JessZ Posted December 22, 2006 Share Posted December 22, 2006 My wimpy 4 speed in my 240z is not holding the l28et's torque. I have have an option to buy a '79 5-speed. I like this idea because of the fifth gear, but will this 5-speed also not hold the stock l28et's power? Is there a performance clutch I can use with this tranny? Thanks. Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 22, 2006 Share Posted December 22, 2006 There is nothing whimpy about the 4sp tranny, unless you are refering to the "A" type used in the series one cars. As far as 5 speeds go, get a 81-83 N/A 5speed, and mate it to a 3.9 or 4.11 rearend. Forget about the 79 5sp....really weird gear ratios. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 22, 2006 Share Posted December 22, 2006 I gotta disagree. For turbos wider gear ratios and tall rear gears seem to do best, at least according to those who drag race them. The 79 is the same as a regular old 280Z 5 speed, they didn't change ratios until 80, 80 is exactly the same as 81-83, but has a marginally closer 5th gear. I think the T5 is stronger and that should be your focus, but if you need a trans right away the 79 should be better than the 80-83 for your turbo application, and a tall rear ratio like 3.36 or 3.54 should be better as well. This might help: http://www.geocities.com/z_design_studio/ Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 22, 2006 Share Posted December 22, 2006 Jon, I will digress and partially agree with you, as far as tranny strength goes, I was refering more to the fact that the 81-83 N/A tranny main shaft nut is threaded opposite as the earlier trans and therfore will try to tighten as the tranny gets older. And regarding the diff ratio, you are correct, 3.5 or 3.7 would be a better ratio matched with the close ratio box. Quote Link to comment Share on other sites More sharing options...
JessZ Posted December 24, 2006 Author Share Posted December 24, 2006 Hey Jon how's it going up north? I'm in SLO town visiting old college buddies. I drove the datsun down from S.F., and you're right about The City, I'd rather not live there. I've read, Jon, on another post, you mentioning the wide ratio 5-speed coupled the gears I have now are better for turbo'd cars. So that's nice, this guy will sellme one for $50, and it runs sweet. About the second post dtsnlvr, what do mean about that nut tightening? From reading your comment it seems all the trannys do this? Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted December 24, 2006 Share Posted December 24, 2006 About the second post dtsnlvr, what do mean about that nut tightening? From reading your comment it seems all the trannys do this? The 81-83 N/A 5sp box main shaft nut is threaded opposite from the main shaft nut on all the other z-car transmissions. It was done to prevent the main shaft nut from loosening as the tranny aged. I have opened and repaired many 4 and 5 speed datsun Z boxes, and to a "T" I would either recommend staying with the "B" type 4sp or install a 81-83 N/A 5sp. The 77-79 5sp was a bastard box....essentially a 4sp that was converted and or modified to make it a 5sp. The 81-83 5sp was a purpose built (to last) 5sp gearbox. As far as your issue goes, your problem is prolly not tranny related at all, but clutch, and for the record...the quickest, as in 0-60 time, L-6 powered Z I ever drove was Turboed with a 4sp and 3.54. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 24, 2006 Share Posted December 24, 2006 I don't see a huge difference in strength between the 280Z and ZX transmissions. I've got to rebuild my ZX trans because the main shaft nut has backed off, so that LH thread thing doesn't assure you of never having that problem again either. The "strong" trans is the T5, and even it isn't very strong for increased power levels over the stock turbo. As for things here in Seattle, I'm just keeping busy with the car, biding my time, and waiting to get the hell out. Should be May-ish... we'll see. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 25, 2006 Share Posted December 25, 2006 Tremec TKO2 and a Ford input spline on your clutch... Shifts snick-snick-snick through the gears, with about a 1000 rpm spread between gears, and a nice overdrive! $3400 though... Then again, with G-Force offering 600ft-lb capable upgrades to T-5 Boxes, that also opens up a viable option... Quote Link to comment Share on other sites More sharing options...
JessZ Posted December 25, 2006 Author Share Posted December 25, 2006 Dtsnlvs, that's cool about your quickest 0-60mph being with essentially the same setup as what i have now. I've decided to just stick with the 4-speed and go with one of those $269 Centerforce clutch kits from Summit. I am making the order after Christmas, so if anyone knows of a cheaper and effective clutch, I'm listening. Jon-I did last minute shopping in my flip-flops and shorts. Don't know how the weather is in Seattle, but it's been a California day here in SLO, and the ladies, ohhhhhh the ladies. cheers and drive safe... Quote Link to comment Share on other sites More sharing options...
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