debating weights

[vega]

I am debating something with my setup.

1. Has anyone stripped an 87 up z31 turbo 5speed? If so what was the weight? I am trying to find out how much I can get a z31 stripped down to within reason.

2. Why is it that people are swapping out the rear sub frame for an s14 sub frame? Aren’t the q45 diffs stronger? And also have an r200v? Plus stronger axles.... I don’t get it. Is it the suspension? Is it sooo limited on the z31?

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Right now I have a 1990 s13 coupe 5 speed base model. I finished the ka24de swap. I'm board. I want to know if I should continue with the s13 or sell it and get a z31 more or less.

The type of racing I do is m2 class racing in rally cross. The car needs to be "streetable" so none of the Hoosier I have one line a tread tires. I get a deal on the re11 tires so that’s what I’m going to use (a set for 200 not 600!) I was planning on ripping out the ka24de for a sbc 383 stroked vortec motor carbed. Using the q45diff and axles a highly modded we t5 trans and a bunch of other things. Now I’m curious if the z can get as low a weight as the s13 with the v8. If so- then I may just go z31 instead.


-------------- S13 project info---------
I’m about 140 pounds
The car stock is 2606 pounds (wet weight)
The ka24de is 371 pounds (240SX KA24DE Engine Weight: KA24ET / KA24DET Forum: Nissan Forums / Infiniti Forums - NICOclub (http://forums.nicoclub.com/zerothread/299879))
The ka24de trans is 169 pounds (can’t find the link hmm... she sure is heavy though)
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The sbc with alum intake/heads is about 525 pounds
The WC t5 trans weighs about 90 pounds (aluminum case :p)

So...
The sbc+trans = 615 lbs
The ka+trans = about 540 lbs

A difference of only 75 pounds oooo- big deal and the trans is pretty much in the center of the car. now I have read allot on what people have done to lighten up their s13 the lightest vie seen was 2179 lbs. cant find the link for that guy but he had an excel sheet for it I have it on my desk top.

So add about 100-200 lbs for a cage that’s 2379 lbs
Add 75 pounds for the v8 swap that’s 2454 lbs
And lastly me (140 lbs) that 2594 lbs

So let’s just say 2600 lbs to be safe. So now we are pretty much back to stock weight but with a HUGE hunk of v8 in the front. I haven’t really added the weight of the axles and new diff though... so this is a guestimate.

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So can I get the z31 down to 2600 pounds or there about?

[Def]

A KA/SR trans is more like 80-90 lbs - definitely heavy for how much power it holds, but no where near what you quoted.

An S14 rear subframe has better geometry - less anti-squat - built into the RLCA mounting points.

I imagine an S13 will always be lighter than a Z31 - it's a smaller car.

[Def]

Also, S13s have R200 diffs - it will hold up to an NA 383 just fine. The R230 diff is pretty damn big and would require some work to fit. At that point, I might just opt for an aluminum case Cobra 8.8 diff and save quite a bit of weight over the R230. The stock R200 will hold fine, the axles might not depending on what you're doing with them though...

[Matej]

Shave the transmission. I have always wanted to see a smooth shiny transmission, haha.

[vega]

Also, S13s have R200 diffs - it will hold up to an NA 383 just fine. The R230 diff is pretty damn big and would require some work to fit. At that point, I might just opt for an aluminum case Cobra 8.8 diff and save quite a bit of weight over the R230. The stock R200 will hold fine, the axles might not depending on what you're doing with them though...

the q45 had a r200v no a r230v the z32 tt had the r230v
references:
Install Guide: Q45 Differential swap into 240SX subframe - S-Chassis.com (http://www.club240.com/forums/showthread.php?p=328500)

Nissan Final Drive Gear Ratios (http://www.nicoclub.com/Greg/ratios.html#240SX)

Welcome to Q45 (http://www.q45.org/techinfo.html)

also i was just now told at hybridz that you can only get teh z31 down to 3k thats geyh. oh well i guess the 240 WAS the best bet in the first place... plus it has a better rear. meh