The quest for 520hp: Cargraphic / RS-Tuning / RUF

[Bradford]

Originally Posted by Kevin

Just to mix up the discussion a little. I have enclosed a picture of a K26/24 cartridge and compressor housing machined/CNC'd into a K16 turbine housing. It is not a easy task.. Massive amounts of metal have been removed within the housing and all diameters have been increase. I have customers that do NOT want lag. One can read Ziad's post. They do not want to sacrifice the bottom end to shift any gains on the topend.

Yes, I have K24 turbine housings available for those that need and want the K24's. But as a business owner I have to adapt and offer components that customers want. We can look at the VNT 997TT housings, they are a tad larger than the K16's> but one can quickly machine a K16 turbine housing to exceed the internal volume. The K24 tubine wheel is a full frame size larger over the K16 turbine wheel. and it does dwarf the K16 turbine wheel in blade area and diameter. FYI, it is the turbine wheel that sets the frame size of the KKK nomenclature. When one machines the K24 turbine into the K16 turbine housing it does add another twist and options to customers.

How do these turbo's compare to the 3076R?

[TB993tt]

Originally Posted by JBL930

Toby, do you know whether Martyn's car uses stock orange injectors, and is it single or twin plug?
More importantly, how certain are you that Vic's GT2 was running the RS 520 kit? Wayne said it only posted 470-480bhp when it came to him, maybe Vic had changed the turbos or cams and something was out of kilter? I know you said he had gone twin plug, but that wouldn't loose power would it

The car had the RS 520 kit on it when Vic bounght it. Another firm did a twin plug then I think Vic let our mate Colin piss about with it some..... need I go on ?

They probably changed out other stuff during the twin plugging.

Lots of things can lose you power including not having it in the first place via didgy dynos - as we know

[JBL930]

No wonder it was down on power if it went to Colin first, he probably ported the heads or something

Do you know whether Martyn's engine uses the stock injectors? What injectors does your 993 use?

[phelix]

Originally Posted by JBL930

Toby, do you know whether Martyn's car uses stock orange injectors

Some time back Martyn was kind enough to send me a copy of his bill for the upgrade. No signs of different injectors, just a 5 bar FPR.

[TB993tt]

Originally Posted by JBL930

No wonder it was down on power if it went to Colin first, he probably ported the heads or something

Do you know whether Martyn's engine uses the stock injectors? What injectors does your 993 use?

what Felix said.

RS seem to prefer using stock stuff and only change when the engine dyno says limits are r/breached and other alternatives work etc. No idea of the limits of stock injectors altho I imagine there is the usual amount of BS around about how big you need to go for X amount of hp.....

Edit: AFAIK my 580HP 3.8 used stock ones also

[Jean]

Originally Posted by TB993tt

No idea of the limits of stock injectors altho I imagine there is the usual amount of BS around about how big you need to go for X amount of hp.....

Edit: AFAIK my 580HP 3.8 used stock ones also

Maximum HP that can be achieved with injectors is a function of both, injectors + FPR (assuming the fuel pump flows enough of course)

For stock 44lbs injectors, the maximum FWHP achievable with stock FPR is 500-520FWHP..

With a 5 Bar FPR, the maximum you can reach with stock injectors is around 580-600FWHP..

These numbers in both cases are stretched and you need to ensure you have excellent engine dyno/chassis tuning performed or else you risk going lean.

[Kevin]

Viggo, K24 turbine housings and K24 turbine wheels are used with the RS/Cargraphic based design>they have to be used. Guys the RS tuning>mapping does not account for the load or early boost request if you insert K16 based turbine housings.

The Ruf 490 kit is K16 based. There are ZERO K24 components in the turbochargers on the turbine "hot" side.

It would be "very" helpful if Toby can post the early published data between the RUF 490 and the RS Tuning 520 kit.

For the record, the RUF 996TT 590 turbochargers are more similar to the "build sheet" of the RS Tuning 520 kit than the Ruf 490 kit

Stepping forward 12 years the hardware tweaks that I have done on the K24's allow us to have boost alot earlier than previously had. While I would like to say that it is possible to get .5bar of boost at 2200 RPM's with the K24 turbine section with the NEW 997GT2 compressor stage>that would be a stretch. BUT we will see .5bars around 2900 to 3000RPM's ramping up very quickly..

[WHB Porsche]

Originally Posted by Kevin

Stepping forward 12 years the hardware tweaks that I have done on the K24's allow us to have boost alot earlier than previously had. While I would like to say that it is possible to get .5bar of boost at 2200 RPM's with the K24 turbine section with the NEW 997GT2 compressor stage>that would be a stretch. BUT we will see .5bars around 2900 to 3000RPM's ramping up very quickly..

So could one use the actual VTG turbos from a 7-GT2 on 993TTs?

How are they actuated? Via oil pressure? I imagine it wouldn't be too hard to fab up a control system for them.

[Kevin]

There are a few hurdles that need to be addressed. On the 997TT and 997GT2 the ECU will pull timing and slow the turbine wheel when the exhaust gas temps reach 970 to 980 degrees C. This VNT turbocharger is running higher backpressure level vs "any" turbocharger that we have fitted to the 930 thru 996TT.

What is the implications on the combustion temperatures on the air-cooled engine>cylinder head temps. How much boost can you run with what level of backpressure before we see detonation.

The 5.2 Motronic cannot read the EGT's nor does it have the built in electronic to control the electro-mechanical servo that operates/sweeps the turbine vanes.

Yes, you could design and build a controller that would monitor RPM, boost, EGT, and backpressure. This unit would then be programmed to control the vanes. $$$$$

The cost for a new set of 997GT2 turbochargers is around $9500 pair..

[WHB Porsche]

Originally Posted by Kevin

The 5.2 Motronic cannot read the EGT's nor does it have the built in electronic to control the electro-mechanical servo that operates/sweeps the turbine vanes.

Yes, you could design and build a controller that would monitor RPM, boost, EGT, and backpressure. This unit would then be programmed to control the vanes. $$$$$

The cost for a new set of 997GT2 turbochargers is around $9500 pair..

The fact that it's an electro-mechanical system makes the standalone computer sound rather viable. I think this would be a very interesting project to pursue. Seems like adjustable geometry is the next step after today's hybrids as far as quick spooling and overall power output.

But back to Viggo's upgrades - sorry to steal your thread!

[JamesE]

For those of us running Motec, that would be very easy. Kevin, why the increased back pressure on the VNTs?

[Kevin]

James> Boost control on the VNT is a function of moving the vanes to SLOW down the turbine wheel. Similar to a jet engine when you land, you feel the thrust reversers. Backpressure is increased.

With our K16's or K24's when the ECU directs the turbochargers to lower the boost, a gate will open and divert the engine exhaust away from the turbine wheel. The result is LESS restriction "backpressure" on the engine.

[WHB Porsche]

Originally Posted by Kevin

James> Boost control on the VNT is a function of moving the vanes to SLOW down the turbine wheel. Similar to a jet engine when you land, you feel the thrust reversers. Backpressure is increased.

With our K16's or K24's when the ECU directs the turbochargers to lower the boost, a gate will open and divert the engine exhaust away from the turbine wheel. The result is LESS restriction "backpressure" on the engine.

So are there no wastegates on the VTG turbos? Vane angle the only method of boost control?

[JamesE]

Why not just run external wastegates and control boost that way. You still obviously keep the other benefits of the VNT?

[vhanzon]

Originally Posted by Kevin

Stepping forward 12 years the hardware tweaks that I have done on the K24's allow us to have boost alot earlier than previously had. While I would like to say that it is possible to get .5bar of boost at 2200 RPM's with the K24 turbine section with the NEW 997GT2 compressor stage>that would be a stretch. BUT we will see .5bars around 2900 to 3000RPM's ramping up very quickly..

Now this is where it get's interesting.. I pretty much have my mind set on the RS-Tuning turbos. The ideal situation would be a tweaked version of the RS-Tuning K24/26 ZC turbos, integrating this new 997GT2 compressor stage. Is that possible?

If it's possible, do you think that you could use the existing RS-Tuning software that comes with the kit and that the tweaked turbos will just improve on overall performance with higher low range boost pressures etc.? Or is custom mapping preferable?

Also I have 100cell cats on my car, is there any way of checking if they are up for the task? I suspect they are Gemballas but not 100% sure. I'll try to get the car on a lift and snap some pics. If the 100cell cartridges are 130mm in diameter, I should be all set? I think I have the standard cats with the cartridges replaced with 100cell ones.


Still waiting to hear back from RUF. But I did some calculations and the difference in price in the end is huge with the TurboR kit vs. RS-Tuning 520 with UMW tweaked turbos.

Will keep you posted as soon as I hear from them.

Originally Posted by WHB Porsche

..

But back to Viggo's upgrades - sorry to steal your thread!

I don't mind at all Charlie, feel free to vent your thoughts!