RS2 GT3071R dyno results

[A80Avant]

As Dmitri says

[prj]

Something is wrong then.
What is the duty cycle on solenoid?
What ECU do you have?

Might be a hardware fault too.

0.63 A/R should be full boost around 3900 rpm in 3rd. with 7A cams.

[A80Avant]

I wouldn't have used 7A cams with this setup or any setup with 0.63ar. It's meant to pick up from low and you have used cams to counteract that. Also 7A cams will be more powerful at the top end when the 0.63ar will have nothing more to give.

[prj]

I wouldn't have used 7A cams with this setup or any setup with 0.63ar. It's meant to pick up from low and you have used cams to counteract that. Also 7A cams will be more powerful at the top end when the 0.63ar will have nothing more to give.

My dyno results prove otherwise.
I prefer a 0.82 with stock cams though.

0.63 on the 3071 has so much surge there is no difference once you are past getting rid of the surge.

[A80Avant]

You were using 0.82ar mostly weren't you?

Do you disagree that for the way the 7A cams are working having 0.63ar is worse than 0.82ar?

[prj]

You were using 0.82ar mostly weren't you?

Do you disagree that for the way the 7A cams are working having 0.63ar is worse than 0.82ar?

I have dyno plots of 0.82 AR stock cams and 0.63 AR 7A cams.
7A and 0.82 has too little low-end imo.

You can build it both ways.

[A80Avant]

What are the results of stock vs 7A on power and torque? At which RPM as well?

And by stock you mean AAN/ABY or ADU?

The theory is to use a turbo matched to cams. Cams as 7A which tend to have more aggressiveness above 5000rpm or so they say, would be meaningful with a matched turbo ie larger or with higher AR to produce more power.
All mid range garrett with small ARs need mid range cams to make use of the midrange potential. From 3500 to 6000rpm.

That's the way I see it. Sure you may still be able to get some good results either way, but for me ADU cams on 0.63ar is better than 7A cams for someone aiming for quick low end pickup.

[diesel des]

I have dyno plots of 0.82 AR stock cams and 0.63 AR 7A cams.
7A and 0.82 has too little low-end imo.

You can build it both ways.

Dimitri at what rpm do stock aan cams drop below 7a cams for power on any given setup? Between 4 and 5 k rpm?

On my urq stroker build with a gt35r with larger billet compressor and tial 0.82 ar housing I have gone with 7a cams. This is because I feel the turbo will need to be over 4 k rpm to have some boost so why go with cams that work well below this rpm? Good or bad decision? Its mostly a track car...

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[Tesa]

I have VEMS on 3B engine converted to FSI coils on spark plugs.
Im using the MAC solenoid controling the upper chamber of the original wastegate, and im runing T-piece between manifold pressure, solenoid, and the bottom chamber.
The gearbox is not that long like on original S2 so lets say my 3rd gear is slower, but it doesnt do much difference.
Sorry i was wrong with target - the target was 1,9 and duty cycle was 72% givving 1,6 boost.

[prj]

What are the results of stock vs 7A on power and torque? At which RPM as well?

And by stock you mean AAN/ABY or ADU?

The theory is to use a turbo matched to cams. Cams as 7A which tend to have more aggressiveness above 5000rpm or so they say, would be meaningful with a matched turbo ie larger or with higher AR to produce more power.
All mid range garrett with small ARs need mid range cams to make use of the midrange potential. From 3500 to 6000rpm.

That's the way I see it. Sure you may still be able to get some good results either way, but for me ADU cams on 0.63ar is better than 7A cams for someone aiming for quick low end pickup.

Except 0.63 on a 3071R with stock cams is not an option. It spools exactly the same as 0.82 after you limit it to prevent surge and has less top end. Remember, it is the same exact turbine as the 3076R, but the compressor wheel is even lighter. There is already surge on the 3076R with the 0.63 housing, and the 3071R is simply unusable... It is possible to make it work with software, but it will be worse in every way than a 0.82 housing.

Dimitri at what rpm do stock aan cams drop below 7a cams for power on any given setup? Between 4 and 5 k rpm?

On my urq stroker build with a gt35r with larger billet compressor and tial 0.82 ar housing I have gone with 7a cams. This is because I feel the turbo will need to be over 4 k rpm to have some boost so why go with cams that work well below this rpm? Good or bad decision? Its mostly a track car...

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The crossover point is about 5-5.5k.
Sounds good to me.

I have VEMS on 3B engine converted to FSI coils on spark plugs.
Im using the MAC solenoid controling the upper chamber of the original wastegate, and im runing T-piece between manifold pressure, solenoid, and the bottom chamber.
The gearbox is not that long like on original S2 so lets say my 3rd gear is slower, but it doesnt do much difference.
Sorry i was wrong with target - the target was 1,9 and duty cycle was 72% givving 1,6 boost.

Your wastegate control is most likely at fault. Also make sure you haven o boost leaks.

1. Do the control the stock way. Control bottom wastegate port only and use a stiffer spring (0.9 bar). Your current setup will not work.
2. DC should be 95% on spoolup, and only when the actual is reaching setpoint (just before) it should make a downwards spike due to D.

[diesel des]

Except 0.63 on a 3071R with stock cams is not an option. It spools exactly the same as 0.82 after you limit it to prevent surge and has less top end. Remember, it is the same exact turbine as the 3076R, but the compressor wheel is even lighter. There is already surge on the 3076R with the 0.63 housing, and the 3071R is simply unusable... It is possible to make it work with software, but it will be worse in every way than a 0.82 housing.



The crossover point is about 5-5.5k.
Sounds good to me.


Your wastegate control is most likely at fault. Also make sure you haven o boost leaks.

1. Do the control the stock way. Control bottom wastegate port only and use a stiffer spring (0.9 bar). Your current setup will not work.
2. DC should be 95% on spoolup, and only when the actual is reaching setpoint (just before) it should make a downwards spike due to D.

Thanks

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[A80Avant]

When I was using the 3071 setup on the 0.63ar the only drawback I had was on 5th and 6th gear. Other than that it felt lovely on lower gears and quite snappy.

When I used 0.82ar I had nothing on All gears until 4000rpm. And then you get a freshly serviced engine that compression is fine, a few thousand kms down the line it gets worse.

But all that are just points of view. I see your point for the surge though

[Tesa]

Dear all, sorry for late reply. You know how is it with the time to our hobbies..
So I have checked the blow-off valve, and unfortunately it was leaking on the idle, and higher boosts. Also there was one small boost leak by vakuum hoses. Now everything fixed.
It seems now, the car is ready to be tuned now.

This is run on fifth gear.
Hilariously rich, but do not mind now, but will be fixed soon, I hope.

Thanks,

Radek