This is the style of the one on my car, and this is how they sound from *inside* the car
That seems to be a great deal. I'd like one myself, but unfortunately I had to make a hybrid one myself for the conversion, so it neither is stardard V6 ot VR4!! Good luck, look forward to some reviews
Did you say "from turbo"? That I guess rules out any TD04 owners...Originally Posted by wrdmotorsport
sorry i think soDid you say "from turbo"? That I guess rules out any TD04 owners...
Area of a circle is ~3.14*r squared
2.5" pipe - 3.14 * (1.25*1.25) = 4.9"squared
3.0" pipe - 3.14 * (1.5*1.5) = 7.0" squared
3.5" Pipe - 3.14 * (1.75*1.75) = 9.6" squared
4.0" Pipe - 3.14 * (2*2) = 12.56" squared
5.0" Pipe - 3.14 * (2.5*2.5) = 19.6" squared
So as you can see, as pipe diameter increases by a factor of 2, the actual flow rate increases by a factor of 4
from that you can see that two 2.5" pipes flow a little more than one 3" pipe. However, to match the flow rate of two 2.5" pipes, you only need a 3.5" pipe.
It is important to remember this when dealing with pipe work.
yes and from your own calculations Kenneth you can also see that 2 X 2.5"pipes comes to 9.8" squared that is almost 1/2 of 3" again,
IE 7.0" divide by 2 = 3.5 which is almost the difference between 9.8 and 7.
so in conclusion it will be the 3" pipe that is going to be the restriction.
how big do you need to go.
also the turbos are 2 1/4" outlet so that makes the tubo outlet 3.14*(1.125*1.125)=3.97"square that makes the 2.5" pipe over 1" squared bigger.
OK so does this put it to bed we are going to use 2.5" pipe
At no point did I say that the 3" pipe was NOT going to be the restriction.yes and from your own calculations Kenneth you can also see that 2 X 2.5"pipes comes to 9.8" squared that is almost 1/2 of 3" again,
IE 7.0" divide by 2 = 3.5 which is almost the difference between 9.8 and 7.
so in conclusion it will be the 3" pipe that is going to be the restriction.
how big do you need to go.
also the turbos are 2 1/4" outlet so that makes the tubo outlet 3.14*(1.125*1.125)=3.97"square that makes the 2.5" pipe over 1" squared bigger.
OK so does this put it to bed we are going to use 2.5" pipe
I thought my calculations made it very clear that indeed even with 2.5" the down pipes would outflow a 3" system from the collector on.
There were 2 main reasons for my post.
First off is this statement
This statement is incorrect. While you may or may not have said it as a quick generalisation, I feel it is important to give the correct information, even if only so that people are not mislead and possibly later embarrassed, when the repeat what they heard from someone who they believe knows what they are talking about.
The second is that you only need to go 1/2 an inch bigger in diameter to get almost the same flow as two 2.5" tubes. I haven't been under the car in a while, so I am unsure if a 3.5" exhaust would fit. If it does, it may be worth a look.
OK......kenneth i totally agree i did state that incorrectly i didn't sit down and calculate the square inch of two 2.5" pipes. but as you have also pointed out there is no need to go to 3" as other people were saying.
As for 3.5" i don't know off anybody with 3.5" zorst so i think it will be pointless to go for 3"down pipes.
PS sorry if my last post came across badly, im just trying to point out that there is no need to go to 3",as you are as well kenneth
Last edited by wrdmotorsport; 15-01-2007 at 04:16 AM.
When I spoke to Longlife Exhausts about a custom exhaust, they seemed to think that a 3inch pipe on a std car would actually loose power. However, if I was planning on going for 320+ BHP then a 3 inch sytem would be justified. Don't know what these figure were based on, but as they stood to make less money from the 2.5inch system, I assume they were genuine in their advice.
Prices I was quoted were:
2.5inch cat back: £449.00
3inch cat back: £780.00
High flow cat: £169 to £299 depending on which model I went for
Downpipes: £399.00
Which again makes WRD's pipes a bloody bargain.
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My Blitz system is a 3 inch cat back job. With the cat on - it feels a little more lively than standard.
Decatted, it really comes into it's own and the power hike is impressive beyond 4000 rpm (even against a decatted standard system).
No worries mate. Bit of a mix up is all. I am looking at doing some exhaust work myself, after looking at the figures I am sorely tempted to try for 3.5" collector back... be interesting to see how it works out.
Thinking more, I don't know if there would be enough room to bolt 3" downpipes to the turbos... not a great deal of room on those flanges...
Think you would struggle to get a 3" connected directly to the turbos as the bolts for the flanges are just over 3"'s apart , only option would be to use 2.5" then flare it out to 3" once clear of the stud's
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well, there is a small possibility that you could loose a marginal amount of torque at low RPM, but this is more than offset by the increased turbo response.
With a 3" exhaust and 2.5" downpipes I was able to get over 15psi boost at 3000 RPM in 3rd gear. I think it was around 12psi at 2500RPM
edit - btw... this was found on a later run with a MBC installed and set at about 15.2PSI
The guy at the dyno (Robin) was was amazed at it, and came out and had a chat with me. Apparently the best boost response he has seen.
I have attached my dyno sheet. The Blue line suffers electrical misfire at high RPM, so thats a bit stink as there was no indication of max power.
However the Red line is with the 3" exhaust installed (Blue is standard with de-cat)
They put the boost reference in wrong for the Red run though, so the boost line is pretty useless... probably peaks at about 12PSI though.
To cut a long story short, the graphs clearly show that from 2000RPM up, the 3" exhaust gives better performance.
Me please!
Whats the ETA and how is it going
Cheers
Tim
Which Tuesday then?the test car will be on the rollers tues then after fitting
you just can't get the staff, bloody slack bast...
The best things in life have to be lubricated
car has been on the rollers and the first ones will be done this weekend
Any idea if these are going to be made to order, or if they will be make a load at a time?
Defaintly interested @ £200 though.
We are making up a batch of 10 at a time , and the price is certainly within the 200 pounds area , once we have the first batch made we will give a fixed price etc .
but they are looking sooo nice
Pictures! Pictures! Pictures!
Get on with it!
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