Boost onset question for Triple-K variants

[Tippy]

Simplest question; what RPM can you hit 1 bar in your 930 in 1st gear?

Why I ask is I'm still trying to sell my Holset HX40, and I'd hate to sell someone a turbo that is laggier than the Triple-K.

Of course my Holset is a T4 footprint with a larger turbine and all the Triple-K's are T3, correct?

[RarlyL8]

Some engines will not be able to reach full boost in 1st gear; 3rd gear is a better test.
The K27 and 3LDZ for Porsche are T3.
As you know that is a loaded question due to all the variables involved. List the build parameters and someone will have done it while using a K27.
The lowest RPM at full boost I have personally seen on a CIS engine was 1.0bar at 2600RPM. This was accomplished with 1/2 bay IC, headers, tuned fuel curve, and custom ignition curve. The engine put down 400whp. The turbo was a custom K27 hybrid. The K27-7200 in my old Red Rocket hit full boost at @2700-2800rpm.

[Tippy]

Wow, I assumed all 930's hit 1 bar in 1st since it's so tall. Ok, this Holset is living up to its name. I can hit 0.6 bar in 1st with the super low gearing of my G50.

[RarlyL8]

My personal car will hit full boost in 1st gear with the 3LDZ or the K27-7200 but some cars will not. It depends on what mods have been done.
If your engine is stock 1st gear is tall, but if even slightly modified 1st gear is just right. My enigine currently is 930S spec and I find 1st gear perfect. That is with the 3LDZ. The next test wil be with headers and a K27 shooting for 400whp. At that level 1st gear is useless and goes so quick that it may not hit 1.0bar before grabbing 2nd. You certainly won't be able to watch the boost gage to see.

[JFairman]

"You certainly won't be able to watch the boost gage to see."
True, a mechanical NHS/VDO boost gauge with an accurate telltale needle that can be reset will do it.

[RarlyL8]

Data logging is probably the most accurate. I had one of those VDO gages until the tattletale needle broke after one year's use. What it recorded was not max boost but boost spikes when the throttle was lifted. The 965 BOV I had was not much quicker than the 930 version so a tiny spike was still seen. I didn't know that was happening until adding boost to the data log. It also showed full boost was being hit as the tires spun in first gear.

[JFairman]

Yeah, every car is different. With two blow off valves (one recirulating the other to atmosphere) and long neck intercooler I never have boost spikes when lifting and my VDO boost gauge that is around 10 years old now with telltale works perfectly and it is accurate.
I've turned the needle clockwise so it isn't inhibiting the main needle movement and watched it in 3rd gear. The telltale doesn't hold back the needle.

The gauge was in the car when I got it.

[Tippy]

I'm referring to datalogs too when quoting numbers. Reading the gauges ain't happenin'