XelderX's BG FSP Build

[gavin_leslie]

I'm having to fabricate a way to attach the pillowball mount from my AWR camber plates onto the stock BG upper strut mount while lowering the spring perch down 1" to compensate for the shorter rear wheel/tire combo.

I havent had breakfast yet so Im just thinking on the fly with this... but am I hearing this right? you plan to use 13"s in the rear, 15"s in the front and keep the chassis ride height level(as if you were using equal diameter tires front/rear). If thats so, it sounds kinda weird from a chassis geometry standpoint.

Originally I had figured that you would have the chassis raked upwards in front. It would look odd, but that keep the front/rear roll centers about equal. If the chassis is set at level when youll have the rear roll centers higher than the front (by what...3/4"..20mm or so after lowering the front?). Your roll axis will have moved to the front and the car will have a tendency to understeer(a bit, a lot..Im not sure). Whats your plan to combat that? More front spring?

Gavin

 

[xelderx]

I'm not using the 1" spacer on the rear to so much level the car as I am using it to make sure the rear strut doesn't get to the end of it's travel. I have the shortened Koni inserts and I'm worried that setting the front on where it needs to be would make the rear ones too short to reach the upper perch without topping out when the rear unloads. I ran into this same problem when I put the 245 tires on the Protege5. I had to raise the car slightly (.5-.75") to keep from rubbing he fender. That caused the front inserts to hit the top of their travel severely when the front unloaded. I reworked the fenders so I could lower the car back down and everything was much better.

 

[xelderx]

Here is what I've spent the last 12 hours on. The black piece used to be a BG stock upper rear strut mount and the silver piece used to be an AWR camber plate. Staring at this trying to figure out what I'm doing will only cause confusion. Just accept that I'm about half finished with it and when it's done the pieces will be reversed with a 1" spacer between them.

The three little threaded spacers need to be welded to the plate. That is why the "camber plate" is bolted on the other side...to hold those in place until I can get to a welder. Once they are welded I can remove the aluminum plate from the backside and then bolt it to the side where the spacers are.

 

[gavin_leslie]

I'm not using the 1" spacer on the rear to so much level the car as I am using it to make sure the rear strut doesn't get to the end of it's travel. I have the shortened Koni inserts and I'm worried that setting the front on where it needs to be would make the rear ones too short to reach the upper perch without topping out when the rear unloads. I ran into this same problem when I put the 245 tires on the Protege5. I had to raise the car slightly (.5-.75") to keep from rubbing he fender. That caused the front inserts to hit the top of their travel severely when the front unloaded. I reworked the fenders so I could lower the car back down and everything was much better.

I have to admit, I had to read this a couple times before I got the gist of it.

So you want the rear struts to extend further downwards(more rear droop effectively).

Is this really a concern on the rear of the car? I could see this as an issue for the front (high roll angle, full droop on the front struts leading to tire off the ground/wheelspin), but the rear are undriven and do not initiate steering(they just kinda hang there). As a practical matter I wouldnt imagine that you would get full extension out of either (short or lengthened)configuration with a large rear swaybar anyway.

.....er, just how short are those struts compared to the stock units? They must be s00per short.

PS: are you going to add some adjustabilty to that rear upper strut assembly?

Gavin(sleepy)

 

[xelderx]

This pic was taken with the front at full droop, but there is 1" cut out of the fender.

The strut probably only has around 4" of usable travel. I'm not to worried about the rears unloading fully while cornering/braking, but we have some rather bumpy courses locally. When the struts top out completely they start to bounce badly. I don't want to have an issue with that mid-corner. I will have some adjustability in the upper mount once I see how much room I have to play with back there with it all bolted up. The main issue is that if I move it too much I won't be able to get my Koni tool on the strut dampening adjuster. Hopefully I can get the car setup where I can leave the rear struts full stiff and just adjust the fronts to suit.

 

[Auto-Xer]

Hopefully I can get the car setup where I can leave the rear struts full stiff and just adjust the fronts to suit.

I have been told that it is not good to run the Konis at "full" anything...at least a fraction of a turn off of the stop is preferable...

 

[xelderx]

I have been told that it is not good to run the Konis at "full" anything...at least a fraction of a turn off of the stop is preferable...

Yea...I spoke with Lee Grimes from Koni about that at Nats last year. That's more or less what I meant. 1 turn off full was where the Protege5 spent most of it's time.

 

[Auto-Xer]

LOL...go with whatever Lee says. That guy has forgotton more about dampers and and springs than most of us will ever know.

The amount of knowledge he has is staggering.

 

[xelderx]

Yea, I need to send my one good rear insert to him and have him check it and then send me a new one for the side that got hit in the accident.

I can finally see a light at the end of this tunnel. Once the rear suspension is done I'll be down to only a few more items before the car is ready to go. I've got the seats and steering wheel ready to go in. I will have swaybars, rear bushings, endlinks and exhaust on the way in the next week or so. All that is left is to sort out the brakes and get the motor running. Once all that is done I can save up for the wheels and tires.

 

[gavin_leslie]

I'm not to worried about the rears unloading fully while cornering/braking, but we have some rather bumpy courses locally. When the struts top out completely they start to bounce badly. I don't want to have an issue with that mid-corner.

I hear you on the bumpy courses(we have one thats cracked chassis and broken many a SP/Prep/mod car....they dont show up much there), but dont sell the car short for a compromise on rough courses.

I will have some adjustability in the upper mount once I see how much room I have to play with back there with it all bolted up. The main issue is that if I move it too much I won't be able to get my Koni tool on the strut dampening adjuster. Hopefully I can get the car setup where I can leave the rear struts full stiff and just adjust the fronts to suit.

Bah..damn the adjuster tool and full speed ahead! Dont wimp out on the engineering because of the tool. I ran into this issue because of some castor adjusters/spacers I made. http://www.teamunemployment.com/gavin/suspension/castor spacers/DSC00263.JPG
Koni adjuster?...not happening. Solution? I made a new adjuster(nothing special either..SS round stock cut @ 2" long, pounded sorta flat on one end with and an "L" hex wrench j-b welded in the other end).

I dont know how your konis are valved/revalved, but I know theres no way I could run on full firm in the rear(st00pid high rebound=rear end skips in the corners...now running at 3/4 turn from full soft with 650lb springs). My point...dont paint yourself in a corner in terms of adjustment. It would suck to have to pull the car down to re-engineer something so simple that could have been done ahead of time.

Gavin

 

[xelderx]

I finally finished one of the rear upper mounts. The other one should be finished tomorrow. I'm going to lighten these a little after I get them bolted up and see if I need to change anything.

 

[xelderx]

Well, I got the rear suspension mounted up yesterday so that i could figure out the rear wheel offset. From the looks of things I won't be able to run a 13" rim in the back. There is a pointless bit of metal on the spindle that would hit the wheel with them tucked in where I need them and they may not clear the brakes...my test rim was barely rubbing the caliper. 14" rims aren't much of an option right now unless spending big bucks for custom Kodiaks or the like. It looks like the car will be getting 15" rims front and back now with the 15X10s (275/35-15) up front and 15X8 (225/45-15) in the back until I decide if expensive lightweight rims will be worth it.

 

[Auto-Xer]

Well, I got the rear suspension mounted up yesterday so that i could figure out the rear wheel offset. From the looks of things I won't be able to run a 13" rim in the back. There is a pointless bit of metal on the spindle that would hit the wheel with them tucked in where I need them and they may not clear the brakes...my test rim was barely rubbing the caliper. 14" rims aren't much of an option right now unless spending big bucks for custom Kodiaks or the like. It looks like the car will be getting 15" rims front and back now with the 15X10s (275/35-15) up front and 15X8 (225/45-15) in the back until I decide if expensive lightweight rims will be worth it.

Are you going with the steelie Diamonds?

 

[gavin_leslie]

Well, I got the rear suspension mounted up yesterday so that i could figure out the rear wheel offset. From the looks of things I won't be able to run a 13" rim in the back. There is a pointless bit of metal on the spindle that would hit the wheel with them tucked in where I need them and they may not clear the brakes...my test rim was barely rubbing the caliper.

Odd, I wonder how Will Kalman cleared the setup on his car. I think I remember him using Bill Schenkers(sp) 13" panasports at the SD tour. Maybe they have extra clearance bulit into them?

It looks like the car will be getting 15" rims front and back now with the 15X10s (275/35-15) up front and 15X8 (225/45-15) in the back until I decide if expensive lightweight rims will be worth it.

expensive? http://www.949racing.com/index.asp?PageAction=VIEWPROD&ProdID=5&HS=1 (The BG is 4x100 bolt pattern right?)

949 is also building a 15x9" as well....just to complicate things

Gavin(runs on 15x10.5" and 15x9" staggered setup.....I like)

 

[xelderx]

Odd, I wonder how Will Kalman cleared the setup on his car. I think I remember him using Bill Schenkers(sp) 13" panasports at the SD tour. Maybe they have extra clearance bulit into them? expensive? http://www.949racing.com/index.asp?PageAction=VIEWPROD&ProdID=5&HS=1 (The BG is 4x100 bolt pattern right?)

949 is also building a 15x9" as well....just to complicate things

Gavin(runs on 15x10.5" and 15x9" staggered setup.....I like)

Kalman's car had the wheels sticking out quite a bit, IIRC. I was grided next to him in 2006 in Topeka, but I can't remember what the rears looked like. There is a possibility the rear spindles are different on his Escort. That is where my main interference would be. I'm pretty sure the front spindles are different between the BG and the Escort, but not sure on the rears. I keep forgeting about 949 making those wheels. I'll be checking in with them. I need to do some calculating on that offset. I have so much stuff running through my head right now that I'm lucky I can remember my own name. I have trouble falling asleep at night, because I'm constantly thinming about what I need to finish up on the car.

 

[aMaff]

I have trouble falling asleep at night, because I'm constantly thinming about what I need to finish up on the car.

Ugh, I hate that. I find writing it down helps

 

[apexlater]

Ugh, I hate that. I find writing it down helps

I find spanking the monkey helps.

 

[aMaff]

I find spanking the monkey helps.

How did you know I had a monkey!?

 

[xelderx]

I think in my case...just getting it done would help. I finally ordered the new Koni insert today to replace the one that was broken in the accident. Now I just need to replace all the rear suspension bushings and most of the major fabrication will be done.

 

[gavin_leslie]

Ugh, I hate that. I find writing it down helps

Good advice. I was in the same boat as well and found that writing things down got my thoughts in order...streamlined the order of what needed to be bought/done/gotten, etc.

Just remember....5/10/15 min a day and it *will* get done. I promise

What bushings will you be using for the rear of the car? Urethane? Delrin? A combination of both? The rear suspension moves in non-linear planes (the hubs sorta make little wavy arcs) so hard delrin doesnt work too well as it kinda restricts movement. A combination of the super hard urethane that AWR uses for their engine mounts and delrin would be great. The regular poly that Noltec or superpro use have issues over time/with hard use.

I took a chance and used a combination of UHMW polyethelyne and delrin.
http://www.teamunemployment.com/gavin/suspension/delrin bushings/IMG_2017.JPG
http://www.teamunemployment.com/gavin/suspension/delrin bushings/IMG_2019.JPG
The UHMW is harder than nylon but still a little softer (relative term) than delrin. For the lateral links delrin is used on the inner subframe mounts and UHMW on the hubs. For the trailing links delrin is on the hubs and UHMW is on the chassis mounts. The hope is that things are hard enough to be located well, but not bind and restrict the natural motion of the rear suspension...or crack the very custom delrin bushings. A nice bonus is that UHMW is self lubricating(called poor mans teflon).

Gavin