Re: Intercooler for your BMW 335 TT?
Different applications will place different emphasis on minimizing lag. Applications like autocross and technical rally will demand least lag (at the expense of system (flow and thermal) efficiency), whereas high speed cruise like offshore powerboats or Bonneville record setters will place near complete emphasis on system efficiency (at the expense of increased lag). Big open courses like Mosport, La Sarthe, Monza, etc. will favour flow efficiency because there is usually a lot more than 70% of time spent at WOT or at least large throttle openings. Also the sorts of corners you have to pull from and the gearing gaps (engine throughput (volume) at resumption of throttle increase reference to earlier mentioned system volumes).
This is the reason why you see such big differences in turbo systems depending on application. One of the best ways to learn about all above is to study current turbocharged WRC and LMP cars, as well as past 80s turbo F1 stuff, but always in light of regulations since that modifies conclusions somewhat. Race winning road race, drag race, offshore powerboat, land speed record turbo systems also are good to learn from. Just about everything else that is contrary to these systems you know is false, unworkable, or impractical.
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PerverTT again makes a good point about IC mounting. Dedicated ducting (both pre and post core) really helps more than any of the things that people usually argue about (core type and orientation, end tank design), provided they are in the ballpark and provided you have enough space in the bay to the heat exchangers around and run proper ducts. Things like V-mounting the radiator and the IC, etc.
Skim read, so probably missed other things, but this statement really stood out as completely false. Volumes matter very much, coming right after how well the turbo is matched to the engine. If the kit you've bought has been well developed and/or tested, or if you've done your own research properly and bought your own turbo, then the turbo match WILL be in the ballpart and volumes will be your next concern in minimizing lag. Exhaust valve to turbine inlet volumes, compressor outlet till intake valve volumes, and volume from throttle blade to intake valve.Some people believe that if they fit a very big intercooler with large ducts, the volume of charge air within it will unduly slow throttle response. Their concern is unjustified however - throttle response problems (for example, turbo lag) are largely the result of other factors within the forced induction system, not the volume of air within it.
Different applications will place different emphasis on minimizing lag. Applications like autocross and technical rally will demand least lag (at the expense of system (flow and thermal) efficiency), whereas high speed cruise like offshore powerboats or Bonneville record setters will place near complete emphasis on system efficiency (at the expense of increased lag). Big open courses like Mosport, La Sarthe, Monza, etc. will favour flow efficiency because there is usually a lot more than 70% of time spent at WOT or at least large throttle openings. Also the sorts of corners you have to pull from and the gearing gaps (engine throughput (volume) at resumption of throttle increase reference to earlier mentioned system volumes).
This is the reason why you see such big differences in turbo systems depending on application. One of the best ways to learn about all above is to study current turbocharged WRC and LMP cars, as well as past 80s turbo F1 stuff, but always in light of regulations since that modifies conclusions somewhat. Race winning road race, drag race, offshore powerboat, land speed record turbo systems also are good to learn from. Just about everything else that is contrary to these systems you know is false, unworkable, or impractical.
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PerverTT again makes a good point about IC mounting. Dedicated ducting (both pre and post core) really helps more than any of the things that people usually argue about (core type and orientation, end tank design), provided they are in the ballpark and provided you have enough space in the bay to the heat exchangers around and run proper ducts. Things like V-mounting the radiator and the IC, etc.