4-1 and 4-2-1 manifold differences...

[Rich-D]

Ok, I know that a 4-1 and a 4-2-1 manifold both give a nice increase in power and torque, but with different gains...

One gives more low end grunt and the other more peak performace, or so I am told.

Question is, am I correct and if so, which one does which?!


TIA

 

[Matbrown]

AFAIK 4-1 is better for peak performance as seen in the willy and 4-2-1 is better for low down torque as seen in the 16v.



Mat.

 

[Ben j]

u want a 4-2-1 .. better

 

[Rich-D]

Apparently...

4-2-1 - for low end
4-1 - for top end


Ties in with what you guys said too.

Cheers

 

[BenR]

Aparrently............oh dear, i see pub talk has set in from far too long ago.

its now been prooven far too many times that a 4-2-1 system with long primaries provides a better power curve without loosing any performance at all, and even in some cases picking up power at most points.

Only a few rare cases where a single primary into collector and one of them is the 3-1 system on the mini, simply because the siamesed ports create very funny flow and pulse patterns.

 

[Leigh]

Bens right

the 4-2-1 has better air flow !! It has been proven on sooooooo many occasions that the 4-2-1 is better !!

So it does make you wonder why Renault put the 4-1 on the willy !! There must be a reason ??

 

[BenR]

the 172 is also 4-1, as are the majority of std rd cars

 

[Rich-D]

Quote: Originally posted by BenR on 15 April 2003

the 172 is also 4-1, as are the majority of std rd cars

So does my 306 Rallye...

Nice tubular 4-1 manifold like the 172 gets, but then it goes into a single pipe at the downpipe/cat section and its this part I am wanting to change.

Options from Peugeot Sport are either a twin Group A de-cat or a single Group N de-cat and I am trying to work out which is going to be better.

 

[Anders]

Group A twin all the way mate.

I think the Grp N is only singlular because of the homologation rules.

 

[1.6 16v]

Small world. Seen this in uk.rec.car.modifications. Interesting to see you got a much better response in here

 

[Rich-D]

Quote: Originally posted by 1.6 16v on 15 April 2003

Small world. Seen this in uk.rec.car.modifications. Interesting to see you got a much better response in here

Yeah, Ive posted it allover the place...

Get a wider audience then and hopefully some good advice.

Always tend to get good advice in here though!

 

[Ben j]

whats on a valver as standard then?

 

[BenR]

the 16V works out as a 4-2-1 but if you look close, it resembles a 4-1-2-1.....but thats jsut getting anal on my half...lol

Rich, th grp A, i have seen pics of the pug one and the GrpN one is nothing spesh.

 

[BUTRE]

anyone tried the willy std exhaust manifold on the valver? if yes, what was gained and/or what was lost?

BenR, I disagree in the valver exhaust manifold. eheh

here some pics of mine.

http://perception.no.sapo.pt/pics/colectoresf7p.jpg
The manifold itself.

http://perception.no.sapo.pt/pics/4_2f7p.jpg
The "exhaust exit of manifold" 4-2 till now.

http://perception.no.sapo.pt/pics/downpipef7p.jpg
The "downpipe" 2-1.

When everything bolted... its a 4-2-1 manifold+downpipe exhaust.

 

[BenR]

Quote: Originally posted by BenR on 15 April 2003


the 16V works out as a 4-2-1

Do i really need to quote myself!!!

 

[BUTRE]

eheh yeap, all the time!

 

[BenR]

shame......

 

[weight]

BUTRE - Thats disgraceful, get the gunk out immediatley!

 

[Rich-D]

Quote: Originally posted by BenR on 15 April 2003


the 16V works out as a 4-2-1 but if you look close, it resembles a 4-1-2-1.....but thats jsut getting anal on my half...lol

Rich, th grp A, i have seen pics of the pug one and the GrpN one is nothing spesh.

Not sure if the Rallye manifold has a divider in it (like the 16v one in the pics above) or not, but if not it would be a 4-1-2-1 as well with the Group A downpipe and this point has already been raised on one of the Pug forums. Any issues with it being 4-1-2-1 then?!



This is a standard Rallye/GTi-6 manifold >>>

http://www.peugeot-gti.net/photopost/data/506/68manifoldb4-med.jpg

http://www.peugeot-gti.net/photopost/data/506/68manifoldafter-med.jpg

(without the lagging as standard though)

Now that aint my manifold in the pics, I "borrowed" those pics, so Ive not actually seen one close up and its mounted at the rear of the engine and is not easy to get at from the top.

Glad I aint trying to remove it!



These are the downpipes in question >>>

Group A:

http://www.cartv.org/Merchant2/graphics/00000001/mn_3061.jpg



Group N:

http://www.cartv.org/Merchant2/graphics/00000001/mn_3060.jpg



Neither one is cheap though...

 

[BenR]

no probs with it really, give it a go...if no, jsut sell it...plenty of people will want it.

 

[Rich-D]

Looks like Im getting a Group A one then.

Good job I know a guy selling one thats only a couple of months old and a LOT cheaper than new...

 

[BenR]

it looks like the grp A one gets rid of a downpipe

 

[Rich-D]

Quote: Originally posted by BenR on 16 April 2003

it looks like the grp A one gets rid of a downpipe

They both replace the same bit of pipe (with the cat in it) and it is a downpipe itself.



Just found out that the lad with the Group A one for sale has now basically sold it and a lad has posted him a cheque, so unless it falls though...

Know of a Group N one for £50 so Ill try for that before lashing out full pirce on a new one.



Cheers for the advice.

 

[BenR]

I was asking because the it looked like the mating flage was at a diff angle, now i realise the Grp N is on its side! lol

I cant see any provision for a lambda on the Grp A one?

How much is a new one?

 

[Rich-D]

The Group A one also has a mounting point for the lambda, but you cant see if in the photo becuase of the angle it was taken at.

New price is £160 +Vat +p&p so not cheap...

 

[Rich-D]

Well, Ive managed to line myself up a second hand Group N one now...

Should be £120 +VAT +p&p and Im getting it for £50 so not bad!



See what its like and if its good then Ive got a bargain, but if not, or in the future after more mods I can easily sell it for the same amount and then get a Group A one.

Shame it wont be on the car for York on Monday...

 

[BenR]

lol....oh well!

at least you get factory parts........

Renault sport are the least helpful people around!

I work for ren and the only time they talk to you is when your face to face and they cant excape! Paris motorshow they were very helpful, but once your not physically there, *poof* theyre gone.

 

[Rich-D]

Yeah, Peugeot Sport do seem quite good...

 

[BenR]

Especially ther readily available S1600 parts!

 

[Rich-D]

For all their cars...

Look here >>> http://www.rallycar.comwww.rallycar.com



This is not actually direct from Peugeot Sport, this is an agent for them, but its all the same bits, at all the same prices.

Just buy direct, or through a dealer and I get discount anyway.