Compression ratio. Static compression means jack! its the dynamic compression you need to worry about. You can bleed compression with more overlap, hence the use of cam gears are good here.
Thicker head gasket..... waste of time, might allow more boost, but ask yourself why!
Is it more pressure that makes power or the quality of combustion?
These issues are particular to your setup, b16's typically like more overlap (scavenging), to draw in the charge at lower piston speeds (b16s have long rods) as an example.
Are there any issues with overlap or too high of a lift on these VTEC's when turbo'ing them?
Or any other issues with high compression or weak internals?
I think the issue is more to do with overlap with the Hi Cam when at the end of the exhaust stroke both Exhaust and Inlet valves are open, this good with NA cars as exiting exhaust fumes draw in air/fuel for the next intake stroke.
With Turbo Vtec's I don't think there is a problem with pressurised air blowing straight through both intake and out the exhaust valves when the overlap exists (correct me if I am wrong) Because the Hi Cam only comes in to play at high rpm, therefore I don't think there is enough time for both Intake and exhaust valves to be open for the pressurised air/fuel to blow through. Again I am not sure so any other theory's would be appreciated.
With regard to standard engine internals etc. Honda make a strong motor as standard. With a proper Turbo setup and tuning there should be no problems. I am running 9psi on my B16A2 with standard internals.
generally there arent any issues with overlap, not sure if that will be the case with your MIVEC though spetz. Also the internals are normally strong enough for 8-12psi depending on the engine. No need to decompress either.
Like everyone says, boost the bugger, 12psi and you will love it and make sure you get it tuned by someone who has done it before and you should be fine.
well what you are saying is correct, to get the same gains from NA mods is gonna cost you a crapload of money if its even possible to do in this country (as you say the amount of MIVEC expertise here isnt great).
Quite simply, i dont think you could go wrong with, say, a GT28R at 6psi
well we just done a turbo set up on my mates mivec lancer. he strrated off with the na setup and got 130fwhp (we could rev the thing to 10grand on a microtec). he decided to turbo it and used a gsr lancer exhaust manifold and turbo and a haltec cause he didnt like the microtec. the problem about the mivec is the huge compression. we put a 2.2mm head gasket and had the boost at 15psi because we couldnt get it lower, we also have a big front mount and the thing was so quick for about a week till we blew the headgasket. lol its got a new head gasket and getting tuned now. u want the four banga ai?
well we just done a turbo set up on my mates mivec lancer. he strrated off with the na setup and got 130fwhp (we could rev the thing to 10grand on a microtec). he decided to turbo it and used a gsr lancer exhaust manifold and turbo and a haltec cause he didnt like the microtec. the problem about the mivec is the huge compression. we put a 2.2mm head gasket and had the boost at 15psi because we couldnt get it lower, we also have a big front mount and the thing was so quick for about a week till we blew the headgasket. lol its got a new head gasket and getting tuned now. u want the four banga ai?
Thats a 4G92 MIVEC, Spetz is running the 6A12 MIVEC motor. The 4G92 shares the same exhaust manifold patten as the GSR motor (4G93t) and actually has some room left in the engine bay. The 6A12 barley clears the firewall and radiator.... It's a bit like the H22 of lancers except V6
Actually my SOHC loves high lift that my stage2 cam brings. There are some nice articles out there on overlap,l and it seems the old ways of thinking dont really apply these days to our hi-po vtec's.
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Originally Posted by spetz
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