The B20VTEC discussion thread

**ALLMTR996** · 24-01-2010 12:32 PM

Originally Posted by Chr1s

Interesting topic.

I'll be starting with a 2.5" setup on mine, however with my 2.4L nissan that barely breathes as much as a b20vtec would, I noticed gains all over my powerband when I went from 2.5 -> 3". It could be placebo, I will try it again one day...

Datsuns need all the help they can get and bigger is always better on them,BYP did alot of header and exhaust testing on there B20 and if 3" worked dont you think they would have run it,now K series is a different story.

**mocchi** · 25-01-2010 10:34 AM

Originally Posted by ALLMTR996

Datsuns need all the help they can get and bigger is always better on them,BYP did alot of header and exhaust testing on there B20 and if 3" worked dont you think they would have run it,now K series is a different story.

what is the difference? k20 & b20

**ALLMTR996** · 25-01-2010 10:59 AM

Originally Posted by mocchi

what is the difference? k20 & b20

K engine's like very little pressure in the exhaust system, bore/stroke/rod ratio/cyl head flow/cam timing/header design all play a very important part in choosing the correct size exhaust system

whoops forgot GEARING is another very important factor but no one listens to Toda AU he has been saying that for years

**mocchi** · 25-01-2010 11:10 AM

if you don't mind, can you please elaborate? i would like to know more.
thanks

**bennjamin** · 25-01-2010 11:32 AM

Gearing is everything. The correct application can also increase or decrease your power output on a dyno too.

**eg5civic** · 25-01-2010 12:12 PM

Originally Posted by mocchi

if you don't mind, can you please elaborate? i would like to know more.
thanks

I cant elaborate but just a general note alot of dc5r's run 3" exhaust afaik

**TODA AU** · 25-01-2010 06:23 PM

LOL...

**eg5civic** · 25-01-2010 06:26 PM

^^ wut?

**Cooker** · 25-01-2010 06:59 PM

Originally Posted by TODA AU

LOL...

Hahaha, true Adrian

**bennjamin** · 25-01-2010 07:39 PM

come on guys lets keep it someone serious

**Slaz** · 25-01-2010 07:52 PM

That would make a good logo for some people on here.

But ill put in a comment in just for Ben

My B loves the bigger system, but it runs a 3in and then into a twin system and i havnt tried a smaller system either as when i did the design, it all should have worked and it does, i was going to go 70mm but getting the piping wasnt easy, but saying that it also is pushing alot more revs then most of the B20 builds as the more it was revved, the more power it makes, but as Dave has said, the bore/stroke/comp/flow/cams/timing and header all come into this, as does its application and the powerband required from it.

As for gearing, well many seem to miss that and alot address it later on which is fair enough after they have just dropped alot on their build, but then wonder why for example some of the big K24 engines with massive power arnt much quicker down the 1/4 or through the traps.