Another little spanner.

I've shamelessly lifted this off WV Vortex.

The manifolds in the blue area are (don't quote me on this) for the large port head. As you can see the ABD manifold flows a lot better than stock and, shock horror the Dahlback unit at nearly twice the price.

I think I might get one of these Dahlback Racing ones.

Another little spanner.

I've shamelessly lifted this off WV Vortex.

The manifolds in the blue area are (don't quote me on this) for the large port head. As you can see the ABD manifold flows a lot better than stock and, shock horror the Dahlback unit at nearly twice the price.

I think I might get one of these Dahlback Racing ones.

Oright.... smarty pants!! :holmes:

I'd be interested in the background of those results. Flow rate isn't everything anyway (this is me clutching at straws!). A massive bucket would probably flow more than all of those! But yeah, surprised by those results.

Get the 007 then. Or the SEM Motorsports one, which also looks the biz.

SEM

Dyno results look a little too good! 38hp my ar*e!

Don't get me wrong, I'm not just trying to be an awkward git, I like getting debates going because they always bring out the meaty details, and all the options. The sort of info and experience that Del's supplied is golden.

Has anyone used the APR manifold? Looks nice.

High flow isn't necessarily everything though. You may well get more air through it, but that's not what dictates what power and, in particular, torque it produces.

The Dahlback design has clearly been engineered to perform a specific job and, judging from the length of the runners, maximise torque ouput at mid range rpm. I would suggest it's either a copy or outright first principles design for a restricted Group A engine where top end power (and hence flow) is limited. Either way, it's around the same flow rate of the standard intake which can easily achieve 300bhp or more. I would be very surprised if overall manifold flow rate was the limiting factor of power in any 1.8t as you need a hell of a lot more restriction in the intake to be worried about that. As an example, the 600cc bike engines we used in Formula Student were limited by means of a 20mm air restrictor. For those of you who can't be bothered to get a ruler out, that's a bit smaller than a 2p piece. Despite that, it's still possible to get over 100bhp out of them normally aspirated, so unless you're looking at tuning your car to over 1000bhp, then restriction to air flow is not going to be the problem. Furthermore, the valve ports are still the same size whether you have a standard manifold or a 2ft wide drainpipe attached to it.

The two main things you want from a good manifold are good swirl (controlled turbulence) and a good compromise between runner length and packaging space/throttle response. The last thing you want in the manifold is lamina (non turbulent) flow, as it won't mix the fuel very well and also results in poor air balance between cylinders. A good example of what happens with no swirl can be seen here:

http://home.comcast.net/%7Ehughhenderson/pics/Intake_CFD/velocity_contours.png

The red areas show high velocity flow, and the blue, low. Because the air is entering the airbox in a lamina non turbulent state it heads directly down the nearest port. The Dahlback manifold looks very much like it's a version of a design used by Audi in the 80's on the Group B Quattro's that feeds the air round the outside of the manifold to a long slot that runs along the length of the casting. This helps to distribute the air as best as possible and swirls the air in a great big tumble before it heads down the runners improving mixing when it does get to the injectors. Rather than just comparing maximum flow rates, it's much better to compare the flow rate balance between the cylinders. The number below are the difference between the highest and lowest flowing ports on the various manifolds:

Monster 007 Big - 18

Hypertune - 9

APR - 21

Ross Machine - 7

Homebrew - 24

Monster 007 Small - 9

ABD - 4

Stock Large - 27

Dahlback - 5

Stock - 23

The clear winners are the ABD and Dahlback and both I would say are pretty much as good as you could hope to get for flow profile. The APR and the Big port Monster are pretty shocking, although not really any worse than standard. Having not seen any of them apart from the ones posted here and the standard ones, I'd guess from the flow profile they're simply copies of the standard runner and plenum design that have been enlarged. In the case of the Monster and APR ones, I'm going to take a guess that the throttle body has been moved to the other side as the leaner cylinder opposes that on the standard intake. Out of the ABD and Dahlback, the Dahlback will provide the better overall performance with more torque since the runner length is significantly longer than standard. As I said earlier, it looks like it's designed for a rally engine where torque is everything.

In my opinion, I would say that you'd be better spending your money elsewhere unless you're making a race engine. Dahlback are an experienced tuning company who make and enter cars in various motorsport events. Their stuff is properly engineered and the tuning stuff (apart from their 900bhp Golf admittedly!) is designed to provide maximum PERFORMANCE. That's as in reasonable power but with a good spread of torque and driveablity, which is precisely what long intake runners and a swirl inducing intake will do. Power isn't actually everything!

If of course the real reason is a bit of bling (which I suspect it is!), the by all means go for it, but you'd get a better power result from a new turbo or internals. Or if you're after better mixing, get the ports polished.

Edited 9 October, 200916 yr by ArosaMike

Whoa Mike lol

I'm lost lol.

But thanks anyway:thumbup:

Yah but it's shiny!!!!!!!

Whoa Mike lol

I'm lost lol.

But thanks anyway:thumbup:

It's Mike......you know, with the Arosa!

It's Mike......you know, with the Arosa!

Yes yes, I know who it is spelling boy, it's Mike innit. Drives a little Seat.

I did drive an Arosa yes :P It was a laugh on the back roads and sounded better than Octavia, but had the steering rack out of a boat which was completely at odds with the rest of the car!

Sorry my dissitation there is probably a bit heavy going :P I'm afraid when you spend all day with other engineers, it's hard to switch out of that mode!

To summarise IMO

-Spend you're money elsewhere unless you're just after a fancy looking manifold

-If you still want a manifold, there's a lot more to it than just flow rates

-The Dahlback one is probably designed for a restricted engine and hence is designed to give high torque and not necessarily high power. It is basically the same design as that found on the 2.0l (bored out 1.8l) WRC engines they used to use in the Octavia WRC:

This APR design is good and, from reading the VWVortex thread, they do (despite what some of the keyboard warriors say) really know their stuff:

This 007 intake is not particularly good:

-Longer shift the torque curve down the graph (make it more torquey)

-Shorter ones shift it up (make the engine more peaky)

Sorry my dissitation there is probably a bit heavy going :P I'm afraid when you spend all day with other engineers, it's hard to switch out of that mode!

I wasn't extracting the urine, please carry on, we more stuff like this for dullards like me, it's quite interesting, honestly:D:D

we more stuff like this for dullards like me

You been on the Jamaican Old Holborn again.

You been on the Jamaican Old Holborn again.

Errrrrr.................................

As an example, the 600cc bike engines we used in Formula Student were limited by means of a 20mm air restrictor.

Ahh another ex-FS nerd like me! We had a 19mm restrictor on ours as we were running E85. We managed to get Williams F1 to rapid prototype our intake plenum the last year I was in the team. Was superb, but we managed to blow the poor thing up! We were running 8 injectors on the R6 engine, 4 in the plenum, 4 in the standard position by the ports. Good fun all that stuff, don't miss the stress of it all though!

Cheers for all the info mate

Blimey, it is a wealth of knowledge on here!

I really must stop reading posts like this though. Makes me think, what do I do after I've had the stage 2 map done?!

Porsche brakes probably...

Ahh another ex-FS nerd like me! We had a 19mm restrictor on ours as we were running E85. We managed to get Williams F1 to rapid prototype our intake plenum the last year I was in the team. Was superb, but we managed to blow the poor thing up! We were running 8 injectors on the R6 engine, 4 in the plenum, 4 in the standard position by the ports. Good fun all that stuff, don't miss the stress of it all though!

Cheers for all the info mate

Brookes, Herts or Bath? :P I was at Brum until last year. Was epic fun, but like you say, the stress and all nighters were not a huge amount of fun! One of the years on our team we successfully set fire to the dyno...that wasn't too clever :P

If it wasn't for taking delivery of a Caterham next week, I'd definitely be modding the Octy. Ultimately, I guess you need to ask yourself what you want to achieve from your mods. There are two clear directions from a performance point of view.......drag strip or race track. Personally I'd go the track route, but I'd imagine the two different types would go something like this:

Drag:

Performance aims:

-350bhp full boost 450bhp with Nitrous for the end of the run

-Sub 12s 1/4

Chassis:

-A good set of uprated shocks, but not coilovers. You'd want plenty of compliancy to deal with the power and to shift the weight during acceleration.

-Uprated bushes in the suspension and engine to reduce the compliancy

-No rear ARB, softer front ARB

-Strip as much weight out as possible

-Full cage

-Standard 17s with trackday tyres on the front and the hardest compound you can find at the back.

-TT forged ally lower wishbones

-Lead posts in the engine bay to add ballast if you're having problems off the line

Engine:

-Forged rods and pistons to make the thing as bulletproof as possible

-Billet crank

-1.9 or 2.0l displacement increase for better torque off the line

-Big turbo kit. Turbo lag doesn't matter!

-FMIC

-APR exhaust manifold

-Race cat

-New exhaust

-New larger TB

-APR Intake manifold

-Gas flowed head

-New or reprofiled cams

-100bhp Nitrous kit with programmable boost strategy for different gears

-Possibly a thicker head gasket to lower the compression ratio for big boost. May need testing to validate though.

Electronics:

-DTA or MoTec programmable ECU with TC and Launch Control

-Flat shifter

-5th injector and anti-lag turned on

-Adjustable boost

Powertrain:

-TDI 6 speed box

-Uprated clutch

-Quickshifter

-LSD with agressive clutch ramps in it so it's basically locked the whole time

-Driveshafts out of a 1.9TDi if they'll fit or if not, some custom ones

Track:

Performance aims:

-Around 240-260bhp

-Reduce weight to around 1100-1200kg

-Sub 7s 0-60 (Maybe about 6.5s)

-Over 1G lateral in steadystate cornering

-Similar Nurburgring lap time to the Megane R26R

-Great fun on a good B road!

Chassis:

-Good set of fully adjustable coilovers to give the adjustment. You could subsequently sell them and get some custom valved struts once a good setup had been found.

-S3 lower front strut brace

-Uprated suspension and engine mounts

-Adjustable front and rear ARB's

-Half cage

-Take most of the sound deadening out, the spare and rear seats, but leave carpets

-6 point harness for the driver, 4 point for the passenger

-Some decent Recaro buckets lowered about an inch from the lowest standard seating position

-Remove airbags

-Retrim the standard wheel with an alcantara rim

-Lightweight 17in motorsport wheels

-TT forged lower wishbones to stiffen things up and reduce camber change from deflection

-Adjustable top mounts

-Leon Cupra R front calipers with EBC Yellow stuff pads and groved discs

-EBC Yellow stuff pads on the rear

-Quickrack from the LCR/TT/R32

-Toyo 888s or similar

Engine:

-APR KO4 upgrade

-Uprated panel filter in standard airbox

-Race cat

-Miltek exhaust WITH resonator so it doesn't give you a migraine on the way to the track day, but so you can hear the engine with a helmet on

-FMIC to keep boost levels consistent when doing hard track work

Electronics:

-Standard but remapped ECU

-Lap timer

-Leave the aircon in because it really won't make that much difference and let's face it, most girls don't like people who drive modded cars and they like sweaty people driving modded cars even less!

Powertrain:

-Light-medium acting LSD

-6 speed box if possible

-Uprated hubs from the LCR to deal with increased loads

You can probably tell, I thought about it quite a bit in the past :P