Cockpit Adjustable Boost for Twin Turbo S4

[Herr-Kuhn]

I grew very tired of smoking off my rear tires in 1st and 2nd gear on the twin turbo since I turned the boost up to 12 psig. I simply don't need all that boost on top of the gear ratios down low. Once I'm into 3rd or maybe 2nd in some cases I like to have the higher boost levels.

There is a very clever way to modulate boost from the cockpit of the car and this is with an electronic boost control unit. This method of cockpit adjustable power is easy to have with a turbocharged car and you don't give up any efficiency of the system by overboosting and bleeding off boost, etc. It's a turbo exclusive arrangement. No other power adder can offer this setup so simply. There are some huge benefits with a boost control unit including, but not limited to the following:

1. Faster boost rise as the control unit eliminates wastegate greep
2. Ability to toggle between user defined "low" and "high" boost settings
3. Ability to turn boost way down for lower octane fuel and up for higher octane
4. Ability for user to dial up or down depending on the road conditions, other drivers (aka wife, girlfriend), etc.

This unit will allow me to toggle between my high and low settings with the touch of a button. It's like having a +/- 100 HP switch inside the car and that is no joke. I opted to go with an older model Profec B unit because I don't like the digital readouts and bells and whistles of the newer stuff...I just like it simple and straightforward. I have wired in a secondary "heat of battle" switch to allow for easy switching while driving the car.

Removal of the lighter and ash-tray allowed for ample room for the control head. Notice the ease with which the "red button" can be reached just by dropping your index finger.

Some Pictures:

[rhjames]

so, does this control the fuel application, or adjust the pop-off pressures....?

Either way, it seems to me you could apply this to other systems as well.

murff's, carl's, etc......

not necessarily turbos, but belt driven SC's as well.

twin screws would be a challenge though......

--Russ

[Herr-Kuhn]

Russ,

It controls the wastegates, which limits the rotating assembly speed, thus slowing down the compressor or speeding it up on demand.

There are only two ways to control boost pressure levels with centrifugal compressors like in the turbo or centrifugal supercharger:

1. Control the compressor speed (this is what the typical wastegate does)
2. Use a wastegate on the outlet of the supercharger to bleed off boost

Very old turbo cars used no wastegates and boost was controlled through restrictions in the intake system...what a bad idea that was!

I'm unclear on how you would do this with a centrifugal supercharger other than to have a complicated variable speed drive or waste off pressure after you built it up. The wasting off would force you to put more heat into the charge and then bleed it back causing more intake charge heat.

All new turbocharged cars typically have some form of pulse-width soleniod control over the wastegate circuit and that's all I've done here. It can be done very cheaply with a mechanical valve, but the control is not nearly as good and switch at the push of a button is not possible unless you have some complex system of valves and piping.

[rhjames]

I thought it was a waste gate item.....

Seems to me I read Carl's latest SC kit had a waste gate of some kind.

That's where I was going with this....?

--Russ

[sonett3]

Russ you are talking about a blow off valve on carl's kit not a waste gate .

[Mule]

John, the turbo drag race cars use progressive boost controllers, whenever rules allow. They put nearly 2000 hp on a 10.5" wide, 28" tall tire and 3000hp on an 11.5" X 33" tire.

[Herr-Kuhn]

That's the point...modulate the power by controlling the boost from inside the cockpit with the touch of a button. I'm sure it will pay big dividends for my car and the other thing I like is if I ever have to run lower octane fuel I can just dial it back to a safe level.