My subaru 1302 build thread

[evilC]

Thanks to all for the good wishes.

Originally Posted by Eatoniashoprat

Clive have a nice time away

I just checked QA1's site and they have a 140lbs 9" spring for the rear and that would go just right with the 944 TB's (which I already have).

I looked at 9" coil over spring length because that's what Sandeep used (going by his pics). But I'll have to do some measuring to see what spring length to use, might be different than Sandeep as he is using 400lb springs so a 10" spring might be in order for 140-150lbs.

have a good weekend

Mike

Mike, the length of spring will be dictated by the ride height (and any variation you might want to dial in later) and the maximum compression allowed that'll be defined by the bumpstops. With that criteria maximise the spring length for two reasons:
1) It'll give you maximum range of spring selection and strain the spring less.
2) It will load the damper lower down the tube where its stiffer and lateral bending won't be an issue.

Originally Posted by Eatoniashoprat

So I might win the dumbest thing of year award on this site, I don't want to admit this but I did not have the front body mount bolts installed.

Single best modification to my beetle: connecting the body to the frame.

When I bought my car it was just bare steel that a guy had done a bunch of body work to, so I'd never taken a beetle apart before to see where everything goes. He also replaced front body mounts with some new steel but there were no holes or anything to bolt to.

I had to drill a 5/8" hole in the inner fender to gain access to the inside of the body mount to fit a nut inside there,drill a hole up from the bottom and hold the nut tight with a screw driver.

All I can say is WOW does it drive better now . The k-frame and body before were flexed apart by about an inch, and the bolts sucked them together.

Mike

I feel for you, we have all forgotten to fit/tighten fixings so don't be embarassed and if it reinforces the checking procedure then highlighting it is well worthwhile.
By far the most interesting aspect of this tale is the effect of the body to the overall chassis stiffness. There is a presumption that because the floor pan is a separate element labelled 'chassis' it is as stiff as it needs to be. That is not true as shown by your experience. Extending the philoshopy that the body stiffens the chassis, then providing additional strut stiffeners by way of roll cage and struts in the luggage and engine bay can be of demonstrable benefit for car control. I have a suspension strut brace but I will also be looking at additional bracing in the luggage compartment as well as a cup brace in the engine compartment and your experience has dispelled any lingering doubts about doing so.

Clive

[Eatoniashoprat]

More adventures in suspension tuning!

I installed the 944 rear TB's (still with 150lbs front springs, 19mm front AR bar and no rear AR bar). And the car actually feels somewhat balanced now, what a difference! The front is still quite a bit stiffer than the rear but with no throttle I can make it oversteer! This felt like a major accomplishment consider how bad it used to push.

Even just during the daily drive to work the turn in is much more responsive.

I want to try the 944 rear anti-sway bar as the next change. Right now if you force it into an oversteer situation the rear comes out very sudden and my hopes are that a rear anti-sway bar will make it more predictable at the limits. Does this make sense?

Further, after putting a few thousand miles on the 150lb front springs they feel a little stiff, like they barely move driving on the street. I'm thinking, since I want to go to a taller spring (or threaded sleeves) for more adjustment, 130lbs might be the right balance (and go figure it matches exactly front and rear what judgie is running on his race car).

Mike

[evilC]

Hi Mike,
With 150lb/in springs on the front the 944 rear TBs will be a little too soft to balance the car (I think), especialy with the heavy Scooby motor. I'm running 100lb/in front and 944TBs on the rear with a standard T1 motor. It has a 14mm 944 rear A/R bar but that is for autotesting and if it gets too tail happy for my wife and daughter I will simply disconnect it until I need it. Springs in 2 1/4" format are quite cheap so it is eminently feasible to try 100lb/in and 130lb/in springs to see which gives the best balance. You then have a choice to increase your roll stiffness - thicker/add AR bars or increase the rear spring rate. Your dampers are I assume adjustable to cope with the varying spring rate?

I do have a gut feeling that the best balance/drivability will be 130lb/in front springs 19 AR bar, 25.5mm equiv TBs with a 14mm A/R bar.

Clive