Turbo upgrade (project!)

after putting a hole in the black gta turbo's gearbox i have decided to have another winter rebuild project!!

this time i am going for more bhp.

1st of, i need to remove engine, box, subframe etc, repair the gear box and give the subframe etc a freshen up, powder coating etc.

..........THEN the engine????

1: replace the head gaskets, not blown yet

2: port and polish the heads

3: fit new cams, fast road?

4: new larger turbo

5: adjustable fuel regulator

6: larger injectors (to be fitted when DG ignition system is finished???)

i have a nice stainless free flow exhaust from meca (sorry david), so i was wondering if i need anything else?

looking for 250-260 BHP

brakes will be the next thing and ART adjustable suspension is currently fitted.

if the thing breaks down or throws a tantrum within 3 months of completion, i will burn the thing

am i wise??

or should i just leave it alone??

Intercooler ,intercooler ,intercooler

Richard, your car was previously running 10psi, otherwise standard.

Bigger turbo, chargecooler, and 15psi on standard management will net you the power and torque you want and feel much faster to what you are used too.....and still keeping maximum factory reliablilty.

.........and what about cams, since the heads are coming off??

Good if your going to race it and want more of top end torque, but as we discussed before, with the standard manifolds it will still only max out around 6000rpm power wise, so it narrows the power band.

Its not like on your atmo, where you can now rev it round to 7000..

.....ok then, what will i do?

1: port and polish the heads

2: new larger turbo

3: adjustable fuel regulator

4: larger injectors?? (pending adjustable ingition)

5: chip thing?

2 & 5 instant increase ,no messing about setting up

I would suggest that the £1000 or so you'd spend on a decent port and polish would be better spent on other things....chip, exhaust and turbo work nicely. Bigger injectors are a waste of time without a programmable ECU to sort the ignition out.

[Alpineandy]

IIRC polishing a turbo head is a waste of time and money, whilst porting is worthwhile but less effective on a turbo.

P&P is more effective when the engine is trying to suck in the mixture (atmo) but when it's being pushed into the cylinder (turbo) the it has little benefit.

Or maybe my memory has gone completely...

David G keeps reminding me that £ per bhp, the chip is the first priority, every time!
£105 for at least 30 bhp, maybe upto 35-40ish. This is £3 per bhp, fantastic value.
If only it were possibele to get 300BHP out of a turbo GTA for £300 ???

..you can buy 3 chips and try it if you want....

........ok then, turbo and chip(s)

what if i use a stage 2 turbo and the chip with a higher boost setting, will the standard fuel pressure regulator be up to the job and also will it be leaner with the standard injectors? ( i know that you tried the larger injectors with poor success peter )

I think the regulator is up to it .I have run mine @ 18/20 psi but not for long tho .

I run my car at about 16psi all the time and have had no fueling troubles (apart from when my fuel filter clogged up) with the standard regulator(s).

Yes, the more boost pressure you run, the more pressure is applied to the regulator diaphragm.

i.e at 0 psi vacuum, the fuel pressure is 47psi, and every pound of boost adds a pound of fuel pressure.

..but fuel flow is not exponential to pressure when increased so you can only run so much boost before the regulator needs upgrading.