widespread user base


seriously look very closely how you spend here.. it is all important to any future goals you may wish to make .. direct fire ignition is very important at that 350 + rwhp and should not be overlooked

as should not be the abilty to change to a different trigger system for hp exceeding 400 rwhp
( or at least the ability to tune out the timing drift in reluctor systems )

the adaptronic is also user friendly and has a significant support base .. and can also be found plug and play if that stock look is all important




the stock turbo at around 12 psi will hang together longer than another at 15 psi
.. but its flow is down there at around 225 rwhp on a good engine
( a good stand alone and a decent exhaust will take you there on the limits of the stock fuel system and injectors )

as an aside, i think i found out why turbo life is so short. one of the brochures mentions the stock turbo is doing 130,000rpm, and if you look at a compressor map for a comparable compressor 130,000 is actually kind of high. so more airflow = higher rpm, and we're simply over spinning the thing.

its why the larger compressor helps so much, shaft rpm can be lower..