99greenwagon

iTrader: (39)

hi,does anyone know if the blitz cat back system fits a 2.5" and/or a 3" decat downpipe(classic)
it narrows down as its 80mm pipework but will it also fit a 3" decat downpipe pipe?

JonMc

iTrader: (51)

I've got my Nur Spec fitted to a Cobra decat - the IDs are the same in the decat and the step on the blitz so no flow issues

BBB3

iTrader: (7)

i will tell you later in the week as i have just brought the 3'' s/s off triple fillted

chocolate_o_brian

iTrader: (22)

I had a Nur Spec R on my last Impreza. The centre section of the Nur Spec narrowed down to 2.5" so mated well to a normal downpipe. I just had a 3" downpipe which narrowed down to 2.5" as well. You can modify the ends to both be 3" as some have done on here.

I remember your other thread however where you said you had the standard system for quietness... a Nur Spec-R is not quiet

JonMc

iTrader: (51)

That's what I assumed, but when I measured mine the ID of the step is 2.75" which equates to a 3" OD. The blitz is a true 3" system with a 3"ID, whereas most other systems, including the Cobra, are a 3" OD which is a 2.75" ID.

99greenwagon

iTrader: (39)

so..... will a straight 3" decat downpipe fit the blitz system?(one that dosent reduce to 2.5")?

99greenwagon

iTrader: (39)

a full 3" cobra decat that dosent narrow down?

JonMc

iTrader: (51)

As I said, I have a straight 3" Cobra decat (with no taper to 2.5") and it has bolted straight onto my Nur Spec system - be warned, it is loud though

99greenwagon

iTrader: (39)

thanks mate,its not for me,im selling a blitz and someone wanted to know.

sp00ks

iTrader: (11)

mmm this advice is for me cheers ;-)

howver i think there is a slight bit of confusion...

i have a 3" RCM downpipe with a 3" flange connection and would like too (maybe) fit a blitz nur spec system too it...

will i have too modify the connection on the Blitz or will it be a straight fit?

Sp00ks

99greenwagon

iTrader: (39)

this in theory should be the same

99greenwagon

iTrader: (39)

yes but the one you have bought reduces down to 2.5".

JonMc

iTrader: (51)

When fitting to a 2.5" flange you will still use the cone gasket and spring bolts, but when you convert to a 3" downpipe you use a standard flat gasket and bolts. Only time you will have a problem is if you have a cone gasket on a 3" flange as the blitz won't sit right over that.

The Rig

iTrader: (13)

The Blitz Nur spec R system i have,has the 2.5" reduced section to mate to the standard 2.5" downpipe,i have a Ninja Sports Cat with 2.5" flange.

The Blitz Nur spec R mid section i have uses a flat gasket and normal bolts not cone gasket and spring bolts

confused Now LOL

I did buy it 2nd hand so maybe i have fitted it wrong,and should be using the cone gasket and spring bolts ????
Dont know if there is/would be any ill effects of this ?

but if so,its fitted perfectly fine with flat gasket and normal bolts

JonMc

iTrader: (51)

You'll be fine. In short, if the sports cat/decat manufacturer followed the OE pattern it would use a cone gasket - I had a third decat pipe that did, but not all of them will. The Blitz does taper down to suit a 2.5" cat (cat replacement) and using a flat gasket is not a problem if your cat/decat doesn't have the flange to mount the cone gasket on. Despite the taper I suspect, as I did, if you took it off and measured the ID at the narrowest point it will actually be 2.75" which is the ID for a lot of aftermarket 3" systems whose measurement is based on the OD.

The only possible side effect of not using a cone gasket/spring bolts is that unless you have a flexi pipe in the system there is no freedom for the exhaust to move as the engine twists under acceleration/decceleration and after time may crack. If that happens you repair it by getting a flex joint inserted. A lot of non-slip jointed systems have no flexi joint and it is a matter of opinion whether or not they are beneficial. Some say it will provide that freedom to accept engine movement, others see the flexi joint as the weak point on the exhaust and the first place to wear and blow.

Horses for courses at the end of the day.

99greenwagon

iTrader: (39)

so a 3" flat face flanged downpipe will bolt straight up to the nur spec?(just to clarify?)lol

sp00ks

iTrader: (11)

anybody able too answer this final question?

i have an RCM 3" downpipe and would like too know if the blitz will connect too it...

the RCM downpipe is a flanged 3" connection. and the Blitz reduces down to 2.5"

Thanks ;-)

99greenwagon

iTrader: (39)

the measurement is not 2.5"

sp00ks

iTrader: (11)

what is it then bud? ;-)

99greenwagon

iTrader: (39)

When fitting to a 2.5" flange you will still use the cone gasket and spring bolts, but when you convert to a 3" downpipe you use a standard flat gasket and bolts. Only time you will have a problem is if you have a cone gasket on a 3" flange as the blitz won't sit right over that.

sp00ks

iTrader: (11)

You see thats what i currently have at the moment is a normal flat gasket and bolts fitting upto my 5Zigen 2.5" flange connection (similar too the blitz connection in the picture you sent me) and i am having problems with exhaust gases leaking out from this connection.

I'm thinking that the RCM downpipe can only be used connected to a 3" flange :-(

99greenwagon

iTrader: (39)

As I said, I have a straight 3" Cobra decat (with no taper to 2.5") and it has bolted straight onto my Nur Spec system


these answers should clarify shouldnt it? lol

JonMc

iTrader: (51)

Yes, I have a Cobra 3" downpipe with a flat face 3" flange bolted straight onto my Blitz - no blows and fits fine. I used some exhaust paste (gun gum) just for peace of mind and to ensure the seal, but it's probably overkill.

The Blitz reduces to fit a 2.5" standard downpipe, but the flange has elongated exhaust holes to allow it to fit different size flanges. It will fit both 2.5" and 3" systems and I have had mine fitted to both

It measures out as 2.75" ID.

99greenwagon

iTrader: (39)

i have just been out to measure the connection.....its 3" bore id at the flange,so will definetely fit that rcm downpipe as long as its a flat face,the blitz pipework is obviously more than 3".

99greenwagon

iTrader: (39)

pipework is 80mm,the size of the hole at the downpipe connection is 3".it will fit.

sp00ks

iTrader: (11)

am i right in saying that it looks like this ;-)

https://www.scoobynet.com/drivetrain...or-400bhp.html

if so it does look like it should mate up...

99greenwagon

iTrader: (39)

yes it looks nearly identical to that,i believe its 80mm with is slightly larger than 3" then it reduces down to 2.75-3" and they have made it like that so that you can use a cone decat downpipe(2.5" to fit ) or a 3" flat faced gasket type to fit also(which is what your new downpipe is) i can see clearly now....it will definetely fit.when i held the tape measure across the hole at the downpipe flange end i instantly thought.....**** me its 3" anyway!!

sp00ks

iTrader: (11)

Yeah so it must reduce down and then open up abit too cater for both 2.5 and 3" downpipes....

Mmmmm now i must decide lol!

99greenwagon

iTrader: (39)

correct mate.

sp00ks

iTrader: (11)

Mmmm trying too decide mate RCM or your blitz :-s