Volvo K24 turbo in audi application.

[URQguy]

Wow, that tells the story Chris. Unreal that the 7400 is spooling identical to the standard k24 7000.

[Billman]

is it stock S2 or a chipped one? If not maybe it is better to compare it with one of pauls homefries as maybe is there something to gain spoolwise. Apart from it I dont know if Ruffiano is using MAF or the stock plumbing in general thus having less restriction on the intake path that can cause pressure drop and affect spool.

However it seems that this K24 7400 is a fine alternative to the unreasonably priced k24-7200.

@Ruffiano
Did you made any VEMS-log while on the dyno?

[Ruffiano]

@Ruffiano

How does your boost profile looks like?

what is the best way to pull that from Vems and show you?

[UrS4boy]

Yep, and that's why it makes much less torque as well....
I don't think you are running anywhere close to 28psi on that chart.

Not my car (one of our Vancouver BC UrS club members). If I remember correctly, he does hit 28 psi boost at WOT, if not 28 certainly 26 psi.

[Wheeljack]

Overlay showing no torque lag vs stock k24:

[URQguy]

Here is a dyno plot for an AAN with RS2 turbo, EM, MAF and injectors (but no exhaust cam) with MTM/Dahlback s/w (at sea level), much less peaky:

You are comparing apple to oranges. What did a stock b7 rs4 pull on the same day as that AAN you posted? If you do not have a benchmark, they are just numbers.

As was said above, Dave got crazy torque because he gave it boost where he had turbo flow. If he ran *only* 14psi, his curves would look just like the rs2s.

The same story with my day at the dyno. I will post up on my own thread, but I basically came back to run the hta gt3582r at full tilt. I had made 520whp/460wtq a few months ago at around 29psi. At that level, I was able to hold 29psi to redline. The curves were fairly flat. This time around, I ran the turbo balls out, with the wastegate clamped shut(disconnected wg line). I hit 38 psi at torque peak of 5100, but was down to 32psi by 7500, and 29 by 8500. Well I made the same power at redline, but I now made 612whp/527wtq at the area where I had more flow.

[Billman]

@Ruffiano

How does your boost profile looks like?

[prj]

Yep, and that's why it makes much less torque as well....
I don't think you are running anywhere close to 28psi on that chart.

[UrS4boy]

Can't do anything. You need a turbo that flows up top. The reason that the power peak on the stock RS2 is so high, is because the Stock RS2 doesn't run that much boost (~1.4 bar). It runs fairly flat boost almost to redline, whereas tuned cars run high boost midrange for crazy torque, and then the turbo runs out of steam...

Here is a dyno plot for an AAN with RS2 turbo, EM, MAF and injectors (but no exhaust cam) with MTM/Dahlback s/w (at sea level), much less peaky:

[prj]

I find the peak hp to be great but the curve is surprizingly peaky. I went looking for a factory RS2 (K24-7200) hp and torque graph but all I could find is this (below) which mentions the peak RS2 hp is at 6500 RPM. So what can you do to extend this power peak, prj?

Can't do anything. You need a turbo that flows up top. The reason that the power peak on the stock RS2 is so high, is because the Stock RS2 doesn't run that much boost (~1.4 bar). It runs fairly flat boost almost to redline, whereas tuned cars run high boost midrange for crazy torque, and then the turbo runs out of steam...

[UrS4boy]

You need to tune your boost control a bit it seems...
Seems to take a sharp dip there.

I find the peak hp to be great but the curve is surprizingly peaky. I went looking for a factory RS2 (K24-7200) hp and torque graph but all I could find is this (below) which mentions the peak RS2 hp is at 6500 RPM. So what can you do to extend this K24-7400 power peak, prj?

[prj]

so, where's that motronic chipset for this thing? ;-)

Coming this summer (tm)

[Wheeljack]

From what I can tell, your torque curve rise is pretty much on the same line as mine...meaning no torque lag from mine to yours, which is pretty amazing considering the capacity of the volvo k24...that sounds like a nice next step for me...so, where's that motronic chipset for this thing? ;-)

And regarding the dyno, it seemed pretty inline with my expectations...maybe I'm making more power than I think?...And these are all corrected (to STP) numbers, so the elevation is largely irrelevant, unless you are considering the potential secondary effects of air density?

[prj]

You need to tune your boost control a bit it seems...
Seems to take a sharp dip there.

Thanks for the graphs.

[URQguy]

This dyno is a heart breaker, and we are at 4500' of elevation. Dave mentioned it in his post a few pages back, but the benchmark of what kind of power he is making is the 3 b7 rs4s that ran the same day. he was clumped in the middle of a 10whp spread with them, and 2 of them were fresh off carbon cleanups from the dealer. They are rated at 440hp from the factory, and that is what I believe Dave is making with this volvo turbo.

Stock STIs make 220whp here(rated 300hp) and Stock EVOs make slightly less. If you go by these three vehicles, 25% is even a tad low for drivetrain loss on this dyno.

I have seen several guys bash on the dyno for reading very low on local forums, but it is what it is. If you have benchmark stock vehicles running on the same day with the same basic drivetrain, it is easy to compare them to derive the drivetrain loss. I would put this dyno at 26-27% based on those vehicles.

BTW, as for the 3" debate, I made 612whp on the same dyno as the above on the same day with a 3" exhaust. On road trips, I slip in a 2.5" restrictor in the exhaust to keep the exhaust manageable for 400+ mile trips. I want to dyno the results, but my butt dyno says I am atleast 300whp down. At some point I will probably make a 3.5" exhaust or probably dual 2.5s.