Brettus

iTrader: (2)

Editing the throtttle maps can make throttle control much more precise ..................

logalinipoo

:Harlan, have you thought of using a throttle position to control boost level. IE at 50% throttle you only get 50% of max boost.

slash128

Interesting that the first time I see Brettus new ***** avatar is on a post regarding controlling boost levels

Brettus

iTrader: (2)

Everyone knows boost and ***** go well together

slash128

Harlan

iTrader: (3)

I thought about it, but instead I'm using throttle differential pressure. By maintaining around a 5psi differential across the throttle plate it should makes the car much more driveable. For example at cruise the manifold is about -8psi and the charge header is 0psi (ish) so the WG is failed open. Once you open the throttle the pressure difference drops and the turbo engages. This prevents tip-in situations where there is 10psi on one side of the throttle and a slight vacuum on the other. I haven't had a chance to test it yet though, but I'm hopeful.

TeamRX8

iTrader: (25)

Still looking at the wrong brand IMO

Borg Warner at SEMA... BIG NEWS S200/300 SXE bread and butter billet - RX7Club.com

Brettus

iTrader: (2)

Interesting read . Would have been worth considering , but my Garrett is already on the way ....

Looking into it further .... there are a few reasons I wouldn't go that way anyway . Compressor entry diameter too large , journal bearing only , extra large turbine wheel (slower spool ) , T4 flange too big .
Not to mention that you can't even buy them yet .

Brettus

iTrader: (2)

That can be minimised to the point it is no issue quite easily , without the need to get complicated .

Harlan

iTrader: (3)

I already have the sensor installed, and it gives the same benefits as TPS based boost control. The overcomplicated stuff is working for me, it's the simple stuff I have problems with.

Brettus

iTrader: (2)

Nice ....


54 would be sweet but ....
I saw an earlier post from you that was saying way less than that ???

Brettus

iTrader: (2)

Siamese port issues :

In an NA it doesn't matter that the siamese port exits the same hole as backpressure is minimal . But what about when there is backpressure from a turbo .... the rotor chamber can potentially be getting flow from the other side greatly increasing EGR and potential for detonation .
Or ... is the opposite rotor covering the port sufficiently to eliminate the possibility of gases tracking from one side to the other ?

Thoughts ?

Harlan

iTrader: (3)

I wouldn't worry too much about EGR and backflow into the opposite rotor.
EGR is a good thing where detonation is concerned, or at least a non issue. Our backpressure problems are about temperature. Keeping the exhaust gas pressure high keeps it hot too. For example if you have 1600deg exhaust at 1Bar (Atmospheric) you have 2000deg exhaust at 2bar. (rough math)

The engine internals can handle contact with 1600deg exhaust easily, but 2000 is a bit more challenging. Especially since there is a lot more mass, so a lot more heat capacity. The side exhaust ports do not help with this... but there are ways to increase cooling.

This is also why you need colder plugs when boosted.

9krpmrx8

iTrader: (46)

Yeah you are right, my bad. 54trim, 44lb/min (from AMR). The Comp Turbo billet compressor wheel was added after AMR built it originally but it was the same size as what was on there.

"
• Water & Oil Cooled CHRA
• BIG TD06H Turbine Shaft
• 54 Trim 44lb/min Billet aluminum compressor wheel from Comp Turbo
• New Bearings
• New Seals
• Machined Compressor Housing
• Machined Turbine Housing
• Balanced"