Guest bastaad525 Posted July 1, 2003 Share Posted July 1, 2003 Drax (or anyone) what kind of difference are we talking about? In a car performing near the level of Jerseys car, how many tenths might the 3.54 shave off? I have a 3.9 in mine, and the car I'm pulling my turbo motor from has the 3.54's...... I thought the 3.9's would be better for off the line, but I can see how it would keep you from hitting maximum boost, that's why I was thinking of launching in 2nd gear, rev to like 4k and dump it, should build boost aplenty by the shift to 3rd? As for the 3.54 in the turbo car..... damn my tight budget but maybe I can have him hold on to it for me and swap it in later, if it really makes that much of a difference Quote Link to comment Share on other sites More sharing options...
yo2001 Posted July 1, 2003 Share Posted July 1, 2003 I wouldn't mess with diff, 12.8 iis stout wit that set up. I bet it'll slow you down with 3.54. I'll take that bet. Every turbo car I know of that has compared has found the 3.54 to be faster in the 1/4. You just don't have time to build boost with a 3.90 in first gear. (or possibly even second) OK, I still believe you need alot of gear to get the car out of hole on manual turbo car. And I never had a problem with the car not spooling in 1st gear with 3.90, 11lb flywheel, and small crank pulley. Quote Link to comment Share on other sites More sharing options...
Jersey Posted July 1, 2003 Author Share Posted July 1, 2003 dj - sorry, i have a 3.54 sitting on the garage floor from one of my other donor Z's. If i have a 3.90 in there, i'll probably swap the guts like you mentioned or try finding a 3.70lsd. I like the limited slip option, just don't know if it would be low enough (numerically) for how i want it. yo - i'll bet the 3.54 will definitely shave a little off my time. It's not building any real kind of boost in 1 & 2 and i'm really stretching it out in 4th across the line. It would help me all the way through i think. Drax - exactly the way i'm thinking/experiencing. Not enough time to build boost. 525 - if i revved to 4k and dumped it in 2nd, i think my Z would sit and puke. Sliding the clutch out of the hole starting in second wouldn't be feasble either. Possibly if i had a 4.11 but not with a 3.90...if that's what i even have! ha. Whattya guys think of running a 3.70 with the T motor? Think a 3.54 would be better? i'm leaning toward the 3.54 but the LSD option would be very very nice! And i'm sure i can get something built but, i'm not rich like you guys!! Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 1, 2003 Share Posted July 1, 2003 I second that Jersey. Friday, the first time out with the 3.54, 2nd gear felt a lot stronger, I was building 10 psi. And 1st is actually useful. Before with the 3.90, I had huge problems with wheelspin. As soon as I get used to launching with the 3.54, I'm sure it will be easier to modulate the wheelspin, as I've less mechanical advantage. It may be harder on my clutch though. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted July 1, 2003 Share Posted July 1, 2003 I'm getting full boost in 2nd. with 60-1 and stage III turbine. Hit 6-7 psi in first. I guess 3inch DP helps Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 1, 2003 Share Posted July 1, 2003 Jersey, if you have a 3.54 sitting on your garage floor, by all means run that. I would suspect that as you get faster the LSD option will help you get out of the hole, but I'd certainly try out the 3.54 first and do some direct comparisons. (and share them please) As for how much you'll pick up, I have no idea. I'd suspect it will be a significant amount with a good launch though. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted July 2, 2003 Share Posted July 2, 2003 I run a 3.7 LSD in my turbo car with 1.8xx 60' times on drag radials. Here's the rub - my street tires are 25.0" tall and my drag radials (245/50/16) are 25.5" tall to your 24.4". My car (before) with the stock turbo and 3" DP and exhaust would get lots of boost in first. I would recommend a change to the 3.54. I believe it would come out close to the overall ratio that I have in my car. I am going to change over to ET streets or wrinklewalls soon. IMO drag radials are just a stopgap unless you want to run them all the time on the street. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted July 2, 2003 Share Posted July 2, 2003 Bingo on the spider gear, I messed around with my open diff that is setting out on the garage floor and if you spin both "wheels" at the same time you get the correct gear ratio on the driveshaft. Scottie has also posted before that every time he has went with higher gearing(lower numerical) he lowers his ET. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted July 2, 2003 Share Posted July 2, 2003 come on jersey give it a try like I said whaddya got to lose.... one run outta 12 isn't much of a loss... who knows it maaaaaay just give you a quicker time.... if you really have a 3.9 in there I dont think you'd bog taking off in 2nd, I do it all the time and have nowhere near the power you have coming out of your engine, and dont bog unless I just dump the clutch. Question though, will the turbo build boost revving it to 4k or more, in neutral? or does it only build boost under load? Quote Link to comment Share on other sites More sharing options...
Jersey Posted July 2, 2003 Author Share Posted July 2, 2003 Thanks guys for all the advice. I think i'm going to go with the 3.54. Now i'm just hoping the cv halfshafts pop into the '78 3.54 R200 i have and that the front flange will bolt up to the Turbo DS. If not, it'll be a little more work. O'well. Drax, i will share what i do after i get back to the track in a couple of weeks. I have a feeling i'll be able to launch much better with the 3.54. The 3.90 i believe that's in there now was real hard to control it from spinning the wheels. Doug, thanks for the advice. My budget (wife) doesn't have any near future plans on spending for the ET's or wrinkles, but if i come across a pair cheap enough...i'm sure i can convince her it's better than wasting my street tires Moby, thanks for checking it out. I'm still curious why the R200 i'm running that's out of the ZXT has an aluminum cover, not finned. Just didn't know they came like this or, the ol' man that owned it before me swapped it out? 525, Nothing to lose and if i had the chance to go to the track more often, i would give it a try. The next time that i do go, i will be running 3.54's. I used to really like that gear when i ran it with my N/A motor. I pulled a 1.7 60ft with the 3.54, '78 5sp & 10:1 L28 w/SU's....even though my fastest ET was a 15.026 You said in your previous post to rev it and dump it at 4k, that's why i said my Z would bog...because of the turbo. I did that with my N/A motor and it was the best way..actually a little slip of the clutch helped. With the T motor, the boost doesn't build unless you have a load on it. That's why i'm revving it up and down at the line, like the old day street racing, because i think it helps spool the T if you're on the upward swing of the R's as the tree drops. This is how I seem to do my best and please don't think i know a thing about dragging at the strip, this was only my 4th time there. I just go with what feels right, for me. Guys, you've been a big help. Now lets hope the previous owner swapped a 3.9 in there and i can drop to a 3.54! Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted July 2, 2003 Share Posted July 2, 2003 yeah I figured you'd have the diff swapped by the next time you went..... I know the track around here, you only usually get like 3 runs in a night.... anyways I'm still a little ways from having my car 'track ready' anyways, not to mention I rarely have that much free time. Ah well...... if you get a chance to try it, awesome, I'd love to see some track-timed results, if not no biggie, will be interesting to see though if you do have a 3.9, just how much faster if any you'll be with 3.54's. I look forward to that one Quote Link to comment Share on other sites More sharing options...
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