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

[Bram]

GT3071R vs. CT355

Just to mention the difference between the Garrett GT3071R 0.63 vs. the CT355 0.63 setup, I will sum up my observation. I have to admit the cam re-clocking is of some influence here, but nevertheless I think there are a lot of differences between the turbos.

GT3071

- Starts to pull from 2900 RPM with positive boost (0.5) and hitting 1.8 bar at 3200 in the higher gears. It's a very short RPM range where the boost is build up and feels like an on/off switch. Most of the time the partial throttle control resulted in an outburst of turbo boost, and thus making it a tricky daily driver turbo to get used to.

- Starts to run out of puff above 6000 RPM. Again this can be due to my original ADU cam wheel and cam timing I had then, and the conservative mapping done by my previous Dutch tuner. On the other hand since the turbine wheel is not as big as the CT355 one it makes sense. Probably the GT3071R is good for 450 crank HP when tuned to it's max.

CT355

- Starts to pull from 2500 RPM with positive boost (0.5) and hitting 1.9 bar at 3400 RPM on my re-clocked ADU cams in the higher gears. The power delivery in the lower revves (say 2000-3500 RPM) is a lot better as I had with the GT3071R to control the engine revving up or releasing the throttle (and immediately pushing the throttle pedal again) when driving swiftly in daily traffic. Since the compressor wheel is larger as the Garrett one, the CT355 compressor wheel makes it a bit slower in spool-up, but the efficiency is a bit higher I would say. In short the CT355 is a responding more progressive in building up the boost.

- The CT355 simply starts to pull hard from 3400 till 7000 RPM. I do not have the feeling that this turbo has seen the max, yet due to air filter restrictions, the "slow" but comfy exhaust my car has, etc. as mentioned earlier by Jyrki. Compared to the GT3071R this CT355 allows you to have such a wide power band that I think already this is such an improvement, that I really do not care if I have 475HP or 530HP.

The engine response is feeling just great, now I can compare it. Before this time I was already happy with the GT3071R, but I will never go back to it again

I can recommend you guys to get in contact with Jyrki to help with your projects if you are serious about it. This man knows his job and can help also with daily driver projects like mine, or high HP projects like the one from T. Paavola.
For me the building of the basic things like engine internals, turbo, inlet, engine mounts, etc. is doable, but I am so not an expert when it comes to how combustion engine works, airflow, ignition timing, cam timing and most of all know where the limit on the setup lays that I gladly spend money to fly in a professional like Jyrki.

Cheers dude

[Bram]

Via this way I also would like to thank Carsten Wagner for his great products. I think the big IC, the short IM and cast EM are working great and are reliable for a daily driver like mine. I think the max intake air temp at 2.2 bar in 5th gear at 6500 RPM was about 50 degrees Celcius. Jyrki was positively surprised about this result.

Let's hope these morons stop copying your products and you earn the money that you deserve as originator of good design and reliability.

A virtual pint for you too!

[Jamo]

Via this way I also would like to thank Carsten Wagner for his great products. I think the big IC, the short IM and cast EM are working great and are reliable for a daily driver like mine. I think the max intake air temp at 2.2 bar in 5th gear at 6500 RPM was about 50 degrees Celcius. Jyrki was positively surprised about this result.

Let's hope these morons stop copying your products and you earn the money that you deserve as originator of good design and reliability.

A virtual pint for you too!

I echo that also Morons stop buying them because it seems the knock offs are cheaper.

Well done Repo, now Bram get the car to a dyno!

Certainly the CT turbo sounds excellent and your happy you've changed. Maybe in a few years when I get bored

[Bram]

If more people have experience with large air filters I would like to get a recommendation to replace my too small filter.
I hear that the Green one should be good, but also that it leaves traces of some sort in the inlet track. Can anyone confirm this?

Cheers

[A80Avant]

Good results.

throttle responce is also because of the way vems handles throttle and boost,so it is not easy to compare just with the change of equipment. obviously the reverse manifold makes a difference as well, but i had almost 500rpm faster boost with the use of VEMS, and no change in equipment at all.

[VU-002-RS]

Just to mention the difference between the Garrett GT3071R 0.63 vs. the CT355 0.63 setup, I will sum up my observation. I have to admit the cam re-clocking is of some influence here, but nevertheless I think there are a lot of differences between the turbos.

GT3071

- Starts to pull from 2900 RPM with positive boost (0.5) and hitting 1.8 bar at 3200 in the higher gears. It's a very short RPM range where the boost is build up and feels like an on/off switch. Most of the time the partial throttle control resulted in an outburst of turbo boost, and thus making it a tricky daily driver turbo to get used to.

- Starts to run out of puff above 6000 RPM. Again this can be due to my original ADU cam wheel and cam timing I had then, and the conservative mapping done by my previous Dutch tuner. On the other hand since the turbine wheel is not as big as the CT355 one it makes sense. Probably the GT3071R is good for 450 crank HP when tuned to it's max.

CT355

- Starts to pull from 2500 RPM with positive boost (0.5) and hitting 1.9 bar at 3400 RPM on my re-clocked ADU cams in the higher gears. The power delivery in the lower revves (say 2000-3500 RPM) is a lot better as I had with the GT3071R to control the engine revving up or releasing the throttle (and immediately pushing the throttle pedal again) when driving swiftly in daily traffic. Since the compressor wheel is larger as the Garrett one, the CT355 compressor wheel makes it a bit slower in spool-up, but the efficiency is a bit higher I would say. In short the CT355 is a responding more progressive in building up the boost.

- The CT355 simply starts to pull hard from 3400 till 7000 RPM. I do not have the feeling that this turbo has seen the max, yet due to air filter restrictions, the "slow" but comfy exhaust my car has, etc. as mentioned earlier by Jyrki. Compared to the GT3071R this CT355 allows you to have such a wide power band that I think already this is such an improvement, that I really do not care if I have 475HP or 530HP.

The engine response is feeling just great, now I can compare it. Before this time I was already happy with the GT3071R, but I will never go back to it again

I can recommend you guys to get in contact with Jyrki to help with your projects if you are serious about it. This man knows his job and can help also with daily driver projects like mine, or high HP projects like the one from T. Paavola.
For me the building of the basic things like engine internals, turbo, inlet, engine mounts, etc. is doable, but I am so not an expert when it comes to how combustion engine works, airflow, ignition timing, cam timing and most of all know where the limit on the setup lays that I gladly spend money to fly in a professional like Jyrki.

Cheers dude

i haw same ting between the Garrett & CT, I can compare it between GT 35R 106ex & CT4367 63ex ,same cam setup
mi GT35 was exploding from 3300rpm(0.1bar) full boost at 4200rpm(2.0bar), CT4367 spoll at 2500rpm(0,1bar) build up fool boost at 5000rpm or less (2.0bar)
i hate filing mi RS2 is faster wit GT35 bat testing was better wit CT67
garet 100km-200km 8.4sec
CT 100km-200km 7.5sek
i hat olso GT35R with 0.63e & 3B cams setup end i felt big power drop in 4-5 & 6 gear

[terrybullwon]

i haw same ting between the Garrett & CT, I can compare it between GT 35R 106ex & CT4367 63ex ,same cam setup
mi GT35 was exploding from 3300rpm(0.1bar) full boost at 4200rpm(2.0bar), CT4367 spoll at 2500rpm(0,1bar) build up fool boost at 5000rpm or less (2.0bar)
i hate filing mi RS2 is faster wit GT35 bat testing was better wit CT67
garet 100km-200km 8.4sec
CT 100km-200km 7.5sek
i hat olso GT35R with 0.63e & 3B cams setup end i felt big power drop in 4-5 & 6 gear

So the CT67 hit full boost at 5000rpm?

Do you have a dyno graph for this set up?

P.S Sorry for the off topic. Car is looking schweeet

[VU-002-RS]

So the CT67 hit full boost at 5000rpm?

Do you have a dyno graph for this set up?

P.S Sorry for the off topic. Car is looking schweeet

yes full boost at 5000rpm
i have not dyno graph with CT67

Sorry for the off topic your car is a bomb i lake it

[quattro84]

Interesting results. Especially that vacuum meter. Best would be to measure @ compressor inlet and before the filter in the box. A difference would suggest a restricting filter.

What is the smallest diameter in your inlet traject upto your compressor inlet? What did you measure in the airfilter box? Near to absolute vacuum? It that's true the following is true:
600hp roughly means you consume 0,65 cubic meters of air per second.
Air choking starts around the max speed of air (~330m/s @ 20 degrees C).
So if you calculate that back then a max. area of 1970cm^2 would be limiting, effectivly being a diameter of 50mm.

Compressor inlet is like what, 3" ? Keep the entire inlet path upto the compressor inlet at that diameter and you must be fine IMHO.

Changing cam timing will result in a completely different (offboost) engine, and higger offboost power (= more turbine energy) will enhance turbo upspool.

[Error404]

If more people have experience with large air filters I would like to get a recommendation to replace my too small filter.
I hear that the Green one should be good, but also that it leaves traces of some sort in the inlet track. Can anyone confirm this?

Cheers

If you mean the HKS "mushroom" filters yes I can confirm that their filteration is 5hlt. they do flow well though, you have to make a choice i suppose
Car sounds great, i hoep you're enjoying it

[A80Avant]

what do you mean their filteration is sh!!t?

[Error404]

I mean they are 5hlt at filtering out small particles, that is how they are able to flow well i think

[A80Avant]

hmm are they good enough to prevent particles hitting the turbo and damaging it?

[Jamo]

This is well known, can't have both very easily, too flow you need to have larger filtration gaps. HKS is about the best on the market for high power applications however i've heard of no alternatives that can support high bhp

anybody?

[Error404]

it is tiny particles like 1 micron so it is long term wear potentially - they are very widely used by lots of people, but I wouldn't touch them personally