Full exhaust system questions

[slyboogie]

What gains would be had from a 4-2-1 manifold? Also, can someone give me a link or somethign that would explain to me exactly what i need to do? Also, are stainless steel K11 ones available as i know you need to use the K11 one with K10 flanges, i just don't understand the rest.

Also, what would be the best size exhaust system tubing?

And lastly, what would be gained from a 4-2-1 (or 4-1 if their available/better) followed by the right size diameter straight through exhaust through to a stainless backbox?

Other mods planned are CBR600 carbs fed by a bonnet vent and custom air box/feed from scoop and a reprofiled cam.

I'm just trying to guestimate what costs and gains are ivnolvved here. I know the cbr carbs would be around good 30Bp, maybe more with my custom vent and box work, all i need to find out is teh gains from the exhaust system and cams?

thanks to everyone who helps.We should be seeing a mental micra in no more than a year =)

 

[Arnold]

You really need to search the forums. All this information is on here!

 

[slyboogie]

i'm useless with searches, i can never find what i'm after! lol. i typed in straight through exhaust and it came up with more about carbs than exhausts ¬_¬

 

[squarepants]

gians/power:
its proven that a 4 branch manifold and 2'' system and an uprated filter will get you around 75-100bhp at the fly...and around 60-70ish at the wheels on a 1.3. BUT thats on a k11, dont know about k10.

size/diameter:
if your having the car NA a 2'' diameter exhaust is right, if you have a car with abit more power i.e sr20 a 2.5'' diameter is in order, and lastly if you have a turbo high power car 3'' is ideal.....

system layout:
a straight through exhaust on an NA is good on top end power wise, but rubbish on hills as there is no back persurre, even with a back box its likley to be therriable...on an NA i would keep the centre cat and have the back box, obv if turboed the turbo will provide back persurre and will/should rid of some noise.

cams:
these will give you near power through most of the rev range but will need setting up with the ecu being re-mapped, coupled with a manifold these are awsome.

as said some information on this will apply more to the k11 than k10.
hope this helps you abit.

 

[slyboogie]

Hi,
kool, so ideally i need a small second silencer to build up some back pressure? I have a K10 pre-cat so i don't have a cat as standard. I may just remove the rear silencer and stick a backbox on, i'm tempted to do a Zr conversion on my 216SI Rover anyway! Put sipmply, to me the micra's a bit old to invest silly money in whereas the rover has had £1500 spent on replacing engine parts including all new valves etc and because of a small ead skim the compressions been raised, hence its now faster than stock.

And before anyone starts having a go at rovers headgaskets, their not as bad as you think, its usually the waterpump failings fault or lack of care (oil etc) that causes it. Just hope to put some myth's to dust =]

That said, their still never as reliable as my micra lol! Although, looking at power my 1.6 rover would be faster than a carb'd micra now.going on BHP/Tonne using 1 tonne as a rough guess, wouldn't weigh anymore i doubt!