1.4SR 4-1 or 4-2-1 Manifolds?

[mikeoxford]

spoke to spanishfly at MK (not doubting your word - just wana see opinions ;)) and hes got a 4-1 manifold and says he sees considerable difference.

i can get me grubby lil hands on a 4-1, black painted mild steel exhaust manifold and downpipe for ?40 and wondered wether to get it?

i dont no what the diference is between 4-2-1 and 4-1 other than the physical side of things, what gains will i see, and which do you guys think is best?

thanks guys (and spanishfly 2 :P)

[barnes]

you nly really need to start messing with exhausts when ur car is more tuned to be honest. a 4-1 is a great thing to have if ur car is putting out a fair bit more than factory bhp as it will make it breathe easier. on the other hand putting a 4-1 manifold on a std engine, by std i include bolt on filter and back box etc coz that probably pulls the bhp down a tad. the manifold wont actually do you any favours, ie the back pressure isnt great enuff to warrant it. something like a 1400 on 40's, modded head etc will deffo need one.

even nova gte/gsi's dont really benefit much from things like 4 branches coz the vauxhall stuff is failry adequte for a max powered tuned car (filter and backbox and super 4's)

[mikeoxford]

it has a full mongoose stainless system front to back, weber 32/34 carb, ram air bolt on filter.

spanishfly runs a very similar setup, and said that he did notice an improvement, thats why i started going down this road.

must b sum more opinions out there!

sum of you must have either had one or other of em at some point what would you lot say!?

thanks again all & (barnes, and spanishfly)

[cornish]

I've got a 4-1 manifold on my 1.4SR and i defo noticed the difference.

What you lose in bottom-end torque you gain in peak power.

[barnes]

be honest, a 1400sr is slow enuff that if you loose bottom end tourque its just gonna suffer a hell of a lot.

as for that being a modded engine??? well, maybe 2-3 bhp over std. a system doesnt exactly give more bhp unless you have a manifold to suit and theres no point really.

as for noticing a difference??? you dreaming mate, the 2bhp max i might add is not gonna exactly chuck you back in yer seat is it. it was all in yer head, it feels exactly the same.

i know, ive gone down this road before

[mikeoxford]

any more for any more?

[barnes]

what?

[mikeoxford]

any more people for any more posts............

never heard that b4?

[Dicko]

i just had an induction kit on my sri engine, i went from a performance syetm+backbox to a full magnex system with 4-1 manifold, there was a bit of difference at the top end, it jus wants to keep revving, however it took me a few days to get used to the lack or torque at very low revs!

[spanishfly]

lack of torque isn't that noticable!! i reckon 2000 rpm down!!!! if u have a good system and add the manifold i reckon theres more power output than 2 bhp :lol: by the way u say the vaux stuff is good!!! nope it isn't far to restrictive!!!! barnes ask chip about my car he was quite impressed!! 32/34 carb on 1.3 manifold (i know it's different than 1.4) ashley full zorst set up!!!

by the way super 4's would make no difference at all!!!! if ur lucky they may give u a better spark! i had them and threw them vauxhall v6 plugs a well better! twin electrode platinum :)

[CP]

In the fiddlings I've had I would say that there maybe a some difference that someone who knows his car well could spot. Generally I would say it would be minor IF both are manufactured to similar specs. I've read tests in CCC where they have played with the tuning and design of Zorsts (mainly on highly tuned Vaux/Rover powered Caterhams.) They found that 4:1 gave the highest power reading but not by much. The 4:2:1 gave nearly as much top end but filled in the torque hole mid range that the 4:1 created. In other words the 4:2:1 is the best alround design.
The other rule of thumb thats generally accepted is that the primary pipes should be at least 30 inches before starting to join up. The ones I've had have been short of this.