introduction and dyno results: What do you think

[bogreg]

This is what I thought as well looking at the dyno porkkis posted. Simply taking the cats out and putting a 3" downpipe on would not only make the turbo spool better, but also a lot more noise. I have had an avant with no cats and 3" exhaust. That was fun for some time, but I don't want that again. It made too much noise at low revs, which made it tiresome in town and at crusing at low speeds, basically in every moment when you want a car to be silent...
Because of the long pipes and the trunk avants tend to do this. I like the way the stock exhaust sounds. Maybe with small BB turbo the spool could be improved, flow is limited by the exhaust anyway.

[bogreg]

Slightly off-topic but that is a MINT looking interior!

What do you use to keep it looking so new? Or has the car only got 20k miles on it??

I bought it almost like this with 160k. There were two places where there was a sign of some usage. The gearknob: I replaced it with new OEM one; and the drivers seat: I had it dyed where it needed and had part of the leather shrinked? back to its original size. Now it looks almost like new. Apart from these I have done basically nothing. I am trying to keep it clean and away form UV. Not really using it every day. Probably that is what matters.

[Jamo]

This is what I thought as well looking at the dyno porkkis posted. Simply taking the cats out and putting a 3" downpipe on would not only make the turbo spool better, but also a lot more noise. I have had an avant with no cats and 3" exhaust. That was fun for some time, but I don't want that again. It made too much noise at low revs, which made it tiresome in town and at crusing at low speeds, basically in every moment when you want a car to be silent...
Because of the long pipes and the trunk avants tend to do this. I like the way the stock exhaust sounds. Maybe with small BB turbo the spool could be improved, flow is limited by the exhaust anyway.

I have a 3" system with 3" milltek centre and back box and there is no noise at low revs or drone at any rev range. Terrybullwon can tell you how nice my car sounds, I've even had my 60 year old neighbour say my car sounds mint

Drone does not come from the downpipe it comes from what type of centre and back boxes you have!

[porkkis]

BB or not BB, that will make no difference in regard of spooling. BB is usually faster to regain boost in gear change and gives better response in off boost urban driving.
Basically you just need a smaller and/or newer design turbo.
Also cams do make a difference. Max torque is around 500rpm lower with std 20vt cams compared to rs2 cam setup. Power level will be around 20hp below rs2 with "std" cams and timing.

Original B5/8D RS4 exhaust should fit your car with moderate modifications. I'd probably go that route in a RS2.

[EspenW]

Factory claims of peak torque vs rpm are usually misleading on turbo engines, since the factory dyno test is done at static rpm, while most test on a rolling road are done with a dynamic sweep test. The higher the gear, the lower the rpm for peak torque, but it will still not match the rpm of the factory claims.

I only have graphs from 2nd gear pulls with stock and chipped RS2, and they both hit peak torque around 4500rpm, I would assume that they would hit the peak at around 3700rpm in 4th gear (normally what is used on a RR).

[bogreg]

I have a 3" system with 3" milltek centre and back box and there is no noise at low revs or drone at any rev range. Terrybullwon can tell you how nice my car sounds, I've even had my 60 year old neighbour say my car sounds mint

Drone does not come from the downpipe it comes from what type of centre and back boxes you have!

At the age of 60 your hearing is not really at its best anymore. I can see how mine is loosing the ability to hear very high frequencies for example. But so far the drone has come through all the way
I had two simple boxes, the centre with no chambers, the back with chambers. Probably that was the one responsible for the drone, although I had it changed a couple of times with several designs, but it has never really got any good...so I am trying to be more careful on this matter.
Does the milltek system produce noticable gains with the cats on as well? Has anyone measured it in any way? Am I right thinking that the RS2 already came with metal cats, so there is not much point in replacing them with sport cats unless they are clogged?
Or using the stock system with a 3" downpipe? Does that improves anything or worth nothing without making it 3" all the way?

[bogreg]

BB or not BB, that will make no difference in regard of spooling. BB is usually faster to regain boost in gear change and gives better response in off boost urban driving.
Basically you just need a smaller and/or newer design turbo.
Also cams do make a difference. Max torque is around 500rpm lower with std 20vt cams compared to rs2 cam setup. Power level will be around 20hp below rs2 with "std" cams and timing.

Original B5/8D RS4 exhaust should fit your car with moderate modifications. I'd probably go that route in a RS2.

I mean BB AND newer design. I am happy to go smaller as well if it can still produce approx. 350 bhp safely, but that would make it around RS2 size. I was hoping a more modern design can improve responsiveness and spool without any sacrifices.
Changing the exhaust cam back to ABY/AAN seems like a bit of a downgrade to me, although I understand what you mean. I have tried both s2 and rs2 cams in my previous car and I always missed the top end with the s2 one. (Factory timing in both case, I had no adjustable cam gear)
I have some experience with the K26/GT3071/0,63 and I was not truly impressed. Spooling threshold did not seem much lower compared to RS2 and it run out of puff at the top end. (Of course it is a bigger turbo, could easily reach 400bhp, maybe even 450 at the very end, but that was all) The only thing which was truly great is lag/reponsiveness: at the right rpm range it really spool up very quickly. This is exactly what you wrote on the benefits of BB.
But I am looking for less lag and a wider rpm range this time, trying to benefit of the at 15 years of development in turbo technology, without sacrificing top end power. Can you suggest a bolt on solution in terms of turbo with the least possible modifications?
B5 RS4 exhaust? Do you mean the parts after the cats? I would assume the downpipes are completely different on a V6, although I have never really seen one. Also getting hold of a rs4 exhaust does not seem particularly easy to me, but maybe worth checking if they are really so great.

[bogreg]

Factory claims of peak torque vs rpm are usually misleading on turbo engines, since the factory dyno test is done at static rpm, while most test on a rolling road are done with a dynamic sweep test. The higher the gear, the lower the rpm for peak torque, but it will still not match the rpm of the factory claims.

I only have graphs from 2nd gear pulls with stock and chipped RS2, and they both hit peak torque around 4500rpm, I would assume that they would hit the peak at around 3700rpm in 4th gear (normally what is used on a RR).

Yes they are, as I have just learnt
The dyno I posted was done in 4th gear and we got peak torque around 3700 as well. At least I know that the car works all right for a stock RS2. I may seem to be a bit unsatisfied with the results, but honestly there is not much to complain about. After 15 years and 168k she still produces stock numbers with ease. That is not bad after all.
I just can't help thinking how this could be even better...:mischeif:

[pnanassy]

Milyen szép autó !!

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[bogreg]

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