Rally Car 2010 prep!

[A1337STI]

Well with the 09 season done with, and my car having some issues. It times to fix, repair, and improve It!

My motor seems pretty Done, its been driven very hard with no exhaust on it a few times (shearing headers in rallies, and driving it home like that once, 700 miles) my gas millage used to be about 30, now its 20 or 19. the motor pushed coolant / consumed it at my last rallyX, and one of the cylinders is reading low (90) I can pick up a used one that tests at 150 compression on all 4 at D&D for about $400

Kragen has fly wheels for the 1.8L for 63$ (since i'm fairly certain the one i'm on is heavier than it should be its from a 2.5 RS) I'de love to get a clutch kit from reno clutch and brake but seem to have issues getting them to be more helpful. maybe now that they have been in their new location a bit longer they will have an easier time helping me out.. if not napa maybe , kragen ...
Though i'm allowed to go light weight... seeing how going heavier sucked (except that now i can peel out with a 2500 rpm launch)

If its possible to use a 4.11 from an automatic transmission (93-96?) in a manual transmission i could swap out my 3.9 final drive for a 4.11 ..... I'm just not sure if that's possible or not... Anyone? that would Definitely make my car a LOT faster.


Bushing / suspension. a few of my suspension bushings (most of them) Are rather shot. some of them could be considered failing. you can grab my right rear tire and move it changing the toe, it appears to be the bushings that are allowing the movement..

Stock ? Group N ? pollyurithane ? oh my transmission mount bushing is toast too... I know it needs to be replaced. not sure if there would be any performance to be gained, but certainly it will make the car last longer and be much easier on it...
Beyond manufacturer matainance and repairs i'm allowed everything/anything under : 3.3.3.6 http://www.nasarallysport.com/rules-...s-Section3.pdf Basically just flip to page 14

[sperry]

Call up Turn in Concepts. I believe they have bushing kits for just about everything. And if they don't, they can probably make them for you anyway. Should be able to get some high-duro polyurethane bushings for cheaper than all the Grp-N rubber stuff. It'll be noisy as hell, but they'll be really firm.

[Libila]

It's too bad they don't allow updating/backdating because a 2.2 swap would help you a lot, especially with your upgraded diff. I swapped out my 220K+ mile EJ18 for a much younger EJ22 and it's great.

With how strict the rules are in your class (if it were me) I'd go for a lightened flywheel. I know the cost is steep but I know first hand how much of a dog that 1.8 is and any extra performance you can squeeze out of it should be done.

I don't know enough about the FWD compatibility between Subarus to comment on your gearing question, sorry.

For bushings your choices are pretty limited. Whiteline, Group N, or Super Pro. If you're going to replace a few you might as well replace them all.

Tranny mounts are even more limited. Group N or Cusco, and I wouldn't use Cusco mounts on a rally car.

[Dean]

Any stiff bushing is going to transfer more energy to the rest of the components. I would guess Group N may be as stiff as you want to go anywhere. Deflecting rubber is usually better than bending metal.

[A1337STI]

Ya a 2.2 swap would bump me up to Group 5 for CRS events, and open 2wd for USRC. I get scored in there reguardless but wouldn't get scored in product 2wd any more.

RA a 2.5L is game for group 2, and CRS might change that rule next year. which would be .. omfg in that car maybe grab a cf hood+trunk and lexan/plexiglass windows

Seeing how i can not find a minimum specified weight in my 1993 impreza service manual (the big 2 books) Looks like light weight fly wheel is on the menu , nasa says same material so it has to be steel.
so i'll probably go with a 12.55 lb light way steel flywheel i'm seeing on ebay for about 168, and a new clutch kit is 98. (guess i can give Kevin his kit back if he wants it )

so Dean your thinking the whiteline suspension bushings will be too stiff and i'll start bending metal?
damn i just priced out all the whiteline stuff with turn in ... hmm... maybe i'll double check with them and see what they think... I am on softer suspension now and usually use like 30 psi .. hmm... maybe i'll rethink or ask on special stage.

[sperry]

Originally Posted by A1337STI

Ya a 2.2 swap would bump me up to Group 5 for CRS events, and open 2wd for USRC. I get scored in there reguardless but wouldn't get scored in product 2wd any more.

RA a 2.5L is game for group 2, and CRS might change that rule next year. which would be .. omfg in that car maybe grab a cf hood+trunk and lexan/plexiglass windows

Seeing how i can not find a minimum specified weight in my 1993 impreza service manual (the big 2 books) Looks like light weight fly wheel is on the menu , nasa says same material so it has to be steel.
so i'll probably go with a 12.55 lb light way steel flywheel i'm seeing on ebay for about 168, and a new clutch kit is 98. (guess i can give Kevin his kit back if he wants it )

so Dean your thinking the whiteline suspension bushings will be too stiff and i'll start bending metal?
damn i just priced out all the whiteline stuff with turn in ... hmm... maybe i'll double check with them and see what they think... I am on softer suspension now and usually use like 30 psi .. hmm... maybe i'll rethink or ask on special stage.

You shouldn't be bending anything in the suspension due to stiffer bushings unless you're regularly bottoming out your struts. Stiffer bushings should just isolate movement to the springs/dampers better. As long as they can take the punishment w/o running out of travel, you won't be risking control arms. But if you're coming down on the bumpstops, then I could see how a bunch of rubber in the suspension linkage might be preventing damage.

The only exception to this is your swaybar endlinks... making them stronger than the swaybar mounts can tear the mounts loose, instead of just breaking the endlink... I'd stick w/ the softer OEM stuff for those.

And if you're crashing into stuff in a direction the suspension isn't designed to handle... like smacking the wheel face when sliding into a boulder, or maybe wedging the wheel into a massive pothole and torquing on the strut, I could see rubber lessening the energy into the control arms, etc. But in those sorts of situations, I don't think rubber bushings are going to protect the suspension significantly better than polyurethane would... you're probably going to bend something either way.

I'd rather have the better handling that keeps me from crashing in the first place. But I'm not a rally guy, so what do I know.

[Dean]

It was the bashing into stuff I was thinking about. Travel not in the direction or beyond the limits of the basic suspension design. The same reason rally cars don't use 22"s. The sidewalls save the rims in the extreme bashes. The bump stops and top hats protect the struts.

Maybe Group N bushings would all be Delrin if permitted??? I'm not a Rally person either, so what do I know, just thinking that very hard bushings may cause other things to start bending/braking.

You have obviously worn some out, just suggesting you think about what might have worn out or broken instead if those had been solid? While your car is not AWD, I would ping the WRX/STI teams and suppliers and ask the questions.

[sperry]

Originally Posted by Dean

It was the bashing into stuff I was thinking about. Travel not in the direction or beyond the limits of the basic suspension design. The same reason rally cars don't use 22"s. The sidewalls save the rims in the extreme bashes. The bump stops and top hats protect the struts.

Maybe Group N bushings would all be Delrin if permitted??? I'm not a Rally person either, so what do I know, just thinking that very hard bushings may cause other things to start bending/braking.

You have obviously worn some out, just suggesting you think about what might have worn out or broken instead if those had been solid? While your car is not AWD, I would ping the WRX/STI teams and suppliers and ask the questions.

Well, I beleive all the Group N stuff is rubber because it's required to be the same material as the "factory" part per the rules... even though technically all the Group N bits are factory parts, since they're sold out of the FHI catalog. And they're all stiffer than the normal OEM parts.

So, I've got to think, if Group N rules allowed it, all the FHI Group N stuff would be poly or delrin or metal. If softer were better, why would they bother making the harder rubber stuff?

[Dean]

Originally Posted by sperry

Well, I beleive all the Group N stuff is rubber because it's required to be the same material as the "factory" part per the rules... even though technically all the Group N bits are factory parts, since they're sold out of the FHI catalog. And they're all stiffer than the normal OEM parts.

So, I've got to think, if Group N rules allowed it, all the FHI Group N stuff would be poly or delrin or metal. If softer were better, why would they bother making the harder rubber stuff?

Despite what "she" might say, I don't think harder is always better.

Where is Austin when we need him?

I would assume there is some sort of trade off between stiffness and breakage. A little compliance in different directions has got to do something for you or everything would be solid non-compliant stuff for motorsport applications.

Soft mounting is not just about NVH as far as I know, it is also about about a designed wear/failure item/point.

Even on tarmac, there are impacts in non-standard compression/rebound directions as you hit the sides of rumble berms, drop a tire, etc... Those forces have to go somewhere? Metal fatigue is the alternative to rubber fatigue I would think. A worn bushing is easier to replace then welding a cracked/broken sub frame.

Also, If you solid mount an engine or tranny, do you end up having to add weight to reinforce those mounting points and/or use larger hardware to take the added shock load not dissipated in the rubber?

Shock loads break stuff, or so I get the impression. They sure loosen lug nuts with much less apparent effort than static pressure appears to.

[A1337STI]

Originally Posted by sperry

Well, I beleive all the Group N stuff is rubber because it's required to be the same material as the "factory" part per the rules... even though technically all the Group N bits are factory parts, since they're sold out of the FHI catalog. And they're all stiffer than the normal OEM parts.

So, I've got to think, if Group N rules allowed it, all the FHI Group N stuff would be poly or delrin or metal. If softer were better, why would they bother making the harder rubber stuff?

Ya pretty much!

its sort of a "showroom stock" for a while it required stock interior and rear seats. all the parts have to be made by that company, there are ralliart, subaru, puegot and probably other "group N parts" but i'm not exactly sure in what way the companies are limited in the parts they put out ...

Either way due to finding no other options it go it will be:
Group N Engine Mount,
Group N Transmission Mount 5Mt,
Group N Front Strut Top Mounts

I could go Group N OR Whiteline for : Rear A-Arm bushings (Caster offset +.5) , rear Lateral Link bushings, Trailing arm bushings

$782 (All Group N ) Versus $770 Mostly White line

Going All group N for the same price also gets me :
Front A-Arms bushings, Rear Cross Member bushings, stopper pitch

Probably $266 for a 12.55 Lbs flywheel and oem clutch kit

$400 D&D Motor testing 150 comp on all 4 ..

Also going to upgrade my fire extinguishers from 5BC to 10BC, install some sorta trunk wall in case of epic crash to keep tools from coming into the cabin. bleed the brakes, and 2 new tires.
think that's where i'm gonna say Uncle.

Though if anyone has some good ideas i'm game. though i'm pretty limited in stock classes. hehehe

[A1337STI]

Saving money and maybe not bending/breaking metal on impacts, tweaks (sliding into a rut that catches your momentum and changes your direction) ... Or a lil more control and maybe not needing the extra compliance... ... ARG

i'm tempting to keep it cheaper while getting the extra bushings.. Group N over 17 year old stock bushings i bet will be a huge leap up in control already ... hmm...

[sperry]

The full grpN set will probably be night and day better. Plus you know that it's all legal if anything should be disputed. Plus it'll be a hell of a lot quieter than a bunch of poly on the transit stages.

[Libila]

If your getting hung up on the Whiteline vs Group-N then wait a few weeks until I get back. I've got the full line of Whiteline bushings waiting to be installed. You can drive my car pre and post install to get an idea of the difference they make.

[A1337STI]

Cool!

oh i found out the rally notes team is using energy suspension bushings, they are Polyurathane. he won the prod 2wd usrc 3 years in a row, and Pstock /SW RA once.

But i'm sure either one would be good. ya i'de like to feel the pre/post bushing upgrade. I'm digging the "more control so you don't need the extra compliance" methodology boot i'll see.

can we take your car out on some dirt... ? hehehe j/k

[Kevin M]

I think this comes down to how bad you want to win. The faster you want to go, the stiffer your bushings need to be. But, the stiffer they are the more they will wear out other parts and you're that much more likely to break things. Whether it's going to be a control arm every day or one per 2 seasons is totally unknown.

[A1337STI]

So I've found the following options:
Group N Motor Mounts : 120
Group N Stopper Pitch :50 or $120 for an aluminum one
Group N Transmission Mount : 75

So that's $ 245 for the cheap route, I'm thinking a mental stopper pitch would be bad but and i'de rather not spend the extra for something that won't help

Kart boy Front shifter bushing 35 they claim it makes shifting more crisp seems like a good idea.
Group N Front Strut Top Mount : 128 I bent my first set of kport top mounts, and now i'm on camber plates which worry me so i'de rather not worry while going over jumps.

Here's where i have some options
I found an energy suspension bushing set for imprezas for $119 from summit.

Item -------------- GroupN ---- Energy --- WhiteLine
A Arm bushings (4) --- 148 ------- X -------- 186
front Sway bar (2) ------ --------- X
Rear Sub Frame (4) -- 68.96 -
Rear Trailing Arm (4) - 86.2 ------- X -------- 118
Rear Track arm (8 ) -- 106.3 ---------------- 148
Rear sway bar (2) ----------------- X
Front shifter mount ---------------- X

Going Energy suspension and Whiteline for the rear track arms is $267 which is only $40 more than dropping in Group N for the rear track arms. I could go Group N for everything but at an added cost.
I could also skip the rear sub frame bushings, but since that's where the rear track arms attach to it would seem a bit dumb to leave those as the 17 year old stockers...

Sounds like the Polyurathane will offer the best handling while sacrificing some ride quality and it will reduce the protection offer by having more compliance. esp with scotts wording i like this option more, and its my cheapest option. My transmission mount is really beat so its due for replacement my track arm bushings are shot. I'm not sure if I should change the front sway bar bushings, is that going to (to a small degree) act like a stiffer swaybar since it won't be able to deflect while twisting as much?

Also Rally Idaho was crazy crazy smooth roads, should i think about using a 19 mm front sway and perhaps a rear sway @ that event ? (and maybe going back to a stiffer spring set that i have, and used very successfully last season) Hmmf.

12 pound fly wheel : 168 Could skip this but it will probably help out in rally cross a lot where like autox its almost all 2nd gear driving
D&D motor $400

Ansel has a 1.8L head gasket set i could use on it, and i got a timing belt set for it (water pump + oil seals) so if i want to stay Production 2wd USRC legal that's everything i can do to her. To the best of my knowledge there was never a FWD Impreza with anything but a 3.90

So i think that's about that.

[Libila]

Originally Posted by A1337STI

But i'm sure either one would be good. ya i'de like to feel the pre/post bushing upgrade. I'm digging the "more control so you don't need the extra compliance" methodology boot i'll see.

can we take your car out on some dirt... ? hehehe j/k

Of course!

[AtomicLabMonkey]

Originally Posted by Dean

Despite what "she" might say, I don't think harder is always better.

Where is Austin when we need him?

I would assume there is some sort of trade off between stiffness and breakage. A little compliance in different directions has got to do something for you or everything would be solid non-compliant stuff for motorsport applications.

Soft mounting is not just about NVH as far as I know, it is also about about a designed wear/failure item/point.

Even on tarmac, there are impacts in non-standard compression/rebound directions as you hit the sides of rumble berms, drop a tire, etc... Those forces have to go somewhere? Metal fatigue is the alternative to rubber fatigue I would think. A worn bushing is easier to replace then welding a cracked/broken sub frame.

Also, If you solid mount an engine or tranny, do you end up having to add weight to reinforce those mounting points and/or use larger hardware to take the added shock load not dissipated in the rubber?

Shock loads break stuff, or so I get the impression. They sure loosen lug nuts with much less apparent effort than static pressure appears to.

I'm not an off-road guy, so I don't know what the proven norm is for bushings in rally car applications. I do know that the offroad trophy trucks I've looked underneath have had solid mounts and metal bearings everywhere. They have custom frames and are built like tanks, though.

As a general rule, stiffening bushings/mounts and limiting deflection is a good thing for performance (obviously). However, it does increase the impact force seen by the mating components, which could shorten their lifespan. Whether or not this is anything to be concerned about completely depends on the specific parts & chassis involved.