14 replies to this topic

[Helter_skelter]

Hi there need a bit of help.
Looking to decat my spi for a little bit and swap back for mot.
Im not 100% sure on what exhaust I have(it was on when I bought it) .
My back box looks like this one so I'm guessing it's that.
http://www.minispare...g-bore-exhaust/
As for the rest I'm not sure if it's just a back box or full system or manifold back.
I've had a look under the car and I have manifold into the flexi, cat then to the back box.


Wondering if this would be the correct knew to fit? It looks about the same length as the cat section in the car which has flanges on either side.
http://www.minispare...ent-pipe-steel/

[bangermadness08]

As far as I know all exhaust fit each other as there's only 2bolt holes on every exhaust. I've played safe though and fitted a sportex system throughout

[FlyingScot]

Mmmm cat worth about 1 bhp, not worth removing it IMHO. Plus the twin box DTM has a poor rap on power

I would dump the DTM and get the RC40 back box.


FS

[Steve220]

Removing the cat will also make your car sound like a dry fart.

[FlyingScot]

Removing the cat will also make your car sound like a dry fart.

Which is the technical reason you shouldn't do it....

[Steve220]

Removing the cat will also make your car sound like a dry fart.

Which is the technical reason you shouldn't do it....

And ethical reason!

[Helter_skelter]

Ahh okay cheers for the replies. I was just looking for small things to improve power and sound a little(maybe the odd pop ). Not doing much major as i am hoping to start my conversion shortly, only doing the cheaper smaller mods just now. 

what about a manifold then if i don't have one, will that make a difference? if so whats the best way to check if i do or don't have one without being underneath as don't have a ramp handy atm.

As for the dtm is it the one box twin tip one that bad on power as i thought it was the twin box ones that were problems?

[humph]

My spi is fitted with a Minisport Superflow exhaust, LCB, & link pipe. This sounds nice & pops nicely.

 

http://www.minisport...m-cat-back.html

 

http://www.minisport...lyst-92-01.html

[Richie83]

I've got a full maniflow system with cat and it sounds good.

[Helter_skelter]

Mine sounds pretty good. Very loud and quite bassy. So I'm guessing if I have a look the standard manifold is cast and any aftermarkets will he tubular?
So Is my dtm one definitely bad for power or is it only the twin back box ones?

[Helter_skelter]

Bump. Also if the one i have is poor for performance is there any that have the same look? 

[brivinci]

From what I have read, its more about the proper amount of back pressure in the system. Center exit systems do not provide the right amount. A side exit, like the RC40, is THE best performing exhaust system and is one of the only that was designed by a true and proper specialist. This is what I have read...and it wasnt off the RC40 website:-)

 

I remember reading a exhaust shoot out years back in one of the big mags and some actually made less power then stock.

 

On the cat, they are very efficient and like said above, only take about 1hp at the very peak of the rev range. 

[Helter_skelter]

Ahh Okay fair enough. I I do want a side exit one but the issue is I'm on hydraulic suspension and it hits the floor so I'd need to tunnel it etc I think

[Midas Mk1]

I'd say try it, you'll be surprised.. I was.

[Helter_skelter]

I think the last time I checked the skirts literally sit on the floor 😂 might just have to see what other systems will fit. If I don't have a manifold will get one though