Iain P's Brake Duct Design
30 December 2000, 01:21 AM
#1
Scooby Regular
Thread Starter
nice idea, i hope thats not self tapping screws i see, because they have a nasty habbit of falling out. I dont fancy a puncture mid craner curves thanks. 
Use rivets or bolts please.
It really needs some high temp flexible ducting from the outlet to the centre of the disk to be of any real benefit.
Use rivets or bolts please.
It really needs some high temp flexible ducting from the outlet to the centre of the disk to be of any real benefit.
30 December 2000, 08:17 AM
#2
Cheers, Puff........... and soooooo big!!!
Made from the following parts (B&Q) - 2m x 2" downpipe (£6.77); 2 x offset elbows (£2.61ea); superglue & superglue gell; 4 self tappers; 2 cable ties.
I fitted them on Thursday this week and have been out in the car but obviously haven't had a chance to really see if they reduce brake fade but am confident they can only help. The top picture is of the wheel of full lock - incidentally there was less room between the wheel and the liner on the near side by about 12mm and needed more messing about to get the right shape of the outlet elbow to get full-lock clearance (the pictures were taken before the mods)! The first section is about 13" long and moulded into an oval section at the front (I used heat from the gas cooker)with approx 20 deg angle to take into acount the offset between the bumper hole and the undertray routing. The oval end should then be flared out to fill out the rest of the bumper duct (the material is fairly eay the play with when it's hot enough) and will need a few trip between car and cooker to get it right. The second section is approx 8" long with a slot to allow the oulet elbow to be directed into the right area (one side of the elbow is flattened to get the air out closer to 90 deg (experimented with a hair drier to get the outlet flow right). The self tapper is a 1/2" with a blob of superglue gell on the end so it can be loosened for adjustment but wont fall out. The 2 pieces will need slight trimming to achieve the best angles for tucking away along the undertray side and should be first joined together using the superglue then apply the superglue gell to complete the bond and fill the gaps (if you cut the tubes with a hacksaw the ends wont be perfectly square).
The whole assembly is held in place with a single cable tie so will need an extra hole to be drilled below the existing hole in the undertray sides. The flat end of the pipe should be inserted into the bumper duct by 1" the held in place with a self tapper (as shown in the first picture, it out of focus) and again use a blob of glue to keep it there.
Obviously the elbow can be extended to get closer to the disk but this would require more cutting and shutting of bits of pipe to avoid all the moving parts. I workrd on the basis that some STi models (98MY bumpers) had the 4 pot setup with a very simple duct without many reports if brake fade but on the 99MY bumper the ducting was deleted.
Hopefully this has given an option to anyone who is pee-ed off with brake fade but doesn't want to sacrifice warranty or spend out on upgrades. I just hope it works as good as it looks (well, I am pleased with it!). Let me know if you try this and get good results. Happy modding.
iain
Made from the following parts (B&Q) - 2m x 2" downpipe (£6.77); 2 x offset elbows (£2.61ea); superglue & superglue gell; 4 self tappers; 2 cable ties.
I fitted them on Thursday this week and have been out in the car but obviously haven't had a chance to really see if they reduce brake fade but am confident they can only help. The top picture is of the wheel of full lock - incidentally there was less room between the wheel and the liner on the near side by about 12mm and needed more messing about to get the right shape of the outlet elbow to get full-lock clearance (the pictures were taken before the mods)! The first section is about 13" long and moulded into an oval section at the front (I used heat from the gas cooker)with approx 20 deg angle to take into acount the offset between the bumper hole and the undertray routing. The oval end should then be flared out to fill out the rest of the bumper duct (the material is fairly eay the play with when it's hot enough) and will need a few trip between car and cooker to get it right. The second section is approx 8" long with a slot to allow the oulet elbow to be directed into the right area (one side of the elbow is flattened to get the air out closer to 90 deg (experimented with a hair drier to get the outlet flow right). The self tapper is a 1/2" with a blob of superglue gell on the end so it can be loosened for adjustment but wont fall out. The 2 pieces will need slight trimming to achieve the best angles for tucking away along the undertray side and should be first joined together using the superglue then apply the superglue gell to complete the bond and fill the gaps (if you cut the tubes with a hacksaw the ends wont be perfectly square).
The whole assembly is held in place with a single cable tie so will need an extra hole to be drilled below the existing hole in the undertray sides. The flat end of the pipe should be inserted into the bumper duct by 1" the held in place with a self tapper (as shown in the first picture, it out of focus) and again use a blob of glue to keep it there.
Obviously the elbow can be extended to get closer to the disk but this would require more cutting and shutting of bits of pipe to avoid all the moving parts. I workrd on the basis that some STi models (98MY bumpers) had the 4 pot setup with a very simple duct without many reports if brake fade but on the 99MY bumper the ducting was deleted.
Hopefully this has given an option to anyone who is pee-ed off with brake fade but doesn't want to sacrifice warranty or spend out on upgrades. I just hope it works as good as it looks (well, I am pleased with it!). Let me know if you try this and get good results. Happy modding.
iain
30 December 2000, 02:52 PM
#4
Scooby Regular
Join Date: Aug 2000
Location: Where age and treachery reins over youthful exuberance
Posts: 5,275
Likes: 0
Received 0 Likes
on
0 Posts
Ian, good idea. But don't you need to get the pipe closer to the disc, and you'll have to do something about the brake backing plate (like just cut it back, I guess).
Have you seen the ScoobyMania ducting, which is very similar. Visit
Have you seen the ScoobyMania ducting, which is very similar. Visit
30 December 2000, 03:34 PM
#5
As I said in my note, you can extend the ductiong. I didn't like the scoobymania set 'cos it stuck out below the bumper and being mounted to the suspension, wouldn't last very long - OK for a trackday but not practical for road use. The STi4 ducts (98MY bunmper) didn't extend as close as these and I'm sure there weren't too many complaints about brake fade (with 4 pots). Like, I said, this is the first step and I think it is quite a neat permanent installation and for £12 or so, definately worth a go! There have been some great ideas on this BBS for DIY mods and usually, the next set of suggestions/iterartions improve the original idea. I've picked up some good tips here and am glad to contribute. Any constructive criticism welcome!
Trending Topics
31 December 2000, 02:31 PM
#8
John, why so anti self-tappers. They are used extensively in automotive applications, including engine components. You just need to use the right 'tapper for the application with the correct hole size.
31 December 2000, 05:02 PM
#9
Scooby Regular
Thread Starter
sorry iain, self tappers have no place on a race track, i have seen too many punctures/crashes because of them. They have a nasty habit of vibrating loose and falling out.
Personally i dont believe they should ever be used externally on a car, but at least in most vehicle apps they have the sense to use spring clips that keep the thread under tension to minimise the effects of vibration.
You wont find a single self tapper on any of the cars i prepped for motorsport, i will only ever use top quality rivetts, bolts with K nuts or one use only nylocks, or where bolts go directly into bosses etc they are always wire locked. Where wirelocking isnt posible i will use a thread locking compound.
There is an excellent book by carrol smith called "screw to win", it tells you all you need to know about building something that wont fall apart.
Personally i dont believe they should ever be used externally on a car, but at least in most vehicle apps they have the sense to use spring clips that keep the thread under tension to minimise the effects of vibration.
You wont find a single self tapper on any of the cars i prepped for motorsport, i will only ever use top quality rivetts, bolts with K nuts or one use only nylocks, or where bolts go directly into bosses etc they are always wire locked. Where wirelocking isnt posible i will use a thread locking compound.
There is an excellent book by carrol smith called "screw to win", it tells you all you need to know about building something that wont fall apart.
31 December 2000, 08:36 PM
#10
Scooby Regular
Join Date: Oct 1999
Posts: 1,274
Likes: 0
Received 0 Likes
on
0 Posts
IanP,
How about using plastic number plate attachment nuts and bolts instead of self tappers.
They tend to be of a self locking type thread on the nut, and dont usually work loose, and even if they did, shouldn't pose a great puncture risk, to other cars.
Nice idea though.
I do like the use of B & Q motor factors.
John,
The plastic undertray on the Impreza, is held on with a self tapper at each side, as std.
If you look close at the 3rd picture from the top, I think it is next to the cable tie Iain has used to secure his brake duct.
Cheers MTR
[This message has been edited by MTR (edited 31 December 2000).]
How about using plastic number plate attachment nuts and bolts instead of self tappers.
They tend to be of a self locking type thread on the nut, and dont usually work loose, and even if they did, shouldn't pose a great puncture risk, to other cars.
Nice idea though.
I do like the use of B & Q motor factors.
John,
The plastic undertray on the Impreza, is held on with a self tapper at each side, as std.
If you look close at the 3rd picture from the top, I think it is next to the cable tie Iain has used to secure his brake duct.
Cheers MTR
[This message has been edited by MTR (edited 31 December 2000).]
01 January 2001, 05:16 PM
#11
Thanks for your comments guys. Originally, I used a band clamp but it required both hands to hold the assembly and needed a fair amount of force to tighten. I can see your point about self-tappers - if there were several dozen used on the car then chances are that 1 will fall out! I certainly would be annoyed if I got a puncture because of someone elses car! Will get a chance to see if it works tomorrow.
04 January 2001, 11:43 AM
#12
Tried them properly for the first time this morning on my way to work and didn't get any fade (brakes start to make a low frequency rubbing sound, is the first sign) at the usual 4/5 locations that they normally do, i.e. coming off slip road, going into roundabout after a long straight, etc.... Very pleased. Might not have to go to the next stage of the conversion - electric ducted fans from a model 'plane! Need to do a few more miles to see how good they work.
04 January 2001, 11:44 AM
#13
Tried them properly for the first time this morning on my way to work and didn't get any fade (brakes start to make a low frequency rubbing sound, is the first sign) at the usual 4/5 locations that they normally do, i.e. coming off slip road, going into roundabout after a long straight, etc.... Very pleased. Might not have to go to the next stage of the conversion - electric ducted fans from a model 'plane! Need to do a few more miles to see how good they work.
04 January 2001, 06:56 PM
#14
Scooby Regular
Thread Starter
Oh dear ian, i think your losing the plot a little 
all you need do is make sure the airflow is directed to the centre of the disk, get some flexy piping in there to do it properly.
all you need do is make sure the airflow is directed to the centre of the disk, get some flexy piping in there to do it properly.
04 January 2001, 11:14 PM
#16
Scooby Regular
Join Date: Aug 2000
Location: Where age and treachery reins over youthful exuberance
Posts: 5,275
Likes: 0
Received 0 Likes
on
0 Posts
Ian, Donington track day on Sat 13th Jan. Can you get some heat paint and do some real back to back testing? Best of luck.
Hoppy
Hoppy
05 January 2001, 05:30 PM
#17
Wont be able to make Donno unfortunately but would love to hear from anyone that is going and fitted this type of Ducting. I really gave them some stick this afternoon and not once did they fade. If and when I experience any problems I will improve my design further - next stage would be to add an extension to the existing outlet then maybe modding the back plate. If this still is insufficient for, say, a track day, then I'll be down to my local model shop!!!!!!!
Thread
Thread Starter
Forum
Replies
Last Post
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
28 December 2015 11:07 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM