300 hp festy

[FestYboy]

ok guys, just to fill you all in: the swap is a built BP+T and EGT hydro trans (or XR2 if he wants it), braced/stripped Festy chassis. the goal is under 1800 Lbs and 250-300WHP. having the engine to make and trans to hold the power isn't the issue so much as keeping the front tires on the ground and NOT making a smoke show.

[Hot_Wheels]

the kia G trans is stonger then all the other bp fwd trans, stonger case and larger gear shafts, your correct the mazda speed lsd does fit in the trans but you will need to convert to 28 spline axles. but for the price the msp lsd which is about 400 i would go with the mfactory and it comes in 26 spline applications

[gtrfestivia]

1.8

i have a 1.8 l engine out of a ford escort.

[Gforcefd]

Yep Clubprotege.com has the group buy going on as HotWheels was saying, but the big issue is the transmission case is weak link after you instal the helicoil LSD. the Kia box is stronger but you would need the 28 spline axles to go with it, which means I am guessing custom built axles to the lengths you need, as the xr2 half shaft is 26 spline count.

You can stick with the EGT case, add the LSD, and throw on some drag radials, but eventually that case is going to break from too many hard launches.

[Damkid]

very stiff suspension, slicks, stiff motor mounts, wheelie bars??

[Jimmy812]

BF 323 GTX's are not AWD like an Evo, STi, etc are, they are 4WD - not full time and not intended to be used in 4wd mode on dry pavement. I suspect this is why people complain of them being weak. It says right in the owners manual not to engage 4wd mode except in low traction situations like gravel or snow. Running in 4wd on dry pavement will sure as heck break one.

I'm not sure about the BG GTX's...

A MazdaSpeed LSD is helical, apparently so is the MFactory one. Helical LSDs are more for handling and cornering than for acceleration. They work great for keeping a car going though a corner from spinning the tire that has less grip, but once a wheel starts to slip, they become an open diff.

As a result, they are not great for putting a lot of power down off the line - not really any better than an open diff, because with both tires having equal load, if you accelerate hard enough to get one to spin, all the power is going to be routed to that tire, just like an plain old open diff. You would have to adjust your launching style to not get that wheelslip in the first place, which you could just do with a open diff anyway.

The only real advantage in acceleration with a Helical LSD is that it might *MIGHT* help reduce torquesteer when there is not wheelspin as both tires will be fed the same amount of torque.

They really are mostly for helping power out of corners at speed.


At the risk of sounding like a broken record, because I've writen this a few times here, the key to getting power down in a Festiva is going to come from fabricating new control arms.

The lower arm in a McPherson strut suspension serves two purposes.

It defines the motion of the wheel vertically - like when you go over a bump

It also located the wheel front to rear inside the wheelwell when you accelerate of brake.

Some McPherson setups use what is called a Tension/Compression rod to serve this second purpose.

When you accelerate, the wheel tries to move forward in the wheelwell. The tension rod takes this motion and transfers it into the body of the car and makes the car go forward. The forces try to compress the rod.

When you hit the brakes, the wheel tires to stop, but the body tries to keep going. The effect is that the wheel tries to move toward the rear of the car. The Tension/Compression rod sees this force as tension and it transfers this force into the body, stopping the car.

Some McPherson strut setups do away with this rod and instead have A-arm at the bottom. By the fact that the arm is shaped like an A or a triangle, it transfers the forward and backward forces into the body without the use of the Tension/Compression rod. This is the design you see on most newer FWD cars.

The Festiva front suspension is different than both of those designs. It uses the sway bar as the tension compression rod. As a result, what would be the tension/compression rod has a bushing at the front and a bushing at the back. It was done this way on the Festiva to reduce manufacturing cost by eliminating a few parts - namely the tension/compression rod. It's cheap to build, but it doesn't really excel at doing anything.

My Girlfriend calls it Diabolically Cheap.

The bushing at the front is called a pillowblock. In most cars, the only load that sway bar bushing sees is to hold the sway bar in place and turn the up and down motion in the suspension into torsion on the sway bar. In the Festiva is does that, but it also is resisting the force of the wheels wanting to move front and back when you accelerate and brake. It is doing double duty.

The bushing at the rear (the one in the control arm) is also doing double duty. It is seeing the force of the wheel moving up and down vs. the sway bar trying to keep it from moving. It is also seeing the force of the wheel trying to move forward and backward as you accelerate and brake.

As a result of being called upon to resist force in so many direction, compromises were made in the overall design. Whenever you make a compromise to make something serve two different functions, by necessity, it does neither function as well as it could if the design concentrated on one function.

An F-15 is a great fighter plane, an A-10 is a great attack plane. Both of them perform their prospective functions better than a plane that is designed to do both - like the F-16. It's a decent fighter, it's a decent attack plane, but it's not as good at either as planes that concentrate on one function. But I digress.

"Get to the point Jimmy."


When you accelerate hard in a Festiva - especially with an engine with far more power than the Chassis was designed to accommodate, the tires scramble to grab traction.

The bushings between the control arm and the sway bar start to compress as does the pillowblock bushing at the front.

The weight of the car starts to transfer to the back of the car - the effect of which is the front tires start to move upwards.

The tires start to lose traction because of the reduced load.

Some of the compression in the bushings is released because the tire no longer has enough grip - due to the reduced weight.

The wheel moves slightly backwards.

The acceleration slows slightly.

The weight comes back onto the front wheels.

They start to grab a little more traction because the load it starting to settle back on them.

The bushings again start to compress.

The cycle repeats.

This happens at a very fast rate. This is the experienced by the driver as the phenomenon known as wheelhop.


Stiffer springs and bushings will help remedy this to some degree because it will take more force to compress the bushings and the tires will move up and down less as the weight transfers back and forth.

On a car with 150ish hp, it might be enough to keep it under control enough to get a decent launch, but it's not a cure - especially as you add more and more power.


The real solution is to get rid of those bushings all together.

The solution on most FWD cars is to add traction bars. Traction bars are like adding Tension/Compression rods to cars that have A-arms. They are a rod that usually goes from the control arm to the bottom of the radiator support. They use spherical bearings instead of bushings.

They do not add stiffness to the suspension in it's normal direction of travel, they just keep the wheels from moving forward and backward in the wheelwell.

These are not practical on a Festiva for two reasons.

Festivas don't have a good way to attach them to the control arms.

Festivas don't have room for them to fit around the sway bar.


The solution on the Festiva is to get rid of the sway bar and to make new control arms that triangular that have spherical bearings instead of bushings.

They could attach at the same points where the stock control arms pivot at the "frame" and at the same point where the pillowblocks bolt under the radiator support.

By doing this you will be sacrificing cornering ability for traction at a drag strip. Again with that jet fighter analogy. You are concentrating on straight line and doing it better than something that is trying to serve two purposes.

[muscle_Car1]

BF 323 GTX's are not AWD like an Evo, STi, etc are, they are 4WD - not full time and not intended to be used in 4wd mode on dry pavement. I suspect this is why people complain of them being weak. It says right in the owners manual not to engage 4wd mode except in low traction situations like gravel or snow. Running in 4wd on dry pavement will sure as heck break one.

Really thats weird & wrong. The engage that you are talking about is to LOCK the center differential on the AWD transfercase.

OH and all AWD trans are a weak link as the take a greater beating than the 2WD variants. WRX's blow their trans after warranty is up, mitsubishi is making better AWD trans than it used to (DSM) but still is & will be the weak spot

I'm not sure about the BG GTX's...

Same setup

A MazdaSpeed LSD is helical, apparently so is the MFactory one. Helical LSDs are more for handling and cornering than for acceleration. They work great for keeping a car going though a corner from spinning the tire that has less grip, but once a wheel starts to slip, they become an open diff.

As a result, they are not great for putting a lot of power down off the line - not really any better than an open diff, because with both tires having equal load, if you accelerate hard enough to get one to spin, all the power is going to be routed to that tire, just like an plain old open diff. You would have to adjust your launching style to not get that wheelslip in the first place, which you could just do with a open diff anyway.

The only real advantage in acceleration with a Helical LSD is that it might *MIGHT* help reduce torquesteer when there is not wheelspin as both tires will be fed the same amount of torque.

They really are mostly for helping power out of corners at speed.

Anything helps since an open diff will not do anything. It still locks the wheels together. Its just a different type vs clutch or welded spidergears

http://www.flashoffroad.com/features/Torsen/Work/torsen_works.htm

At the risk of sounding like a broken record, because I've writen this a few times here, the key to getting power down in a Festiva is going to come from fabricating new control arms.

I FULLY AGREE WITH YOU ON THIS ONE

Oh and mazda trans are weak compared to most other fwd transmissions.

[Mizery]

well i had a little traction issue with mine it made around 190 wheel. but i had 1.8 60 foots. all i did was slick and suspention. strapped down the rear so no rebound. i had no wheel hop. i used the fms springs and gr2 stuts..

[gorgonheimer]

limiting straps on the front would help to keep the weight over the front wheels...

[BUSTIVA]

My coilovers cured my wheelhop and traction issues.

[Nerd Racing]

BF 323 GTX's are not AWD like an Evo, STi, etc are, they are 4WD - not full time and not intended to be used in 4wd mode on dry pavement. I suspect this is why people complain of them being weak. It says right in the owners manual not to engage 4wd mode except in low traction situations like gravel or snow. Running in 4wd on dry pavement will sure as heck break one.

I'm not sure about the BG GTX's...

A MazdaSpeed LSD is helical, apparently so is the MFactory one. Helical LSDs are more for handling and cornering than for acceleration. They work great for keeping a car going though a corner from spinning the tire that has less grip, but once a wheel starts to slip, they become an open diff.

As a result, they are not great for putting a lot of power down off the line - not really any better than an open diff, because with both tires having equal load, if you accelerate hard enough to get one to spin, all the power is going to be routed to that tire, just like an plain old open diff. You would have to adjust your launching style to not get that wheelslip in the first place, which you could just do with a open diff anyway.

The only real advantage in acceleration with a Helical LSD is that it might *MIGHT* help reduce torquesteer when there is not wheelspin as both tires will be fed the same amount of torque.

First, you are correct, they are 4wd. The BF GTX is not meant to have the differential locked on dry pavement, but when it is unlocked it still does transmit power to the rear wheels when needed.

The BG GTX and GTR have a viscous LSD center differential (quite heavy I had to take one apart to ship it) and a viscous LSD rear differential. They are full time 4wd and do not have a center differential locking capability.

On to the Fwd LSD's, the mazdaspeed LSD is not a helical! It is a viscous center differential meant for the Masdaspeed Protege so any case it goes in other than the one for that car, will need some modification to work. (Speedo ring gear machined to fit, housing clearanced, diff pin welded or it will grenade your trans eventually, and ARP ring gear bolts to bolt on your old ring gear).

The Mfactory LSD is a straight up drop in LSD, all you need to do is bolt on your Ring gear. Also with the helical LSD it may transmit power the same as an open diff when wheel spin occurs, but it does not have all of that power going through one spider gear. When you do burn outs with an open diff one of your spider gears is flying and they either break themselves, or send your diff. pin flying, grenading the rest of the transmission.