Just wondering what people think of running a low boost on DTA. It's probably hard to say if the low boost setup is at the limit of what you'd want to run on standard compression but I'm wondering what sort of gains you might expect to see running DTA. Could you run a little more boost?

Alternatively could you simply go for a thicker head gasket and another psi of boost?

Essentially for about 1k for the ECU and mapping you could have around 280-300bhp?

Part of my reasoning behind this is that I'd like to drop the max rpm of the charger down under 100,000 rpm at the redline. I personally think the restrictor should be removed or widened a little and a larger pulley should be put on the charger to limit the max RPM as it seems daft to be overspinning the 'charger while there's a restrictor in place.

I don't see how increasing the pulley size will reduce boost provided you open the restrictor up. The C30-94 is good for 400bhp so I just don't see why it's spinning over 100,000 rpm to make 250bhp.

Definitely having the throttle downstream would be good and mapping out the stalling that some people have seen would be nice too.

I think I'd be willing to sacrifice a little low RPM torque to keep the charger within it's operating limits. We'd only be talking 500rpm and only a small reduction in torque that would probably be compensated for with better mapping.

I was thinking at going down this route in the future too, quite keen to see how much i can get out of the low boost setup before it goes bang

My Rallye made 268bhp on one set of rollers and 259bhp on another so not exactly sure where it's at in terms of power but never had any issues with setup

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Just Drive It

Tempting - http://www.dp-engineering.nl/decompr-xu10j4rs-88.html

I don't think that matters, it's still a 127mm / 85mm ratio which means anything over 7000rpm is overspinning the charger.

ratio of bottom pulley to charger pulley 1:1.49
ratio of C30-94 input shaft to turbine 9.49.

Rich said that given the fraction of a second you're over 7k that it's not an issue and I agree. It's just that it's not necessary given the operating envelope of the C30-94.

I've just been looking at the documentation and the low boost setup is running a Pressure Ratio (PR) of 1.72 and requires approx 0.21 kg/s of air.

Look up those 2 points on the following compressor map and the low boost setup COULD be making full power at maximum compressor efficiency at approx 75,000rpm.

I suggested similar in the other thread and would love to see this setup done.

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supercharged China gti6 - Thu 16th Sep 1999 - sold
2010 megane rs250

What allan says, just drop the limit if you're that concerned, that way you only loose the very top end power and not the midrange.

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