There is a turbo lag that is basic to the turbo charger, engine displacement etc. That can be influenced by a low restriction air filter. But until the engine gets CFMs from a standing start that are suficient to get the exhaust turbine going, you have a lowish compression ratio 2.3 liter four cylinder engine. So off the line things are always going to have this lag.

But, the stock boost control system, and the T5's were much worse, add to this lag. So the result is boost lag that can only be worse than the turbo's lag.

The SMBC allows you to get a lag equal to the turbo lag instead of the boost lag. So that is faster. The intent of the SMBC is to approach that and that is does well when properly adjusted. Those who seak to increase boost well beyond that objective are on there own. I can't see the point of that when you start getting problems where further performance exceeds tire traction.

So the SMBC does do well what it is intended to do. If someone expected boost off the line, then they did not understand the basic physics of whats happening. The SMBC reduces boost lag to appoach the inherent turbo lag of the system... and that is all there is. A low restriction air filter will improve the turbo lag, and with a SMBC that will be noticable.

As for non linearity, that is from the characterist of the turbo charger and thats all there is. If you don't like that, then you need to introduce some boost lag via a boost controller, and thats where we started from.

posted by 65.68.102...

• Viggen boost question, Todd , Fri, 11 Jun 2004 08:02:54
  • Install an SMBC and you will get your desired result (+, MatthewB, Fri, 11 Jun 2004 10:01:43
    • Re: Install an SMBC and you will get your desired result (+, Tim, Fri, 11 Jun 2004 14:00:52
      • SMBC, boost lag VS turbo lag, expectations VS reality, Dean, Sat, 12 Jun 2004 08:27:22 <-- Viewing This Message
        • Re: SMBC, boost lag VS turbo lag, expectations VS reality, Tim, Mon, 14 Jun 2004 06:41:28
          • Not scientific fact, but..., MatthewB, Tue, 15 Jun 2004 04:56:27
      • My SMBC experience, RobInfo, Fri, 11 Jun 2004 17:59:37
        • boost bogging, Dean, Sat, 12 Jun 2004 08:35:21
        • Re: My SMBC experience, Dean, Sat, 12 Jun 2004 08:15:52
        • Seemed like the placebo effect to me, Steve88SiS, Sat, 12 Jun 2004 06:47:31
          • Re: Seemed like the placebo effect to me, Dean, Sat, 12 Jun 2004 08:09:22
            • Re: Seemed like the placebo effect to me, Tim, Sun, 13 Jun 2004 14:21:45
            • Did anybody ever check results on a dyno?, Steve88SiS, Sun, 13 Jun 2004 09:51:06
          • Maybe it was just the cool, moist weather, RobInfo, Sat, 12 Jun 2004 07:54:02
      • Differing opinions are good, Jeff in ATL, Fri, 11 Jun 2004 14:39:47
        • May be a silly Q, but can I use SMBC on an auto? nm, J Lew, Fri, 11 Jun 2004 18:48:48
        • Re: Differing opinions are good, Tim, Fri, 11 Jun 2004 15:13:17
          • Some others have noted..., Jeff in ATL, Mon, 14 Jun 2004 11:39:36
            • Re: Some others have noted..., Tim, Mon, 14 Jun 2004 12:40:30
        • SMBC, Todd , Fri, 11 Jun 2004 15:03:29
          • Re: SMBC, Dean, Sat, 12 Jun 2004 08:32:23

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