mke
mke Dork
6/18/24 10:41 a.m.

In reply to DaewooOfDeath :

For sure there is a lot of I don't really understand going on.  I do (think) I know from the fsae design days that chassis stiffness is critical to having bar cause any meaningful front/rear weight (actually reaction force) transfer.  With a stiff chassis you can do a lot but with a flexible flier you really are stuck tuning the ends basically separately.....and a 308 GTS chassis isn't close to stiff.  

I measured a 1 wheel bump at about 0.5"/g and if I ignore the bushing and tire contributions then with the current springs about 25% of the wheel movement is chassis flex.  That doesn't seem like that will allow much end to end force transfer and tuning needs to be more about keeping roll rates in the ends similar.....which I guess makes getting a good setup about twice as difficult because it's almost always change both ends sad

The whole soft spring- big bar vs big springs-soft bars I've never really known right from wrong.  I'm pretty sure I know you want the suspension as compliant as possible to get the max mechanical grip possible......but the best way to achieve it.......I tend to go heavier on springs thinking it lets me run the car lower and that is probably a better starting point.  Guesses though.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
6/18/24 1:54 p.m.

In reply to DaewooOfDeath :

Bars don't convert roll to weight transfer, lateral load vs. the center of gravity creates weight transfer, playing with bars converts how much of that happens at each end, by altering the lateral load dependent spring rate.

 

So he's sort of right, but also wrong in the Herb Adams way, when he would say that antisquat can create over 100% load transfer.  Maybe momentarily but not steady state.

mke
mke Dork
6/18/24 10:17 p.m.

In reply to Pete. (l33t FS) :

I think a lot lot of people, myself included, say a lot of things that aren't exactly right.  

 

Really thinking about the spring/bar thing I'm pretty sure on a smooth surface where the suspension doesn't do a lot lighter springs and bigger probably works best.  But on rougher surfaces where 1 wheel bumps are very real then bigger springs and less bar is probably better.  When there are competing setup thoughts that are known to win it usually comes down to details somewhere.

 

In other news I just got the long awaited email, the head gaskets are ready to ship!  Sadly though I'm only 1/2 done with my floor refinishing work crying

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
6/18/24 11:14 p.m.

You could call up the factory and ask what they ran for spring rates and bar sizes when they rallied 308s.  They usually stuck to tarmac rallies but they've been seen at gravel events.  It would be an interesting compare/contrast to see how they approached the two issues.

 

(I don't honestly believe that they would tell anyone what the rates/bar sizes were)

DaewooOfDeath
DaewooOfDeath SuperDork
6/19/24 4:46 a.m.
Pete. (l33t FS) said:

In reply to DaewooOfDeath :

Bars don't convert roll to weight transfer, lateral load vs. the center of gravity creates weight transfer, playing with bars converts how much of that happens at each end, by altering the lateral load dependent spring rate.

 

So he's sort of right, but also wrong in the Herb Adams way, when he would say that antisquat can create over 100% load transfer.  Maybe momentarily but not steady state.

I'm familiar with the traditional view, and yeah, I don't know for sure. The argument he presented was that a Segway would roll less and transfer more weight with a swaybar. This is supposed to be the case because the bar transfers what would be roll and literally presses down on the outside wheel to resist it. Almost everyone I've talked to with a math/physics background has given me a different answer on this. 

I do know that F1 tries to make every mode of motion go through its own set of springs and dampers separate from the rest, so  I'm not sure if that plays by either the traditional or the Hoelscher rules. 

mke
mke Dork
6/19/24 8:20 a.m.

In reply to Pete. (l33t FS) :

You'd be surprised what you can get from the factory.......and they have figured out ways to charge for all of it.  I know a guy restoring an old group4 car, I could ask if there are log/setup books of any kind.  Tires have changed a lot though so hard to know how useful it would be?  

I bought the car in 2000 from a salvage yard/parts suplier....they got it in and decided it was maybe worth more whole and sold it to me. Anyway, thinking back I'm remembering asking about shocks/springs.  Stock are like 180/200 which is honestly a pretty strange setup.  The street upgrade was like 350/?? and I remember him telling me the track only setup was 800/??....which is now my street setup.  He had 7/8, 1, 1 1/8 bars available for front and rear and im remembering 1"F, 7/8 rear what he normally sold.....none are generally available any more but I do know a couple guys with those bars.

 

mke
mke Dork
6/19/24 8:44 a.m.

In reply to DaewooOfDeath :

I think the easiest way to look at it is a sway bar transfers spring rate from the inner wheel to the outer during roll which can be very helpful....provided your not seeing any 1 wheel bump type suspension action. 2 wheel bump all is good, but in 1 wheel bump action the bar messes up everything and can lift the unbumped tire right off the ground on a large bar small spring setup, I've watched that happen.  This is what got my head to big bars on smooth tracks thinking.

Way back in HS I put a much bigger front bar on my car.  Since then I think I've gradually moved to heavier springs and less bar on my street cars with the 308 the first time I've ever removed a bar.. ...they just seem to drive better with less bar. 

I've also generally moved to less low speed damping, but I'm thinking the shocks I liked with the 400/250 springs are feeling underrated with the 800/500 springs.  For sure it's much smoother/softer riding than the supra I bought my son and that car is box stock. The shocks are 22 years old now?, probably time to have the oil changed, new seals and maybe some new valving too......I want to get a little more time on the new springs and ply with the adjusters a bit more so I know what to ask for.

mke
mke Dork
6/24/24 5:53 p.m.

Sooo pretty

...and come with some pretty interesting instructions like start the engine without coolant and let the heads come to 40-50C.  Then water only to full temp. Then coolant.  We shall see! (once I free of house work)

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
6/24/24 10:18 p.m.

In reply to mke :

Those are lovely. I sincerely hope they seal as good as they look.

Keith Tanner
Keith Tanner MegaDork
6/25/24 12:32 p.m.

So many holes :)

Keith Tanner
Keith Tanner MegaDork
6/25/24 12:38 p.m.
DaewooOfDeath said:
Pete. (l33t FS) said:

In reply to DaewooOfDeath :

Bars don't convert roll to weight transfer, lateral load vs. the center of gravity creates weight transfer, playing with bars converts how much of that happens at each end, by altering the lateral load dependent spring rate.

 

So he's sort of right, but also wrong in the Herb Adams way, when he would say that antisquat can create over 100% load transfer.  Maybe momentarily but not steady state.

I'm familiar with the traditional view, and yeah, I don't know for sure. The argument he presented was that a Segway would roll less and transfer more weight with a swaybar. This is supposed to be the case because the bar transfers what would be roll and literally presses down on the outside wheel to resist it. Almost everyone I've talked to with a math/physics background has given me a different answer on this. 

I do know that F1 tries to make every mode of motion go through its own set of springs and dampers separate from the rest, so  I'm not sure if that plays by either the traditional or the Hoelscher rules. 

Roll is a manifestation of weight transfer, not a cause. The sway bars increase roll stiffness, so there's less roll for a given amount of weight transfer. On a two-axle vehicle, the weight transfer is also distributed as a function of the relative front/rear roll stiffness but the total amount remains the same. 

Sways allow for the suspension to separate two-wheel bumps (dips, crests, etc) from one-wheel bumps and roll. This also has an effect on how you'd tune low speed damping. They're also the easiest way to adjust steady state handling balance and - unless you go crazy - seem to offer more overall compliance for a given level of roll stiffness. 

mke
mke Dork
6/25/24 7:31 p.m.
Keith Tanner said:

So many holes :)

And I think he charges by the hole.....$810 with shipping which is nearly 1/2 my annual car fun budget  crying 

The funny (to me) thing is these are clearly designed to stop leaks everywhere but the cylinders.  Hopefully once I shim the cylinders to get the correct protrusion everything is well.....but for sure these heads are not coming off again even if I need to run straight water with liquid head gasket to make that happen.

mke
mke Dork
6/25/24 7:33 p.m.

In reply to Keith Tanner :

That all sounds exactly right.  Where my brain is still struggling is smoother vs rougher surfaces.....I'm pretty sure smoother likes less spring and more bar where rougher likes more spring and less bar.....at least that is how it works in my mind.

Gammaboy
Gammaboy New Reader
6/26/24 12:43 a.m.
mke said:

In reply to Keith Tanner :

That all sounds exactly right.  Where my brain is still struggling is smoother vs rougher surfaces.....I'm pretty sure smoother likes less spring and more bar where rougher likes more spring and less bar.....at least that is how it works in my mind.

Smooth surfaces the spring driver is controlling pitch I guess, whereas on rough stuff, decoupling side to side via soft/no bars allows the suspension to behave independently. 

Of course, this all goes out the window once downforce becomes involved.

mke
mke Dork
6/26/24 9:54 a.m.

In reply to Gammaboy :

Yes, then the question is what are soft or stiff springs?  1.5-2.0hz is soft and 2.0-2.5hz stiff maybe?  But I don't even know how to think about bar specs or compare between setups?

Usually what happens is most of us just call a supplier like Keith who has a setup they run successfully and buy a copy....which is WAY easier and cheaper than trying to develop it.  For me there just isn't a lot of good setup info out there, 308s haven't really been raced in 40 years.  Suppliers in the space are catering to street use really, how to lower it a bit and have it not ding the front valance or ride rough on the highway are the main setup concerns.

Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
6/26/24 10:03 a.m.

I suppose the end purpose of the car will play a part as well.  As I've gotten older, I have come to prefer street comfort over all-out performance and definitely over track performance the car may see once every few years if that. 

mke
mke Dork
6/26/24 2:08 p.m.

In reply to Ian F (Forum Supporter) :

Yes, getting old.  Am I allowed to admit that I've been kind of looking at electric AC options since I couldn't fit the original mechanical compressor?   I really have no plans or intentions of ddriving this thing as transportation...but most autox events are an hour or more away.  Noise canceling ear buds and AC would make the drive more pleasant.

Gammaboy
Gammaboy New Reader
6/28/24 5:54 p.m.

In reply to mke :

I too have been looking at electric AC for my 60’s Italian...

Rigante
Rigante Reader
6/29/24 12:06 p.m.

I always thought this would make an amazing grand touring car. Autocross seems a low bar to aim for. 

Harry drives the snot out of his supercars

https://www.youtube.com/watch?v=fxF4TRIuH4g

mke
mke Dork
6/29/24 2:33 p.m.
Rigante said:

I always thought this would make an amazing grand touring car. Autocross seems a low bar to aim for. 

Harry drives the snot out of his supercars

https://www.youtube.com/watch?v=fxF4TRIuH4g

I watched the first bit of the video and a quick eyeball comparison of his garage vs mine makes me suspect there is more than a small difference in his financial situation vs mine  wink

I used to drive the car quite a bit, one summer it was my only running car for about 3 or 4 weeks.  The exhaust was quieter back then, ride height taller and the engine WAY more stock (just a small blower making 8-10psi, 300rwhp).  I drove it all the time, I drove it 5 hours each way to a job interview, I trusted it and it was fun to drive.

It will be some time before I have any trust in the new engine like I trusted that one.  Also I'd say that now its just SOOO over powered, there is no reason the tach should really ever cross 2500 on the street and sticking to 2500 or maybe sneaking to 3k it won't get a noise ticket or really piss off my neighbors and its still making as much hp and a lot more torque than that old blower engine.  So its fine, but its not really driving it.  That is where the autoX comes in...its not that I'm building it as an autoX car, but I would like to get it competitive in one of the street car classes so I can make so noise and slide it around a bit now and then.

AC...its hot here in the summer so working AC would mean more opportunity to actually enjoy driving it but its not critical most of the time.  Getting it running well it pretty high priority, getting the suspension rebuilds and safe is a not so close second....AC  or even the heater working (its missing its fans/blowers which were in the way of the last engine's intercoolers) is about 9 or 12 on the list i guess...but I do have a brand new condenser that should work with the way not stock radiator I have and all the other OEM stuff is still there, so if I had a compressor, I think I could have AC.  

2-3 more weeks of floor refinishing it looks like then maybe back to the engine.

 

mke
mke Dork
6/29/24 9:05 p.m.

I'll expand a little on the last post, and this really goes back to stuff that was done before I started this thread.

This is meant to be a street car, full stop. Originally the whole point of the engine swap was to keep the car about the where it was with the 2nd pretty big blower engine hp wise which was around 450rwhp or maybe 550 crank , but get rid of the blower whine.    The plan was do the TR head swap and port the heads and I thought it should be pretty close even with the stock sad cams.  easy pleasy and it would be very much a GT car.  But I made a couple mistakes, 1st was the firing order was different TR to 400i so the TR cams were never going to work.  2nd is that when I started porting the heads I was remembering 2.4cfm/hp@10 in h2o a buddy had told me.....but I was not not remembering that number was for rwhp so I was working really hard to hit flow numbers that were roughly 20% higher than I meant so its an 800hp race engine not 600hp GT engine with not so GT 7k torque peak and 9k hp peak where I meant 5 and 7k like a TR

Once I realized what I'd done I did try to make the best of it and tame it for the street.  The headers don't really match the engine all that well, but they are designed to tame the engine.  The cams have a lot of lift but not a ton of duration to make sure there is a bottom end.  I maybe didn't go into it is a lot of depth but I was pretty proud of the smooth idle at 700rpm when box stock idle spec is 1000rpm and more than a little proud of that is has the torque at 1800rpm to tear the tires loose in 2nd gear that is just about where the stock 3rd gear was ratio wise.....lots of streetable power just as I'd hope and much more than I expected.

The goal with the suspension is also good street car.  I read stuff, see what other 308s do and end up scared....but I had a speedster kit car with a custom frame that ran rod ends on the A-arms and the same spring hz I now have in the 308 and I thought it drove just fine as a daily driver so I know there is nothing to worry about with the suspension changes I'm planning....but there's still an irrational fear that creeps in.

So I'm not planing a proper GT car, but very definitely a good street car for local use and maybe it will also be ok to fine for trips and hopefully also fine for an autox day.

mke
mke Dork
7/1/24 9:33 a.m.

Nothing to really do with the ferrari but the supra has been to a couple autoX events now and he's been seeming to have a good time, hard to tell with teenagers what they are thinking.  Yesterday mountain bike racing season practice starting emails arrive...but apparently we only race cars now.  1/10 the work and 10x the fun....at least when dad is paying for the car.  It is further motivation to get my car running I though and he has been talking smack about when will he get a chance to kick my butt.  Chores should wrap up mid July so August maybe.

Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
7/1/24 9:39 a.m.

The issue with electric A/C is the power still has to come from somewhere.  How big of an alternator can you fit?  You'll also need to look at the entire electrical system - especially if the car has a remote battery some distance from the engine bay. 

mke
mke Dork
7/1/24 9:43 a.m.

In reply to Ian F (Forum Supporter) :

Yes!  I think its 80A now and barely adequate with all the EFI stuff sucking power.  And yes the battery is up front, but I did run a pretty big cable, 0 gauge I think it is?  Big anyway so that should be ok if I can upgrade the alternator which is kind of why I'm thinking about it now when the engine is out.

Gammaboy
Gammaboy New Reader
7/2/24 8:08 a.m.

Yeah, the electric AC systems all seem to suggest you need 150amp alternator minimum... Still, I'd rather that than trying to wedge an engine driven compressor into the thing

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