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On 20 Mar 2003 at 19:44, BOB2TYPE3S@aol.com wrote: > These numbers start getting close to a FI dizzy when you look at the > numbers.The vac numbers work at the lower end though. Example of the 311 905 > 205 AE (from type3 Bentley book) mech advance begins at 950-1200, @1800 its > got 11-16 degrees and mech ends at 4000rpms with 19-23degrees.The vac side > starts at 90-120mmHg, and ends at 150-170mmHg with 8-12degrees. So what do > you think? The problem with trying to use both advances from a FI dist are that they will give too much advance (~40 deg) if they both kick in at the same time. Now40 degrees is okay at light load, and that when the FI intake and dist will give you that, because it only gives a strong vacuum AT LIGHT LOAD. But if you do this with the dual carbs, and then take it out and drive it spiritedly, then you will find that there are times when you have the rpms up and WOT which is when the carbs give THEIR max vacuum. You now have ~40 deg of advance. Of course it feels great. It would even feel greater at 50 deg. Would any of us recommend that for our cars? I doubt it. The problem is that the carbs give out their max vacuum under different circumstances than the FI intake do. Each of them came with a distributor that worked with the other half ot the system, and worked well. That doesn't make either one better than the other, but it DOES mean that if you want to go an play mix and match, you'd better understand what you're doing, or your engine will suffer. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ------------------------------------------------------------------- List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org