GT3582R 1 bar at 2,850 rpm
 

After some final tuning of the ECU, here is some video of the roll on boost results (background on the set up in below thread)

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/674121-how-much-rwhp-gt35r-lightly-modded-efi-motor.html#post6764058

Porsche 930 gt35 turbo boost threshold - YouTube

This set up is a torque'y son of bithc, right off idle it pulls, and you can toodle around at 1800 rpm with decent pickup. It build boost from 2,000rpm and shows 0.8 bar at 2,600, 1 bar at 2,850rpm, and just rips to red line eating up my 500cc injectors (96% at red line) so it must be making some good power.

Very very impressed with the turbo, but less impressed with the GSF header wastegate design. Does anyone know how to remedy the horrible boost spike you get when sitting at about 4000rpm in 2nd and stabbing the throttle. The boost swings wildly past the set point.

The poorly designed elephant nose waste gate circuit on nearly all aftermarket headers will lead to boost creek in higher horsepower applications. Better to take a signal from each bank at a smooth angle. That was one of the design parameters for my headers.
With these headers and proper fuel/ignition tuning threshold for a K27 is 1800rpm with 1bar boost at 2700-2800rpm.


http://forums.pelicanparts.com/uploa...1340464227.jpg

It's not so much creep I get, but overboost when the boost shoots up to target when the engine is in mid to high rpm. For example holding it in second at 4000rpm then flooring it. Could be a function of taking the signal of the IC instead of closer to the compressor?

If your definition of boost threshold is a few psi positive, I'm also getting this at 1800 so the gt35 appears comparable, but I think it will ultimately make more power

Yes boost threshold is established on a flat road in 3rd gear as the rpm where the needle begins to move.
Full boost should be rock solid at the pre-set point nomatter where you measure it. Overboost from ill designed header waste gate pipe will manifest as sustaining boost levels above the preset. Boost spikes are different and are typically measured before the throttle body where a snap throttle event will momentarily back up the boost pressure into the intercooler as the BOV opens.

The pictured header has just as poorly designed. The design has exact same (low) effect on boost control and spool-up as the one criticized, however labeled "true split plenum". RarlyL8, you should consider your sales info shared along the picture just as on the website: "Split Plenum T3 Turbo Flange - System is a true split plenum with both banks isolated..." That is big time misleading information

How have you setup your vacuum - is it done correctly?

1) top mount WG hose goes to where ?
2) bottom mount WG hose goes to where?

???
Not sure how you figure my setup is no better than an elephant nose. The version pictured has a common waste gate, we also offer dual waste gates which completes the division of the banks. That may have been what you are referring to.

Your pictured header has not seen anything close to a split bank. Here you inform of the unique advantages from your "each bank signal" - you do not have split banks. You might think you have, but then you do not know combustion pulses on a header + turbo setup. This is misleading labeling and information for those non-experienced. Same info issue on your web - you announce "true split banks" with that particular picture and then you list two wg as optional...you tell me, how does that add up??

The banks are split at the turbo flange. It is obvious by looking at the picture that the common waste gate Y will joint the banks on the single waste gate version. The advantage of each waste gate signal is just that, you get a clean signal from each bank feeding the waste gate. The angles of both pipes are much better than the 90° plus used by the elephant nose.

That is where you are wrong in your understanding and information!

What do you think happens with combustion pulses 1cm above your split wall in a single inlet turbine? or in your common wg collector by even having split turbine housing?

Jakob, it appears his headers can be outfitted each with secondary pipes that don't mingle, and when bolted to a dual inlet turbo be exactly what you are hinting at.
Are you trying to say something different, (wrong picture caption?) otherwise let's just move along here. You sound like you have an axe to grind.

Based on your definition of boost threshold, in 3rd gear my boost gauge shows positive anywhere from 1500 to 1700 rpm. From as low as 1650 rpm the boost gauge moves steadily north. From 1200 to 1700 it shows .15 bar. Its a bottom end stomper this set set up and I really like it.

Porsche 930 gt35 turbo boost onset in 3rd - YouTube