I'm just putting a few idea's together to take my MY05 uk sti up small stage and could do with some guidence regarding the exhaust.

What is the diameter of a Milltek system is my main question and will a 3" open neck decat down pipe marry up to it ok ?

I'm on a new age learning curve here, I know where I am with the generalised parts but it's the finer points that I have to re learn


Thanks
Simon

 

You can get the Miltek in 2.5" and 3" mate. I have a full 3" turbo back sports catted Miltek system and apart from being fairly quiet it is a very good system. I am running 340bhp with it on

 

It was on the car already so not 100% sure what it is I was assuming it was a 2.5".... I need to go and look through the paperwork that came with the car thinking on it as I know there is a reciept in the folder somewhere. It would appear the car was mapped for a full decat and then somewhere along the line the oem cat was dropped back on, I had attempted to contact the owner that had the map as I have his details with no success plus I have spoken to Tracktive who mapped it but they can't confirm anything.

Martin you may not have fully answered the question but you certainly jogged my memory !

 

Ok I have some paperwork it does not state a diameter but I do have some part numbers... I hope someone out there is good with part numbers...

It's hand written but read as follows and was fitted mid 2009

MSSUB116 & MSSUB114

Simon

 

I do have my receipt at home for mine from the previous owner but I'm in Florida at the moment. The parts numbers do look familiar though so it may be 3"

 

Thanks Martin, now I have the numbers I'll give the supplier of the exhaust a call and see if they can back track on the paperwork.

Enjoy the rest of your holiday there bud

 

Thanks pal, when I get back I will have a look if you have no luck

 

The standard dia for the STi is 2.75" If you want the 3" you'll have to specify the Spec C system. You can get the single scroll resonated downpipe to suit but you will have to be absolutely sure that if you already have an existing d/pipe, that it will match up for length. The Milltek is a system in it's own right.

JohnD

 

The standard STI downpipe CAT, will be restrictive for the gas flow, especially with your miltek system. Why didn't the last owner just put in a high flow sports cat.

What power are you running with this current exhaust setup. Sorry to say, but its a bit of a mish mash.

 

Thanks John that matches with what I found today as I called the original supplier of the Milltek, as you say it is a 2.75" system that is fitted.
I have found that Milltek sell a de cat down pipe which replaces the first 2 section both with cats in, this is a 3" open neck that fits to the 2.75" centre and rear.

I agree with you on that and the answer is I don't know the car's already had an ecutek map and I don't have a graph or any info from the mapper other than what the previous owner has quoted of around 312bhp.

Martin I have found out today that the oem exhaust is in 4 sections. The first is a down pipe plus cat, second short section with cat in it, third is centre section with resonator and forth is back box. What I can do now is make it a 3 section Milltek system, first down pipe, second centre section, third back box. This techinically makes it the same as a classic set up and the up pipe is cat less on the Sti so no need for me to look at changing that.

It's worked out a lot cheaper than I initially thought to re work the exhaust

 

Measure any sections you're not sure about by wrapping a tape measure round it to get the circumference, C. Then determine the internal diameter, d, by:-

d = C divided by 3.14. Then subtract about 8-10mm (the thickness of the walls: c.4-5mm x 2).

But you might have reduced OEM-sized 2.625" mating flanges - despite a bore of 3".

 

Silver Scooby Sport, I'm having difficulty reading your posts, as your avatar is rather scary!

 

That's a usefull bit of info I'll note that incase I need to double check anything

Sorry about that it's the inner Moderator in me