£40 RIP kit anyone?

[bongodave]

Seen these kits are silly expensive. How about this for an alternative. stainless 3" rip kit.

Bloke says more you buy, cheaper etc and bonus here is smooth inside. There's a guy selling stainless clips cheap too.

This is for 1 metre plus delivery but cheaper if enough ordered. Seen this stuff used on mates Cosworth and v.v.v.good quality and look!

Group buy possibility?

http://www.ebay.co.uk/itm/76mm-3-Flexible-Polylock-Stainless-Steel-Flexi-Tube-1-Metre-Exhaust-Universal-/111189994791?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19e370ad27

[p fandango]

i wouldn't touch the flexi stuff, when you pop in you can have a look at the rip kit i made

[bongodave]

i wouldn't touch the flexi stuff, when you pop in you can have a look at the rip kit i made

This aint yer average flexi tbf. It's designed for exhausts and to be welded, so not your spin-dryer stuff.

Catch ya later mate.

[Wobbly Dave]

76mm is too wide IMHO - you'll just end up cancelling any advantage you had by filling the void with air, and inducing more lag.

I made my own kit from the ebay universal ones. Only issue is you'll need to find a way to bead the cut ends. I bought the tool that does that.

[p fandango]

76mm is too wide IMHO - you'll just end up cancelling any advantage you had by filling the void with air, and inducing more lag.
& when is your opinion going to be based on anything? I keep posting the video of JT's car with 3" RIP & no lag what so ever, yet here you are again with your theory

& just to remind you

http://www.youtube.com/watch?v=6dBohlkhqEs

[graemewelch]

id love to see a rip kit made with this stuff. maybe it can be done but to what standard. alot of people take pride in there motors and dont want to bodge them together. if i went to view a car and saw this stuff on it id run a mile as fast as i could. if you cant do it properly dont doit.

[M-R-P]

Then there's the internal drag caused by the way the stuff's constructed. The inside of the pipes needs to be as smooth as possible.

[Wobbly Dave]

& when is your opinion going to be based on anything? I keep posting the video of JT's car with 3" RIP & no lag what so ever, yet here you are again with your theory

& just to remind you

http://www.youtube.com/watch?v=6dBohlkhqEs

It is based on maths & science. I did a lot of reading up on it & whilst I only have a BSc (Hons) in Anatomy & Developmental Biology rather than mechanical engineering or the like, but there is an optimum diameter for these things - depends on a lot of things but which air becomes turbulent vs laminar flow - depends on its speed - which is directly linked to the pressure/temp and the volume of the pipe. I did my calculations, based on the CFMs for the GTX - & TBH I don't give a fig if you think I'm wrong or not.

So whilst it may not appear laggy on JT car - I postulate that it could be improved but no-one believes me anyway, so it doesnt really matter.

[t5 pete]

It is based on maths & science. I did a lot of reading up on it & whilst I only have a BSc (Hons) in Anatomy & Developmental Biology rather than mechanical engineering or the like, but there is an optimum diameter for these things - depends on a lot of things but which air becomes turbulent vs laminar flow - depends on its speed - which is directly linked to the pressure/temp and the volume of the pipe. I did my calculations, based on the CFMs for the GTX - & TBH I don't give a fig if you think I'm wrong or not.

So whilst it may not appear laggy on JT car - I postulate that it could be improved but no-one believes me anyway, so it doesnt really matter.

I believe you wobbly its quite simple really if you have a compressor pumping out xxx cfm and two sealed boxes one larger that the other it will take longer for the larger box to reach xxx pound.
I do feel the difference between the 2.5" pipe and 3"pipe will be minute there for jt not having lag but if it could be measured ide put my money on the smaller pipe reaching its peak pressure first

[p fandango]

It is based on maths & science. I did a lot of reading up on itwell put the Beano down & try it, you never know you might like it


& whilst I only have a BSc (Hons) in Anatomy & Developmental Biology rather than mechanical engineering or the like,so totally irrelevant to what we're talking about then?


but there is an optimum diameter for these things - depends on a lot of things but which air becomes turbulent vs laminar flow - depends on its speed - which is directly linked to the pressure/temp and the volume of the pipe. I did my calculations, based on the CFMs for the GTX - & TBH I don't give a fig if you think I'm wrong or not.i'm not saying there isn't an optimum. But with the results that have been PROVEN to work in the real world it shows your calculations/theory about 3" creating excess lag are wrong somewhere along the line

[stribo]

Isn't it a bit late for us to go searching for popcorn ladies?

[p fandango]

its quite simple really if you have a compressor pumping out xxx cfm and two sealed boxes one larger that the other it will take longer for the larger box to reach xxx pound.
its not as simple as filling a space, we're talking resistance & restrictions. You take 2 balloons the same size, now blow one up normally by putting it directly to your mouth. Now try blowing the second up by blowing thru a drinking straw, how much fun do you think thats going to be?

[p fandango]

Isn't it a bit late for us to go searching for popcorn ladies?
you should know by now to always keep some too hand lol

[M-R-P]

Sod the popcorn, I'm grabbing another beer :)

[stribo]

Sod the popcorn, I'm grabbing another beer :)

Good call mate, I'm off to the fridge. :D

[p fandango]

Good call mate, I'm off to the fridge. :D
we've got no room in our fridge, & i can't stand warm beer :(

[stribo]

we've got no room in our fridge, & i can't stand warm beer :(

We have 2 fridge freezers, and still manage to fill them ;)

[Wobbly Dave]

Well I've had 2 colds in the last 2 weeks - bit of a sniffy Christmas - & I can't sleep because this cough is keeping me awake. So I've drawn a large Highland Park 12YO and hope that this benylin will kick in soon. In the meantime, here's my take on it.

Outlet diameter on the compressor housing of the GTX as with most turbos I've seen is about 57mm, including my own GTX. On my 3" core FMIC - the connections are both 57mm. I can't speak for JT's set up but pushing air into a 3" space to only then bring it down to 57mm via a reducer cannot be logical. I think Pedro's theory about the straw has merit. If the pipe diameter is too small then back pressure could become an issue, but you'd have to apply that logic all the way through and have 3" connectors - law of limiting factors and all that. The big question is - how small is too small?

According to what I've read .4 mach is the speed at which air becomes turbulent & does not flow as well.

2" piping
1.57 x 2 = 3.14 sq in
300 cfm = 156 mph = 0.20 mach
400 cfm = 208 mph = 0.27 mach
500 cfm = 261 mph = 0.34 mach
585 cfm max = 304 mph = 0.40 mach

2.25" piping
3.9740625 sq in = 1.98703125 x 2
300 cfm = 123 mph = 0.16 mach
400 cfm = 164 mph = 0.21 mach
500 cfm = 205 mph = 0.26 mach
600 cfm = 247 mph = 0.32 mach
700 cfm = 288 mph = 0.37 mach
740 cfm max = 304 mph = 0.40 mach

2.5" piping
4.90625 sq in = 2.453125 x 2
300 cfm = 100 mph = 0.13 mach
400 cfm = 133 mph = 0.17 mach
500 cfm = 166 mph = 0.21 mach
600 cfm = 200 mph = 0.26 mach
700 cfm = 233 mph = 0.30 mach
800 cfm = 266 mph = 0.34 mach
900 cfm = 300 mph = 0.39 mach
913 cfm max = 304 mph = 0.40 mach

My GTX's greatest efficiency flows between 360cfm >> 600cfm.

http://www.full-race.com/store/images/full/garrett-gtx3071r-turbo-content-1.jpg
The 77% peak efficiency island for the GTX lies within a pressure ratio of 1.6 to 2.6 which assuming certain atmospheric pressure and temp conditions would be a gauge pressure of between 0.8 bar and 1.7 (11.6 psi >> 24.65)

1lb/min = 14.472 cfm

assuming therefore that according to my graph my CFM could be as high as 650 - I should be OK on 2.25 inch pipe.
55cfm - the max that can occur before the choke line on the GTX is 795 cfm.

According to Garrett, to make target peak horsepower of 400 Hp will require 36-44 lb/min of airflow to achieve that target from the GTX.

I did think about investing in Blackbeasts FMIC because it has 63mm connections - but changing the connections for the same depth of FMIC would only make sense if 57mm wasn't enough to carry the planned pressure based on the CFM chart for the GTX. I ran the numbers.

My conclusion is that 57mm is adequate to carry the required flow prior to the 0.4 mach limit at which point the air becomes turbulent. Increased diameters only make sense if all the connections are the same diameter all the way through.