|First off I'd like to give a HUGE thanks to Mike @www.tyrolsport.com, Phill @www.bshftw.com, and Scott @www.usrallyteam.com. These three businesses gave sizable contributions to conduct this test with nothing to gain or lose by "sponsoring" this test. That alone speaks volumes about their support and interest in the advancement of the 1.8t community. Also, everyone that gave a contribution, no matter how small or large, we thank you as well. Lastly, the manifold contributors are owed the biggest thanks. Without your help and the use of your hardware, this test wouldn't have happened.
Now on to the data. The only real way to rank the manifolds with regards to flow would be total flow through all four runners. This is the easiest way without getting into standard deviation and outliers in individual runner flow. This does NOT correlate into which will make the most power on a given setup. Intake manifold flow is dynamic and undergoes turbulence, heat change, as well as sudden transitions, like during a WOT lift to shift. All testing is done at 28 in of water to ensure accuracy in comparisons, but flow in vacuum is entirely different than positive intake manifold pressure. All of this must be noted when trying to compare the different manifolds. The most interesting thing to me is the variance in individual runner flow.There weren't any huge surprises in regards to results of total flow, but there were some interesting notes from individual runner flow. Stock style manifolds starve the first runner. Notice the similarities in runner flow between the stock OEM big port manifold and VariantStg3's affectionately labeled "Homebrew" manifold, which uses OEM big port runners and flange. It seems as if most all the manufacturers could spend some time focusing on equal distribution. ABD and RMR seem to have the best distribution, the biggest plenums. Obviously the larger the amount of flow, the harder it is to have a manifold that evenly distributes this. For example, the Dahlback manifold, which uses the Lehman style of dual plenums for even distribution, isn't that even.A variance of 3-4 cfm isn't huge, but it is a variance. That said, a variance of 8-10 cfm isn't going to affect much in the real world anyways since this is under vacuum, and adding boost will more than likely even these out somewhat.
Another thing to pay attention to is the throttle size. All of the small port manifolds used stock throttle bodies, except the 007 small port which uses a 12v VR6 throttle. The big ports are even more varied with APR's RS4 and 007 using the R32 throttle, RMR accepting a variety of throttles, Homebrew's manifold accepting a 3" DBC throttle, and Hypertune not even having a throttle plate. We added a comparison graph between the 007 small and big port manifolds and nother between the OEM small and big port manifolds as well.
Comments from the flowbench operator that did the testing:
RMR big port Retail price $699.95
The operators spoke highly of this manifold. They thought it had plenty of plenum to get the job done, with very nice runner design and injector placement. He also noted the distribution- a variance of only 7 cfm from highest to lowest runners. (which is only 3 or 4%) They also commented on how short the runners were, and how that would shift the torque curve up in the revs signifigantly.
Homebrew Cost is up to end user lol
Said that it looked like it could be a good alternative to spending big money for an aftermarket manifold with a little revision. They seemed to think that the angle of the throttle plate and the 'flat' entry was killing the first runner. "Once air is moving so fast, its just not gonna turn like that, you know?" They also liked the radiused runner entrys in the floor of the plenum and that the OE injector bosses had been ground down a bit to increase the cross sectional area.
Dahlback Retail price is $999.00
They really didnt have anything good to say about it other than the fittings were nice and that it looked well made. They said that the Lehman style, while it may help distribution over stock, kills flow. And that this plenum design didnt do anything that a well thought out plenum and throttle angle couldnt do; basically saying that it was a trade-off that didnt have to be made.
ABD Retail price is $499.00
They said it was a big piece of crap. They remarked on how sloppy the lower flange was with regard to port alignment. (which i confirmed by comparing to an APR and my 007). They also complained about the casting slag. They didnt like that it used OE injector bosses. They basically said that while it performed moderately well, that it just wasnt a nice part.
APR Retail price is $899, $1299 with the throttle body
They really liked the build quality this one, and remarked on the quality of the casting. They did however say that the throttle angle needed to be changed in order to get it on par with regard to distribution and that the injector bosses again should not be protruding into the port entry, because it was what killed the flow.
Hypertune Retail price is $1399
When i pulled this out of the box, Dan smiled real big and said "Bling, bling." Again, they thought the machine work on this was phenomonal. and that the injector mounting was great. But they absolutely hated the plenum. They said it was far too thin for a big boost, big power or sprayed car. Dave said one good pop back through the intake would blow it to pieces, and then remarked on a flaw in the weld on the inside of the plenum.
007 Small Port Retail price is $699.00
This was the first of the aftermarket manifolds that they saw. Their initial reaction was to the throttle angle and plenum design in regard to how it should distribute air much better than the stock small port he held in his other hand. But he said that the most signifigant improvement to flow would certainly come from the injector bosses being nixed out of the runner unlike stock design.
007 Large Port Retail price is $699.00
This was the overall winner in their eyes. Like the small port, they liked the runner shape and injector placement. However they did say that they thought the distribution could be a little better if the entry angle and the backside of the throttle plate was revisited to compensate for such a massive throttle. They concluded by saying that if they were to build a VW, they would use this intake based on the performance vs. dollar value it has. (said they would use the 800 price diff between it and the hypertune to buy spray lol)
OE Small Port Comes free with your car.
Hated the throttle angle. Again, they commented on air not wanting to make that kind of turn, and said they (VW) set themselves up for failure from the get-go by pointing the throttle at the roof of the intake over cyl 2. And again, they hated on the injector bosses.
OE Big Port Retail price is $319.00
they basically said all of the same things they did about the OE small port.
Before anyone comments on their comments... Please bear in mind that they had absolutely nothing to gain or lose by doing this testing or providing the opinions they did. It should also be noteworthy that these guys build absolutely ridiculous engines for some fairly high profile race teams, and have years of building and racing experience. So please think about the commentary and its value before any remarks are made about it. [IMG]http://*****************.com/smile/emthup.gif[/IMG]
Unfortunately, due to some manifolds needing to be returned as soon as possible and a lack of planning (DOH), we don't have pictures of all the manifolds. Most of you know what most of them look like and we do have pictures of some of them. silvercar has some that I'm having trouble getting access to and they'll be posted later along with his measurements of the different manifolds (runner, port, plenum, throttle, etc). We just wanted to get the data out as you've all waited long enough.
007 Big Port, APR, and Hypertune (top to bottom)
007 Big Port plenum
007 Big Port port
APR, 007 Big Port, and Hypertune ports (top to bottom)
Check back later this evening for more pics and measurements. Thanks again to everyone who made this possible. And lets try to get as many back to back dynos with different intakes to see how all this adds up. :thumbsup: