Hi guys

I've been looking at increasing the power of my gt4 but it seems that I'm at my limits unless I want to risk blowing the engine.

I would like to hear your views on how to move forward with the car.

The current spec of the car is
Standard internals and charge cooler
Standard turbo running 1.1 bar using blitz digital boost controller
Aussie down pipe
Sports cat
Blitz nurspec r exhaust
Unichip piggy back ecu

The car has 90,000 miles on the clock

At the last power run at 1.1 bar the car was running 333hp at the fly

I was looking at bolting on a hybrid turbo but have been put off the idea due to the car may already be at its limits without work to the engine.

What I would like to know is, what is the best way forward to get the car to 400 - 450 hp

I think the first step would be upgrade the ecu correct me if I'm wrong but I think the unichip is very limited. What are your views on a replacement ecu e.g what make etc. I would preferably like something that is readily tuneable and not be restricted to 1 tuning shop in the country.

Step 2 would be to upgrade the internals. This is where I need the most help.
I have no idea what needs to be changed other than the pistons. What other things will need to be done to get to my power goal?

Step 3 new turbo and fuel pump then mapped

Now I may be well off the mark with this so I would really appreciate your views.

Cheers

If you want to run that sort of power then I'd ditch the standard water to air intercooler and fit a front mount intercooler. If you don't then you will find that the air charge temperature will skyrocket if you use prolonged boost. Hot air entering the cylinders will mean there is more likely to be detonation which will destroy your pistons, even forged pistons are not immune to this. I did try using water injection to keep the charge temps under control but this was very marginal and eventually I blew my engine when the water injection airlocked.

If you want an ECU that can be tuned by anyone then its hard to argue against a MoTeC although I know some on this forum would argue that any competent engine mapper should be able to map almost any ECU. In practice its easier to find someone close at hand and get an ECU they are familiar with mapping.

You should add a set of larger injectors and a fuel pump and regulator to suit otherwise you risk running the stock injectors above the recommended 85% duty. Not a good idea.

A set of uprated cams would also make it easier to achieve your horsepower goals.

I don't know what your budget is but all of the above won't come cheap even if you do a lot of the work yourself.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

I tottaly understand this is not going to be cheap.

Engine wise other than the pistons should I be looking at changing anything else for example rods etc?

I have foud rods and pistons at a fairly good price from the US. but if rods are not needed then I may not go for this.

Yes...Go for forged rods and pistons.

_________________
Vice Chairman
1990 White UK Celica ST185 - Project DTM
1997 Cream BMW R1200C (as seen in James Bond "Tomorrow Never Dies")
2005 Jaguar X-type 3.0 Sovereign AWD Automatic
Blood Bikes - https://www.freewheelers.org.uk/

Ok no problem, I have seen many company's selling head work for the 3sgte does the head need any modification.

To achieve your aims of 400/450bhp then yes you'll need some head work done.
You will almost certainly need uprated IN & EX camshafts (e.g. HKS 264 or similar).
At the same time you should have the head ported and polished to aid flow.
If you want to go the whole hog then go for some oversize IN & EX valves (e.g. 1mm + ferrea or similar), uprated valve guides (e.g. JUN or similar) and uprated springs (e.g. HKS or similar).

_________________
Vice Chairman
1990 White UK Celica ST185 - Project DTM
1997 Cream BMW R1200C (as seen in James Bond "Tomorrow Never Dies")
2005 Jaguar X-type 3.0 Sovereign AWD Automatic
Blood Bikes - https://www.freewheelers.org.uk/

Keep in mind that it is easily possible to spend as much money on the head as on the bottom end!

I would set yourself a budget, find out exactly what parts you need and try to stay to it.

I would also decide on where you want to get the car at the end and be realistic!

I would also look at your oil and water cooling systems, these will be badly overloaded at 400bhp.

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GT4DC Events Co-ordinator
1996 ST205 UK

I have priced up the cams already,
Im slowly putting together a shopping list of parts. I want to get an idea of how much this is going to set me back.
I dont want to do half a job then regret it.
Im alreading running a stanless rad so possibly a swirl pot may help too.
Im not sure what oil cooling systems there are out there, ill look into it.
thanks for your ideas. its much appreciated. Im no mechanic so your help means a lot

regarding engine internals, the way i see it, for 400 bhp you need only buy forged pistons and ARP fasteners.
no essential need for new forged rods or high lift camshafts or extensive head work / larger valves


...but for 450+ > 500+ > every little helps, buy everything ££££
budget increases exponentially and service life of engine between rebuilds is shortened


for 450 + more cost effective to buy this : http://www.gt4oc.net/forums/viewtopic.p ... 4#p1329024


^^^ or at least look at the spec list

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ST165 turbo 4WD
ST185 GT-FOUR RC Carlos Sainz Limited Edition 825•5000
ST185 turbo 4WD Carlos Sainz Limited Edition 2541•5000

Funny you should mention that car. I have been looking at it on eBay. Very nice motor. I'm surprised I have never seen it as I'm in Swindon and I believe this car is in Marlborough.

It's a very good spec for the money but I don't fancy 2 cars. It is tempting tho. Shame it's not white.

Reson why, i think the owners parents live in Malborough, but i think the seller is currently working down in Cornwall...

_________________
ST165 turbo 4WD
ST185 GT-FOUR RC Carlos Sainz Limited Edition 825•5000
ST185 turbo 4WD Carlos Sainz Limited Edition 2541•5000

That may explain it.