Gt3071r - which A/R to go ?

[prj]

In a lighter car the peak boost arrives later.

Also, 3071R/0.82 with 7A cams makes absolutely no sense to me.
I'd fit a 3076 then...

[Guslotti]

In a lighter car the peak boost arrives later.

Also, 3071R/0.82 with 7A cams makes absolutely no sense to me.
I'd fit a 3076 then...

So I believe that I will choose for GT3071R 0.63 A/R + 7A cams.

[prj]

Yes, this should be fun to drive.
Keep in mind, that it goes from almost nothing to 570nm in less than a second.

So if you want to drive it fast, better keep it on-boost all the time

[Guslotti]

Yes, this should be fun to drive.
Keep in mind, that it goes from almost nothing to 570nm in less than a second.

So if you want to drive it fast, better keep it on-boost all the time

Thanks for your tips. I was looking for this kind of reaction because I'm building a Sport Quattro replica. I believe that will be fun too.

By the way I didn't install your chipset yet. No time and space to stop the car for a long time to do this and other services.

[Ross]

My old coupe was a GT3071R with 7a exhaust cam and stock head. It made a very similar power curve to that Dmitri posted, 428hp peak but that maxxed out injectors so there was a little left. It felt great round town, had a little surge but near instance response above 4k revs.

[macspring]

So how would he be fixed with a GTX3071 .82 on a JNL Head with ABY cams,and an RS4 mac ?

[newsh]

Never dynoed, but by butt-dyno, the top end feels somewhat stronger
With 0.63 and 7A cams it still surges a little in high gears, but not too much and can be mapped out. With stock cams and 0.63 it is pointless. After mapping out the surge you end up with almost same spool like 0.82 A/R. Transient spool is a bit better, but with a BB turbo it's close to instantaneous anyway.

So, sounds like I need to put my 7A cams back in before you map my car? Do you recommend both cams or just the exhaust?

I have 3071 with .63, RS2 Evo EM and Wagner IC and Rev IM, full 3" Exhaust. Stock cams, its a 3B at the mo. No dyno plot though.. Actually when it was mapped it was running stock RS2 manifolds and was surging.

[caterpillar]

someone tryed even bigger exaust pipin.. 3,5" downpipe and the 0,82 turbo with 7a camset???

[prj]

So, sounds like I need to put my 7A cams back in before you map my car? Do you recommend both cams or just the exhaust?

I have 3071 with .63, RS2 Evo EM and Wagner IC and Rev IM, full 3" Exhaust. Stock cams, its a 3B at the mo. No dyno plot though.. Actually when it was mapped it was running stock RS2 manifolds and was surging.

Sure, go for it. Always both cams.

[Guslotti]

Yes, this should be fun to drive.
Keep in mind, that it goes from almost nothing to 570nm in less than a second.

So if you want to drive it fast, better keep it on-boost all the time

Dmitri, a tubular exhaust manifold or a SQ replica would be a solution for this? With one of these EM would be less ON/OFF?

[prj]

The 7A cams is what will make it on/off.
You can see from the dyno graph I posted.

[A80Avant]

3071R turbo on 0.63AR is quite snappy on ADU cam and sprocket setup.

here are 2 old performance box graphs i digged up which show that the ON/OFF experience is there even without the 7A cams. Maybe you feel it more with them, but the turbo spools so fast and hard that you get the same sensation.

these are 2 4th gear pulls, one on vems and one on motronic. The delayed torque curve was on motronic to avoid surge. However on vems it was easier to tune without too much of it and much less lag. The absolute crank power is not exact, but the torque curve is very accurate in it's shape.

[prj]

It's more pronounced with 7A cams as they are worse off boost.

[Billman]

Sorry to deviate from the original subject.

What would be the characteristics of:

1. Stroker with ABY cams and HX35/40 with 0.7 turbine housing
2. Same with 7A cams

[DJones]

Mine is running standard cams ported head RS2 ex manifold and it produced 480bhp on a GT3071.82 with very little lag at 1.8bar.