Hi,

As I have just spent most of my money on a set of P1 wheels for my My99 wagon I now only have enough for a downpipe OR Back box.
I want to improve low down torque rather than the looks/sound so wondered if anyone out there had tried replacing just the downpipe whilst retaining the std mid section and Bbox ?

Comments would be most welcome.

Cheers
Lambo

 

I havent done it, but gains wise it would certainly be a better option.

The dfference restriction wise between the standard downpipe and the standard back box is significant enough that replacing one with an after market product yields better gains.

mostly by removing the cat, mostly.

 

I changed my system in stages(MY00),first the downpipe(PE T75)and noticed small gains higher up the revs,then the back box(magnex)and noticed no difference but highlighted a flat spot at about 4500rpm,then the centre section(magnex)and it seemed to give the biggest gain of them all ,most people do the b/b then c/s and leave the downpipe until last and then notice this as the biggest gain.

I would try and source a second hand complete system as I would bet that once you change one part you will be desperate to change the next.to help low down in the revs I personally believe a 2.5" bore to be better as a friend with a MY98 put a 3" mongoose on his car and on the road it seemed to loose a bit of low down grunt but higher up in the revs the thing pulled like a train,far better than my car higher up.

john

 

Lambo,

I had a Magnex backbox and mid with a K&N panel filter. I had it Dyno'd at 230 bhp. Then put the Magnex Downpipe on and got 232 bhp. Not much difference you might think but to drive it's unreal!

The pull at low revs is so much harder. Given that I would go for the DP. You won't stop there though, you can upgrade as you go and the whole thing will give you the full power / torque benefit.

The Prodrive upgrade includes the backbox and filter, as from their research it gives the best power gain for the dosh.

MB

 

I've run an SS d/p with standard mid and rear sections. It's definitely better than just a backbox swap.

Be aware though - once the downpipe has been changed, you'll also notice a performance difference (maybe 5%?) by swapping out the crap OE backbox.

If the downpipe's not done, you get nothing but aural performance increase with a bb swap.

Richard

 

I had a Prodrive bb fitted a few months ago: nice noise, very slight increase in performance. Scoobysport d/p done the other week, huge difference. Turbo spins up quicker and the car generally feels more "eager". The other thing I've noticed is that the early morning reversing-off-the-drive juddering has completely disappeared. Magnex centre goes on later this week......

 

I have run a SS BB for about 18 months and recently took the plunge to fit a SS DP.
I only held of in the past because of noise levels, but although there is an increase, it's not as bad as I thought it would be.
Performance increase on the other hand is great.
All the reports about extra urge, quicker turbo spool etc are all spot on.
I'm told that there is little increase in peak bhp but that the power is more accessible throughout the rev range. I would imagine that the power curve will rise sooner in the rev range?
Regardless, the DP makes a lot more difference than the BB on it's own.

Neil.

 

Lambo

I currently only have a Scorpion downpipe fitted. I used to have the Magnex centre and back but took them off later.

For driveability I reckon the downpipe is the best because it helps the turbo to spool quicker.

Thanks

Sonu