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Drag race Z's anyone else in 9's with indep rear?


Guest Anonymous

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Guest Anonymous

I see a lot of people with fast Z's but im more drag race oriented..

 

First off I use the JTR conversion < made it myself from the diagrams in the book> a griffon alum radiator and a black magic fan

 

motor is a 383 with a turbo 350 transmission.

and aprox a 3000 rpm stall.

 

I got a few questions..

 

1. How strong are the halfshafts realy...I know you have problems when you lower the car but my car is a purpose built street racer..

There for the rear end was raised half inch in the chasis and was permanently mounted with a solid alum front mount... I also removed the bushing from the mustash bar and solid welded it to the bottom of the frame .. ... SO the rear never gets under the wheels except on hard launch right at the start and the half shafts are almost level when going down track under power .

 

I ran mid tens for over a year with this setup and never broke a half shaft.. cutting 1.6 60foot times..

 

My current engine is capable of 750 rear wheel horses and almost 900 torque when its on the bottle.. < 383 solid roller cam 11-1 compresion 200 shot of nos >

 

What can be done to keep the rear alive... I have never broken a half shaft or a ring gear BUT I have broken a u joint before and the roll pin that holds the pinion shaft in keeps breaking on me and the pinion shaft rolls out and clips against the pinion..I realy want to keep the indep rear because its is a sleeper aspect no one exspects my car to run what it does with that setup..

 

I will get some pictures up of the car soon as I can..I exspect mid nines around 144 to 148 when its all dialed in.. I currently run it on m and H racemaster 235 60 14 cheater slicks..and would also like a cheap way to fit a larger tire preferably somehting like a 26 x10 15 inch slick etc .. < I am buying weld rims for it also >

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Wow, sounds like a lota ponies! Love to see some pictures. I know the answer for many here is the CV conversion, so I'm just adding info I've been told. The owner of Northern CO drivelines has been preaching to me for a while that a ujoint 1/2 shaft is stonger than CVs. CVs work better when wierd angles are applied, but will ultimately fail a twisting sheer before a good u joint system. He's offered to fabricate a set if I ever get into the big leagues! Keep the rear angles in check and who knows? Sounds like you've found the other weak links in the system.

JS

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I am assuming an r200 has been swapped in already? If not, that is where to start. Do you have a limited slip? If so, is it a 300zx? Datsun Comp? Gleason? (I would guess strength in that order.) If you are still running a single track, wheel spin from the right rear can soon groove the spider shaft, significantly weakening it. Shaft in a limited slip should have significantly less wear. You could have a machine shop make a hardened shaft out of stronger material. This might be real expensive, but shouldn't be too hard to find someone capable of this. A better choice might be a brand new limited slip from Reider Racing. Note that the only ones available now are for the 12mm ring gear bolts if you have an older r200 (81 or earlier)although it is just an assumption that the pin would be stronger, but at least it is new and would have no grooving or reduced clearances.

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Guest Anonymous

Get rid of the 350 too low of first gear get a glide . My buddie has 28" x 10" slicks tucked up in the wells he moved the spring perches up . says they rub just a lil 1.5 60' though just motor not runnin right yet 350 12 1/2 too 1 comp solid roller 700 lift .WELDED REAR icon_biggrin.gif

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John, I understand the opinion of your driveline specialist on u-joints versus CVs.

 

The problem is to get a Z to launch well, it seems the trick is a soft-ish rear suspension, and there you are going to have a bunch of squat.

 

That means a bunch of angle on the u-joints, and where the angle will be largest depends on how high the diff is raised.

 

If you raise it by removing all the mount material above the mustache bar, then this minimizes the u-joint angle at full squat to some degree, but then the u-joints will have a larger angle when it's not squatting.

 

Don't raise the rear of the diff, and the angle will be large when at full squat.

 

I think this is the reason the CV is a better solution for the rear of the Z or any other IRS in most instances.

 

Put a stiff set of springs and shocks/cartridges in the rear and you can keep the u-joint angle variation due to suspension travel to a minimum. But I keep hearing that this is not a good recipe for a good launch in the Z.

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Pete, understood, squat is transfer of weight making the Z a great car off the line. As Ron Jones was saying about the video of Nozcar, a lot of time is spent squatting instead of forward motion. Would be quicker with a stiffer rear. I agree CVs are the best for anything but a dedicated drag car, but for someone insisting on dragracing an IRS, with sticky and big enough slicks, perhaps the ujoints 1/2s might be stronger. Hmmm don't most tracks frown on sub 10s w/o a solid rear?

JS

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I have found the stock half shafts rear end and stubs have held up very well to repeated 10 second passes ,must be my steeper 3:90 gears. The largest tires I have found to work on my car are M/T 26x10.50 15 et streets. (actualy measure 26x8.5 on stock rims )

The track I race at is constantly giving me a hard time on the speeds my car is running, and I think they won't stop until it has a solid rear and a full cage.

PS. What gears, and rpms are you running off the end of the 1/4. And are you launching on the juice? John C

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Hrm, what stubs are you running? If it's 240 stuff I might consider skipping moving to 280 stubs icon_biggrin.gif I wonder if the weld can be strengthened in some way...

 

If you're running those kinds of speeds and don't have a full cage you're insane! All it will take is one stub axle to take a dump or maybe a U-joint snapping with the halfshaft getting tangled up in the control arm and you'll be on Mr. Toad's wild ride! Be safe man, it's not worth your life to keep it looking sleepy. Heck, my 8pt cage isn't all that noticable and at least one member has a much nicer one that follows the pillars down right through the dash - it looks really sweet!

 

Oh, and I think I'd agree on the Powerglide. Supposedly those suckers will really pick up a lighter car and take much less power to turn. Not sure how they might be on the street if you're doing that sort of driving but... might buy you several tenths if what I've read is true.

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Guest Anonymous

Well i just left the track first night out with the new setupp..

 

Only runing a 150 shot to keep it alive.. ran 10.27 @138.98 .. problem is i broke ANOTHER dam rear in a street race after I left the track 8( I am running 3.54 geared OPEN R-200 rears.. as i said before I HAVE NEVER broken a half shaft and only ONE ujoint in 3 years.. its the rears that are dying..

 

I personaly believe the U joint setup to be STRONGER then the CV shaft long as the angles are kept in check its when you lower the car or have excesive squat that problems arise., and as high as my car sits and as high as I have moved the rear end i have no angle problems the half shafts are prety much LEVEL when runing down track under power..

 

However the pinion shafts and the dam cross pin keep shearing.. I do not know what I did to this rear end .. I managed to limp home with it sounding like popcorn .. I probly broke the spider gears again..

 

the car is a 280 Z so itr came with a R-200 i always run R-200s out of 280Z's with 3.54 rear gears wich equall about 7500 rpm redline and about a 145 mph top speed in the traps .. < with the 200 -250 shot >

 

the glide would maybee be worth a coupel tenths but the required 5000 rpm converter would make the car a pain for the street < wich is where i do alot of my money raceing >

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Guest super280z

1fstz,

 

ahh i see we have a Ca$h racer in our midst now! well its good to have you on. i always love to see what people do with these cars. sounds like a pretty sweet ride you've got.

 

you'll see that most people on this board are running 11-13 sec time slips. there are faster cars but it's my impression that noone wants to find out just how strong or weak the r 200 actually is. wahat i mean is that i havent seen anyone with a juiced z putting 750 to the ground.

 

i guess all my doubts have been put to rest though icon_wink.gif it shouldnt even blink at my lt1. guys on here putting down power for 9's are using a solid rear axle swap or some kind. anyhoo, good luck on your hunt for 9's. i'd love to check out your swap sometime, im down in Corpus and i get up that way every once in a while. drop me an e-mail sometime

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Guest Anonymous

zome pictures of the Z and a couple mpegs of runs can be found here..

http://www.geocities.com/sacarguy/

 

ITs a pos site i just tossed up to post a couple pics.. I need to get some of the under side and a few other things also so you can see it better..

 

Just not in a hurry to do it until its painted and looks good hehe icon_wink.gif

 

[ September 29, 2001: Message edited by: 1fstz ]

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Hae you looked into an R230 rear diff? These are found in Q45, 300ZX (late model) and 300ZXTTs. Those cars all made 300 or more ponies from the factory and are limited slip (viscous). They might be what you need to keep things together. Trouble is bolting one in is nowhere near as simple and would probably mean CV joints for you.

 

Guys, how fast are the hopped up 300ZXTTs running these days? Is this a worthwhile idea? icon_confused.gif

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Guest Anonymous

hehe i have stresscracks clean in the suport tover ther rear quarter window..

all way across to the rear hatch..

 

Ya i know im crazy

 

the car runs 138-139 in traps on a 150 shot of nos..with the 200 i have gone fast as 9.70 @ 146..

but that kind of et gets me tossed out imediately.. at least in the tens they will let me slide 3 or 4 passes before I gota leave

 

10 point cage and a r 230 probly going in it soon should put me in the 9:30 range when i get the 60 foots down around 1.40 where they should be for 700 horses.

 

[ September 29, 2001: Message edited by: 1fstz ]

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Yes, PLEASE put a cage in that beast!

We want you around for more than just a few more runs!

 

That's an awesome ride you have there. The motor looks and runs SHWEET!

 

It sounds (on the videos) like you're starting out in second gear - is that right?

 

[ October 01, 2001: Message edited by: pparaska ]

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Guest Anonymous

No what im doing is leavieng in first easy then I slap it into second at only 4500 to 5000 rpm and spray it..

 

im afraid to use the NOs in first gear with the R 200 rear

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