Yep, clearly a 6th gear pull to 6krpm required for more data points :)

Maybe the traction control kicked in and closed the throttle plate?

that was my thought too ... till i found a log where that had happened .....with no timing pulled !

I think/hope it was what Slash suggested ... an anomally .

Traction control implies there is traction to begin with :lol: /troll

How is transient response? I got an idea the other day, sadly Koenigsegg have been thinking about it before me: Christian von Koenigsegg - Koenigsegg | Koenigsegg
Theory is that when you close the turbine inlet, there is no flow. At no flow, turbine does not perform any work(pressure x flow), therefore compressor will turn (a lot) lighter, so that the initial turbine speed will be higher, and you do not have to accelerate turbine as much when you go from cruise to WOT. Would be very interesting to test, and not too complicated.

from anywhere over 3000rpm I'm getting really good response.
I'm not sure what you are suggesting . Do you mean diverting flow away from the turbine by opening the wastegate ?
I had something like that earlier on , wastgate open at cruise . It killed reponse completely as it took too long for it to close and start spooling the turbo.

Can't see how what koenigsegg did on a centrifugal SC could have any relevance to a turbo.

Why do you tune it on 93oct and not 98?

I do tune it on 98 ..... which is same as 93 (r+m/2) in the US .

I see i had forgotten
Do you use the US measure in Kiwi?

No ... same as aussie ... Just easier on this site to refer to the US measure . Otherwise everyone is like ......WTF ?

You close on the coldside inlet, keeping wastegate closed.
- Wastegate is closed, so all exhaust gas is going through turbine
- Compressor inlet is closed, so you have close to no flow through it(only leaks)
- Compressor turns easily due to no work(Press x flow = almost 0) is, and hotside see less resistance due to this
- Because less resistance, hotside turns faster when you are at cruise

No idea of numbers here, but if you for example increase turbine speed from 20k to 60k during cruise, turbo lag will be less. You have a 40k difference that turbine does not have to cover. Acceleration of the wheel will inevitably take some time, the more inertia wheel has, the more time it takes, increasing lag. Even though you are in a RPM where you eventually will get the boost you want when you step on it.

would that not be harder on the turbo once you do open the throttle/plate closing off the compressor?

Yeah, I still haven't figured out what "tyres" are :dunno:

I think i might have already tried this idea to some extent . By opening the BOV at cruise . I did this by fitting a very light spring in the BOV which allowed it to stay open when UIM was in vacuum . This is the same principle that the synapse BOV employs http://www.motoiq.com/MagazineArticl...ter-Valve.aspx . I really couldn't get any noticeable difference by doing this .

Yes, this is the same way of thinking, but opposite. Here you'll have flow, but no pressure. I would guess closing inlet would work better, due to loss in BOV loop, and possibly in compressor. And what setup did you try this, your old one? I would expect gains to be increased with size of turbo, as larger wheel gives more inertia.

Yeah that was on my greddy setup . Maybe worth another try with the synapse DV . But i can't see it being worth putting another throttle body in .

I'm not very qualified, but the reason I think a TB will work better, is that when BOV is open, air circulated will have to go through a loop with relative sharp bends, with flow this will build a small pressure, and thereby work will go from approx zero to a little bit more than zero, and thereby load to turbine.

I'm sure it would work better ..... but would it be worth the exercise ? I can't see it improving response much on a system that already has near instant response .

New muffler is fitted , check out the difference :



This was the first attempt :

Sounds "full" if ya get me.

Nice work.

Travis

Thanks ... I'm liking it now . It's also lost that farting noise at medium loads which was really bugging me .

Now to see if backpressure is any better :)

that sounds great brett!

Lol just say no to fart noises.

i like it :)

Turbine backpressure results for newest muffler @12.5psi :


.................Front scroll ..........rear scroll....RS no muff......1stmuff.....newmuff
3000..................5........................4.. ............3...................3.............
4000.................11.......................9... ............7..................8............7
5000.................14......................13... ...........9.................12...........10
6000.................18......................17... ..........12.5.............15...........14
7000.................24......................22... ..........17................19...........18
8000.................30......................27... ..............................24...........21.5



This is a really good result ! Basically only 1-2psi more backpressure than an open pipe and total reduction in backpressure between old twin exit muffler and the new single exit is 5.5psi @ 8000rpm
Difference between 1st muffler and new muffler is that we replaced one of the two louvered mufflers with a more free flowing perforated type , plus got rid of the short radius bend at the join and replaced it with a long radius bend.

WOOT !

Did you pickup any noticeable power