jeffp Posted August 12, 2002 Author Share Posted August 12, 2002 LOL funny James, you sure you can get that light rear to stick to the ground??? Maybe some lead weight may help. anyway, maybe I screwed up what I was doing, when I found out the dampener was toast it kinda messed me up a little. we will see, I think I am going to hold off on doing anymore runs until I get this new dampener, the idea of breaking a crank sure doesn't sound lik my idea of fun. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted August 12, 2002 Share Posted August 12, 2002 i have heard rumors that a diesel crank will break if spun more than 7000 rpm.most of rebellos engines are headed for scca use .a turbo engine and a track engine are 2 different things.that diesel crank is heavy-i have pulled them out at pick&pull. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 12, 2002 Share Posted August 12, 2002 That would be a long drive for Jeff to make just to race. I was curious about the mudhole reference. Are you trying to say we have bad roads in ALA? The problem I see with the diesel dampner is that a diesel doesn't turn the rpms that Jeff is turning his engine to. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 12, 2002 Share Posted August 12, 2002 Originally posted by Lockjaw:That would be a long drive for Jeff to make just to race. I was curious about the mudhole reference. Are you trying to say we have bad roads in ALA? I don't think it has any specific meaning, aside from being equivalent to "kick your ass". I think James just likes the way it sounds... Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted August 12, 2002 Share Posted August 12, 2002 It is just a taunting and has nothing to do with dirt roades in Alabama! Hell, when I visited Tim in Detroit I thought I was driving down an Iraqi air strip! The myth about the stroker being heavier is a myth from what I remember. The difference being about 2-3lbs. My crank is actually 84mm which is 1mm more than the LD28 crank and I spin my car to 7K all day long with no worries. I use the Euro pulley and have had no problems. I did spin the rubber on my 2.8L setup, but I think that was from getting oil on the pulley from a front seal leaking. My car hasn't hooked up because of crappy tires, but I put my new Nitto drags(275-50/15s) on the car Friday and do not anticipate traction problems. Lead weight, that was funny! Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 12, 2002 Author Share Posted August 12, 2002 THE BEST COME BACK : Oh yea! LOL Maybe I was not clear enough on the dampener. The first issue regarding the Diesel part, not going to work. They are dfferent, and for that matter I have found a good percentage of them that have done the seperation thing, and they dont get anywhere near the rpm's I am spinning my engine to. As I said I looked at a number of different manufacturers and like Donna said she needs a stock configuration on the pully assembly. I could have gone with the ATI unit but I need the stock configuration also, so that was out. This dampener is going to be made by BHJ, you can call and talk to brian at (510) 797-6780 I made my requirements very clear to him regarding the stock configuration on the pullies for this dampener and that is not a problem. The difference is the dampener only, it will be made from higher quality materials, lighter and will last allot longer. I really havent noticed much difference between the stock L28 crank or the LD28 crank on the dampener question. All of them seperate when you start spinning the engine to 7000 rpm's, 6000 rpm's and they last just fine, but the higher range is where they start failing. Anyway, why dont you give Brian a call and talk to him about it, tell him Jeff Priddy sent you, maybe that will get it completed faster if he gets a few calls wanting them. Quote Link to comment Share on other sites More sharing options...
johnc Posted August 12, 2002 Share Posted August 12, 2002 > i have heard rumors that a diesel crank will > break if spun more than 7000 rpm. Not true unless there's a balance problem. Its a forged crank with a slightly longer stroke and weight is about the same as the regular crank. BTW... I forgot to say, "Congratulations" to Jeff. 450+ horsepower is quite an accomplishment for an L6. Quote Link to comment Share on other sites More sharing options...
clint78z Posted August 12, 2002 Share Posted August 12, 2002 Most vibration dampers have a certain shelf life, and a rated number of hours until failure. The rubber starts to dry out after so many years even if it is never used. Don't bolt on a straight pulley, you are just asking for trouble. It always makes me cringe when I see unorthox doing this to try and get more power, definately a high rpm reliablity no no. The fluidamper seems to make a bit more sense to me, seems less likely to wear out. Good comments JohnC, doesn't the added rod end angle and piston skirt tipping add more stress to the crank. The weight difference isn't that much, they are all damned heavy and long. Luckily Nissan blessed it with good balancing and a solid forging. Quote Link to comment Share on other sites More sharing options...
D83ZXT Posted August 12, 2002 Share Posted August 12, 2002 Big toys for big boys...... OK you guys...real men (and women) don't mess with small turbos, they go for the real thing...check out : http://www.users.bigpond.com/jon-paterson/Turbo%201.jpg Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 12, 2002 Share Posted August 12, 2002 Well I can see we are going to have to weigh a standard crank and a diesel one to get to the bottom of the weight issue. TopEnd says they are heavier, although I would not say they are the difinative source of info on the Z's yet. Donna that turbo ought to be right up TimZ'z alley. HAHA Quote Link to comment Share on other sites More sharing options...
Guest Tom Scala Posted August 12, 2002 Share Posted August 12, 2002 BHJ is a good company,they make balancers for most popular V8's. It isn't going to be SFI approved probably which may or may not be a problem. If you show up at a NHRA or IHRA sanctioned track with a car they've never seen and run some insane numbers the tech crew might crawl all over the car looking for violations. As long as you have a good cage,driveshaft loop,jacket,and your harness is up to date they usually won't hassle you but I did see a guy get bounced for running a stock damper on a 10 sec car once. Quote Link to comment Share on other sites More sharing options...
johnc Posted August 12, 2002 Share Posted August 12, 2002 An L6 crank (regular or stroker) will have a lot of torsional oscillation as a result of the power pulses occurring every 120 degrees of crankshaft rotation. A greater impact on the torsional stresses is how the torque is delivered as opposed to crank throw length. A high compression normally aspirated (HCNA) engine will deliver peak cylinder pressures sooner than a turbo or supercharged engine of equal power. The HCNA produces a greater stress on the crank because more of the torque is applied when the rod is more vertical - typically between 10 and 12 degrees ATDC. Its kind of the difference between slapping your wife's butt and giving it a nice hard rub. Both induce oscillations but one gets you a smile and another gets you frown (unless she was prepped correctly)... Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 13, 2002 Share Posted August 13, 2002 Its kind of the difference between slapping your wife's butt and giving it a nice hard rub. Both induce oscillations but one gets you a smile and another gets you frown (unless she was prepped correctly)... John, you crack me up man!!!! Does you wife know you're talking about her butt like that?!! Tim Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 13, 2002 Share Posted August 13, 2002 I have tried it both ways and still get only the upside down powered curve with no pulsations. Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 13, 2002 Author Share Posted August 13, 2002 I can weigh a diesel crank. I have one still hanging out in the garage looking for a home. I have weighed them and if I remember correctly they weigh in at 56 pounds and some. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted August 13, 2002 Share Posted August 13, 2002 I just weighed my diesel crank using the digital bathroon scale. Mine weighs in at 48 lbs and my L28 crank weighed in at 45 lbs. Although the weigh myself, then weigh me and the crank method isn't perfectly accurate, it should be relatively close. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted August 13, 2002 Share Posted August 13, 2002 I don't guess the static weight doesn't matter much. What make the difference is that the weight of the moving crank is more as the stroke is increase since the journals are offset farther apart. Right? Centrifugal force thing. Kind of like when you tie a string to a wieght and spin it around. as the string gets longer, the weight get to harder to turn faster. Also moving more rods and pistons too. My theory there. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted August 13, 2002 Share Posted August 13, 2002 Thats fairly close, I measured mine against a regular stroke before use and came out 2lbs differnce. Although I'm using the Findanza (spelling?) Alum Flywheel, I still wish I'd have had a few lbs taken off just for shits and giggles. My motor dosen't seem to mind the extra arm weight though, so I'm not complaining, just wishing. Again, I think we all know that when it comes down to it, a properly sized turbo/ wastegate set up is the key to lag... .02 joel Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 14, 2002 Author Share Posted August 14, 2002 Well now that I have bought the new turbo, I will tell you what it is. I decided on the 62-1 wheel, the TO4E housing with the 60 A/R The T350 series exhaust turbine wheel big shaft stage 5. I was able to get my hands on a stock Nissan .82 A/R exhaust turbine housing and it will be machined out to fit the stage 5 exhaust turbine wheel. I am going to at this point run the stock waste gate. I know you are not going to like this to much James, but if the turbo will maintain 8 psi (because I tightened up the actuator arm) under high rpm levels like it does now, then there really is no reason to go external on the waste gate. I think this will get me to where I want to go with the horse power. I need about 30psi of boost and I am looking for a turbo that will build about 35psi to give me some head way. The flow rate is right in there for what I need, With that, I am going to leave the car that way and finish up the rest of the modifications I have been waiting on. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 14, 2002 Share Posted August 14, 2002 Originally posted by jeffp:I know you are not going to like this to much James, but if the turbo will maintain 8 psi (because I tightened up the actuator arm) under high rpm levels like it does now, then there really is no reason to go external on the waste gate. Add me to the list of people that don't like that idea ... The fact that the wastegate will maintain the boost at 8psi has no bearing whatsoever on whether it will maintain boost at higher levels. Remember that adding a turbo makes your system non-linear. The more boost you run, the more airflow you have. The more airflow you have, the more boost you run. And on and on, until something breaks. Without a wastegate, the system is actually unstable from a controls point of view (poles in the right half plane - that sort of thing). When you limit the boost pressure to 8psi, you are severely limiting the amount of flow through the engine, and a small wastegate will work just fine. You could probably get by with a 25mm gate at this level. As you start running the boost up, the airflow increases exponentially (if left unchecked). So, it becomes harder and harder to control the flow through the turbine, and more and more exhaust gas needs to be dumped away from the turbine. You really need to go by the horsepower level ratings (horsepower is referenced to flow, not boost pressure) that are given for the various external wastegates, and remember that they are talking flywheel hp for these ratings. Like I said before, I would not even consider anything less than ~45mm for a 600hp engine. It may seem like overkill now, but believe me - it's a huge pain in the ass to change this later... Quote Link to comment Share on other sites More sharing options...
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