exhaust bore size?

[Russ_16v]

seen an exhaust i like for my 172, but its a 2 inch bore,now i would have thought thats a bit small?

 

[Da]

Nope, it's 2" standard isn't it?
I know the 182 is until the tailpipes which are 2.5" from memory.

 

[Jamesstone]

I heard that 2" is the best size for the 172's, providing thats throught the silencers

 

[TheJesus]

the cat on a 172 is 2.5" which steps down to 2" at the joint,

 

[Russ_16v]

is that good or bad on a 172?

 

[Brasseye]

2.5" max

 

[TheJesus]

2.5" is optimal for flow and boasts the most gains,

 

[Russ_16v]

i have a funny feeling thats what my blueflame is now

 

[mattjk]

Not that I know but from reading on here it would be 2.25 for a mildly tuned engine or 2.5 for a heavily tuned engine. Cant see there being a big difference either way though to be honest

 

[Rob Clark]

erm my 172 is 2.25 as standard for middle and back sections with aftermarket ones going to 2.5 for optimal performace for the 2.0 engines

 

[Russ_16v]

il measure my blueflame later lol, so 2inch too small?

 

[mattjk]

^ It would seem that way its probably 2.25 though.

 

[Andyman]

Read on here recently that some folk have been advised to use a smaller 2.25'' bore. I say rubbish, 2.5'' all the way is what you want.

 

[Russ_16v]

thats what i was thinking, im always very sceptical about bore size, i know it can make a difference so i wanna get it right

 

[bmh.01]

My magnex is a 2.5" bore iirc and it freed up at higher revs without a doubt.

 

[TheJesus]

ive had both 2.25 and 2.5

not much difference tbh, apart from 2.5 is louder

laura

 

[Turner]

ive had both 2.25 and 2.5

not much difference tbh, apart from 2.5 is louder

laura

thts what i was thinking too 2.5 will be louder but anything with a larger bore than standard 2 inch is going to be better free flowing anyway

 

[Russ_16v]

so are we all agtreeing that the 2 inch bore is too small for a 172? as my old hybrid had a 2 inch system and that had no problems with power (see martins vids lol as you all know) and i wouldnt have thought that the difference between an F7R and F4R would have that much?

 

[JMR]

The inlet into the cat is 2.25"

Out of the cat and backwards is 2".

This is the standard exhaust part sizes on a ph2 172. Measured on Angelworks ramps:approve:

I had a powerflow made which replicates the original system [what i asked for to keep it nice and quiet]

Turner will confirm that there are NO performance issues with my car. Would note that my free flowing SS exhaust responded nicely to a re-map too.

 

[DrR]

The shim on my 172 exhaust is 58mm which is 2 1/4inch so it's slightly smaller than that.

 

[Russ_16v]

im even more confused now lol

 

[JMR]

2" is fine if you like the look and sound of the exhaust.

 

[Russ_16v]

well its one iv had before, and its been all good on my previous mk1 clio's but i was sceptical about bore size all of a sudden lol

 

[Turner]

can defo say that jmrmonacos exhaust is defo a very good option as all you hear now adays is 'I want a ss exhaust which isnt ny louder thn standard'! look and listen to james and i think itll make your mind up as i anwers all your questions tbh
p.s no performance issues either

 

[JMR]

can defo say that jmrmonacos exhaust is defo a very good option as all you hear now adays is 'I want a ss exhaust which isnt ny louder thn standard'! look and listen to james and i think itll make your mind up as i anwers all your questions tbh
p.s no performance issues either

I would like to have it RR'd tbh.

 

[Turner]

me too now ive had the inlets done as its sooooo much better now
would like a before rr then it remapped the same day then rr after the map

 

[JMR]

Bit off topic, but nonetheless, do you think its worth spending the money on the inlets matching?

 

[Turner]

YES!lol

 

[Andyman]

The inlet into the cat is 2.25"

Out of the cat and backwards is 2".

This is the standard exhaust part sizes on a ph2 172. Measured on Angelworks ramps:approve:

I had a powerflow made which replicates the original system [what i asked for to keep it nice and quiet]

Turner will confirm that there are NO performance issues with my car. Would note that my free flowing SS exhaust responded nicely to a re-map too.

How would you know unless youve had a 2.5'' fitted and mapped up to compare?? Very easy to say theres no performance issues but for all you know your car might respond better to the bigger bore size

Most after market systems use a 2.5.

For example Yozza plug their 2.5'' syetem as a 'race system' with gains and their 2.25'' 'road system' as a direct replacement. Go figure ...

 

[Laura]

For example Yozza plug their 2.5'' syetem as a 'race system' with gains and their 2.25'' 'road system' as a direct replacement. Go figure ...

aye but its not that all the way through, i know for a fact the road system drops to 1.75" inside the back box,

 

[Russ_16v]

really laura? im getting more confused by the minute lol, what size shall i get arrrhhh

 

[Andyman]

For example Yozza plug their 2.5'' syetem as a 'race system' with gains and their 2.25'' 'road system' as a direct replacement. Go figure ...

aye but its not that all the way through, i know for a fact the road system drops to 1.75" inside the back box,

Yes, the same as the standard Renault system hence the reason why the 'race system' uses the 2.5'' bore all the way through gives gains and the road system is a direct replacement



Mate, 2.5'' bore the end :rasp:

 

[JMR]

How would you know unless youve had a 2.5'' fitted and mapped up to compare?? Very easy to say theres no performance issues but for all you know your car might respond better to the bigger bore size

Most after market systems use a 2.5.

For example Yozza plug their 2.5'' syetem as a 'race system' with gains and their 2.25'' 'road system' as a direct replacement. Go figure ...

Hang on a second before I "Go figure..." Theres no need to come in with your sharp replies like an ar5e.:nono:

The OP's question was about 2" being suitable. IT IS the standard cat back exhaust size, and a direct replica in stainless in 2" pipework with free-flowing silencers IS suitable.

I am sure the 2.25" and 2.5" would give better gains than the 2" pipework [along with an increase in noise]

I had a 2" Powerflow system, ITG Panel & RS Tuning re-map, and driven back to back with Turners car, 2.5" GDI exhaust, de-cat and ITG Maxogen, Adam and I both agreed that my car was considerably faster, and more rapid through the rev range.

Would be interesting to see what difference Adams matched manifold makes.

 

[Rob Clark]

The OP's question was about 2" being suitable. IT IS the standard cat back exhaust size

erm, maybe on your system, but on my ph2 172, cat to backbox is most definitely 2.25" as my backbox went last week and i measured it !

 

[JMR]

erm, maybe on your system, but on my ph2 172, cat to backbox is most definitely 2.25" as my backbox went last week and i measured it !

But was that an original exhaust Wolf?
And was the 2.25" o/d over the flared end which fits over the other part of the exhaust?

 

[CHRISK172+]

I know you get more noise with a 2.5" system

 

[JMR]

I know you get more noise with a 2.5" system

:lolup:

Driving thro Collingham in your car was an amazing experience:race:
It was like the f*cking pit lane at Silverstone

Legendary mate.

 

[Rob Clark]

yes it was oem exhaust and was a 1 piece system with no flared end as fitted to new cars (had been replaced under warranty 18 month ago) so had been cut and a 2.25-2.25 sleeve used

 

[CHRISK172+]

I know you get more noise with a 2.5" system

:lolup:

Driving thro Collingham in your car was an amazing experience:race:
It was like the f*cking pit lane at Silverstone

Legendary mate.

Vroom vroom......who needs a f***in stereo with Magnex music :rasp: :rasp: :rasp:

 

[Turner]

and I both agreed that my car was considerably faster, and more rapid through the rev range.

just for the record,i didnt say it was considerably faster or more rapid as we never had a race side by side just the fact it was a hell of alot quieter and alot smoother power delivery maybe because of the remap etc
we will have to race properly some time i think youl be very surprised as i wasnt doing to bad against dazs throttle bodied clio the other night