e-bay exhaust

[dapinky]

Not sure on the percentages for gas flow as quoted by steve (but i'm not saying he's wrong) - i've never done any dyno testing or otherwise......


....but the maths (which i don't believe has changed since i was at school - but with exam results the way they are in the UK, I may be wrong on that as well!)...

area of a circle is pi x r2....

so a 2" pipe will have a cross section of ~3.14 sq inches

a 2 1/4 pipe will have a cross section of ~3.97 sq in (26% increase)

a 2 1/2 pipe will have a cross section of ~4.91 sq in (56% increase)

Obviously, these numbers are expecting the available cross section to be constant throughout, which they aren't, and also doesn't allow for thickness of the pipe walls.....

I don't know how the actual gas flow compares with the area due to dynamic losses etc, so Steve may well be right with his numbers.

[Jeemy]

Wow. Did not realize it made that much of a difference. I've recently found out my exhaust was a bodge job (looks like a good stainless steel aftermarket from the back, but underneath its garbage) and will go for the 2.5 on that basis - thats a lot of power for not a lot extra!

[Pascal]

Hello from France,

i consider changing my exhaust line before it turns to dust, has someone compared the performance and noise between the 2'' 1/4 and the 2'' 1/2 ?
Obviously, bigger should be better, but the cost is also ''better'' .
And i am always careful when something seems obvious .

I was also wondering if the 2'' 1/2 does not require engine settings modification ?

Pascal

[epipete]

All performance issues aside, my problem is the increased noise since fitting my 2.25 exhaust which makes me rather self conscious when working on the car in regard of the impact in my neighbours!

[rip]

All performance issues aside, my problem is the increased noise since fitting my 2.25 exhaust which makes me rather self conscious when working on the car in regard of the impact in my neighbours!

What have you got then?
I don't feel my Piper is 2¼" is that noisy. Mine has the 2nd silencer but I can barely tell the difference between it & Dapinky's single-silenced 2¼" Piper ... or G UK's single-silenced 2½" Piper. All are quiet at idle but make a nice noise when you boost through a tunnel in 3rd gear

[epipete]

Apparently it's a PNM Engineering 2.25 S/S which I purchased 'slightly used' from (Simon) 'Turners' breaker last year.

It has made me smile more broadly given the increased performance and on the road the noise is not so worrying but on the drive or in the garage it is outrageous!!!

[Pascal]

Hello,
about the differences between 2'' 1/4 and 2'' 1/2 :
i had from Piper this very fast and professional answer, could be useful to someone :

' '
I can supply part TLOT7BSJ - LOTUS ELAN - 2.5" S/S SYSTEM - NO SILENCER OR
CAT. It does fit to the stock downpipe and a fitting kit with gaskets is
included, on some engines this setup can cause 'boost creep' this is where
the turbo spools up too much, producing excess boost, this can cause the
engine to enter 'limp mode' for a short moment. Solutions to this include
porting of the wastegate and/or installation of a Mountain chip or similar.
' '
Comments are welcome, my english is not 100% reliable and using the goggle translator is simply funny for this text, especially 'porting of the wastergate' ( i didn't know i was driving a steam train).
Regards,
Pascal

[rip]

Pascal,
All the above info can be found on this forum.

Start by reading through this thread.

Both the 2¼ & 2½ systems can cause boost creep. This is more noticeable in cold weather.
A mountain chip has a marginally higher overboost limit. It is highly unlikely that your boost will creep to somewhere between the overboost level of a stock & mountain chip...so a mountain chip is definitely not a solution to control boost creep/overboost.

[paul27848]

Just purchased the Ebay Peco system today. Buy it Now price was £255 plus £15 postage, or Make Offer. I offered £240, to effectively get free postage, and they accepted immediately. Therefore they would probably accept a lower offer, but I NEED it now and can't mess about making low offers and waiting for counter offers. If you are not desperate you might get a really good price.

Paul

[rob/d]

This thread has become very interesting this weekend as my exhaust has packed up overnight .
Yes, in know , it hasn't packed up but on friday night all was well .Saturday morning and a big ( pinkie finger ) size hole on the backbox end plate . Rust.
The cybox option looks like the one for me , the price seems fair .
pictures to follow .

[rob/d]

Just back off hols and bid £250 inc delivery from cybox . Needs must.

[rob/d]

ARGHHHHH.

Exhaust came today , looks beautiful .
Had it fitted by local garage . £40 , nice , get on with it .
Job done , sounds wonderful.
Took it up the road , loads more power , great.
Gave it a bit of beans and ARGHHHHH , f*****kin loads of boost and major engine shutdown and lights on dash board coming on and power dropping off like a flipping anvil .
Obviously i thought i would be the exception and boost creep would be the other guys problem , but ....
I will reflect on today's drama and have a sit down in a quite room with a nice cup of tea before forming a plan on going forward.
Did i mention that i had a new exhaust today ?

[steve matthews]

Rob, welcome to the club. You will get through this with a few $$$$$$$$
then will look back and laugh.

Steve

[rob/d]

Already laughing steve
Plan today is to run the car till poor weather arrives , yeah don't say it , and then tackle the wastegate .
Driven at 80% the car will be fine .
I am confident in doing the work , worried about getting the assembly off without snapping manifold studs .
hey ho.