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Post Edited (May 11, 7:22pm)
 

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well when you snap axles it doesn't mean that the diff wouldn't break as well. It just means that the half shafts could be breaking at a lower limit then the diff.
 

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But...

The R230 is even bigger than the venerated Ford 9"...
Do the math, it's .17" diameter larger...
 

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Yes Tony I'm aware a R230 (230mm) is larger than 9", but it still has IRS which means u joints, CV's or some connection other than straight axles. It isn't just the size of the rear, I contend the R200 could be tough enough if it had straight axles (might be anyway), I haven't heard anyone shattering one, but I have seen or heard U joints and CV's creamed. Now add IRS rear squat on launch, and the angle of the shafts do not stay optimal long, if it is ever optimal.

PS From Hybrid the conversion to a R230 can be as low as $1000. Note I'm stating the low number! And there is no guarantee they will take the levels he is talking.

PPS No Sparky I'm not kidding what is your idea to take the power levels >500 HP and matching ft lbs? Solid u joints on a 200 or CV's? Once you cross 500 lbs and HP numbers other than Corvette IRS the possible solutions are few. If you think you have a solution by all means tell us I hope I'm missing a solution. Jeff's numbers with his boost exceed 500, but even 500 is tough to handle with IRS.

PPPS Yes Z boy the design of the u joints is meant to give way before diff, and you are right, if you get the setup to take the HP, like using CV's then will R200 give out? Many have converted to the R230, but Jeff is at a level that most haven't gotten to. I have heard some mid to low 7's in 1/8, but none faster that aren't consistently breaking things. The levels being discussed here are HP that should take a Z into the 6's in the 1/8.

The fastest I know of someone using a Z rear end is running 6.9 1/8, but he is converting to the 'dreaded' hahahah 9" because he is sick of breaking things.

So I think it comes down to once you have a problem with differential or axles taking the power, you have a few choices...

1. Slow up and present system might hold
2. Convert to R 230 and hope
3. Win the lottery and buy a Corvette IRS
4. Tub and put a Ford 9" in it
5. Find something no one has published that is IRS and will take HP without causing you to sell the farm.
6. The Ford T bird in the late 80's had an IRS which might be a candidate?
7. Sell it

None are good, but unless I'm missing something those are the choices when you get around 500+ hp. I didn't put leave it as is and change parts as they break since that is totally unacceptable.

Would love someone to post better alternatives.



Post Edited (Apr 29, 8:22pm)
 

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I don't know what jeffp's budget is but from I think the name is orvette Recyclers the corvette IRS is about $2000 course there would be the narrowing the rear end to make it fit inside stock fenders with "stockish" wheels, and then fabing it into the car,

I believe that ScottieGNZ's rear end was out of a C4 and if memory serves me right it was a total of about 80Lbs lighter than a R200 proabably could put it into the car for less than 5 grand???

if the numbers on the weight were right I would put it in my car, after considerable saving, that would be about a whole year of tution for me or about 50% of my yearly earnings. Of course I am a self pronounced weight nazi
 

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Discussion Starter #27
Well, the thought of strait axel has occured to me more then once today. Also, just fixing the car and selling it also has occured to me today to. The R230 with all of its retro fit design wasalso a consideration, that is the strongest setup I will be able to get in the half shaft configuration.
I looked at the dif and it would appear thet I had excesive pre loading of the pinion gear and that is what started all the problems. Remember this diff has only about 150 miles on it since the install, the pinion and ring ate each othere up, bottom line, the sedamant(VERY FINE metal debree, along the linesw of graphite) were al over in the oil and bottom of the diff.
I installed the flange myself the last diff( the bad one) and I did have some reservations of installing the flange with not knowing anytrhing of how it woulfd affect the diff. I went by the age old just swap it out, no problem, that always bothered me because I understand how the parts are installed with what type of bearings.
Tonight I got another diff, installed the flange I am running, tightened it to what felt good to me and spun the flange attached to the pinion, the bearings were binding, I dcould feel it when I turned the gear, so I loosened the flange up and retorqued it to a less torque foot pounds and the binding was not there.
SO to simply to say just tighten down the replacement flange to the tightest you can get it is VERY bad advice. It may work at 200 hp or torque, but not @ 600. Please listen to this comment, you CANT just replace the flange for your particular driveline without chacking the preload on the THIRD bearing before you assemble the diff carrier. YOU NEED to ensure it is not to thight, or you will waste the bearings.
I firmly believe this was the cause of the failure of this diff, However, I am not convenienced the R200 gear set is big enough to handle 600 plus of torque, forget about hp as the torque is the kiler in this situation.
I got another dif and am going to have Robello setup the unit again asI dont have ther shims to do th job, but we shall see what the diff can handle. another 300.00 bites the dust!
And guys keep in mind, I am not bragging here, this really pisses me off as my choices re becoming limited here, and the thought of selling the car really has crosed my mind. I am getting tired of rengineerin the car to do what I want t to do. Anyway
 

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Sorry Jeff I was hoping there were alternatives, but as I suspected there is criticisms of doing what will work but little more.

I have priced the 9" conversion, ladder bars, tubbing, coil overs, disc brakes can be done for around $1300 and be indestructable. That includes shortening and Moser axles. I have held back doing it until I could consider all known alternatives, but I will prolly do mine the end of this month. A friend is a machinist and welder and has offered his facility to do the change. There are pics of a similiar change at hybridz.org

I was hoping to find another solution, but since none can take my 'paltry' 400 or 500 lbs it certainly won't take my motor with the supercharger I have ready to bolt on. I won't be running high boost just about 14 to 16lbs, but should get me mid to low 6's in the 1/8. Enough to justify the change to a suspension that will hold it. Good luck with your beast.

Zboy I wish I had $5,000 to waste on a corvette IRS but I don't. This is a toy and will never please all, but it is my toy I won't tell you how to do yours and I expect similiar courtesy from others for my toy.

It is easy to say what others should do, even what you might do, but when it is your money being taken it is much harder to justify something that costs many times more, and does not improve performance only the purity factor! If I wanted it pure I would build it pure stock, but I'm not into that, and I won't criticise anyone who is.
 

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"I believe that ScottieGNZ's rear end was out of a C4 and if memory serves me right it was a total of about 80Lbs lighter than a R200 proabably could put it into the car for less than 5 grand??? "

Yes my IRS is from a C4 and has the DANA44 diff and no it did not cost me $5K. MOF about half that and only because I went to extremes and just about redesigned the entire IRS. The results speak for itself: estimated 520rhwp/600+lb-ft torque, with a best 60' of 1.36, 6.40 in the 1/8, 10.08 in the 1/4, good street manners and with the right tires would hold its own in the twisties. Obviously if you have 2 left hands and no mechanical skills it will cost more, but like i said, I went to extremes which others might not have to or want to. However, you cannot try to put that kind of power to the ground and also think inexpensive. While even $2500 sounds like a lot, think about how much it will cost to find a diff with 3.08 ratio, buy a Quaife, have it set up properly, buy the CV kit, build axles, etc, etc. One response referred to the R230 swap costing $1000 and that being expensive. It is not if you have the power to require that strong a diff. The average turboZ does not need that, just like the 300hp L28ET does not need to even have the head removed, but that's another debate.

As I read this thread I see so many theoretical responses and the typical fallacies. As for Jeff's problem, I think JohnC is dead on in that the Quaife is probably fine and the lash was probably improperly set. Also keep in mind that when you put an R200 in your big HP hybridZ you are rolling a dice with a used part that could be 25yrs old and probably still have the original lube from Nissan. It's ironic that you see so many people thinking "I would never put a solid axle in my Z" or "I would never put an automatic in my Z" or "Z's do not make good drag cars" or "IRS are no good for drag racing" or "solid axles are no good for handling", blah, blah, blah. When you put an engine in a Z that has triple the HP/Torque that the Z was designed for and you want to run 10s, all those get tossed out the window. If you are intent on meeting a performance goal, you do whatever is necessary to achieve it. If you are intent on maintaining purity or just do not or cannot spend the money, then you accept the compromise or the resulting breakage.

You cannot expect to put 500+hp in a Z and meet a performance goal but maintain its purity or try to do it inexpensively. Jeff, I feel your pain but this is a hard lesson learned. When you finally get that diff repaired you will end up with more in it that I had in IRS or getting a good solid setup. If you want to run 10s, and still cut the twisties, you have few choices. If you go solid you compromise handling a bit but IMHO (and I will get blasted for this) the good handling of a stock Z suspension is as overblown as is the bad handling characteristics of a solid axle. Just talk to Stony to see how much he has dumped into trying to get his RB26-powered Z into the 10s. He finally realizes he needs a solid rear and an automatic but it cost a ton to finally accept that fact. For the purists out there, name me all the L28ET-powered Zs with the Z IRS in the 10s.



Post Edited (Apr 30, 5:59am)
 

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'the good handling of a stock Z suspension is as overblown as is the bad handling characteristics of a solid axle.'
Amen.

Gears for a Ford 9" are $125 per set, and I'm told can be changed easily and quickly.



Post Edited (Apr 30, 7:29am)
 

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Re: Unitrax

Jeff,

Before you try Rebello, give the folks at Unitrax in Anaheim a call. They've solved some serious diff problems with a lot of Viper racers and they do all the diffs for my car. (714) 630-4327.

- John
 

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Discussion Starter #33
Hi there, I torqued the flange to 200 foot pounds on the diff when I changed out the flange. I looked at the specs, only after the diff ate itself, and the specs are 137-159 foot pounds.
This problem is all of my fault! I really dont think Robello did anything out of the mormal setup.
I knew I might have some problems but just ignored what I thought and went along anyway. I did not use a torque wrench the second time, and fortunately I decided to check the pre load. I could tell the bearings were to tight just by turning the pinion gear. I could feel the bearings binding, kinda like a wheel bearing that is to tight, they did not have the smooth turning motion. So I untorqued the flange, got an inch pound torque wrench from TonyD and found that when I did torque the nut to factory specs it was about 3 inch pounds. The book calles out for 7-13.8 so I knew there was no point to go any further and buy a new crush sleeve from Nissan.
The trouble there is that it is on back order here for the last week and a half. I will call tomorrow and get the info on when I can expect the part, and if not then it is off to the junk yard again to get another diff and use that part and get my unit built back up. This is turning out to be a big pain in the butt, so I am the idiot here, it was my fault, and now I am paying for that little screw up.
 

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Shotput Practice...

Perhaps you can launch it like a shotput, and it will fix itself like the O-Scope!

LOL
 

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Once again, scotties logic has me convinced.
I will be a happy man once my L28et makes 300rwhp and shows it in the 1/4 without breaking anything and runs the right times consistently.

After that Im going to stop drag racing it and start drift the crap out of it, after i am satisified the driveline will accept it through flogging it at the drag strip several dozen times. All drag racing efforts and attempts to get faster at it stop, and I am going to perfect the art of driving my car sideways.

It is true what they say, at a certain point in drag racing you spend more money in the back than you ever did on any other part. Getting out for 1000 is CHEAP.
 

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> It is true what they say, at a certain point in
> drag racing you spend more money in the back
> than you ever did on any other part.

And you'll spend twice as much on the back end and steering if you start drifting your car. Got a look at the rear diff of the Dodge "Mopar" Viper that ran a few drift events for DamlierChrysler. Even with a cooler, the ring and pinion were blue. The steering rack and the power steering unit were also trashed because the stops were removed to get more steering angle.

- John
 

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500hp should not be a problem for the R200 at all. LSD anyway. We have seen several folks with 500+hp drag racing and street racing with no problems. I have run the same diff for over 4 years with no problems and my car has made about [email protected] Lash is critical as you have found it can eat parts quickly.
 

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Discussion Starter #39
Hi James, you are corrrect about the hp, but it is the torque I am concerned with for the most aprt. The lash is critical as you mentioned and it was very apparent in my diff.
The thing that bothers me the most is that I made only a few runs on the car before it started making noise, so really the question is can it handle the torque.
Keep in mind that I ran the car at 23 psi of boost and got 471 foot pounds of torque out of the car.
This time I ran it at 27 psi of boost, which doesn't sound like to much more, but it was nearing 600hp and if the torque follows the hp on the same curve then I was looking at very close or over 600 foot pounds of torque.
That is my concern.
The other thing that concerns me is the carrier bearings. The race is worn on both races, and I am not sure if was because of the FOD in the oil or if Robello set it up to tight. Dave did mention he set it up tight. So there is the question.
I have a part that is on back order from Nissan(crush sleeve) and when I get that part in I will reassemble the diff and have a shop here local set up the carrier and that stuff. That will be the real test.
Just to give you some idea of the changes in power. First I brought my cam timing right where it was susposed to be, I had it retarded more then I first thought.
That leaned out the car to the max, 20:1 @ idle and we wont even talk about boost.
So Since I was running @ 4 bar fuel pressure with 480cc injectors, and running that lean across the board. I decided to try my new 72lb injectors and lower the fuel pressure to 3 bar. Well it got me 13:1 @ idle and about 10:1 under boost conditions, I was able to take the boost to 27psi that way, and then the car was still trying to lean out @ 5K so this sucker is making the power with this turbo. I havent gotten the new unit installed as I am stuck without a diff for the car right now, and the tuning really sucks. But, I am still not convenienced the R200 is going to last at this point as my first setup really cant be considered a good test of its capabilities.
anyway that is where I am at right now.
 

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Jeff,
You need to be absolutely sure that your lean problem is from excessive power. I don't know of any pumps that flow well past 60-65psi of pressure. Their flow typically falls off quickly. Have you verified you are maintaining fuel pressure when the lean condition occurs? 72 lb injectors are good for 700hp easily. Unless your computer is not maxing the injector duty cycle this does not make sense. TimZ's car makes [email protected] on pump gas(23psi) and he has never had a problem and the car has been together for many-many years with the same diff. BTW, did you get your boost limit problem resolved? I never heard back from you after my last reply? Also, do you have a dyno graph of your best runs? Here is a pic of TimZ's dyno graph on pump gas. He plans to upgrade his crap cam and I will be making him a custom turbo...GT4240R so we hope his car can generate another [email protected] on pump gas.
 
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