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Location:
Illawarra
Registered:
May 2002
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20V turbo question
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Tue, 02 December 2003 16:12
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Alot of people say that the 20V is great top end but i alittle lacking in the bottom rev department, especially around the streets.
Is there anyway way of placing a supercharger to help the bottom rev range, or turbo that will give bottom and mid power boost, but still spin when the top end begins.
Another question, silly enough is twin turbocharging the 20V possible even thou it run 4cyl, but hooking them up sequentially,
obviously al this can be done if you got the 'g's to back it up
But i am wondering theoritically will any of these work,
i have seen turbo applications used to achieve alot of top end power, but i'm wondering about a decent power band thru out the whole rev range
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Location:
Brisbane - Chapel Hill
Registered:
June 2002
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Re: 20V turbo question
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Thu, 04 December 2003 02:28
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A late model Ball Bearing Turbo should spool up down low ok. Matching the right one to provide boost over the entire rev range will probably be a compromise between that and outright top end power tho...
Take a look at last months Zoom - killer conversions. The front cover has a KE70 20V GT30 turbo pushing 250+rwkw. There's no dyno sheet tho.
certainly the 20V has pretty decent flow, but with headwork i dont see how a 16V bigport couldnt do much the same. Ask Bill Sherwood --> the force is with him 
Twincharging is a great idea, if you can get it right. It's a complex control problem, and you certainly wouldnt be able to do it with a standard computer. As soon as i get one of my forced induction engines on the road, Twincharging will be my next goal --> uber top end power (big turbo) decent low down grunt from a decompressed motor (SC12/14 supercharger)
Honda had a mid 80s factory twin-charged thingo didnt they? someone else would know ... I dont have time for hondas ...
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Location:
Perth
Registered:
September 2003
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Re: 20V turbo question
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Thu, 04 December 2003 02:56
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Nissan's MA09 is a twin charger engine.
it's a tiny little 800odd cc four cyl with a supercharger and turbocharger.
it's overly complicated for the type of power delivery they were aiming for, nothing a correctly sized s/c wouldn't fix anyways.
steer clear of setting up a s/c and turbo at once, it's too much effort for little to no gain - a correctly sized ball bearing turbo will be simpler, cheaper, more powerful and saner.
a lot of people say twins on a four cyl don't work, but i beg to differ. it's exactly the same as turbocharging a 2cyl engine twice-over - similar to a twin turbo V8 setup - and that sure as hell works.
just remember to set the exhaust manifolds up in accordance with your firing order - not just cyl 1+2 to turbo one and cyl 3+4 to turbo two. this works fine with a 6cyl, because there aremore exhaust pulses to keep an even turbine speed. if your firing order is for example 1-3-4-2 then one manifold would run from 1+4 to one turbo and from 2+3 to the other - otherwise the exhaust pulses will be all over the shop and they will boost inconsistantly. the manifold will need to have equal length runners too, so you can imagine the spaghetti look that ensues trying to keep the 2+3 lengths the same as the 1+4 lengths!
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