Downpipe sizes

[pgarner]

What differences does a 3" downpipe compared to a 2.5"

just noticed APR do it in 2 sizes and wondered whats the difference it would make

[prevtec]

whats this downpipe used for??
i dont know what this pipe is used for

[pgarner]

it connects to the exhaust port on the turbo to the mid section it also contains the cat,
done a quick search on it and some are saying the 3" can put more pressure on the turbo.

[pgarner]

ok just read that the 3" pipe moves the torque curve further up and losing low down torque

[walter leever]

normaly the wider diameter gives you a quicker response,

let the turbo spool up more easily and gives you more low torque and a

few horses aswell(at least mine did)so it's better.

Actually a must have if you have a chipped turbo'd car.

walter

[prevtec]

Originally Posted by pgarner

it connects to the exhaust port on the turbo to the mid section it also contains the cat,
done a quick search on it and some are saying the 3" can put more pressure on the turbo.

sorry pg, turbos and exhausts, i dont have a clue

[pgarner]

Originally Posted by walter leever

normaly the wider diameter gives you a quicker response,

let the turbo spool up more easily and gives you more low torque and a

few horses aswell(at least mine did)so it's better.

Actually a must have if you have a chipped turbo'd car.

walter

cheers, this is what im looking for however think i might stick to the 2.5" if i was to get one as it would allow me to retain the standard exhaust

[old-git]

Stick with the 2.5" as I would have thought that a 3" downpipe would be a tad too big. I am using 3" on the Elan.

[walter leever]

It's 3" till the cat,the rest of the system is 2.5"(Ferrita ss)

gives the car a minimum of 20 horses/15 nm plus.

[pgarner]

well that might explain why there both the same price then .
dont think theres much pipe before the cat anyway

[walter leever]

Originally Posted by pgarner

well that might explain why there both the same price then .
dont think theres much pipe before the cat anyway

You're correct,but it's an important little piece,makes your turbo

spool up more faster/easier and puts less restrain on it.

[pgarner]

now the question is do i spend the money on 2 new tyres so i can get the 17"s back on or go for this.

or it might have to be put on hold as trying to book a holiday as well

decisions decisions

[walter leever]

Originally Posted by pgarner

now the question is do i spend the money on 2 new tyres so i can get the 17"s back on or go for this.

or it might have to be put on hold as trying to book a holiday as well

decisions decisions

In my opinion:

-safety first,everyday(new tires)
-must needed rest 2nd(holliday)+fun

-only fun(more power)3rd

[pgarner]

tyres arnt really needed i put the 16"s on when they started to grit the roads. dont like them as much as theres less grip with them than the 17".
holiday i dont think im getting a choise with - wife and her mate have done nothing but look at them for weeks.

[walter leever]

So a holliday it is then?

[pgarner]

kinda looks like it, going to need to do some overtime methinks

[waynne]

A note on exhaust pipe sizes. Wider pipes flow more slowly. Take a garden hose as an example the more narrow the size the faster the jet you create. In an engine you need the exhaust gases to flow out as quickly as possible but you don't want to create back pressure. At high revs the 3 inch is better suited and at low revs a 2.5 is best. This is why the power figure moves up. I think Aston Martins, TVRs and some Porsches use a variable exhaust size which opens up as the revs rise.

The holiday is the top priority - you need to relax. Then the tyres then get the exhaust in time for summer when you drive round with the window open and can fully enjoy it.