gets rid of tvis! good for high power applications. or guys that are fed up with tvis. does require some light modifications for the GE head.
Good to know, I am interested in using one for the re build over the winter. Much modification required?
In terms of eliminating the tvis system, i was thinking about removing the throttle shaft and butterflies and filling in the holes with epoxy resin, or just weld up the holes, simple?
well in the long run, i got rid of mine. technically i grenaded it on the dyno. so i'm running the tvis with no butterflys.
i read somewhere on 6gc that one of the reasons why toyota changed to acis from tvis was because the 8 separate runners provided a tad more restriction that just one runner each? thoughts on that?
Correct - You can't compare T-VIS with ACIS as the head porting is waaay different. The gen1 GE has a low speed intake velocity problem due to it's massive inlet ports, the GTE has smaller ports so may be possible to delete T-VIS on the GTE heads with less drop in low end power Gen2/3 heads are often used with carbs and ITB's without any ill effects and don't seem to mind having the ACIS removed
and same with acis. when the butterfly valves on acis opens, it goes into an empty portion of the intake to lengthen the intake ports (similar to modifying air speed and volume in tvis) and create turbulence (similar to the 'swirl' produced by tvis on closed butterflies). taking from this, it seems that the idea behind it is still air speed/air volume. the only thing different is the routing of the air. acis has one each cylinder, but has a 'detour' route. tvis just uses two parallel routes. as shown in this pic:
As it's a closed box, it can hardly be defined as a variable length inlet. My guess would be something to do with phasing and intake pulse assist - like on rotary motors. Here's what I mean by ports - untill you see them it's hard to understand just how oversize the gen1 GE is: Gen1 GE Gen1 GTE/gen2 GTE FE - same as gen4, Evo, Subaru, Nissan, Honda etc - no compensator required Further pics/reading here - http://www.st162.net/forum/showthre...-amp-4-door-and-many-more-jdm-oddities/page17
