twincharging estimated results 11

[bear1a]

ok, so, if you have a twincharge set up on a chevy small block 400 cu. in motor, turbo feeding roots blower... roots by itself at 4000 rpm produces 6lbs boost...turbo by itself at 4000 rpm produces 15 lbs boost..what happens when we put them in series...turbo feeding roots at 4000 rpm ..what approximate boost will be get?...i'll know soon enough i'm building an engine..but would like some theoretical input

 

[Warpspeed]

More on the spring thing.

A particular spring will have a specific opening pressure, and a rate of opening that are quite independent.

For instance, a very long soft spring can develop the same force at the same loaded height as a much shorter stiffer spring.

How all this feels in the car can make quite a difference.

For instance, boost could rise smoothly with gradually increasing throttle opening from just above idle. That may feel very smooth to drive but may not be ideal.

A lighter spring may allow you to use throttle openings up to and above 50% while seeing zero boost, then have the last 25% of throttle opening really throw you back into the seat.

That lets you easily keep up with the traffic flow without using the supercharger at all. Fuel economy will be as it was originally. But flat out it will really get up and go.

Spring selection really decides how quickly boost builds with increments of throttle opening, as well as the throttle opening where full available boost is reached.

The whole thing is really wide open to driver preference, but with a bit of fiddling around, an ideal spring can absoluttely transform how the vehicle feels to drive.

It is really fun to play with some different springs. But first watch how the wastegate behaves with it sitting on the passenger seat. Get a feel for how it moves with the throttle under different driving conditions.

One thing is for sure, whatever originally came in the wastegate will be far too stiff.

Unless it was designed to control the original turbo boost pressure to perhaps something like 2psi or 3psi. That is highly unlikely. The spring you end up with will be much lighter, and you are going to have to find something yourself by experiment.