gridlock61

Well, I got the tuning issue fixed and the boost controller done at the same time, so not sure how it would have felt with just the tuning fixed without the boost controller. I still like the fact that the engine feels and sounds like it did prior to the supercharger installation during normal driving, which is most of the time. I believe I'm running about 5psi boost. What would be cool if there was some in-car control of both boost amount and threshold.

RichPugh

I believe the stock pulley is at 6psi... mine is. We did 60lb/hr injectors and a custom ECU (converts from MAF to MAP and runs on wideband lambda) and tuned it on the dyno... and we still have some work to do but I totally understand what you mean by it feels "draggy" in low rpm, light/mid throttle. Its like, unless you are full throttle or at least past half throttle, it is just kinda dragging the engine down like having the AC on. But, I drive like a 19 year old so I'm ok with it, LOL. The pedal doesnt stay too upright, haha.

The boost controller is basically just limiting that vacuum actuated valve that shuts and allowing (limiting) the SC to start building boost later. That valve/actuator is TOUCHY and really set to allow the SC to build boost at very light throttle. I ran the car with that actuator valve zip-tied open for months because we were waiting to tune the car properly on the dyno and we didnt want it to build boost. It felt pretty much like stock except without a working varioram, LOL. Now, with the SC building boost at even light throttle as low as 2000rpm, its definitely as if there is more of a drag... BUT the power it is creating definitely outweighs the power it's taking to make it. I think having the boost kick in at like 3500-4000 would feel pretty cool, like a big single turbo car only making 6psi, LOL. I say dial it back to like 3200-3500 max and you'll enjoy it much more.

Quadcammer

this makes no sense.

First, this boost controller as you call it is really just a bypass valve, yes?

secondly, the whole point of a positive displacement roots type blower is the low end torque.

Even so, if your boost controller is a bypass valve, its typically based on rpm but more so throttle application and load.

I don't really get what you're saying.

axl911

That boost controller is probably a device to limit/delay the SC bypass controller which controls the boost.

Juha G

The bypass valve is integrated on the Eaton supecharger. On the TPC setup it is controlled by manifold (before SC) air pressure.
In Rich's case, the ECU has boost control function so I assume he has an additional vacuum valve in that line, that is electronically controlled by the ECU. i.e. he can keep the bypass open even if the throttle valve is open.

I agree that it makes no sense to limit the boost so that it "starts" only after 4000rpm. Kinda defeats the whole purpose of the eaton blower (grunt low down).
For me it worked fine with no boost limitation but I was running Motec so we were able to compensate with the parameters. (same applies to Rich as he has a fully programmable ECU).
If I'd limit boost, I would do it for 1st gear and and perhaps under 1500rpm also for all other gears.

Here's a photo of the TPC setup:

axl911

Yep... controlling bost at low RPM is just as important as high RPM. And not just through fuel maps/AFR which everyone seem to focus on since it's easily measurable. The other important is timing retard. The unichip software is has a ramp-up function which is very useful for this. Heck, after looking at the software, it has plenty of rpm/boost/sensor activated switches and functions to control external boost controllers and other devices such as water injection.