Feedback re GT3071 .63 on an ABY S2 Avant

[macspring]

Was going to decide on a GT 3071 .63 turbo on an 2.2L ABY Avant with rods, worked head, Wagner manifolds, and front inlet intercooler, RS2 downpipe and Milltek RS2 exhaust. RS2 or equivalent. OEM ECU with a custom map.

Looking for up to date feedback on how others have faired when using that turbo with a similar spec engine and ancillaries ?

Does anyone know about that difference between these two turbos below ?

http://www.034motorsport.com/turbochargers-and-accessories-garrett-gt-ball-bearing-turbos-garrett-gtx3071r-billet-wheel-turbo-p-21267.html

http://www.034motorsport.com/turbochargers-and-accessories-garrett-gt-ball-bearing-turbos-gt3071r-p-725.html

When does full boost occur ?

Thanks in advance.

[Jonnybravo]

Is the .63 housing not a bit small for the 2.2 capacity ?

[QuattroFever]

i think it is. But Im using .63 on a 3071. Stock block and head.

On a stock head and cams not much point because the boost comes on so early it just surges and you have to dial it out with the wastegate.

Boost starts at 3k rpm but can only unleash it fully above 4500.

If you have ported head and cams obviously will be able to bring that 4500 lower and have better midrange.

[A80Avant]

reading recently a review on the GTX turbos, they said that the 3071 and 3076 spool excacly the same and the latter produces much more power, when compared against the same turbine housing. So if you are thinking on the GTX turbocharger, go for the 3076 directly.

the GT3071 will only make around 450 at best and spool is as quattrofever says, although with ADU cams, you do get the full boost/torque at around 3600rpm on 3d gear. (that is on .63ar)

[newsh]

I'm on the same turbo, I was told the .83 would make more top end but boost later so I went for the .63 , its a bit of an animal
I've just changed the manifolds from RS2 to Wagner and it seems to hit much harder and sooner. I'm betting it will surge less now too and could probably do with remapping (again ... )

Horsepower is vanity, torque is sanity.

David, what cams are you going for?

[macspring]

Was hoping GT 3071 .63 would give full boost at 3K, or am I just wishing ?

Thinking of that one because I wanted as early a boost as possible, and while GT 2871 would be fine, wanted to avoid the surge, and have some head room, and not be straining it.

Aiming for 410 'ish all day everyday.

[S2central.net]

I believe stock cams and 3071 0.63 will be fine... had worried about surge lines on 2871 before but you have to be asking it to make silly boost very early in order to surge it. Surge lines have some margin on them for end of life performance. For a road car - 'only' 450bhp is plenty enough poke at the top end... Seems to me the 3071 0.63 can make LOTS of torque from 3000rpm upwards on our engines and some care is needed not to surge them.

What CR are you thinking off here David - stock or something lower so you can run more timing ?

[diesel des]

I have a 2871 on mine. If you get up north I could take you a demo...

I did try a 52 trim, gt2871r, a 56 trim gt2871r and now I use a gt3071r 0.5 ar comp cover and back plate on a gt2871r with .63 at exhaust. Basically that's a gt3071r cold side and 28 hot. I had minor comp surge which is tweeked out with the software, and great response. A 3071r cold side will flow 500hp at a push. Sure egt are hot if pushed with the 28 hot side, but for fast road work its great. I have pulled over 7k rpm in 6th with this setup... Also on lpg egt are cooler.

I get 0.5 bar at 2.4k rpm and 1.4 bar at 3k. Then 1.6 bar from 3.5k rpm to red line. That's with no surge. Power Is mid 4xx bhp. Aan urs4.

[S2central.net]

still stock cams & CR - right Des ?

You could run higher boost/torque in mid range with forged rods - comfortably 1.8-1.9 bar circa 4500 territory... Thats getting into 550-600Nm country depending on how much timing it can sustain and that air temps & egt are nicely controlled.

And stock WG spring ?
May not be worth going siffer spring on these because of potential for surging if it causes it too spool faster than it likes...

[diesel des]

Yes, stock cams and comp ratio. I have ran upto 1.8 bar from 4k to 6k rpm. But I like cheap petrol. It's fine and goes better on lpg though. I'm currently fitting a 50% larger intercooler and better flowing exhaust, so might let the boost creep a little.

Exhaust testing http://www.youtube.com/watch?v=Q7e2V...e_gdata_player

During a test off uk roads.... http://www.youtube.com/watch?v=uiZwa...e_gdata_player

[diesel des]

Yea that's off UK roads..

[A80Avant]

i will agree on the above.
when i was using the 3071 i had similar results and was boosting it to 2.1bar which appeared at 3600ish on 3d gear. Obviously on the rest gears it appeared a lot sooner, which made the 6th somewhere around 3000rpm with a bit of surge, but nothing tremendous.
Car felt and was agile but you did feel that anything above 5600-6000rpm was not pulling as much + i needed to keep boost below 1.8bar on the top end to keep EGTs low. That was with rs2 EM, 0.63AR, stock ADU head and dual cats/back system with 2 resonators.

[macspring]

Normal CR and ABY cams.

Approximately when will it / could it make full boost in second gear ?

Thanks for all the comments so far.

[newsh]

David, in second gear everything happens way too quickly to know whats going on

[Ross]

I have to agree with Newsh here - my GT3071R coupe had no issues with lag. In 2nd you could floor it and it would just fly, no idea where the boost came in 'coz it just seemed to be on tap. With my RS2, do that below 30mph and it does nothing for a few seconds. In 3rd I was seeing 1bar at 3,000rpm and from that point onward it went like a rocket.