Hi guys hope you are all well. It's been 9 years since I sold my coupe and I've just been offered it back so most likely will take it as it's my first love.

Question is and forgive me if I'm completely wrong on this as it's been a while. My coupe was running 483bhp on a Gt3076r can't remember the size of the housing.... I think the larger one from what I remember. If I take the car back I'm thinking to get an even bigger turbo in it and see what power gains I can get from it. Would a gen 2 gtx3576r fit in a coupe and would spool be similar to the Gt3076r?

Also anyone know what sort of power gains I could expect obviously if there's nothing else bottle necking it.


Sorry if it's a stupid question been away from the scene a long time.

Hi,
I’d say look at either the g series stuff from garrett or if you want to mess about some more then the efr stuff from Borg Warner probably edges the garrett stuff

Cheers Jamie

There has been a huge improvement in the Garrett turbos since the GT series.

The GTX series provided a decent improvement by simply swapping in a milled compressor wheel. But the new (introduced about 5 years ago ) G series is a complete redesign improving both turbine and compressor efficiency by 15 to 20%. So you can now produce the same power with a much smaller sized turbo.

The compressor map for your GT3076 indicates a maximum flow of 53 lbs/minute (530 hp). The new G25-660 indicates a flow of 60 lbs/min (600hp) but is sized about the same as a GT/GTX2867r So it would spool up a lot quicker than your GT3076r.

The G30-900 is the same size as your GT3076r but flows 820HP

Or maybe the G30-770 - it is similar size to a GT/GTX3071r but flows 700Hp.

An alternative would be the Borg Warner EFR7163. It flows 600Hp and is similar sized to a GT/GTX3071r, but because it has a ightweight titanium turbine wheel it would spool like a GTX2871

Obviously going with one of the higher flow turbos might require engine work, upgraded fuel system, a remap etc. Maybe you might be happy with the G25 or the EFR both of which would give a bit more power but much improved spool?

Thanks for the response I don't know how to read turbo maps so have found it difficult I like the sound of the g30-900 as long as it spools similar to my 3076r I'd be happy as it doesn't drop off boost when shifting. I'd probably just run at 1 bar then turn boost up for special occasions.

I'll be picking the car up soon so will look into this.

Thanks guys if there are any other suggestions let me know.

Nick

Is that turbo not going to be too much for a fwd car like the Coupe?

Even at 1 bar it would be making 600+ HP At 1.5 bar it would be producing 700+HP! I would doubt that the clutch, gearbox etc would cope with that? Traction would also be a problem when it came on boost!

For the Coupe I would suggest that the G25 series is the better option. The turbine wheel is the same size as a GT/GTX28xx but flows the same as the larger GT/GTX30xx. A G25-660 would produce around 450HP at 1 bar, and around 550HP if you turned the boost up to 1.6 bar. All with a spool-up similar to a GTX2867

I agree with golfpro, unless you want a Santa pod monster the smaller offerings overall will make for a much more driveable and faster car

Cheers Jamie

Am I the only one that would like to find out if it does produce 600bhp at 1 bar :-) the car will be sat on the driveway most it's life I would love to see the result so I'll keep you all posted. Will take a few month considering I moved to Cyprus and have to pick the car up when I'm back in the UK.

Also I was looking at flea leader board the other day and found out it's actually a Gt3071r in my car.

That's really cool to see your Coupe is still out there!

As for the new turbos, well I tune them all mainly on Fords now. I regularly use the G series i.e. G25-660, G30-770, G30-990. They need big boost to see the performance, I run 2.4 - 2.7bar on the 2.3 RS MK3 to see 600-700bhp. The EFR7163 is a good option with the T25 fitment, and I even do a hybrid version of this for 580-600bhp on the RS MK3.

Realistically with the Coupe, the gearbox, diff and clutch are not going to like the torque so much. Keeping the torque to circa 380lbs/ft can see 550bhp at 7600rpm. So a steady torque with a very wide powerband is ideal for a fast Coupe.

What do you do to the EFR to make it a hybrid? I have read of people swapping the stock compressor housing for a SX-E cover to increase HP and add anti-surge.