Dose's Sometimes DIY and Pay Someone Home & Boat Improvement Thread

[soviet_merlin]

9 hours ago, Piggaz said:

Have a look at what your rear wheels do under braking. When I did my suspension setup however moons ago, the rear was toeing out under brakes making the car farken scary and quite unpredictable.

How do you work something like this out? Do you strap a gopro on the car?

Genuinely curious

[Duncan]

You need to put the car on a hoist, remove the rear springs, set up strings for a wheel alignment, then check the toe out at full droop, full compression and a couple of spots in between.  Adjust the length of the front upper arm until the change in toe is minimal throughout the range.

It is such a pain that most people won't do it, and the correct length will vary from car to car due to slight differences and different camber. I'm pretty sure GTSBoy posted up the procedure years ago.  It's been done for my race car but the suspension shop did it for me.

[GTSBoy]

3 hours ago, Duncan said:

It is such a pain that most people won't do it, and the correct length will vary from car to car due to slight differences and different camber. I'm pretty sure GTSBoy posted up the procedure years ago.  It's been done for my race car but the suspension shop did it for me.

Nah. I did it with fricken lasers.

I made a mount to hold a mirror tile to the hub. Bolt that on firmly so that the mirror is not going to wobble wrt the hub. Point a laser at the mirror from a couple of metres away, at an angle so that it reflects back to a tall paper target stuck on a board next to the laser.

As you move the suspension through its travel the mirror will reflect the dot up and down the paper, and also side to side. The side to side is bump steer, because this comes from changes in toe. You just adjust the arms to minimise the toe change. Or if you cannot minimise it, you ensure that you're getting whichever change you're least unhappy with. ie, toe in rather than out, most of it under droop rather than compression, and so on.

Very time consuming.

I did write up a more thorough guide to what I did at some point. Probably searchable enough.

[Dose Pipe Sutututu]

MCA vs. Broscience Dose.

We now have 13kg/mm on the driver side, will do the passenger side soon.

Also decided to raise it a tiny bit, might raise it a bit more after a quick lap around the block when I finish the passenger side.

[No Crust Racing]

Also raised mine when I went bump steer correction and sorted the anti-squat/roll centre etc. 

Much Improve. 

[DaymoR32]

PRP have 1 samsonas in stock at special price mate. Get it before it’s too late!!

 

[Dose Pipe Sutututu]

@DaymoR32 yeah nah lol...

I think the next logical move is an OS Giken OR PPG Helical synchro gearset and this shit box is done.

No more mods, just wire up my brake input, clutch, front wheel speed sensor and I am pretty much done. Might do a coolant pressure input too and have it to trim boost if coolant pressure gets a bit silly (good for track use).

Maybe... do a digital dash. The Aim MXP does look good, I refuse to put in an IC-7.

[DaymoR32]

9 minutes ago, Dose Pipe Sutututu said:

I refuse to put in an IC-7.

how come? i like mine, just wish you could mess about with the actual display a bit more, would be good if there was an editor to fully play around with things (like powertune for example)

[Dose Pipe Sutututu]

it's more of the shape of the unit, it really gets to me (very subjective I know, same can be said about the R33 it looks like shit and I agree - but at the time it was a "cheap" track car).

I saw on the Haltech Tuning group on Facebook someone managed to design their own layout, let me find the post.

[Dose Pipe Sutututu]

Found it!

https://www.facebook.com/100022593548533/videos/3493056857609415/

 

[robbo_rb180]

1 hour ago, Dose Pipe Sutututu said:

@DaymoR32 yeah nah lol...

I think the next logical move is a zf 8hp70 and this shit box is done.

No more mods, just wire up my brake input, clutch, front wheel speed sensor and I am pretty much done. Might do a coolant pressure input too and have it to trim boost if coolant pressure gets a bit silly (good for track use).

Maybe... do a digital dash. The Aim MXP does look good, I refuse to put in an IC-7.

FYP 😋

The IC7 is so overpriced as a display. The Aim stuff is great and can send info back to ecu over CAN for when run out of ecu inputs.

When is next track day for HMAS Shiet Bok?

[DaymoR32]

59 minutes ago, Dose Pipe Sutututu said:

Found it!

https://www.facebook.com/100022593548533/videos/3493056857609415/

 

yeah thats pretty cool, i'll look into it!

[Dose Pipe Sutututu]

36 minutes ago, robbo_rb180 said:

FYP 😋

The IC7 is so overpriced as a display. The Aim stuff is great and can send info back to ecu over CAN for when run out of ecu inputs.

When is next track day for HMAS Shiet Bok?

LOL...

The whole DCT or ZF sounds very tempting, however there's so much work involved. Popping in a gearset, which also means taller gearing would mean I don't need to swap out the diff ratios.

If I was to go DCT or ZF, the 4.08 would be way too short.

I'm heading out to SMSP on the 11th July, at night.

[robbo_rb180]

Yeah for a car thats driving and running fine its more effort.

Goodluck, looking forward to see how much quicker you go.

[Dose Pipe Sutututu]

I have an alignment booked in tomorrow to just correct the toe and camber all round as I've raised the car.

Took your advice too, have added a tiny bit of rake into the car. Used a bit of broscience, took off the scuff plate on the driver side and put a spirit level on it. Slightly lower at the front.

[The Bogan]

2 hours ago, Dose Pipe Sutututu said:

I have an alignment booked in tomorrow to just correct the toe and camber all round as I've raised the car.

Took your advice too, have added a tiny bit of rake into the car. Used a bit of broscience, took off the scuff plate on the driver side and put a spirit level on it. Slightly lower at the front.

Question: is it slightly lower in the front to move weight forward to reduce understeer??? Or something else???

For the VX they recommend me raising the front slightly higher in the front to move weight rearward for traction, it currently is 5mm higher in the front than STD FE2 height, although I really haven't noticed much of a change

Disclaimer: the fat old VX doesn't go around corners at any real speed, but, in saying that, I haven't noticed any difference with the car wanting to understeer any more, or less, when I do hit a tight corner under some power

Changing rake is interesting, and like most technical/geometry type things to me, black magic

Post up how the changes feel when used in anger

 

[Dose Pipe Sutututu]

1 hour ago, The Bogan said:

Question: is it slightly lower in the front to move weight forward to reduce understeer??? Or something else???

From my limited reading, a RWD car will always compress the rear suspension when you're accelerating and/or maintaining speed. 

Say if your car had neutral rake when stationary, when it's moving the rake will change so the front is higher than the rear, i.e. negative rake. So by raising the rear ever so slightly, when the car is moving (accelerating to a point) you would have neutral rake. On hard launch, WOT down the straight that's a different story but into a turn you would assume the car is somewhat more neutral thus provide better turn in.

All broscience.

Happy to swap for a M3 F80 

[MBS206]

Raising front to rear is wayyyyyyyyyyy more complicated than weight transfer.

It changes all of your suspension geometry, and one of the main things it will change is how the car rolls in a corner.

Typically, ass up moves the rear roll point higher, and will make the car be more responsive, and too much up, can cause it to become unstable and want to snap about.

Front up typically will make it want to do the opposite and be "more stable".

However, just having the rear X higher than the front, doesn't guarantee this. Changing the height of the vehicle overall, also affects where the roll centres sit, and how the roll centres move as the suspension cycles. (Remember all that bump steer kind of stuff, yep, it all comes into play).

At the same time, it will shift the centre of gravity in the car, typically mildly forward. But it'll be a pretty darn small movement, that driving on the street, I doubt anyone would notice that change in weight transfer as affecting traction.

 

Interestingly too when you look at traction for acceleration, vs turning, a 50/50 weight balance (and the more you get to it) is best for turning. However, for drag racing, while you do want weight on the rear wheels for getting off the mark, having the weight as far forward of the rear wheels in terms of bias, is actually better, and you also want it as low as possible too.

 

Want it to hook better, soften the rear springs up as much as possible, while keeping front roll point low. Go to a larger profile tyre and smaller rim size.

 

Also check out what the suspension is doing on take off, commodores are atrocious that as they squat, they'll dial in quite a few degrees extra camber. It's why all those lowered commodores have epic camber until they fit a "camber kit" which still doesn't properly help dynamic camber issues.

[The Bogan]

7 hours ago, MBS206 said:

Raising front to rear is wayyyyyyyyyyy more complicated than weight transfer.

It changes all of your suspension geometry, and one of the main things it will change is how the car rolls in a corner.

Typically, ass up moves the rear roll point higher, and will make the car be more responsive, and too much up, can cause it to become unstable and want to snap about.

Front up typically will make it want to do the opposite and be "more stable".

However, just having the rear X higher than the front, doesn't guarantee this. Changing the height of the vehicle overall, also affects where the roll centres sit, and how the roll centres move as the suspension cycles. (Remember all that bump steer kind of stuff, yep, it all comes into play).

At the same time, it will shift the centre of gravity in the car, typically mildly forward. But it'll be a pretty darn small movement, that driving on the street, I doubt anyone would notice that change in weight transfer as affecting traction.

 

Interestingly too when you look at traction for acceleration, vs turning, a 50/50 weight balance (and the more you get to it) is best for turning. However, for drag racing, while you do want weight on the rear wheels for getting off the mark, having the weight as far forward of the rear wheels in terms of bias, is actually better, and you also want it as low as possible too.

 

Want it to hook better, soften the rear springs up as much as possible, while keeping front roll point low. Go to a larger profile tyre and smaller rim size.

 

Also check out what the suspension is doing on take off, commodores are atrocious that as they squat, they'll dial in quite a few degrees extra camber. It's why all those lowered commodores have epic camber until they fit a "camber kit" which still doesn't properly help dynamic camber issues.

I'm limited to suspension changes, at the drags all I do is go full soft on the front and full hard on the rear, that let's the front raise, but limits squat in the rear to try and avoid unloading the rear tyre

For the rear I've got adjustable camber bushings, the best I can get it is -0.5° static with zero toe, that is good for tyre wear on the street, more toe would help with any additional camber from when it squats a little, but, that would start chewing out tyres on the hwy

For the drags squat in an IRS is bad, front lifting and staying up is good, I am thinking about getting some 90/10 for the front, well, later down the track anyway, maybe.....

[MBS206]

21 minutes ago, The Bogan said:

I'm limited to suspension changes, at the drags all I do is go full soft on the front and full hard on the rear, that let's the front raise, but limits squat in the rear to try and avoid unloading the rear tyre

For the rear I've got adjustable camber bushings, the best I can get it is -0.5° static with zero toe, that is good for tyre wear on the street, more toe would help with any additional camber from when it squats a little, but, that would start chewing out tyres on the hwy

For the drags squat in an IRS is bad, front lifting and staying up is good, I am thinking about getting some 90/10 for the front, well, later down the track anyway, maybe.....

When you say full hard on the rear and soft on the front, what do you mean exactly?

Spring stiffness? Or shock bound / rebound?