hi alot of people say that the standard box is restrictive but why ? has anyone actually looked inside to see if the pipe goes straight throught the back box or do the pipe just join both ends of the silencer ?

i have put my original back box on the car to reduce noise level and it sounds very quie now ( great )the car is fully decatted.
should this affect the performance of the car ?


sam
MY99, LINK, VF23

sam
thought you had just bought a magnex back-box,fitted mine on thursday sounds good, but still fairly loud.do not think standad box is that restrictive,just quiet with hellish tail pipes,i think that it is straight through as the tail pipes look like they go all the way to the front of the box.i have not noticed any gains as yet with the change (my00),down-pipe done last month made a difference though ,standard centre,possibly need the standard ecu reset,done at d/p change.
that car of yours went like a rocket at crail hitting 100+ mph on back straight(thanks for the run)my dbmica was just over 90mph depending how wide i ran,bloody under-steer,if your car is reliable over the next 12 months i may pinching a few of your mods.

john

Hey John

Finally decided to start posting huh http://bbs.scoobynet.co.uk/smile.gif

Ian

thanks John http://bbs.scoobynet.co.uk/smile.gif

i know it looks awful but it is quite for motor way journeys which is good. it is a straight through pipe then it should not be any difference from all the back boxes you can buy. however if it is not a straight through pipe then it will be restrictive at the top end.
can you look through your back box and see if you can see the other end ?

sam

sam

old box is that sooty it is hard to tell,but
using a torch i am sure that the tail pipe
stretches all the way down to the front of the box,down to "in" pipe,you will see what i mean if you look up one of your tails on car.
did you notice a difference,except in noise,
going back to standard?
i have been told that there is a rolling road day at star performance soon,if your car can get two runs, i can refit the performance box for the second run.any one know the date?
i would be surprised if there is much between them.

john

repeat post

[This message has been edited by Sam Elassar (edited 04 February 2001).]

thanks john
if you could help with fitting the back box for a second run will be great and will settle things once and for all. i think it is on the 25th of feb


i have not really noticed much difference in the performance apart from the noise, but again it can be very hard to tell.

for your car you should notice a difference once it is all decatted, ie you need to loose the mid section.

if the back box is straight through i will just get an STI back box as it is identical to the standard UK one but with a better back end IIRC.

Cheers

sam

sam

did not think the my00 cars had the centre section cat?
should make it on the 25th,it will be very interesting,same rollers,same day etc,my car feels under powered compared to the earlier cars i have driven.i have read of these cars surging between 2500 and 3500 revs,my car does this but only when cold,even then it is hardly noticeable.it's strange,my car can be going great,pulling well in every gear and then for no reason,almost start to hold back,
then a few miles down the road be going great again.thinking of getting a boost guage to monitor turbo,spoke to my dealer about clutch (not judder,but very small biting point leading to jerky gear changes,mechanic friend with my99 drove mine and then checked engine mounts it's that bad)
and they told me car should get quicker and smoother with more miles (currently 2600m).
anyway this is your post so see you at the star day.
take it i'm wrong about you getting the magnex.

john

now i am not so sure about the standard box,looked at it again today and tried to push a piece of wire up a tail pipe,expected it to appear at the the centre section flange
joint but it didn't,made it to the front of the box but would not go any further,tried other way(joint to tail)and again it would only go so far and then stop.
surely someone on scoobnet knows for definite
if the standard box is straight through or not?

john

The standard STI backbox is definitely not straight through.

Chris.

i think it is settled then

i am sure that the sti back box and the standard UK one are just identical apart from the the sti one is SS IIRC and the oem isn't. but they should be the same design, i suppose i will have to get my self a magnex then. how loud is it john on the motorways ?


sam

sam

i will take you for a run at the star day,that way you can hear first hand.
does the my00 have a centre cat then?

john

Sam,

If you do put a Magnex BB on will you post your findings.

I have an STI 5 with a full SS exhaust which I found unnecessarily loud. I have subsequently put the STI BB back on which has made it much quieter and seems to have slightly strangled it. I am now looking for a straight through silence which is quieter than the SS item.

Chris.

hi chris
i have just fitted the magnex BB. it is ok not as loud as my previous one but not as quite as the standard. i am going to donno next week end so this will be the ultimate test, to see if i can live with it over a 6 hour journey or not ?!

i had to alter the map after fitting the exhaust ( link ecu) as with the new back box i was running richer so i suppose i will get better fuel economy with it.

performance wise my boost is rising quicker ( very noticeable )because the system is less restricted now.

cheers

sam

sam still have not reset ecu but have to say car now seems more responsive throughout rev range,are you still changing the b/b for 2nd run?
john

i suppose there will be no need for that now john. if the back box is not straight through it could only be restrictive !! the boost response is better, because it is more free flowing it is allowing the turbo to spin up better. http://bbs.scoobynet.co.uk/biggrin.gif.

it can be very difficult to notice a drop in 5-6 bhp at the top end when the car is producing 280bhp/280torque http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif. but i still think my previous back box was better so will see if there is any drop in power from the last dyno day. although because of the colder weather we should get slightly higher readings than last time http://bbs.scoobynet.co.uk/wink.gif

sam