Lazeum Posted March 10, 2011 Share Posted March 10, 2011 I like this topic a lot! tons of info to learn (and understand...) Regarding the tau layer, I believe some can also used this technique to vaporize the fuel mix. With our "out-dated" fuel injection system (as opposed to new direct injection systems), to have fuel mix going against hot valve & runners can also help. They take some energy out of the mechanical parts, temperature of the mix goes up, liquid mix becomes gases so mixture would be much easier to burn afterwards... Condensation on hot runners is lowered compared to cold one. This is one of the reason why engine when cold needs more gas than when hot. Flow discussions on the side, what would be the effect of a polished runner on tau layer? Can we consider the less, the better? I believe we wan the least possible close to the throttle and some at the back of the valves. Regarding flow, can the valve seat be also design to create some "shape" in the flow such as a swirl. Same remark for valve back face, we could have also grinded them in order to create some kind of swirl. Since it is not done, I guess there's a reason: is Flow > Swirl for max power? Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 10, 2011 Share Posted March 10, 2011 (edited) X-Tau Enrichments WARNING THIS VIDEO WILL GIVE YOU A HEADACHE WITH MORE INFO THAN YOU THOUGHT WOULD BE POSSIBLE: Jim Cowart Video You asked about Tau, you got it! Now, Engine Intake Port Flow questions? Paper 1 Paper 2 Or Buy the WHOLE BOOK! Edited March 10, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
Leon Posted March 11, 2011 Share Posted March 11, 2011 Great video! More? Quote Link to comment Share on other sites More sharing options...
260DET Posted March 11, 2011 Share Posted March 11, 2011 In that Jim Cowart video he talks about fuel puddling, the example he uses shows a horizontal port which would be applicable to a L6 in configuration. But what about most V engines which have downward sloping inlet ports? From what he said fuel would still be deposited on the inlet port walls so the effect he talks about would still exist to some degree but obviously fuel would tend to run down into the cylinders and not puddle as such. The timing of that process would of course be relevant, particularly if the fuel did not run down quickly enough to sufficiently negate the effect he talks about. Which I guess is what happens. Quote Link to comment Share on other sites More sharing options...
t-tom Posted November 11, 2011 Share Posted November 11, 2011 Man this is a Great read! Quote Link to comment Share on other sites More sharing options...
josh817 Posted November 30, 2011 Author Share Posted November 30, 2011 I'd hate to bump but one thing to note in case none of you have noticed on any other motors you may be working on... But the ring on the back of the crank to center the flywheel can also be found in BMW 2002's with their M10 motor. For what it's worth, one version or another of the M10 motor was used as for an F1 car in the 80's... Disregard the knife edged part, that's not stock. Quote Link to comment Share on other sites More sharing options...
260DET Posted December 1, 2011 Share Posted December 1, 2011 It was the M10 block which was used for a BMW turbo F1 engine I believe, could have used a stock crank too although I doubt it. Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 1, 2011 Author Share Posted December 1, 2011 Lucky I said "for what it's worth" in case if it was worth absolutely nothing. Haha Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted December 9, 2012 Share Posted December 9, 2012 Bumping up this awesome thread. People who want 300hp NA should read this Quote Link to comment Share on other sites More sharing options...
didier Posted July 6, 2013 Share Posted July 6, 2013 Bumping up this awesome thread. People who want 300hp NA should read this Yes, we read this, and there is so much to know, and so much mistakes ! Quote Link to comment Share on other sites More sharing options...
Rob L Posted May 21, 2015 Share Posted May 21, 2015 (edited) I know im bumping an old thread for no real reason lol ..... except the fact that the very first page ...first post.....second video of the blue Z on the drag strip..... That should be a damn sticky lol I want that exact same motor....that exact same sound!!! That dude just standing there kills me lol ...i would probably do the same thing! What ever the parts are I want it !........ I would love to know the true facts on that car....is it all Kameari .......or did as-watanabe have something to do with this .....hmmmmm Edited May 21, 2015 by theatriks Quote Link to comment Share on other sites More sharing options...
ericbauer Posted May 21, 2015 Share Posted May 21, 2015 (edited) A similar engine build was used on my 1970 hakosuka - although this specific one is not rated for 400hp Seat of the pants would guesstimate mid 200s. Anyways, I thought I'd throw up a couple detailed pics to add to this thread The build was done by RHFactory in Nagoya - they were pretty well known for L6 builds but the financial meltdown of 2008 did them in - they are now out of business The PO of the car had all this done - I'm the first US owner of the car & have had it 3 years now. Very quickly early on I had to tear it down and refresh it with new rings / bearings - it's been faultless since. 3096cc N42 head & block 89mm bore 1.2mm thick headgasket with a 90.5mm bore V07 diesel crank L24 lightened rods Flat top cast pistons 2.7cc valve relief and 33.5mm pin height N42 cyl head heavily re-worked to 37cc with giant 42mm IN ports & match ported to intake manifold I had Rebello flow test it and he confirmed that in his opinion it was garbage until you got to really high revs - then it sang I never got a full print out / report from him Aftermarket cam I had the cam measured by Isky - I'll have to get you those specs at a later date as I don't remember them by heart. Power comes on after 4k rpm and runs strong up to 7500 - 7750rpm Mikuni 44PHH S5 triple carbs with unknown jet bodies, and 230 main air / 210 main jet / 62.5 pilots / and some hand ported venturis that were 34mm when new (Excessive, right? lol...) Ignition is an MSD7AL2 with an 8500rpm rev cut pill (Funny how the Japanese want US parts, and the rest of the world wants Japanese parts ... ) 12:1 CR by my math Mystery jet bodies 42mm IN ports OS Giken TS2- twin plate clutch Unknown mfg 6-2 stainless. The OD of each pipe at the bottom flange is 50mm. Exhaust is twin 50mm pipes running all the way back I removed PO header wrap and had it JetHot coated instead Kameari makes big port (41mm) IN/EX gaskets for this application The lightened L24 rods Work of art! Cast (Nissan bowtie) piston - looks A LOT like the Kameari street unit ... not sure if it is or not Everything balanced Anyways, hope that helps anyone looking to duplicate something similar ... It makes all the right noises - you can hear it sing here: https://www.youtube.com/watch?v=3LWWS4SsgaE https://vimeo.com/41685762 Edited May 21, 2015 by ericbauer Quote Link to comment Share on other sites More sharing options...
zredbaron Posted May 21, 2015 Share Posted May 21, 2015 Somehow I don't think those are the specs theatriks is looking for. Nice build though! I like the Nissan pistons cast with reliefs. Hang onto those!As for the blue car... ironically, the green one edges it out in the race. Happens right before the guy walks in front of the camera.High-end NA L6s have radically different sounds from the ones I've heard, to include both in this video. The green sounds like a much higher pitch, really gargly. Sounds like it's more highly tuned up to the top of the RPM band, and the blue one sounds like it's the muscle car and has the grunt. But that's my ear.Is that why you like the blue one? Quote Link to comment Share on other sites More sharing options...
Rob L Posted May 22, 2015 Share Posted May 22, 2015 Your pretty dead on ....I love how that blue one sounds mean just like how you described it..... muscle car esque. Quote Link to comment Share on other sites More sharing options...
josh817 Posted May 22, 2015 Author Share Posted May 22, 2015 (edited) I get embarrassed every time this thread pops up. The main contribution is seeing all the internal pictures but that first page on exhaust stuff, when I look at it now, I laugh... For more reading on scavenging and intake runner lengths I would read my more educated thread where I utilized a shock tube lab at our university to relate to pipe pressure impulses: http://forums.hybridz.org/topic/117954-a-better-explaination-to-exhaust-scavenging/ As a quick summary... Had a disk that ruptured at a certain pressure. The pressure traveled down a length of pipe that was open at the end. This was the pressure data from a sensor just after the disk. Imagine the rupturing disk as an exhaust valve opening. There is a region behind it where the pressure is lower than ambient. Time it correctly by varying your primary length and/or diameter. Also don't use tinypic to host images because I just saw one of my posts was some half nekkid cartoon chick that didn't seem to fit in anywhere in my discussion........... I'm still very confused. Another note, your 41mm diameter manifold gasket that fits your ports. I measured the ports on my mystery head at 39mm and I have another picture of someone porting a head with a guide valve labeled "40.5". When my father use to port heads he would use a set of guide valves like these. Valves cut to a certain size so you can ensure a relatively circular port as well as taper the port how you want to. Honestly don't know who the source is anymore. Here is another one of the green car. The sound is nice but honestly irrelevant... Edited May 22, 2015 by josh817 Quote Link to comment Share on other sites More sharing options...
josh817 Posted May 22, 2015 Author Share Posted May 22, 2015 I don't know what type of go juice this one is on. Quote Link to comment Share on other sites More sharing options...
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