S2 Avant MTM -> RS2 -> GT3071R -> CT355

[Jamo]

Wastegate isn't about bhp it's about boost and flow control, if your running flat out or high end then your really not going to use the wastegate that much and a stiffer spring is all you need to stop boost creeping open the wastegate at full manifold flow.

The problem comes if your using a lot of low and mid range transitions where you need to limit boost, if the wastegate can't flow enough gas then the boost will keep creeping up uncontrollably by the ecu.

This can also affected by downpipe size afaik as if you have high back pressure it affects wastegate operation.

[Bram]

i would go for cams from the 7A engine if your aiming at 500 crank, this is a good choice trust me.
u have the adjustable pulley from dalhback racing on exhaust and intake cam then we talking fast spoolups.

Im boosting 2.1 at 4000 rpms but im using a slow spooling turbo ( netics ) T61

Keep it up

I am not after the highest possible HP number, but rather want early spooling. That's the reason I keep my hands off from 7A cams, even in combination with an adjustable cam pulley it will bring later boost as stock S2 cams.

Jyrki Repo has done many S2 cars with stock 3B and ADU cams putting down 530 HP / 640Nm and full boost at 3200-3300 RPM with the CT355 I am going to use. I am after big and a wide torque band It's my daily driver.

[Bram]

Wastegate isn't about bhp it's about boost and flow control, if your running flat out or high end then your really not going to use the wastegate that much and a stiffer spring is all you need to stop boost creeping open the wastegate at full manifold flow.

The problem comes if your using a lot of low and mid range transitions where you need to limit boost, if the wastegate can't flow enough gas then the boost will keep creeping up uncontrollably by the ecu.

This can also affected by downpipe size afaik as if you have high back pressure it affects wastegate operation.

ok, I will first try the new setup with the OEM WG, and see how that goes. With my current setup I think it's working just fine.

[Bram]

the stock Wg should be good enough if u change the spring to 2 kg .

I already run the 1.9 bar 034MS WG spring in my setup

[Billman]

when are you going to built this setup? is there any dyno of this turbo with these numbers? Sounds too good to be true!

[Bram]

Setup will be build in the coming 2 months. I planned a lot of free days in July to work on the car

The numbers I mention come from Jyrki Repo who has tuned a few cars with a CT355 and many more with bigger turbos. He knows where he talks about when it comes to I5 turbo tuning. Jyrki has no RR results to share with us, so I have to trust his word on this. Since his tunes were done with his own incredible good EM I hope to get close to the 500 HP mark with my Wagner EVO T3 EM. I know it will not be as efficient as a tubular.

I will just give it a try Billman, and see where I end up. At least I try it out, while others are waiting or questioning it all the time. It's time to put that CT355 to the test!

I must say that my very good choice of taking the GT3071R was done based on projects described on this s2forum, and I hope to return something back to the forum with the CT355 replacement. Exciting months!

[A80Avant]

jade is also trying out the CT358.No mapping done yet,so we'll see

Bram, let us know what the results will be.Make sure to take lots of photos of the turbo before fitment,and some measurements as well.

Me,i decided to go for a holset hybrid solution myself.Now with VEMS i can try lots of different configurations afterall.For me i can say that i have little time and money to spare for experiments with turbos and tuners who i will just 'have to trust'. But it will be a good thing to have some results on the forum,since everyone seems to be going the garrett way, now you, jade, jogi730 (if i remember correctly) are going to go to the CT turbo solution.

Hope it works out well!

[terrybullwon]

since everyone seems to be going the garrett way, now you, jade, jogi730 (if i remember correctly) are going to go to the CT turbo solution.

Hope it works out well!

Yes i sold my GT35 for a CT

This car is going to be great i can tell

[A80Avant]

oh forgot about you.

so there,lots of comps in the forum.i bet Justin must be very pleased!

[Bram]

Just in time some stuff arrived for my "holiday" to spend time on the Avant and give it an upgrade

[Bram]

And some more detailed pics of the CT355

Big thanks goes to Jyrki Repo who supported me big time with outstanding service, even when he is very busy with the races and communications are difficult some times.

[Jamo]

Ooooooooooooh shiney bling

I have the exact same set of Wagner parts and it will make a hell of a difference, interesting on the turbo hotside they've used a different method, they've taken a .6 2.5 four bolt outlet and welded the v band to it.

ATP / 034 take the 3" GT outlet and machine it to V-band.

Not that any of this in real world matters, interesting to see the different technique i.e welding vs machining

[A80Avant]

very nice parts indeed!!! when are they going on the car???

[Bram]

very nice parts indeed!!! when are they going on the car???

Hopefully in the next few weeks. Still need to look for a person in the neighbourhood to weld the V-band on the downpipe.

[A80Avant]

Bram, ill tell you what,where are you located in the netherlands? Next year i will be travelling from Newcastle to Amsterdam by boat and then drive to Italy to go back home for my MOT/vacation/rebuild. I will have the perfomance box with me obviously, so i can measure your car's power regardless of any dyno sessions that you will have done by then.

Im going next year around the beggining of March