Administrators BRAAP Posted September 17, 2007 Administrators Share Posted September 17, 2007 Sniff, Sniff, I smell Jealousy at someone's DETT project firing up and running... .... Link to comment Share on other sites More sharing options...
hughdogz Posted September 17, 2007 Share Posted September 17, 2007 I think you guys are right, it's not the same: x is different than a*theta Piston velocity is the rate of change of x's position. You can see it is different than r*w (or in this illustration a*(d_theta/dt) I work on a 3D dynamics program that calculates inertial forces, velocities, friction, etc. It would be interesting to use it to see what the effects to the system are for weight reduction on a piston. And Bubbles... without a time slip or 1/4 mi vid I wouldn't even start to compare myself with 1 fast z (no hard feelings B.G.) Link to comment Share on other sites More sharing options...
bubbleguinea Posted September 17, 2007 Share Posted September 17, 2007 Sniff, Sniff, I smell Jealousy at someone's DETT project firing up and running... On the accelerative mass issue, the responsiveness of the engine is directly related to the weight of it's components. What should have been done in conjunction with the weight reduction of the pistons, was an equal reduction in the crankshaft counterweight as it does not now need such a large overhanging weight to 'counteract' the stock weight. The pistons are 150 grammes less than stock, and of a stronger material. It is possible that this setup is more durable than stock! It wouldn't be the first time material thicknesses were reduced without any effect on overall part longevity...and I can point out in some bearings where superior metallurgy was used to greatly reduce thicknesses of races with absolutely no reduction in B-Life. hahahah - you wish. IF the thing fires up i will be impressed...actually, i wont, because i know it WILL fire up. the thing is, IF it runs for more than 14 minutes, THEN, and only then i'll be impressed.... then its just a matter of time, or miles, untill the thing breaks apart....engines arent legos. im not jealous at all. funny though, it was "supposed" to be running over a year ago, and it still isnt running....i would be doing the same thing-taking my sweet time-if i didnt have 100% confidence in the machine. like i said- brilliant engineering. brilliant craftsmanship. good looks. but the functionality is NOT going to be present in that engine. period. i'd like to see it run for more than 10000k miles, or even 1000miles, at FULL BOOST, the 17lbs that i believe he is claiming. but back to the point. congradualations. you just WEAKENED your internal rotating mass, and for the weight you saved, you could have just gotten a lightweight allumnium pulley. :- 10hours of work. 2 pounds taken off rotating mass. completely killing the integrity of the forged piston. realizing you could have done that in 30minutes eleminating the mechanical fan, or getting a single groove pulley??? PRICELESS. hugh- people have seen my car run a 13sec 1/4et....at SEZ....at 105 something mph....with a 2.5 60ft time.... if i could drive, and had better tires, it would have been a low 13 sec car...maybe even a high 12- but it didnt, it ran a high 13. with a port matched N42 head. i shutter to think what my new shaved P90, ported, stainless undercut valve head can do...not to mention, its a stock cam- and its just as fast, if not faster, than it used to be.... once i get time to get in contact with Ron isky- im going to throw a cam in it, retune, then easily run low 13's high 12's.... ON AN L28 in at 2700lb 2+2 for God's sake!!!! its funny, people that have seen this car run that fast dont say a damn word about it, because they know---but all the non believers, make sure to go to the DNI this up coming spring!!! Link to comment Share on other sites More sharing options...
Administrators RTz Posted September 17, 2007 Administrators Share Posted September 17, 2007 How many threads are you going to argue the same thing? Its tired, pointless... and full of holes. Link to comment Share on other sites More sharing options...
bubbleguinea Posted September 17, 2007 Share Posted September 17, 2007 as many as it takes Link to comment Share on other sites More sharing options...
1 fast z Posted September 17, 2007 Author Share Posted September 17, 2007 Let me get this straight, your saying one would get the same gains, from piston lightening, as they would with an "alluminum pully" WOW, you have ALOT of physics classes to take, untill you should be able to post on Hybrid. Link to comment Share on other sites More sharing options...
Tony D Posted September 17, 2007 Share Posted September 17, 2007 Appearing Next Spring? What happened to the Marines? Oops! Link to comment Share on other sites More sharing options...
hughdogz Posted September 17, 2007 Share Posted September 17, 2007 hugh- people have seen my car run a 13sec 1/4et....at SEZ....at 105 something mph....with a 2.5 60ft time.... Okay, so you do have a 13 sec n/a car (I didn't know I swear)! My apologies for doubting you BG. As for the piston lightening, I'm no expert engine builder, but it would seem to me that lightening the piston would have the good effect of decreasing the inertial loads imparted to the connecting rod from the piston. The inertial loads on the connecting rod are highest in tension during TDC of the exhaust stroke (since there isn't an opposing load from combustion or compression). Inertial loads are highest in compression at BDC of the exhaust stroke. With fatigue, the only concern is tensile load. Since F=ma, reducing the mass of the piston will reduce the fatigue load proportionally. As long as the integrity of the piston isn't compromised it can only do goodness. As others mentioned it will no doubt have less "rotating" mass to accelerate. It seems to me like the ring-lands usually fail on forged pistons before the top of the piston running high boost anyway, so he's not even changing the weak part of the piston...but like I said, I'm no expert so I could be wrong. I think it's a pretty clever mod myself...and probably one that will work well. Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted September 17, 2007 Administrators Share Posted September 17, 2007 ....IF the thing fires up i will be impressed...actually, i wont, because i know it WILL fire up.the thing is, IF it runs for more than 14 minutes, THEN, and only then i'll be impressed.... then its just a matter of time, or miles, untill the thing breaks apart....engines arent legos. im not jealous at all. funny though, it was "supposed" to be running over a year ago, and it still isnt running....i would be doing the same thing-taking my sweet time-if i didnt have 100% confidence in the machine. Bubbles, First off, you are coming across that you don’t like 1 fast z. Fine. Please don’t bring it to this forum. Secondly, in regards to engine building, design, theory, tuning, etc, Bryan has walked the walk, and is building creative projects that the rest of us only bench race about. Whether or not Bryans project runs for 5 seconds, 5 minutes, or 5 years, produces only 100 HP or 300 HP, makes no difference. He had the balls to not only conceive such a project, but follow through with it, even if the end result could’ve been duplicated by other means for less money in less time, makes no difference. If you are not going to give him his due respect for that achievement, fine, but please refrain from your negative tone towards other peoples efforts and abilities to take on projects the rest of us only dream about. Link to comment Share on other sites More sharing options...
Tony D Posted September 17, 2007 Share Posted September 17, 2007 Thanks for that Braap, I have posted a blurb on "Machinist's Quandaries" in the other thread saying about the same thing. The reward is the process, as the goal is set so high. When you set high goals, failure is a noble effort. When you set middling goals, failure or success is...well...mediocre. Link to comment Share on other sites More sharing options...
Administrators RTz Posted September 17, 2007 Administrators Share Posted September 17, 2007 When you set high goals, failure is a noble effort. When you set middling goals, failure or success is...well...mediocre. Perfect. Link to comment Share on other sites More sharing options...
Gollum Posted September 17, 2007 Share Posted September 17, 2007 You guys know I'm not the smartest guy in the world, and I don't have years of physics or machine shop experience to really know what I'm talking about... but I do have something else... ...I'm smart enough to tell who's smart. Nissan spends millions in R&D, toyota spends more, and mercedes makes them all look poor in the amount of money they spend. If you look at ALL of their designs over the years, their high HP and more sporty engines have LESS mass where it's NOT needed. When mass isn't needed in a piston, rod, or crank it's TAKEN OUT. Now, WHY they do it we can argue till the cows come home, but the fact of the matter is, is that companies are going through many pains to make it happen, and it's NOT for cost. The new 350Z and G35 engine pistons are A symmetrical and have LESS wall contact on the low load side of the skirt so that they can save that precious weight since it's not needed, they just need to make sure they NEVER install a piston backwards now. I'd bet the new GTR will feature similar pistons. And if the supercars are doing it, I bet there's a reason. 1fastZ has been pushing himself to learn more for a long time, about as long as I can remember on this board and have looked up old threads. He knows more about engines than I'll probably ever learn, and I don't call myself an idiot (just dumb in the light of the minds that roam this place). But I'm smart enough to know that companies don't waste millions of dollors every year on nothing. Link to comment Share on other sites More sharing options...
frank280zx Posted September 17, 2007 Share Posted September 17, 2007 like i said- brilliant engineering. brilliant craftsmanship. good looks. but the functionality is NOT going to be present in that engine. period. i'd like to see it run for more than 10000k miles, or even 1000miles, at FULL BOOST, the 17lbs that i believe he is claiming. once i get time to get in contact with Ron isky- im going to throw a cam in it, retune, then easily run low 13's high 12's.... ON AN L28 in at 2700lb 2+2 for God's sake!!!! ! let your car run 100K first! Even stock it is falling apart he what do you think of compound charging .. sjeess bubbles you are posting an awful lot for someone in the marine! Sorry what is your problem.. even if it runs for 100 miles it is great achievement! even if it blows up at the first 1/4 mile it is! it is insane and great!! and btw engines ARE LEGOS. Link to comment Share on other sites More sharing options...
COZY Z COLE Posted September 17, 2007 Share Posted September 17, 2007 OK...This thread now reminds me of one time in Grade School when a bunch of us guys decided to see who can pee their name in the snow. My friend ED won.... I wonder why???? Then it turned to equipment sizes and I not telling who won... I'm placing this thread back to sleep... LARRY Link to comment Share on other sites More sharing options...
Mikelly Posted September 18, 2007 Share Posted September 18, 2007 Sorry Larry... I couldn't resist... I'm going to start watching a few of the members that posted in this particular thread... One in particular, really... My car has been out of commission for 7 years. Want to comment on my build while you're at it, BG??? We're all friends here. So let's keep it friendly... And before you post more nonsense like you posted in this thread, you better EDUCATE yourself, because the comments you made about weakening the rotating assembly clearly show you need more time in the classroom and LESS bench racing... You're on notice bubbleguinea! Mikelly Link to comment Share on other sites More sharing options...
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