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Feb 6, 2008
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Well i have opened a can of worms with my APR 2+ map....
I think i might need a bigger intercooler and a DSG map :)
The guy that mapped the car said by the third run on the rollers the manifold temps were to high to get good readings?
My question is has anyone done what i have done and gone 2+ then added an intercooler and noticed a difference ?
As far as DSG is concerned i think this needs to be done because even pulling away reasonably swiftly in Drive its changed in to 6th by 30mph where as i would like to be in 3rd for normal driving by 30mph :). before the map it would hold a gear all the while it was pulling until i backed of the throttle a bit.
Bottom line is a Wagner fitted with VAT and a dyno run will be another £1k and i would just like to hear if it's money well spent as i am sure its a route followed by many here already
from previous experience I would say do the intercooler.
dyno runs seem to produce higher temps due to confined space etc but on a hot summers day you'll probably get the same.
Wagner seem to be one of the best intercoolers you can buy for any car at the moment top quality products and flow very well.
I would happily spend the money if it meant optimum performance and not being able to drive the car properly.
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I went reverse. Had stage2+ with twintercooler and then i had it removed (wanted to get different ic as twintercooler had to many pipes for my liking and i think it was a bit lazy at low rpms with it).
Now i got 300x600x76mm ic (also known as wellycooler) for a propper front mount solution but still didn't fit it.
I would say it helps especially on a hot day or if pushing it.
But i think for you might benefit more just from dsg map for now. Then decide if you want to upgrade ic.
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I stuck with an oem all alloy S3 IC with a TTE420 and I never saw any issues in the UK. If you track the car then yes, an uprated IC is a must, but for normal road use, it's really not needed. My inlet temps were only 10 deg above ambient after 6 full runs on the dyno.
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Thanks guys , all very interesting. another spanner in the works is i am running an APR down pipe and 200 cat but a std audi cat back.
so maybe a DSG map and a Cat back would be better than an ic at the moment ?
I think i might go Milltek resonated , the std exhaust actually sound quite nice with the down pipe but it could be restrictive although the guy who fitted the down pipe said the std audi system flows quite well but does it once you are over 350 bhp, it might not be easy mating a powervalve to the APR where as i think the Milltek goes straight on...
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Bcs doesn't sell cat back powervalve if you don't have their downpipe as far as i know.
Dsg map would be my first choice if i was in your place. It would suit the map correctly.
And after that i would look at different things.
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I tried to ask if BCS would add a catback to my APR downpipe and they said no. Not too sure really as their downpipe fits a standard catback and their catback will fit on their downpipe so the BCS catback should fit my APR to my “novice” thinking.
Maybe they don’t want their product on the back of someone else’s.
Nikki Gower recommended the non Powervalve when I talked to him a couple of months ago.
The APR downpipe is quieter than the BCS due to the extra resonator behind the cat. My son had a BCS downpipe with a standard catback on a TTS. Much more throaty than my S3 with APR.
Remember the Milltek is narrower than your BCS.
When I had my APR 2+ installed the 3rd run on the dyno gave lower figures as it got hot. Not been on a dyno since but no complaints about how my car pulls after fitting the Wagner.
As you were told, the standard catback prevents the ultimate APR 2+ Max figures. However 10 extra BHP more is only a 2.78% increase at 360 BHP and would you feel it?
I think I would want that DSG sorting first.
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Thanks prt, nicely thought out reasoning.. I do tend to think if you are not sure then wait and see. I also think its best to do one step at a time and that way you get a better idea of what worked and what was a bit of a waste. I will certainly book the DSG map next week as it £600 and takes 5 mins. Maybe then re evaluate the situation. Rome wasnt built in a day.
It's a psychological thing really with regards the power because the car flies and i am happy TBH but because i know it's about 10-15bhp down on potential it nigels me a bit . Trouble is as you say 10bhp is a very small amount and not noticeable on the road but i was about 40lb/ft down on torque as well. there is a thinking that dyno torque can be improved by a DSG map simply by allowing the torque to transfer to wheels better.
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I came across this article on line which is interesting...

But basically its this......

In the calculations I'll be doing below, I'll be assuming that we are using standard 16 gauge galvanized steel. This has a typical thickness of .065". This is important, because the size of the tubing is outer diameter and we need to do our calculations on inner diameter to be the most accurate.

Thus you can calculate the max HP supported by a 2" diameter exhaust tube through the following calculations:

Find Radius (D/2 = r)

2"/2 = 1" radius

Account of thinckness of the tube wall (r - .065)

1 - .065 = .935"

Find Area (r^2 * Pi)

.935^2 * 3.14 = 2.75 ci

Find Max CFM (Area * 115)

2.75 * 115 = 316.25

Calculate Max HP given Flow Rate (Max CFM / 2.2)

316.25 / 2.2 = 143.75 HP
So here's the estimates:

note: I used Excel to do the calculations here. That's why the rounding is different than in my example above.

Tube OD Tube Radius Tube ID Radius Tube Area Max CFM Max HP

2.00 1.00 0.94 2.75 315.84 143.56

2.25 1.13 1.06 3.53 405.94 184.52

2.50 1.25 1.19 4.41 507.32 230.60

3.00 1.50 1.44 6.47 743.96 338.17

3.50 1.75 1.69 8.92 1025.76 466.26

4.00 2.00 1.94 11.76 1352.73 614.88

So here is an example: Let us assume we have a motor making 400 flywheel horsepower and we'd like a single pipe exhaust.
A 3" single exhaust is good for about 340 crank horsepower. Our motor is 400 hp at the flywheel, we need an exhaust size larger than 3".
Now I'm not saying that 4" would work fine, either. 4" tubing supports much more power than we are planning to make. While the flow would be adequate, the velocity would be too low because the exhaust pressure would be diminished.

Thus, the rule of thumb with the calculations is to use the smallest tube diameter that supports the horsepower you are planning on making.
There's more than that if you really want to get into it. It's all about balance. 4" would probably be overkill on our engines.
Hi S
I thought this would make an interesting debate because there are lots of people offering systems but very few actually quoting like for like figures for stock v their systems, same as intercoolers, very few actually offer info on manifold temps, effect of increased flow rate, at what point a stock item is unable to cope, where any increase is likely in the rev range and effect on BHP to Torque..
For example Wagner offer pressure drop measurements and intake temps through the rev range for their IC against stock but unless others do the same we have nothing to compare these figure too. I am amazed how many retailers and manufacturers seem to sell items because they are "cool to have" rather than based on hard figures which surprises me given the large sums of money involved.

Tin hat firmly on :)
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I agree with you.
Some companies spend more, some less time and money on research and development.
At the end most of the time good marketing sells things and unfortunately bhp before and after is enough to sell car performance products. Make it look good say it adds 20-30bhp and you're good to go.
Then it's up to enthusiasts to find out if they work or not, does it need some kind of modification and so on.
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5 mins on the web and i found that the Wagner IC held an ambient intake air temp of 20c down to 25c between 0-7000rpm against a stock ic that went from 20c to 65c in the same rpm range. I found that given air get less dense with heat the density with a stock IC dropped 15% which is the equivalent of driving at 4500ft altitude. :) I also found that an engine producing 350bhp at sea level will lose 47bhp and 4500ft due to air density :)

So if wagners figures are correct their IC could save you 47bhp at 7000 rpm...hmmmmm make of that what you will. I think i need to double check those figures.
That seems a bit high. There is a power loss during a hot day but not that much.
The reason it seems high is Wagners claim that inlet temps rocket with the std IC

Wag1 copy

They show a test run taking the temp from an ambient 25c up to 65c with the stock IC so up 40c where as Revo show after five dyno runs at temp variation of about 8c from stock to upgraded IC


Maybe someone else can make sence of these figures and show me what i am missing ??
I don't know.
But it might be that one is k03 ic and other is s3 k04 ic? Also ambient air temperatures are different for sure.
I've not seen inlet temps shoot up anything like that with all the dyno runs on my car with the all alloy S3 IC.
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Bottom line is Revo are saying there is an improvement but its not really going to notice and Wagner are saying its essential with these charts.

I am tempted to book it in and get it done, i don't expect any improvement but it might allow more exploratory dyno runs to find out what the underlying problem is.........or i could just save a£1k and leave it as it is. :)
I got my self popular bar and plate "wellycooler". By the results i've seen it beats everything out there.
And it's a fraction of price (even with custom work involved).

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