I have the s52 head sitting on my bench ready for disassembly which is good cuz I can keep running the car till its done then make the switch. Its also a rebuilt low mileage head so I know the guides aren't worn. Just need to order some stuff from supertech and I'll be good and ready
The wv golf tdi has a fuel cooler ,it's a small radiator under the car,maybe the guys with two pumps should try to put one on the return line and watch the fuel temps.
The throat diameter of an M50 valve seat is 28mm, which is an area of 6.1544 CM². A 6mm valve stem is .2826 CM², and a 7mm valve stem is .38465 CM². This is a reduction in throat area of 2% by using 7mm valves.
However, this does not mean there will actually be a 2% reduction in flow. It is actually very important to maintain a minimum throat diameter when porting heads because you need to have a venturi effect in the throat to build some airspeed in the port and get inertia in the air going past the valve seat. The optimal ratio for this is a throat diameter is about 85-90% of the valve seat sealing diameter. An M50 head with stock valve is about 87.5%. Notice this formula factors in the throat diameter rather than the throat area. This is because the geometry of the throat going into the valve seat is much more important than the throat area. The air speed in the port is at its absolute highest in the throat of the port close to the valve seat. The air is rushing around the corner created by the valve seat to get out the valve and airspeed is slower and slower the further you go away from the seat. Even at full lift the air speed near the valve stem is much lower than near the valve seat. At low lift where the majority of the actual air is flowed, the valve stem has absolutely no affect on flow because the the curtain area of the open valve will be far less than the throat diameter. The valve stem diameter is not particularly important because it occupies a space in the port that is not choked in flow.
Last edited by someguy2800; 04-14-2016 at 05:33 PM.
I just looked for a few minutes.. cant find anything on my phone...
I vaguely remember finding someone who posted flow data from a while back and If I remember correctly there was like a 16cfm difference out of something like 200cfm..
1989 535i - sold
1999 M3 Tiag/Dove - sold
1998 M3 Turbo Arctic/black - current
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2011 E82 135i - S85 Swap - current
1998 M3 Cosmos S54 swapped Sedan - current
1998 Turbo: PTE6870 | 1.15 ar | Hp Cover, Custom Divided T4 bottom-mount, 3.5" SS exhaust, Dual Turbosmart Compgates, Turbosmart Raceport BOV, 3.5" Treadstone Intercooler, 3.5" Vibrant resonator and muffler, Arp 2k Headstuds | Arp 2k Main studs | 87mm Je pistons | Eagle rods | 9.2:1 static compression, Ces 87mm cutring, Custom solid rear subframe bushings, Akg 85d diff bushings, 4 clutch 3.15 diff, , Poly engine mounts, UUC trans mounts W/ enforcers, 22RPD OBD2 Stock ECU id1700 E85 tune, 22RPD Big power Transmission swap w/ GS6-53
Good stuff guys makes allot of sense! Thanks
I would be pretty skeptical of that without seeing it with my own eyes. Also small changes such as back grinding the valves and the way the seat was cut, the proximity of the flow bench tube to the valves, and whether or not a clay radius was used on the port opening make big differences in flow. A stock M50 head flows about 240 on the intake.
I happen to be reading an article earlier today where they were testing a wedge type cylinder head and a hemi type cylinder head on the same BBF short block with same cam, similar headers, intake, ect... Long story short the wedge head flows 392 CFM and the Hemi head flows 407 CFM, but the wedge head made 805 hp and the Hemi head made 914. The Hemi head made more power at every RPM tested. The reason is due to port geometry. The air speeds and pressures in a real running motor are much higher than on a flow bench. When I was in school I remember seeing an example of a short stroke SBC NA drag motor where they replaced a 245cc head with an intelligently ported 220cc head and made more power at every RPM even though the smaller head flowed worse at all lifts above .200"
this was the article, its a pretty good read.
http://www.hotrod.com/how-to/engine/...ate-dyno-test/
- - - Updated - - -
When I was learning to port in school I had a SBC dart head that I had brought up to about 320 CFM from as cast which was like 270 or so. I never touched a thing before the throat and this was on a 2.02 valve. Anyway I made a small change to the chamber and went to flow it again only to find it was down 40 cfm. I had accidentally put a 3.75" plate on it rather than the proper 4" plate.
Spoke with the machine shop today, block will be ready on monday.
Just machine the block, I'll be putting it together and gapping the rings.
How quick you need that crank ?
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I have my old motor I broke some pistons on, i can dig it up, i think the crank was okay, ill let you know by sunday if I need it okay.
Frank,
Glad to see your new setup is underway!
Good luck and can't wait to see it at MPact
I haz a s54 crank laying about
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angle for speed + magnitude for torque
The whole point of the brushless set up is that whole thing of pulsing electricity to the motor does not wear on the motor... Every time a brushed motor get power it sparks and creates bad connections where the brushes are brushless doesn't do that... I'm no forced induction expert, however I'm learning a lot from you guys, I do know a lot about electrical engineering though
Last edited by angeleye540i; 04-16-2016 at 12:52 PM.
I noticed that too. I run that castle ESC in my 1/10 scale RC's
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Billet 67x95 comp wheel and standard 64mm turbine in 10 blade trim which should flow more.
Lets see if we can kiss 800whp this season.
Also picked up my block from the machine shop, im pretty much ready to assemble.
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520whp
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Forget kissing it, we want you to smack 800 on the ass! Get to it son!
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