Metal removal at rear, opinions

[4000GT]

NoHachi Wrote:Dicking around with the rear end is a lot easier to get wrong then it is to get right. I disagree that its done and tested. I haven't heard of any fast AE86s on the planet with the S13 rear end doing well in any kind of timed motorsport, but chime in if they exist.

Is a swap like that even allowed in class?

How are you doing in class now? There is a lot of time in setup/tires/data anlysis and driver development. Whole seconds in stead of the tenths you'll find with further weight reduction. How far are you along that curve? Might be a better place to continue looking.

To answer your questions, yes the swap is allowed, its CC driven.

Im probably is the upper quarter but 3 seconds a lap off the top guys. I still have a lot to gain in seat time and full slicks, only on R888's at the moment.

[Eircamae86]

I had a front only s13 swap & it was shit for circuit cool for skids,
Snap under/oversteer but I had an ae86 rear so I cant give you the full balanced picture.

[4000GT]

Maybe you didnt have enough rear end grip? Or the steering angle was wrong going into the corner?

Great to hear your opinions though, would be interesting to hear experiences with both front and rear done.

[Bean]

4000GT Wrote:Ill be using all alloy arms etc so I think the rear end weight might not be that much over the live axle.

for what it's worth the S15 rear subframe is about 2kg lighter (~19kg not sure if that includes any of the arms or diff though) than the S13 one - mounting positions are also slightly different (not sure if these make it easier or not).

PS: did anyone ever attempt to fit the rear end from the FD they should be very similar in width to the S-Bodies?

[4000GT]

Hmm I didnt know it was lighter, and also I have not heard of anyone using the S15 subframe. I just happened to find an S13 one locally for $20, so just got that...

[Bean]

4000GT Wrote:Hmm I didnt know it was lighter, and also I have not heard of anyone using the S15 subframe. I just happened to find an S13 one locally for $20, so just got that...

as mentionied the difference is not much, as far as I remember the mounting points of S14 and S15 are the same and only the S13 is slightly different (narrower). The S13 one has some hefty counter weights which the other don't have, may be that's all the difference in weight there is.
Last but not least 20$ will not get you a S15 one for sure. I'm still intrigued by other rear ends but it's hard to find info on the net as this is not a very common modification.

[4000GT]

Im looking at the subframe now, not sure where the counter weights are, but I will weigh it for everyones reference.

[4000GT]

Ok the subframe with sway bar and mounts and bolts etc without diff and hubs and arms = 24kg.

Hub with arms without brakes (but including handbrake cable) = 15kg each.

[Bean]

4000GT Wrote:Im looking at the subframe now, not sure where the counter weights are, but I will weigh it for everyones reference.

On my European S13 they were in front of the front main bushings (where it bolts to the car)

thanks for the effort - I think the 2kg difference sounds about right for just the frame then. I dug out the measurements from the manual:

S13


S14


S15


and AE86 as comparison


while I'm at it
FC3S: http://i29.tinypic.com/2j2bzuq.jpg

another observation some research brought up is that most cars settled on 1460mm track width (RX7s, Altezza, S-Bodys etc...) ET are more often than not 40-50 which by calculation would make most hub to hub dimensions ~1550mm compared to the 1400mm on the AE86
Also the pick up points for the dampers on the AE are only ~910mm apart whereas most of the aforementioned cars are much closer to 1000mm if not more, which put this mod into N2 wide territory.

[Eircamae86]

After these pics I fitted the sr bigger breaks using an R32 non-abs master which bolts up perfect, now back with all ae86 gear & pedal box