oldeskewltoy Posted June 26, 2017 Report Posted June 26, 2017 What you see below is a 2nd gen "F" head with 4 downward sloping intake ports. My client is planning on running about 10#s of boost though this........ More to come........ :D Quote
7000rpm Posted June 27, 2017 Report Posted June 27, 2017 Cool which turbo are they looking at running? Quote
oldeskewltoy Posted June 27, 2017 Author Report Posted June 27, 2017 7 hours ago, 7000rpm said: Cool which turbo are they looking at running? I've asked... hopefully I'll get a response........ Those 2nd gen intake ports are so steep. That they are..... The intake valves are also bigger, 1st gen 30mm, 2nd gen 31mm ;) That is the extent of the good news... the bad news.... the front oil drain still interferes with the exhaust flow on #1 exhaust port :( more to come....... Quote
altezzaclub Posted June 27, 2017 Report Posted June 27, 2017 Quote the front oil drain still interferes with the exhaust flow on #1 exhaust port Ah, but better than the #1 inlet port! Quote
ke70dave Posted June 28, 2017 Report Posted June 28, 2017 Ohh i like these threads. Looking forward to updates:) Quote
oldeskewltoy Posted June 28, 2017 Author Report Posted June 28, 2017 On 6/27/2017 at 1:01 AM, 7000rpm said: Cool which turbo are they looking at running? Garrett GT2554R (aka GT25R) Ball Bearing Turbo Dual Ball Bearing GT25R Turbo assembly with internal wastegated turbine housng assembly. T25 .64A/R turbine with 5 bolt flanged outlet. Very Good turbo response for 4 Cyl applications. This turbo has a flow capacity of about 250HP. Turbine -Wheel: 53mm w/ 62 trim -Housing: .64 ar Compressor -Wheel: 54.3mm w/ 60 trim -Housing: .80 ar Quote
oldeskewltoy Posted June 29, 2017 Author Report Posted June 29, 2017 So before I can dig into this, I'll need to get it on my flowbench and see what is in her. To do that I need a new valve setting jig. This pair of contraptions are what I used 7 years ago.... It worked.... kinda... but it took most of a day to get readings :( Since this is a clients head, a more reliable, and accurate tool must be made.... and so it began life as most of my valve setting tools do... in plastic Not only is this tool far better, and far more accurate, it takes only a few minutes to set it up. and now that I have the tool, the numbers... please more to come..... :D Quote
7000rpm Posted June 30, 2017 Report Posted June 30, 2017 On 29 June 2017 at 4:07 AM, oldeskewltoy said: Garrett GT2554R (aka GT25R) Ball Bearing Turbo Dual Ball Bearing GT25R Turbo assembly with internal wastegated turbine housng assembly. T25 .64A/R turbine with 5 bolt flanged outlet. Very Good turbo response for 4 Cyl applications. This turbo has a flow capacity of about 250HP. Turbine -Wheel: 53mm w/ 62 trim -Housing: .64 ar Compressor -Wheel: 54.3mm w/ 60 trim -Housing: .80 ar Should go well Quote
oldeskewltoy Posted July 8, 2017 Author Report Posted July 8, 2017 So it has been a while.... and after some digging... there is improvement to be found.... more to come.... . Quote
altezzaclub Posted July 8, 2017 Report Posted July 8, 2017 Interesting how it drops the two small aperture volumes. Are they just the margin of error? I assume if the velocity went up then they would perform better than stock too. Quote
oldeskewltoy Posted July 10, 2017 Author Report Posted July 10, 2017 (edited) On 7/7/2017 at 10:21 PM, altezzaclub said: Interesting how it drops the two small aperture volumes. Are they just the margin of error? I assume if the velocity went up then they would perform better than stock too. no margin of error, there are small drops in volume @ .050, and .100 - after the new valve job I'm hoping to gain some of these #s back To keep it as simple as I can for a wide audience.... Part of the bowls shape, and part of the bowls/ports size, as well as the original valve job "helped" the .050, and .100 lift #s, but the first 2 seriously restricted volume. In essence the original port/bowl shape was to "extend" the 3rd angle(throat angle) of the valve job to an extreme to maximize port velocity, at the expense of volume and the 7AF has very good port velocity - just find a dyno print out of a stock 7A and you will see it makes a nice torque curve. But @ 115hp it leaves volume on the table. The goal here is to increase cylinder filling, and while I know some of the velocity has dropped do to porting, the drop is minor compared to the gains. From a bit of digging (3rd post down - http://www.wheelsjamaica.com/wheels_forum/index.php?topic=165509.0 ) The 2nd gen camshafts are 224 duration overall. 2nd GENOverlap: 8.00 degreesIntake Duration: 224.00 degreesExhaust Duration: 224.00 degreesIntake Installed Centerline of 106.00 degrees ATDC.Exhaust Installed Centerline of 110.00 degrees BTDC. We can do a bit of math, and a bit of guessing( duration @ .050") 18 degrees of ramp(36 total - up and down) are common on 4AG cams, so we can assume this, and then subtract 36 degrees to find the duration @ .050" for the 4/7AF cams: 36-224=186. ASSUMING the ramp is correct, or even close we are @ or near 186 degrees duration @ .050". Now we are given the centerline @ 106, so there is half of our 186 before 106, and the other half after it. Subtract 93 from 106 and we make an educated guess the cam is open .050" @ 13 degrees after top dead center, 13 degrees off TDC the downward moving piston is not yet at peak draw. At this point the cam lift is opening faster now, in the next 93 degrees, the lobe will open to .338". And this is where the volume advantage will fill the cylinder better, for the cylinder will be at its peak vacuum, when the valve is open higher. I hope that wasn't too overwhelming......... For those who like numbers: add up all the volumes at all the lift points except .350" as the cams don't lift to here, now double the result. Now compare before vs after.... Before 1236.2 cfm total, vs after 1354.2 cfm Edited July 10, 2017 by oldeskewltoy Quote
oldeskewltoy Posted July 10, 2017 Author Report Posted July 10, 2017 intake ports almost finished more to come.... Quote
altezzaclub Posted July 11, 2017 Report Posted July 11, 2017 Not overwhelming, it just took a picture of a circle with a cross in it on the back of an envelope... Have you ever seen a K head Dan?? or shall we send one over for you to play with?? I think it would be an amazing educaton for all of us on here! Quote
oldeskewltoy Posted July 11, 2017 Author Report Posted July 11, 2017 12 hours ago, altezzaclub said: Have you ever seen a K head Dan?? or shall we send one over for you to play with?? I think it would be an amazing educaton for all of us on here! a LONG time ago... back when I began, a local friend had a 84 Starlet(?) with a 4KE, and he had spent $$ on a ported head, and intake. Well his ported head had a crack, and so after we bought a replacement KE head, I GENTLY did some porting, mostly to try and match his head to the ported intake. I did a tiny (insufficient) amount of exhaust porting as well. The most significant work I did on it was to clear away casting marks in the top of the head to allow for better oil drainage Quote
MaximusPsychosis Posted July 18, 2017 Report Posted July 18, 2017 I love sitting back and reading over these heads you've done OST, I have learned a lot too, Thank you for sharing! on that note, when I get my 4A-C head back from the shop (getting the clean and straightening) I might just try to chew on the old cracked head to see what damage I can do. unless you want to look at/destroy it for educational purposes? ..then I'll get back to my 7A project. Quote
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