Legionnaire

I don't think it would work. Not because it's impossible to create a big enough or heat-resistant supercharger. First of all, you'll definitely lose more power driving that SC that get back with increased engine scavenging. But not only that, you NEED that backpressure, or to be more correct, the pressure differential across the turbine section to give it power to drive the compressor. So you can't increase VE in the upper RPM range by sucking gasses out of the turbo. Not by any significant amount. You might actually achieve something similar to what you suggest if you add some cleverly shaped piping and exhaust gas cooling. This combination may (or may not) create a momentum large enough to move gasses outward and create some suction at the turbine outlet. Or you can suggest a supercharger between engine and turbo, which will pressurise turbine inlet but will keep engine backpressure low. But this system apparently has even more penalties to it. I'm all for innovative ideas and out of the box thinking, but IMO it should be exceptionally well thought out and calculated/modelled first.

Comp cover does not make big difference. Correct 6/12 blade wheel does. Make sure you ask for not comp cover only, but for a proper comp wheel!

Aren't Mahle pistons shipped with rings? If so, I would expect them to know what rings to use and to be gapped correctly.

The tuner posts some very nice and detailed info, that's great. And wow, better power AND response than previous setup, agreed with SimonR32, looks like it was GT30-based. Win-win. And it loses nothing to factory 4B11.

Yes, 7670 result is outstanding. As for the comparison of the two, we're talking the same thing as 1.06 GT(X)30 vs. .63 GT(X)35 - largest available housing for smaller and smallest for bigger turbo, it may contribute to less than impressive result of the 8374. But I agree, we need to wait for some more results to draw any useful conclusion. Particularly interested in their TS IWG results. Do you happen to know if BW resolved issues with manufacturing of those?

Funny enough, I ended up buying some F50's myself. But mainly 'cause I found them for cheap, if it wasn't for that opportunity, I would have been using sumitomos with larger rotors and larger pads, as per my initial plan. Aren't 324mm rotors too thin for F40's? It's not the first time you post this photo, is it? I've seen it several years ago and saved in to my hard disk for a reference of pad sizes, so thank you very much for that May I ask where was that delamination occuring? Was it the area under leading or trailing pistons?

700- hub hp is a pretty long way from 620 whp, I'm not sure if that much power is lost in tyres, usually it's closer to 30-40hp? But we're also not forgetting the fact that 8374 was it its smallest housing, whereas 7670 was in larger TS hsg. By the way, was that TS housing in 7670 IG or EG?

Well, looks like I know nothing about dynapack dynos. If it's power at HUBS, it's better than really good. It's excellent. Awesome. I wouldn't expect so much power at only 30 psi from 76mm compressor, even on E85. But now things start looking odd. 640 hub hp with 7670 at 30 psi, but only 620whp from 8374 at 42psi? Something is wrong here... Oh, and do EVOs really have 6.4 final drive ratio?

It does look average. I haven't seen a whole lot of them, but many of those I've seen had steep torque drop after ~5000 rpm. IDK why is that so, maybe cams are not hot enough, or something else is amiss, but lots of 4G63's do it. Even on the graph you've posted. Torque goes down by 200lb/ft after 5000 rpm. But not a bad result overall. 640hp (it's a flywheel figure i should think?) on E85, and all in by 4000. With 98RON we can expect slightly better response and 80-100hp less power. Would make a potent turbo for an RB25. GT30 response with almost GT35 power - nice!

When mine was dying, its voltage was doing funny things at idle and low loads. Didn't hold stable output, was dropping voltage to 0v then back to normal rapidly. You may want to monitor AFM voltage output.

So was it a 4B11 or 4G63? They certainly made torque curve hold with those cams. Compared to this: BTW, I'm honestly not into 1/4 mile, is 143mph high or low for a 4wd 470kw car? Edit: Sorry man, didn't see the second part of your post there. 4G, hmm.. I would have thought it was a 4B11 head and port geometry that resulted in that kind of torque.

Makes sense. However available "oversized" pads are not heaps bigger that factory pad, only slightly bigger

42psi with 9.0 comp ratio! That's insanity. And nice to see an evo engine holds torque like that. All previous dyno printouts were showing pretty steep fall of the torque curve in the upper rpm range. Or is it a 4B11 on this dyno sheet? With that mentioned, I would not say the result is all that impressive. 42 psi is what, 3.85 pressue ratio? As per comp map, BW 83mm compressor flows ~74lb of air max, that should give roughly 700-720hp on petrol and some more on E85. So either evo loses ridiculous amount of power through the tranny, or something is wrong. Or compressor map is a bit too optimistic...

Yes, someone have heard about it: Kers

Oh... I see. Canadian guys reported 77mm reimax gears to be good. So I think that's the way to go.

No first hand experience with either of them, but why would oyu want smaller gears with thin metal? Isn't it better to just put 81mm reimax gears into a RB26 pump? It has a good 2mm extra metal for each gear, so IMO is less prone to breaking.

I totally agree with your first point, but not everyone has money/needs/wants F40/F50 or any other a/m caliper, because stock calipers are OK for light track work, and while I hate soft and mushy pedal myself, it can still be improved somewhat with MCS and braided lines. the #2 - sumitomo pad area is small. Why not to use larger pad that fits the caliper? Is there some working penalty to this? Given the same friction compound, braking force won't change, cause area is irrelevant to force, but heat transfer, heat generation and distribution will be better in larger pad. Or Am I getting it wrong?

Isn't it the other way around? N1 pump 77mm gears with assymetric tooth profile, factory RB26 81mm gears with symmetric profile, almost duocentric?

Roy, can't you just fit larger pads, as per OP's suggestion? Or was it caliper curvature that was wrong (too small) for the rotor? Or some inherent problems with PFC rotors that prevented them from working?

we're really trying to say the same thing using different words. I understand what you're saying, and I agree with you. I just think you slightly overestimate the role of compressor efficiency and underestimate contribution of initial pressure in resultant combustion pressure. Don't be so focused on turbo. Look how engineers of restricted turbo motors extract torque out of their engines.

I think he just meant a pump, roots-style, with no internal compression, that would suck gasses out of the engine. Why would that be needed is a totally different question.

Aren't those 343mm brakets a different kit altogether? I mean, basic maths says that 280->324 kit offsets Z/R32 caliper by 22mm. Used with caliper designed for 296mm rotor, same offset gives 296 + (22 * 2) = 340mm rotor diameter

Interesting suggestion, but what's the idea behind this? Improvment of pressure differential across turbine stage of a turbo? It may benefit turbo itself, e.g. make it spool faster and use much smaller wastegates, but I can't see it adding any power to the engine?

Apexi power intake here, although I'm strongly considering putting stock airbox in. 390hp on the flywheel. Never had a problem with it, what happened to yours?

Nah, I was talking about pre-ignition pressures only, there is a well established formula for that pressure: P = Pinit * CR^γ, where Pinit = P ambient + P boost (pressure prior to valve closing), CR - obviously dynamic compression ratio, γ - adiabatic index of medium that is being pressurised. As you can see, no signs of mass or time in this formula, which is quite logical, as in the shut cylinder PV relationships play major role, mass is (almost, ignoring small leaks past rings) constant. In other words, when you compress mixture in the cylinder, it doesn't matter how exactly initial conditions were reached. 20 psi is still 20 psi, either with small or large turbo. The amount of molecules, their composition, density, etc. start to play role when you ignite things.