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Get out the sound meter :D

Your probably right about the acceptable level of noise from a whats legal perspective, but I drive it around with it shut, and only open it for track or big street runs.

They do flow, you were probably asking too much of a dual muffler 3.5" system really as you can never have such quiet and not have minor restriction at that size, for your power/flow levels. E85 just needs a bit more of everything - and certainly costly.

The first muffler on my setup was diagonal orientated with a perforated core, so when the air comes in it then hits next bend with the perforations in the side wall creating unwanted turbulence and vortices I suspect. In regards to a straight through muffler it needs to be dead straight, and not with bends inside. It's ok to a degree with straight smooth pipe, but with the muffler holes, definitely straight. This is pretty much what I believe to be creating my issue, especially with the E85 and more HP. 2 LBS of boost more from this relief of back pressure in my exhaust just goes to show how much it was having an effect. I would have liked to go with a big 4" too Ash, but for what I want out of it, I didn't really want to spend that much more. I would have had to do front pipes too, which isn't cheap at that size.

Yeah my tri-pass radiator was sensational, 5 laps and tip top water temps but then I wasn't using E85 or as much boost, tyres would be off before the cooling system had an argument.

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-9s were all over by around 7500rpm with the same motor config

Is there much difference with the -9's and gt-ss? On my old car with stock cams and heads, my car kept making more power past 7,500 rpm with gt-ss turbos.

http://i49.tinypic.com/2cgbyv5.jpg

Edited by topher_

Whats opinions on HKS split dumps? Is it worth the hassle to change to a set of Midori ones. Also thinking about changing the mines front pipe to something a little bigger as well..

I'm aiming to get into the high 300kw area.

Whats opinions on HKS split dumps? Is it worth the hassle to change to a set of Midori ones. Also thinking about changing the mines front pipe to something a little bigger as well..

I'm aiming to get into the high 300kw area.

Have made over 400 with them...but it ain't the most efficient way of doing it.

Well that's good enough for me. There obviously not the best out there but will do the job. Think I'll save changing em out for when the motor is out.

Money better put towards some twin 3" into 3.5" front pipes.

Well that's good enough for me. There obviously not the best out there but will do the job. Think I'll save changing em out for when the motor is out.

Money better put towards some twin 3" into 3.5" front pipes.

Looking for these too but most tend to be 2.75 into 3 or 3 into 3.

Does anyone know a supplier in melbourne

What size are the racepace front pipes?

And do they have equal length pipes before they merge?

Twin 3 inch merging into a 3.5 or 4 inch. Take your pick. (Why you wouldn't go 4 inch is beyond me).

Forget the japanese junk.... well worth the cash.

You always get used to the power.

Plus you'd still need to do transfer case, front/rear diff, suspension. They make the biggest difference dollar vs gains IMO over power/rebuild - just there is 10k on its own. So add in another 15k for the motor and everything and you've done 25k there. Hence why my GTR was such a bargin really @ 30k, and sold easily :)

can you tell me more about the transfer case mod please???

search drivetrain section - all in there.

Is there much difference with the -9's and gt-ss? On my old car with stock cams and heads, my car kept making more power past 7,500 rpm with gt-ss turbos.

http://i49.tinypic.com/2cgbyv5.jpg

They are identical.

If the graph you linked didn't end @ 7400rpm, you'd see torque fall off even harder than it already has. Boost would be the same as well.

Yeah sure more RPM it might make a little bit more power (10kw), but the turbos are pretty much off the efficiency, falling harder and harder off from boost/torque the more RPM you ask - so you gain nothing by taking it past there. Better off to change gear and fall back into the 6000rpm area.

My comment about it being "all over" by 7500rpm is that both boost and torque have well and truly fallen off by then. Where -5s will keep pressing till 8500rpm on a 2.6 no problem which is a solid 1000rpm more and they aren't falling over.

I've been doing a bit of research here and there, and my exhaust I think is just at maximum capacity for my setup, it seems on 98 and under 400kw, bloody awesome piece of kit. I would have liked to go the RP 4" version.

After researching some more on the -10's topic too, I think I'll stick with the -5's and be happy with what I've got.

A new set of semi's, a brake bleed, and I'll be all good to try the QR clubsprint record again. It's just QR is so setup for big HP over handling, hence the reason I was thinking -10's. Although I'm only 6/10's off the club-sprint record holder, and he is running an R32 with 50kw more. That was my first track day out there with only 15 laps, so maybe a bit more drive time might help.....lol.

-5's seem as they are pretty much one of the best turbo choices for track duties, hands down. The -7's seem good to for a bit less power and super response.

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