Original GTA T3 Turbo Specs

As I am likely to replace my tiring T3 with a new Garrett GT ball bearing style turbo, I would like to know the original A/R ratios and trim and such to make an educated slight upgrade, or replacement decision.

My current thinking is toward the GT28R as a replacement with the GT28RS as an upgrade.

Where are you David G????

Peterg, get back to work and give Mr G a rest. Maybe he is off doing some research before publishing a radical reply / considered opinion?

Ive not been off work!!!!! Worked the lot thankyou very much......unlike David who has been far less prolific in the last 2 weeks than normal.

Ive not been off work!!!!! Worked the lot thankyou very much......unlike David who has been far less prolific in the last 2 weeks than normal.

Far from prolific!...how about the direct plug in mappable ecu, with original map fully installed with software and programming lead which plugs into the standard Renault diagnostic port for programming, by the end of Feb for less than £600!??

Anyway, back to the turbo..

The standard T3 is very small, 0.36 a/r T3 turbine housing and a 50 trim compressor wheel in a 0.42 a/r housing. If your going to fit a GT28, there is the option to get the T3 inlet flange and 5 bolt discharge exit flange. You dont really want the type with the built in internal wastegate, as you will have to modify the original downpipe and mounting flange (though you may still have to do this as the physical dimensions of the GT28 are different to the standard T3)

I wouldnt expect you to minimise the lag, even with the roller bearing type, as the standard housings are so small there shouldnt be lag...the lag is mainly due to the design of the engine (ecu, manifolds) and even the GT28RS wont rectify this ,when the smallest exhaust housing on the GT series are normally 0.64a/r...

Tell me more about the ECU!!!!!

Hi pete

This is a different system to the one I mentioned in the past, but so much better and easier to use. Basically its a new chipset and board that replaces the existing one in the ecu (I need to fit these, so the service is exchange) This system is a direct replacement, so it plugs straight in as usual, no need to change any sensors, nothing. The kit comes supplied with full mapping software to alter all ignition timing and fueling throughout the rev range, if you fit bigger injectors or a higher map sensor, then you just recalibrate the map to suit. All programming is done via a laptop/pc though a supplied cable which goes from the serial port and plugs into the diagnostic port in the engine bay, all programming is done via this port. Also you can write to the ecu as many times as you want, for instance, you or other Alpine owners could swap maps and setups, or you could have various maps stored on your computer for what ever spec you want. The ecu will come supplied with the original GTA map, so you have a base map to start with, so you could start tweaking slightly yourself. There is also a facility (i think) to raise or remove the rev limit if nesseccary. The kit is also supplied with a Lambda sensor datalogging software (if you fit an aux lambda), which will plot the a/f ratio on the map as you drive or RR the car. Via this data, you can then adjust the map accordingly to get the correct a/f ratio, so you can map it on the road with out the need for a rolling road. Price will be £595 inclusive (exchange)

The way to think of this ecu, is like the type used on the Cosworths, where the existing tried and tested setup is fully reprogrammable to cope with any setups.

This ECU will only be available for GTA models (not lemans/or A610). Im having to purchase 10 ecus up front, and the Lemans/610s are different setups, so I would have to order 10 of each design, only feasible if there is demand. This ecu could be fitted to a Lemans, but you would lose the lambda function( and the ecu I would need in exchange would have to be a normal GTA one, as the Lemans chipset is different and wont work with the new board)

Are the GTA's built in boost and rev -limiters removed or made adjustable, I have standard and superchipped ecu's and don't want to waste the superchipped one if the boost limits etc are already removed

Tony, if you look inside the superchipped ecu, youll see the piggyback box thats connected with wires to four of the pins inside. The superchip module is exactly the same unit as I list on my site for £250. You can just unplug it and use the ecu as normal.

Thankyou David. I didn't realise the std GTA T3 would be so small. One turbo business here suggested a GT30 would be the right option. Any experience with them? What sizes are your stage 2 hybrid turbos?

The GT30s great if you want to run 600bhp! Ive never or had any intention of using the GT series yet, mainly because the T series are more affordable, and secondly, because the lag problem isnt turbo related, the RB core wont really make a difference, especially when the RB turbos are bigger anyway which causes more lag anyway.

The stage 2 turbo I do is a T3, with a .48 exhaust housing and a 60trim T3 compressor wheel. Its basically a specification higher than the Europa cup models fitted with an A610 spec compressor wheel.

The stage 3 is a T3 turbine side with T4E compressor wheel and cover, big boost but more lag.

[Alpineandy]

What about a Bi-Turbo option?



stirring the pot......

As opposed to a straight turbo??!!

Is that when they turbo the MX5? Seriously though I considered this with my 3 litre engine but I didn't think the positives over a larger single turbo were enough to warrant the extra cost involved - fabrication is expensive. I think it would be better for lag with well chosen turbos but whether it would be more powerful I don't know. an A610 is 250bhp and a biturbo Safrane 268bhp but I'm not sure if they run the same boost pressure - I'm sure David will know. Alot of japanese tuners swap twins for singles on Skylines and Supras so its probably horses for courses.

The safrane is slightly better, it has 268bhp on 7psi with 2 cats, the main gain being the derestriction in the exhaust system having the two turbine housings instead of the one.

Pity the cars so damn heavy 1695kg!