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Syscrush
Syscrush New Reader
4/12/21 9:10 a.m.
mke said:

The delayed lapping bar let me do the steering but last weekend I moved a fridge into the kitchen that doesn't fit in the cabinetry and fixing the cabinets almost certainly means adding a wall oven.....and the basement isn't finished....and a front door that in no way fits the existing opening.  The vital few weeks I needed to get the engine done and in the car may have slipped away at this point and I'm looking at 12 weeks of construction and yard work :(

Yeah, I hear ya. I've got this 60 year old cast iron pan that needs a full resto. I've been at it for a week and a half, hope to fry eggs on it before May. laugh

DaewooOfDeath
DaewooOfDeath SuperDork
4/15/21 2:44 a.m.

About your roll centers and instant centers ...

I watched the K24 swapped 308 project on Youtube and according to that guy, the stock V8 long block with transaxle was over 600 lbs. Exhaust and accessories brought that up over 800 lbs. That seems extremely heavy for an aluminum 2.9L engine to me, which leads to some potential scenarios with your project:

Possibility 1. The F106 is a really heavy engine. The V12 is (possibly) not particularly heavy for a V12 and therefore you might not gain any weight at all, and might even lose some. If this is the case, and you've managed to lower the engine relative to the V8 the drop in the instant centers may not be noticeable at all.

Possibility 2. Ferrari just makes super heavy engines full stop and your V12 with transaxle and accessories is pushing a thousand pounds. Also, by going from a 90 degree V8 to a 60 degree V12 you've moved those depleted uranium quad camshafts higher in the engine bay, making the COG higher. If this is the case, the drop in instant centers would be a huge deal. 

Possibility 3. The V12 is heavy but you've managed to lower it and dry sump it and remove accessories enough that for all its extra mass, it actually sits lower. The greater weight is offset by the lower mounting and you end up with something that acts, relatively speaking, like a lowered V8. In this case, the instant centers might not be a huge deal. 

This all said, you are clearly a way better engineer than me so take this with a grain of salt. ;)

mke
mke Dork
4/15/21 7:07 a.m.

In reply to DaewooOfDeath :

I've designed exactly 1 suspension so suggest away :)

Sitting in my amazon cart waiting for me to get the engine back together and need it  is scale....I would love to know what this engine weights.  I'm the k24 guys numbers are right...but also wrong.  I have no doubt he measured what he measured, those numbers look similar to what others found, so they are right.  They are also a bit wrong in that as you race prep older ferrari stuff weight comes off...I'm pretty sure race weight on a 308 engine/trans is about 650, still a big number but its a 50 year old design, it was good in its day.  The V12 is very litterally the V8 with 4 more cylinders....the TR heads will drop onto a 308 block....port angle differences but they are the same, boxer pistons fit 2v 308s, TR pistons fit 4v 308s.  The 60 degree v12 block is an older design (which I learned the hard way when I discovered the head stud locations are a little different) but they use the same connecting rods, bearings, cam sizes....so small changes.  All that said I expect the eng/trans with everything I've done to weight about 800lbs, I'll be sad if its 1000 but that is certainly a possibility....but I'll get that number before the engine goes back in the car.

Installed the trans is sitting 1/4" higher that stock....it was that or notch the already soft frame to clear the flywheel.  The engines crank though sits 2" lower and 3" forward of the the V8s so even with the added height of 60deg vs 90 and added weight 12 v 8, I'm pretty sure new mass center is lower and f/r split similar to stock or at least to the V8 with big supercharger that came out....but what to do suspension wise has been on my mind since I first bolted the 80 or 100 lbs of blower parts onto the top or the V8 and I'm clearly still undecided.

New rear springs arrived yesterday, 8" to replace 10"

Siting with the adjusters full up so rear as low as possible here it is

Last time when I measured the front I was looking at the valance and getting about 4.5".  last night I laid down on the floor and discovered 4.5" at the valance is about 3.25" at the frame so the front goes plenty low.  Right now the frame in the back is at 4.5" with no engine.  If the engine is 1000lbs with exhaust and everything and the spring 500lb/in each and nearly 1:1 motion ratio the rear will be 3.5" full low so I guess it works out  as this might work at an autocross but is too low for street use. 

I can rise it about 2" which would be just about stock or perhaps a touch over so these springs seem good length wise.

 

 

 

Rigante
Rigante New Reader
4/15/21 7:44 a.m.

do i foresee a  new chassis build in the future?

mke
mke Dork
4/15/21 1:35 p.m.
Rigante said:

do i foresee a  new chassis build in the future?

yeah......its hard NOT to tear into the frame.  In college I designed and built the frames for our FSAE cars a couple years and won a couple awards for that work and also a few roadrace motorcycle frames so anyone who knows me knows that which leads to questions like "how can you even stand to look at this ridiculous excuse for a frame?" ...and they are not wrong.  

My thinking was the ferrari is what it is and I would be strong.  I've been plotting a 33 ford roaster using the 47 Lincoln V12 sitting under my bench and my thought was it would be wonderful and a pretty cool autoX car, full body but no doors (that is why god gave us running boards right?), crazy rigid.  Very different from the ferrari but also just what it is. 

Lately I'm more torn....I don't mind adding a bit here and there to the ferrari but I don't want to turn it into a racecar, that I'm certain of.  My thought is I need to get the frame into an FEA model and play a bit to see what can be done that is meaningfully  helpful without it looking like a full caged race car.  I know I can make it better.......but first it has to run I guess.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
4/15/21 1:56 p.m.

In reply to mke :

Hell yeah, FSAE! When, where? I did FSAE at Univ of Maryland College Park 1991

mke
mke Dork
4/15/21 6:19 p.m.
AngryCorvair (Forum Supporter) said:

In reply to mke :

Hell yeah, FSAE! When, where? I did FSAE at Univ of Maryland College Park 1991

I think it was 2000? at Union College in Schenectady NY.  you can see the U in the zebra stripes, I'm in yellow.  That is the entire team in the pic so it was a LOT of work.

It looks heavy but I think the bare frame was 28lbs....its mostly .028" wall and over 80 pieces of tubing.   I'm pretty sure stiffer than the 308 frame :(

 

OHSCrifle
OHSCrifle GRM+ Memberand SuperDork
4/15/21 7:20 p.m.

In reply to mke :

How in the hell is that only 28#? 

mke
mke Dork
4/15/21 9:20 p.m.
OHSCrifle said:

In reply to mke :

How in the hell is that only 28#? 

Its been a long time and there were 2 frames.  The one with the body that raced was 28#, but looking closer the one in the pic is the 1st and was 35#, it was damaged in a testing accident then impounded by the lawyers so it never raced.  The 2 look almost the same, but the 1st is all 1" tubing, the 2nd was 20% 3/4" which was most of the weight savings and the roll bar bent to become the seat back and a couple other little things that didn't change the frame weight but reduced the assembly weight....remembering from 20+ years ago.  I could pick either 1 up by the roll bar with 1 hand......028" wall tubing which is about .36lb/ft...its light.  FSAE had a lot of rules but very few were cast in stone...."it must be a min of 1" .065 wall CrMo or equivalent" and we submitted equivalence reports for almost everything except the 2 main hoops iirc. The whole car was 520lbs, which was heavy at the time with design competition winning stuff closer to 450.....toward the end weight just went on, the body was a bout 25lbs with all the filler because there was just not time to fix the mold and we needed a body.

The 33 roadster idea is basically a pair of those frame siamesed together and lengthened.....roughly 80-90lbs and was a thought I  had for a speedster kit car I had years ago. If would certainty work for the 308 too but it just seems a shame to throw away that much ferrari unless I did something like pull molds off the body and start over which I have considered......

mke
mke Dork
4/17/21 9:07 a.m.

This morning I was out putting down weed&feed.  Its kind of earlier but last year while building walls, regrade, and such I really let it go so I decided to hit the show parts of the lawn now then the whole lawn in a month at normal time.  I like to do the fed&feed first thing in the morning when the grass is damp so the stuff sticks....don't know if it actually helps but I've always believed it does so I use the push spreader not to wake the family with the tow spreader making the job slow and boring and giving me an uninterrupted hour to pond Ferrari 308 chassis design and I believe I had an epiphany.....the frames are actually pretty well designed but aren't finished.

Let me explain.  If you look at the FSAE frame I posted its a space frame which means it made straight pieces of tubing and EVERY external opening is a triangle, EVERY node is supported in 3 dimensions.  This means all the frame member are in tensions or compression with virtually no bending loads, the only exception is the suspension mounts which weren't designed yet when I did the frame and honestly none of us were very sure about how to design it so I used heavy members there to allow freedom to make changes.Even the cockpit opening is a triangle which is important becasue removing just the 2 bars that go over the driver's shoulder to triangulate the cockpit reduced the frames torsional stiffness by a factor 3...so remove those 2 pieced the weight about 2 lbs and you have 1/3 the stiffness you started with.   So that is a space frame, wonderful for a race car but clearly worthless for a street car and as a result street cars do not have space frames.

Street cars, and here I mean older street cars that have defined frames all have a version of a ladder frame....2 main rails with cross members. Even most of the new monoque (stressed skin, no real frame) stuff uses ladder like supports.  A 308 frame is made this way.  With a ladder frame there really is no clever way to keep things in tension/compression so the only way to make it stronger is to just make all the part bigger and heavier....I had a '65 vette and its frame tubes were about double the width of the 308 frame, at least from memory.....the 308 frame is pretty spindly really and ferrari use the exact same frame in the 288GTO (just a 4" stretch in the engine bay) and and the same frame on the F40.....

.....why I wonder?  They had to know it was a POS when even a casual observer can look at it say WTF were they thinking? so why?

Racing rules.

Every sanctioning body has cage requirements that mandate, imho, ridiculously heavy cages built in semi-foolish ways.  They do that so its easy to tech and hard to screw up so anything you bring that meets the rules is safe.  Take a street car, remove nothing structural, add all this new stuff.  Everybody needs to follow the rules so it doesn't matter that all the cars are 200-300lbs heavier than they could be, the racing is fair and everyone is safe.

So what does Ferrari, a company who sell street cars to pay for their race program do?  They design a nice bottom section of a cage with very little consideration of street performance to make the frame as light as they can get way with knowing old men driving on the street will never notice the flex (this is no doubt also way the stock springs were so soft, to help hide the frame flex issues) and the racers will add a cage, finishing the frame, and have a lighter, faster race car than anyone starting with a car designed as a good street car who then is forced to carry the heavy street frame around the race track. 

So they were either incredibly competent  or incredibly incompetent. I'm going will they were brilliant.....doesn't help me with my flexi street car issues but it does make a lot of sense. For me, where a cage is not happening there is a bit of a challenge.  The front wheels are basically at the front os the passenger compartment so there is little to nothing to be gained up front leaving the engine bay and passenger compartment.  with both causing about 1/2 the flex. 

The engine bay I can cage.  Once the engine is back in I'll design something to bolt on top.  On the FSAE frame I reamed the holes and used shoulder bolts on ends of the engine access tubes and that working out pretty well so I'm thinking something along those lines but beefier to deal with the bending loads I didn't have then but will have now.

The passenger compartment.....the only answer is more metal.  There is lots of room in the rocker panels but I need to figure out what to do with the cross members....there is a double floor where I lost that steering bolt a couple weeks ago, for sure I can replace that with something quite rigid....I need to model it up and play with it....in my spare time......

 

 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
4/17/21 11:10 a.m.

In reply to mke :

Is the center tunnel structural? how tall is it? If it's feasible, there may be a lot to gain in bending by making a structural center tunnel as tall as possible. 

Will
Will UltraDork
4/17/21 11:27 a.m.
mke said:

Quoting because good god this looks amazing with those bigger wheels.

mke
mke Dork
4/17/21 2:50 p.m.
AngryCorvair (Forum Supporter) said:

In reply to mke :

Is the center tunnel structural? how tall is it? If it's feasible, there may be a lot to gain in bending by making a structural center tunnel as tall as possible. 

The tunnel itself is not structural.  there is a short section at the back that holds the parking brake lever sort of but the rest is just fiberglass covers.  There is a center frame rail in there, its the same about 2x4 oval tubing the whole frame is made from.

When I was researching for the FSAE frame I came across some work from the 60s that showed that is torsional stiffness was adequate then so was bending stiffness so bending stiffness is not a design concern.   This was for cars, clearly for truck bending stiffness means quite a lot and they don't seem to care that you can watch the think twist a couple inches as they accelerate from stop. Anyway, my thought is to focus any efforts on torsion....and that will mean adding weight I then will no doubt feel obligated to remove elsewhere......

mke
mke Dork
4/18/21 8:26 p.m.

A buddy from the FASE days (in the pic) is setting up an RX8 with a GM V6 for endurance racing.  There were some oil pan clearance issues, he sent me a couple pics and asked questions about cutting and welding it.....eventually I told him sent it if you can't get it welded thinking it was just weld a plate over the hole he cut......what showed up looked like a jigsaw puzzle and took a solid 7 hours to put back together...Lana is so mad.

 

Mr_Asa
Mr_Asa UberDork
4/18/21 9:14 p.m.

Should've known it wasn't going to be a quick in and out, nothing related to FSAE is, even when you've been out of it for a decade.

Looks good, though!

Rigante
Rigante New Reader
4/19/21 6:05 a.m.

found a guy 3d modelling and improving a 308 frame

The original frame looks pretty easy to triangulate in places and as you say there is a lot of room in the rockers for more structure

loads of frame images here and a documented build of some serious strengthening

mke
mke Dork
4/19/21 3:22 p.m.

In reply to Rigante :

Very cool!  I had heard something existed but I'd never gone digging to find it.  I looked through it but will need to spent a bit more time staring at everything.  for sure they are working with an older, '76 I think, chassis that is a tiny bit different from mine. 

I think too, and I might be wrong, that they are working with the original homologation specs and saying they need to make changes because the FIA cage rules have changed.....which may limit what they are allowed to change.   I say that because they have some obvious misses like they have a couple diagonals added to the side of the engine bay (red in pic below) but to triangulate the top or bottom so the side pieces add bending strength but little torsional stiffness because the flex just moves to the weakest link location.  Similar issue up front although probably less critical since the front is shorter length but still I'd want to get what there is to get and they didn't it doesn't look like so I suspect a rules issue.

 

ZOO (Forum Supporter)
ZOO (Forum Supporter) GRM+ Memberand UltraDork
4/20/21 8:08 a.m.

This is a terrific thread -- I sure wish there was a way to bookmark to certain pages though? 

It needs a table of contents!

Syscrush
Syscrush Reader
4/20/21 10:32 a.m.

What about stiffening the body through the passenger compartment and using that to stiffen the frame? Bond some carbon fiber beams on the underside of the floor, or do a sandwich construction with layers of foam and carbon sheet?

bentwrench
bentwrench SuperDork
4/20/21 11:02 a.m.

Hey you guys quit distracting him from finishing the motor or it will never get done!  cheeky

mke
mke Dork
4/20/21 4:59 p.m.

In reply to mke :

Got back into the shop and filled the pan with a couple gallons of water figuring its better to know a bout a leak now than find out at the track.  Its dry now and if its still dry on under it tomorrow it will be ready to go home and we will discuss what ferrari should appear in its place....sway bars maybe......

 

mke
mke Dork
4/20/21 5:12 p.m.
bentwrench said:

Hey you guys quit distracting him from finishing the motor or it will never get done!  cheeky

yeah...I"m a little ADD at times....but mcmaster is again saying "this week" on the lapping bar so who knows.

A ferrari guy noticed my 348 seat conversion so I may need new seats soon because everything is for sale.  I have a air of really rough 308 seats a grabbed on ebay a couple years ago thinking I might do something with them, and by something I mean something stupid and time consuming.

mke
mke Dork
4/20/21 5:13 p.m.
ZOO (Forum Supporter) said:

This is a terrific thread -- I sure wish there was a way to bookmark to certain pages though? 

It needs a table of contents!

I think you can book mark a page......and you're right I should put links to the different topics in the 1st post....in my spare time I guess ....... ;)

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
4/20/21 5:16 p.m.

In reply to mke :

I have had an oil pan hold water overnight and seep oil on a running engine.  Much shrieking frustration, especially since the oil pan was about 12-16 hours to R&R.  So I welded it in place, which was an adventure.  (Forgot to fill the crankcase with argon after flushing the pan with carb cleaner.  Boom)

In hindsight, it might have worked to fill it with kerosene and set it in a container full of flour.  But it might have needed engine vibration to make the cracks leak, too.  *shrug*

mke
mke Dork
4/20/21 5:16 p.m.
Syscrush said:

What about stiffening the body through the passenger compartment and using that to stiffen the frame? Bond some carbon fiber beams on the underside of the floor, or do a sandwich construction with layers of foam and carbon sheet?

the issue there is how to attach the CF to the steel?  That is not so easy with structural stuff you want to stay attached....glue and rivets maybe?  With steel sheet I can just weld and know its good so that is where I'm leaning but I'm only t the plotting phase....I must be strong....I NEED a running engine.....

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