Rally Drift Fast Steering Ratio Mod

[SAButter]

this is a steering mod i did for my subie

[carfreak85]

Just finished video #1, interesting idea... I've been looking for a way so hasten my wagon's molasses-slow 4.0:1 ratio.

[baccaruda]

The XT has a quicker ratio than the rest of the late 80s cars; that's what I've got in my wagon. SAButter's idea is intriguing but I don't know if it would be a good idea for a rig that sees mostly street use...

[GeneralDisorder]

That's a great idea.

 

The proper way to weld cast iron like that without it cracking is to pre-heat it in an oven or with an oxy torch prior to welding. The way you prepped it is excelent and it looks like you did a fine job. As a precaution I would anneal the whole area that you welded to prevent stress fractures from forming in the future. Just heat the whole thing to cherry red and as long as it's not cracked - after it cools (just let it air cool) it should have no remaining stress in it for cracks to form.

 

Still - having it magnafluxed afterward is not a bad idea for a street rig.

 

Otherwise - an excelent job and a great idea.

 

GD

[obk25xt]

cast iron

 

 

GD

 

Correct me if Im wrong, but wouldn't that be cast steel, not cast iron? Also, I agree, sweet idea. I will try this, hopefully sooner than later. I should be picking up a welder soon and some other metal working tools... Time for me to have a fabshop!!

[Txakura]

GD praised an idea? (just kidding GD)

 

wow, the videos posted were very good

 

just out of curiosity, you mentioned 1 1/8" as your modification and also that moving it less would result in less interference at full lock and limit the possibility of going too far overcenter with the ball joint

 

how did you settle on 1 1/8" for your purposes? as opposed to say half that, 9/16", or any other number?

 

I have a knuckle on my coffee table (doesn't everyone), this is an amazing idea - what about welding in the old hole and moving it one diameter back without cutting and splicing the knuckle? even a modest 20% improvement would seem worth the effort

Edited March 16, 2010 by Txakura
grammar, and afterthought

[Txakura]

was thinking more on this, my modest ea82 already has a tendency to reach it's oversteer limits rather quickly by traction, that is; pavement is harder to reach the limit on, but the threshold lowers to a different point in mud, gravel, clay, snow, ice etc etc

 

as it is, the car communicates it's intentions rather politely with a vague voodoo feeling in the wheel, that neutraility lets me know I'm coming close to scrubbing the front wheels and making a new and unintended line

 

having more responsives could be useful, very useful, but I can also see where this change in geometry could alter the way the car communicates, or even that it lowers the understeer threshold, or reducs the warning time altogether

 

still, depending on any answer to the above post, it might be possible to calculate a modest improvement in response time, e.g. ratio, and improve the handling the other 99% of the time the car is not pushing any limit

 

I hope there's a follow up to this, not a one hit wonder of a post

[Zefy]

steering quickeners are used a fair amount and definitely a good option if a true quick rack is not an option.

 

i wouldn't be to worried about the arm breaking... the work looks decent, but your reasoning behind it is a little odd. If you shorten the arms like you have, you are making your turn radius smaller.

 

On a rally car, if you go full lock, then chances are you're probably already committed to the ditch. But for any other applications it wouldn't make sense to do this...

 

i've been in cars with true quickracks (9:1ish ratios, vs stock ~14:1) and it is harder to turn but once you're moving there is no real difference as far as effort taken to move the wheel.

[Txakura]

How are you making the turn radius smaller? It doesn't change, you're shortening the distance the rack travels to get the same deflection of the wheel.

 

A 45 degree deflection is still 45 degrees, but you're using a shorter lever to get there. You can swing the tip of that lever 6 feet, or you can swing it 6 inches but it's still 45 degrees. One will take more strength to move than the other, and it takes more time to travel 6 feet than 6 inches, but the angle is still 45.

[Zefy]

How are you making the turn radius smaller? It doesn't change, you're shortening the distance the rack travels to get the same deflection of the wheel.

 

A 45 degree deflection is still 45 degrees, but you're using a shorter lever to get there. You can swing the tip of that lever 6 feet, or you can swing it 6 inches but it's still 45 degrees. One will take more strength to move than the other, and it takes more time to travel 6 feet than 6 inches, but the angle is still 45.

 

now that i think about it, we're both wrong.:-p

 

the rack, no matter what the ratio is, only has a certain amount of movement from left to right. if the tie rod has a throw of 10 inches, and the mounting arm on the knuckle is 6 inches then lets say the deflection is 25 degrees. (just making these #'s up...)

 

if you shortened the knuckle arm to 3 inches and keep the same throw then you would be getting 50 degrees of deflection.

 

the amount of movement capable in the rack is always the constant in this situation.

[Txakura]

I think you're onto something. The rack travel is the same, but the work accomplished is different. because the same lever travels further, the angle changes... ouch, nosebleed

 

still wonder how he settled on 1 1/8", or if it was arbitrary... if he had a solid reason for doing that particular distance, you could infer the travel on other distances

 

for instance, if you filled the original hole and moved it aft without cutting and welding you might achieve some benefit without having to cut, weld, anneal, inspect and repeat...