V-12 Engine into 308 Build, over on Grassroots

86mm bore, 78mm stroke, 5437cc

 

Its mostly in now, just a few little bits left

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There are a few col connectors that lost there clips as did the main TPS so I need to see what I have an order if I don't have replacements. i also need oil filters so the coolant tank is wait as they are easier to reach with it out and somehow I connected my brake pressure sensors to 12V instead of 5V and one seems dead so that needs to be replaced before I refill the brake system.

I ordered some crimpers that I think will be correct for the new ECU pins...or would be if I had normal wirs but mine is almost all the tefzel aircraft grade stuff which has thinned insulation... this will be a project but at least it comes with a speed sticker so definitely worth it

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The springs are done, I should have them soon.
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Tomorrow I guess i start reassembling the rear suspension. OEM camber is 0.5deg front, 1.5deg rear. I'm thinking I want to be around 3? The front gains camber as it turns.....so spacers that add about 1.5 degree? which should be about 8mm and shim from there as needed.

 

Stop! Its chamber time!
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Then a lot of time cleaning stuff
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And finally 1 a-arm in place
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I really thought I'd get a lot further today but it was not to be which made me a little sad. This brake hose made me pretty sad too....

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me and my stupid typos....I thought my mc hammer joke was so funny...without the typo in camber Image Unavailable, Please Login

Did an ECU glamor shot.....no actual ecu inside yet but in pictures its wonderful
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and looked at the crimpers I ordered. One set was just the wrong size, mis-click I guess, replacement will be here Wednesday.
The other seems exactly right yay. There are a few spare pins so no worry wasting 1 to play.
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now back to suspension.

 

+5hp!!!

Me nearly every time I leave my garage....

 

1 done and it is simply marvelous...up and down nice and smooth

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Side 2 is back together. Axles and such tomorrow

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I'm not loving the shock though. For some time I've suspected its leaking slightly. Its on the engine is leaking side, but the oil on the shock is sticky not motor oil and I noticed the adjuster doesn't act right when the shock is fully extended. I really wanted to drive the car a bit before doing anything with the shocks...these are like $280each + parts to rebuild so my though was drive, decide what I think of the damping with the new springs, get them rebuilt and revalved as needed. That could still be the plan, it moves smoothly and is clearly damping....but its not right. I need to drink on it a bit ......

 

I was wondering what kind of of shock they are? Also, since the geometry is now changed and the upper a-arm will be sitting higher by the rough distance of your new hole - would the shock have to be re-valved? Or alternatively, the a-arm shock mount would need to be lowered to maintain the effective dampening range of the shock? maybe I'm thinking about it too much...

 

Yeah, you're over thinking it

Shock damping is based on the speed the shock is being compressed or rebounding, not where the shock is in its stroke. Lowering a car reduces the available travel, that has no affect on damping.

Damping rates are chosen for several reasons, all related to controlling body movement and keeping the tires in contact with the road. There is some math around critical damping rates to prevent the springs from oscillating.....but its more guidelines than rules for how to apply it. That means driver preferences end up playing a pretty big roll on street cars and data system data drives it on race cars.

My shocks are Ohlins single adjustable. They have a large built-in reservoir up top. On the softest setting they are similar to the stock konis, then go to about double in rebound, maybe 50% more in compression iirc. I originally spec's them for the 400/250 springs so they are on the software side for the 800/500 springs so I'm running them full stiff and it seemed ok....the new spherical bearings will change it a bit so I'm hoping to drive a bit and really see where I am feel, ride, and control wise before I do anything.

I could rebuild/revalve myself I guess....but I kind of know that would mean building a shock dyno sold I'm not sure i want to head there

 

Let me just add, some stuff I'm pretty sure of, other stuff is my best guess so please don't take anything I say as anything more than my personal opinion.....I'm sure there are other and quite possibly better ways to setup 308 suspension.

 

Thank you!!! I love learning about this!!! i feel like I have seen some shock manufacturers note there is an "effective use range" so knowing where the main ride height is important to make sure they are built right. Maybe its a specific manufacturer thing. Though I know you want to have a good amount of piston travel to allow all the valves and pathways that do the dampening do their thing.

Ohlins motorsport grade are cream of the crop. Many people don't understand the difference between their Road and Track vs. Motorsport product lines. More like a Penske. It's a crazy looking damper with that bulbous top which most have external reservoirs - cool! You are almost describing a single adjuster but controlling both the compression and rebound on the same "click" thus the setting are tied, but it is more than just rebound.

I heard Steve Dinan give interesting insight to the most overlooked aspect of suspension setup is using the proper bump stop setup (materials and size). I have to look it up...

Very cool man!

 

I think I understand. The general rule is you don't want the shock to have less than 1" travel so when you are laying out linkage or picking mounting points, you want to keep at least 1" shock stroke. Not really a concern on a 308 unless you are making extreme changes.

Then with adjusters you generally want to be in the center like 3/4 kind of avoiding the ends....and right now mine are maxed. They generally don't work as well at the limits like that so when you realized that is where you are best get them revalved to get back closer to the center.

I"ve had these shocks since.....2002? they are STJ which are no longer made. The large top works about the same as a remote reservoir but was legal in a US dirt track class that banded remote res shocks. At the time they were like $150 each cheaper. Technically these are single adjust, rebound only but its more like 90/10 rebound/compression when you turn it. Then the way I had them valved the damping is similar to stock in that compression is about 1/3 rebound but with rebound fully cranked in the ratio is more like 1:4

With the stock springs and shocks the compression is 50% critical damping, the rebound 150% so combined they are exactly the critical damping. I'm currently well under critical.....but it feels and acts pretty good so I'm not really sure how much I want to change it. This is what I was on about the other day....less spring/more damping or less damping more spring will feel similar driving down the road....they aren't the same but ride quality and general responsiveness they do feel similar. Don't know......but I will need to address the right rear shock at some point soon

Snubber......it would take a heck of a bump for me to even even hit mine with the springs I have so not much of a concern. But stock springs in a hard corner you are 100% riding on the snubbers, especially if it also lowered with the spring perches I see people making. For setups like that tuning the snubbers is for sure a good idea. No 1 right answer kind of thing I guess.

 

Oh, and remember I have 18" wheels. My tire OD is 25" compared to 24.9"? stock, so way less tire sidewall. That changes things too.

 

I got so little done tonight. Pulled the damaged brake line and emailed a custom line place asking about repair or replacement. Gave some thought to a shock dyno, I do have the old ECU just sitting and it could easily run that but that is just not a battle I want to fight right now so I think I've settle on just sending out the right rear for now. Install the outer axle bolts, I damaged 1 removing it and a replacement arrived today so too care of that.

A new set of crimpers arrived and they work great on the medium size pins
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but not so much on the small pins.....need to find a 3rd set

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It looks like the STJ is now ILX and double adjustable start5ing at only $850/shock, but also upgradable to 3 or 4 way adjustable at $1250 each.


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I apologize if this is digression.

I don’t think I understand what damper adjustments do. Maybe I don’t even understand what dampers do.

I understand that the shocks dampen the oscillation of vehicle after going over a bump. Seems to me that setting the shocks at the softest setting that dampens the oscillation would be best since you get the softest most compliant ride the springs can provide. (I recognize that having appropriate spring rates front and rear is critical to neutral handling.)

It seems to me that the purpose of rebound adjustment is to control relative axle balance at turn-in. I have Koni rebound adjustable shocks on my track car (a 1987 Fiero GT) (rear-mid engine 6 cyl, 5-sp). I had the rebound on the rear Konis set too soft and the rear would slip until the car took a set for the turn. I firmed up the rear rebound and the car stayed neutral at turn-in and through the rest of the turn.

I can’t think of anything else I would want to adjust.

What do the other adjustments do?

 

here we are, having a nice chat and Brian jumps in with "what's the meaning of life? why are we even here?"

How much time do you have? Shocks are hard. I can share my thought but its what I THINK I understand

First up...why is the shock there? The original reason is to make the system stable. Way back they figured out that if there are bumps that are pretty equally spaced then the the suspension could go into harmonic (uncontrolled and violent) oscillation if you are driving at the right speed and that will break the springs or the tires or just cause the tires to bounce off the road leading to a crash. You need something to damp the oscillations but you have a choice about how fast or aggressively to damp them which is the 2nd reason for having them, feel and control.

Critical damping, or the system setting in EXACTLY 1 cycle can be calculated.
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You can also calculate the speed of 1 cycle or its Hz, this is what I've posted for different spring rate options. I'm running springs in the 2.2-2.4hz range and stock is more like 1.2-1.4hz.....but I increased the spring rate 4x to get a 2x change in frequency (stupid math, but remember this relationship) and shared a chart that gave guidelines for what hz yields what kind of result general driving feel results.....well the same is sort of true with damping. You generally never want an overdamped system of any kind and when done to suspension can lead to the ride height changing as you hit bumps because the shock holds the spring compressed, so over damped is out (mostly, I'll explain in a minute) and critical damping is the most you can have.....but that doesn't mean you want critical damping, its a limit not a really a target. I say not really because critically damped is the most stable a system can be so it often becomes the target....the line you want to walk right up to, at least in a sports car, a luxury car will be underdamped and sea sick from bouncing up and down is the line they might be walking up to. The reason for the difference is ride quality vs responsiveness.

On a stock 308, and many/most? other street cars the factory engineers use a 1:3 rule where compression damping is 1/3 rebound damping. Also for a 308 the compression is way underdamped and rebound way over damped but added together the compression and rebound rates are exactly equal to the critical damping value. This is a compromise to build the most stable system they can but also provide good ride quality. The low compression damping lets the wheel move when it hits a bump so the driver doesn't feel it too bad, then the high rebound prevents any re-bounce or bobbling of the car, so it goes over bumps nice and smooth then settle quickly, most cars do a version of this. The trade off is the tire can and does break traction as the high rebound holds it off the ground momentarily so ultimate grip id reduced and on turn-in to a corner, the outer front will sink pretty quickly which makes the turn-in feel mushy, less responsive than it could/should. So a balance needs to be struck, that 1:3 ration is where most have settled and then the oddly soft stock 308 spring rates are most likely because the damping was as high as they wanted to go for the ride quality target, and from the damping they calculate spring rate so the system is at critical damping. Then they adjusted roll centers and sway bars to get handling where they wanted it....that's my best guess anyway but the spring are a weird choice on their own.

Adjusters
On a 1-way adjustable shock it will almost always be a rebound adjuster. The compression is basically fixed and the rebound determines how quickly it settles. Here are mine with the OEM koni values also graphed (look at the top to see which color line on which graph)

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You can see the compression is more than original, but doesn't change a lot with the adjuster setting. When I had these made I was using 400/250 spring up from ....180/180? i forget, but the point is I added quite a bit more front spring rate so the front damping rates are higher but in the rear springs I only went up a little, so the damping only went up a little....critical damping is the limit. Now remember I said my new front spring rates are 4x the original but only 2x the hz....well note that the front shock full stiff are about double the oem damping so they have JUST enough damping for the springs I now have...mostly. but the damping ratio has changed from 1:3 to about 1:5, its stable but really could use more compression damping and less rebound.

I said before that high spring rates/low damping can feel similar to low spring/high damping....damping slows the front outer settling so turn-in feel quick, but with stiff springs the front outer doesn't ever drop much, so again turn-in feels quick. Stiff shocks make the ride harsher....stiff springs make the ride harsher. They feel similar in general driving, but different at the limits. Stiff springs with softer shocks tend to work better for aggressive side to side direction changes, chicane, or slalom type stuff, where less spring and more damping (and bigger sway bars) is generally better with longer higher speed corners.

Adding a compression adjuster know lets you play with the ratio of compression to rebound damping but the target is still do'nt let then add to more than critical damping which can be very hard to know, a spreadsheet helps. So if I would like a bit more compression and a bit less rebound but I need to have them re-valve to get that whic is where I am right now but was perfectly happy with the springs the shocks were designed for. To adjust 2-way shocks I guess compression and starting turning with rebound to get it stable and see how it feels. Then I try more or less compression (and back of the rebound if I went less compression) then slowly click rebound back in to find the new stable point and see how I like that compared to the only settings. How does turn in feel, is it pushing more or less? settling nicer? Can I be more aggressive? did my laps times get better? Is it bouncing on the curb or anywhere else?

Single adjust is about leaving ride alone and getting it stable. Double adjust lets you play more with the balance between ride quality and responsive handling.



But wait, there's more! 3 and 4 way adjustable!

Most of what you feel as ride quality is considered low speed damping and hitting a pot hole or a curb at the track, high speed damping. Low and high refer to how fast the wheel is moving up and down, not how fast the car is going down the road. Scroll back up to the shock curvers and you'll see the lines are not straight, They are pretty straight for the first little bit at 1 line slope, then bend to a lower slope and are straight-ish again at a new lower 2nd slope. The 1st section is low speed, the 2nd is high speed. 1 or 2 way adjustable move the whole line so to get quicker turn-in (more low speed compression damping ) means you also accept a harsher hit on the inner curb (high speed damping). but with a 4 way adjustable shock I can adjust the 2 regions separately, I can't change the speed (x- axis point) where the transition happens, but can change the 2 regions separately. For street use (and autoX) its really about the low speed damping so 1 or 2way adjustable are just fine. For track use, where different tracks and corners have different curbing it can help to play with the highspeed damping. On tracks I races motorcycles and we don't drive on the curbing so I was totally happy with 2 way adjustable, cars though usually benefit from 4-way adjustable on the track.

 

Gawd. Yeah, it's complicated. You are right: Why are we even here?

I can understand what you're explaining but there is no way my butt is sensitive enough to be able to use most of this information to improve the handling of my car. It is way above my skill level.

Thank you though.

I wonder how many people buy the fancy shocks, discover there are too many variables, and never even get close to setting them correctly.

Much of your explanation centers on setting the basic valving of the shocks for the application. My single adjustable Konis, apparently, were designed by Koni for track use on Fiero GTs. At least so I am told by the previous owner who purchased the shocks (and spring combo) but never installed them on the car. The basic fixed settings of the shocks, presumably, were for those springs on that car. It seems to work pretty good despite the lack of high speed / low speed adjustability.

 

Those pins are such a pia!!!!

 

So, a lot of busy work today

I found and ordered a 3rd set of crimpers, here tomorrow

Filled out the Ohlins shock repair order, waiting on the shipping info

found a place who'll make me a replacement brake line for $45 so I can avoid buying a new $140 set, still need to place that order

Added the little bolts to the rear rotors. I was running without and it was a pain to get the wheel bolts in as the rotor would spin on the splindle and the chopper plate I put behind the rotor seems to spin a different way and it was just awful. Now its fixed
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Yellow calipers.......I need to order ferrari stickers
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Looking at it the camber is obvious but its hard to get to to show in a pic
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but very rough measurement says 2.5deg so close, just needs a few shims.
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Any particular reason you're not running studs Mark?
Also, want to say thanks for sharing your knowledge and experience with the rest of us; especially your suspension primer up above. I know a lot of it was basic theory, but combined with the 308-specific nuggets it will serve 308 owners well for many years to come.
- Dave

 

The real and true reason? The bolts look better imo and are kind of easier to use. The bolt heads are about 1/2 the height of the lug nuts and I think just look better and are a little lighter. Then I had studs but decided they weren't really easier because hold the wheel trying to align the wheel on to the studs was not as easy as popping it on the hub and spinning until a bolt drops in.

If it helps, great!. Last night the guy who did the springs for me stopped by and dropped them off, he's also a motorsports person, rock crawlers and autoX with a little bit of track stuff. We were chatting and his car is set up basically exactly opposite of mine. He's running lightish spring huge sway bars and lots of damping on the course then less damping on the street (made easier by the little adjuster knob on the dash many modern cars have) and is really happy with the setup. That really is the only OEM answer....it works pretty well on the course or track, feels decent and responsive and once to back off the damping is fine on the street. The guys running the QA1 setups are for sure on this path, I read pretty light springs and those shocks hare universal so they have a HUGE range of damper adjust then add a 1" or 1.125" front sway bar and maybe a 7/8" rear to keep the car flatter and its a pretty good setup.

Personally I think that setup suffers from group think....its an "everyone knows this is how you do it!". Maybe its my focus on autoX type handling....street speeds with high cornering load and quick direction changes that makes me question that setup? Not sure but personally I've pretty much always been happier focusing on spring rate first and letting the springs do most of the work, with the shocks and sway bars are tuning aids mostly. Ineed to drive in more.....for sure I don't want the springs stiffer but I have seens packages for the 308 as high as 900/650.....that is too much even for me. For sure 400/250 was too soft for my liking, but maybe 600/375 or there about is a better option? I just need to get it running and get some seat time.

 

3rd set of crimper arrive and work just fine on the small pins. Here is 18 &20g tefzel wire
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for 18g pvc wire (normal wire) I have to pre bent the insulation clamp bits, but that honestly made getting everything in the crimpers a lot easier so maybe the preferred technique for everything. The crimpers says 22-28g....but full lose they seem fine and the pins handle the 18g no problem. I thingk this is sorted and I'm ready to start pinning the connector for the new ECU.
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Ohlins sent me questions instead of shipping info ....those are pretty old, how about some pics so we can see what you have before asking you to ship them. Now I'm a little scared

 

I put a new yellow spring on the left rear....amazing. For anyone in the area I used Full Spectrum Coatings of WestChester, they did a nice job.
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There were a couple marks where they had to hand the springs, so I grabbed some paint as close as I could find.....and also painted the front sway bar. I was not running the rear bar and my plan is leave it off for now until I see where I am f/r balance wise so didn't bother painting that one right now.
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And looking at the swaybar I know what most of you are thinking, "why oh why didn't you paint the air box yellow? It would look amazing though the blue deck lid!". The answer is simple, I know right from wrong and that would be wrong, now stop it, I'm not doing it!

The rubber bushings in the swaybar links are past sad, but years ago I bought rod ends for the sway bars and never installed them, so that will happen.
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Ferrari loves peened nuts, so I have a tool to unpeel them
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Looking at the hub, the back of the rotor, and everything around I an not seeing where the grease ring on the wheel is coming from.
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I will replace the grease seal....but I'm confused....