ITB owners only need apply - Saxperience

sexy_gt · 6th February 2011, 17:26

ive never had an issue with sound limits on trackdays but since i have fit my bodies im a little concerned. its ok passing the static tests but some circuits use a drive by limit too. i know bedford gt is 87.5db at 30ft. i drive there a lot. they have a one strike and your out rule!

any of the lads on here have sound limit issues with induction? my car is loud even with the filter on. i have seen some large box enclosures on a few other cars. are these to shut the buggers up when required or just a form of filtration?

stew

Ryan^p · 6th February 2011, 17:29

mine is very loud. So generally I avoided drive by tracks where I know they are hot on it.

One method is to lift off where the meter is (not ideal)

The airbox will reduce the noise alot (it did with Bic)

adamskiTNR · 6th February 2011, 17:36

Yeah a common problem with itb's. statics usually pass as they are at the other end of the car. This is why a lot of caterham/westfield owners run plenums, as the inlets point straight out the side of the car towards the meter. I would definitely consider running a good plenum or box if you can't afford to go to less restricted tracks

sexy_gt · 6th February 2011, 17:40

i may modify a cereal box lol

AdamH · 6th February 2011, 17:52

is this for your atpower bodies? may be worth asking bic to see if he can make up some carbon ones or even grp if he deals with that?

Ryan^p · 6th February 2011, 17:55

Quote:

Originally Posted by AdamH

is this for your atpower bodies? may be worth asking bic to see if he can make up some carbon ones or even grp if he deals with that?

if you want to pay OTT prices.

There are a few off the shelf units that could be modified, or due to the AT design with the screw on horns plenty of people could even make one

AdamH · 6th February 2011, 18:02

may be worth contacting a few companys with some technical drawings then..

mentioned bic as he would be more then up for making a box but i agree with you on the price part.

(is it possible to get a box and not cut the scuttle? i cant remember if jp had his cut?)

AndySAXO^p · 6th February 2011, 18:05

Yer it will not effect the noise test before but can effect when they test during the track day, are you using a filter?

I have been ok and at cadwell, it was fine, I think 100 dB is alot more than 87, should be ok dont worry too much.

Ryan^p · 6th February 2011, 18:07

if you want any decent trumpet length with straight trumpets you need the scuttle cut.

The old GMC kit used 180degree curved trumpets enclosed in the box which is what yates and josh have.

it was a completely designed system by john to run with the jevney bodies not a real off the shelf item.

The issue with the ATs is the ram pipes point directly at the brake bar due to how they were designed (on a head but on in an engine bay) so even though they are designed for direct airflow to valve there have been a few issues with them in an engine bay.

dannygti · 6th February 2011, 18:07

with open trumpets you will NOT pass the drive by, my car was seriously loud. however with a proper airbox or chunky filter you should get away with it, although it would be touch and go for very quiet days.

AndySAXO^p · 6th February 2011, 18:12

Nothing wrong with flow just can't add lenght to them you can but will never be able to use a filter, but you can run longer truppets like, toads old ones. But I will and think should always use a filter.

I have spoken to some people and fab some new inlets, for the at to bolt on to get a better angle to get long length, and still run a filter, but it still work in progress,

AndySAXO^p · 6th February 2011, 18:14

Yer Danny only on drive by test static test will still be ok as it measure from the exhaust, but yer full song on drive by test at a quoted track day it will be touch and go, but should be ok on 100dB track days.

Ryan^p · 6th February 2011, 18:15

Quote:

Originally Posted by AndySAXO

Nothing wrong with flow just can't add lenght to them you can but will never be able to use a filter, but you can run longer truppets like, toads old ones. But I will and think should always use a filter.
,

I never said there was anything wrong with the flow of them, but that the design was based around the head and not around the engine bay aswell, which is why there is the brake bar issue.

The issue is with the airbox with the brake bar being there it really reduces the space you are working with as unlike the old gmc kit the set up isnt using curved trumpets.

sexy_gt · 6th February 2011, 18:19

i have the atpower bodies and filter too. the filter is 3/4inch thick at a guess. i havnt heard it without. not paying bic a penny tho. over priced yet well made gear. i will make something and insulate it if i need to. i guess i can work my way up the rev range as i pass DB meters on track. they do give a warning if you get close.

im usually 96db on 4,500 rpm static but drive by is completely different as said.

sexy_gt · 6th February 2011, 18:20

Quote:

Originally Posted by Ryan

I never said there was anything wrong with the flow of them, but that the design was based around the head and not around the engine bay aswell, which is why there is the brake bar issue.

The issue is with the airbox with the brake bar being there it really reduces the space you are working with as unlike the old gmc kit the set up isnt using curved trumpets.

im sure i could cut and resape the brake bar to accomodate if need be. i have the standard length bodies.

AndySAXO^p · 6th February 2011, 18:21

Yer miss read your post, I believe these where never tested in the engine bay before selling, which really should have been to get maybe a better angle and more testing involed.

John will never agree and will not tell you this good kit, but maybe more testing was needed, like I said I am looking into getting a better angle but will need testing aswell to make sure, nothing lost too with flow.