The SMBC is to improve spool-up and not to increase peak boost. So things get more responsive. The ECU still controls peak boost and if there is a risk of knocking, it is at peak boost. So the boost safety issue still remains with the ECU.

One should not use a SMBC to move base boost above ECU peak boost. And the base boost should also be set to keep 1st gear drivable and without wheel spin issues that require babying the throttle.

You also need to keep the base boost below peak boost so that the ECU can lower boost if needed in response to poor fuel or a mechanical problem.

So, yes it is safe to use a SMBC with any staged ECU, if you adjust it intelligently and don't try to make it act like a MBC.

A SMBC will improve spool-up more with a manual transmission. Automatics get on boost faster so the relative improvement is less. However on can increase the base boost with the SMBC and get faster and stronger boost in the lower gears that are otherwise torque limited by the ECU. I have used a SMBC with 9-5 Aero T7 manual gearbox, but don't have any T7 experience other than that. Are there situations where the SMBC is not needed at all? Perhaps. With the 5spd autoboxen on the 2002+ 9-5 Aero's boost comes on ver y fast and perhaps there would be very little or no advantage. I should dig out my SMBC that I had used with a 9-5 Aero manual trany and see what that is like.

Speaking of 9-5 Aero's... one could argue that this is a staged ECU already and I do know that the SMBC on the manual gearbox really improved things a lot.

So the key issue is peak boost. If that does not change, then peak temperatures and pressures in the combustion chambers do not change. The SMBC should not be affecting peak boost and thus cannot alter peak boost temperatures A/F etc.

I am guessing that the practical limitation will be 1st gear wheel slip.

• Locating a SMBC for '99 Viggen - Is It Safe in Colo Mtn, WSD, Wed, 26 Apr 2006 13:57:38
  • Re: Locating a SMBC for '99 Viggen - Is It Safe in Colo Mtn, AT, Wed, 26 Apr 2006 14:10:39
    • Re: Locating a SMBC for '99 Viggen - Is It Safe in Colo, WSD, Wed, 26 Apr 2006 14:27:33
      • Re: Locating a SMBC for '99 Viggen - Is It Safe in Colo, Dean, Wed, 26 Apr 2006 15:01:17
        • Dean..., lms, Wed, 26 Apr 2006 15:56:31
          • Re: Dean..., Dean, Thu, 27 Apr 2006 09:17:21 <-- Viewing This Message
            • Thanks much for the info. n\m, lms, Thu, 27 Apr 2006 13:11:25
        • Re: Locating a SMBC for '99 Viggen - Is It Safe in Colo, WSD, Wed, 26 Apr 2006 15:23:36
      • Re: Locating a SMBC for '99 Viggen - Is It Safe in Colo, AT, Wed, 26 Apr 2006 14:39:16
        • Re: Locating a SMBC for '99 Viggen - Is It Safe in Colo, Scottdazey, Wed, 26 Apr 2006 14:59:08
          • Thanks Everyone!, WSD, Thu, 27 Apr 2006 19:19:23

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