fwd welded diff on dirt

[warriorautotech]

Hello all, I am new to this forum but I have been racing since july '10. I race a 91 honda civic hatch, 1.6,5spd. I am considering welding the front diff because I am getting a lot of wheelspin out of the corners. I have heard that can make the car push and I dont want to screw up the handling.
I would like to hear pros and cons from people that have run welded diffs. Thanks

[DeFord11]

it is a plus!! it will make use the paddle a little more but learn to feather the throttle thought the turns and u'll c a difference

[BleedingOrange]

If you weld it, you'll want to run stagger like a welded rear-wheel drive car (smaller left side tire and larger right side tire) so that it will turn with minimal push.

This should be opposite of a non welded diff on the front wheel drives where you would run a larger left front tire (and even heavier spring) to help keep the left tire on the ground, preventing wheel spin.

I did this to my car which was illegal at our track and I only had one person who could keep up/out run me...which, 6 weeks later the tech officials discovered they had theirs welded up too! So, it must have helped.

Like DeFord11 said, you'll definitely be faster but you'll have to learn how to use the throttle through the turn. You don't want to stomp on it...just ease into it as you come out of the turns and drive from high to low to pass under all the other guys that push to the top of the turn on exit.

And just remember, FWD's can be fun. They're like fat chicks and mopeds, they're fun to ride but you don't want to brag to everyone about it!

[be11]

you wont want it on a dry slick track...and stagger will deff needed to be added to make it work to your advantage..
Blayne Ellis #11

[warriorautotech]

Thanks for the input, The rules at the track wont allow running different size tires from left to right, and since the top 4 in the feature go to tech inspection, I wouldnt be able to get away with it. tire size is about the only thing they check in fwd class.Also fwd class races last so the track is always dryslicked by the time we get to race.maybe i will look into a lsd.

[stock car driver]

Different brand tires of the same size have a different roll out measurement.

You will need a good bit of stagger as mentioned above and you can get it with tires that meet the ALL the same size rule.

[warriorautotech]

I am tired of getting passed coming out of the corners so I got the diff welded today, Ill see how it does this weekend. would lowering the tire pressure on the left side help?

[BleedingOrange]

I am tired of getting passed coming out of the corners so I got the diff welded today, Ill see how it does this weekend. would lowering the tire pressure on the left side help?

It would be better than not having different pressures. It will give you some stagger but not as much as you would need for it to work the best it can (I'm making this statement under a few assumptions about your track, etc). What tire pressures do you run? What pressures are you thinking about running? What size is your track and what kind of banking does it have? Tight turns or wide sweeping turns?

What kind of car is it (neon, probe, etc)?

[be11]

if i were you id run tubes and run as low tire pressure as i could.. prolly around 20-25 lf rf depends on the banking and the tightness of the corners... and id get a roll out gauge and buy some tires of different brands but same size and run ur smallest one in the lf and the bigger one on the rf..
Blayne Ellis#11

[warriorautotech]

Right now I am running Achilles 195/70/14 h-rated with 36 psi rf and 25 psi lf, all stock suspension,no sway bar, the changes I am planning are, Camber in the rf tire about 2-3 degrees, shim rf spring with 1" rubber spacer between coils, 1/4" toe out,40 psi rf tire, 20 psi lf tire.25 psi rears. The car is a 91 civic hatchback, 1900 lbs, mostly on the front, no added weight, I have been working on pitching the car high and sideways into the corner and driving out on the inside. The track is 1/4 mile around the outside, d-shaped, dirt, Turns 1&2 are fairly high banked and tight, 3&4 are not as high with the track flattening out toward the end of turn 4.

[warriorautotech]

Any suggestions on cheap 14"or 15" performance tires with more or less runout?

[BleedingOrange]

Right now I am running Achilles 195/70/14 h-rated with 36 psi rf and 25 psi lf, all stock suspension,no sway bar, the changes I am planning are, Camber in the rf tire about 2-3 degrees, shim rf spring with 1" rubber spacer between coils, 1/4" toe out,40 psi rf tire, 20 psi lf tire.25 psi rears. The car is a 91 civic hatchback, 1900 lbs, mostly on the front, no added weight, I have been working on pitching the car high and sideways into the corner and driving out on the inside. The track is 1/4 mile around the outside, d-shaped, dirt, Turns 1&2 are fairly high banked and tight, 3&4 are not as high with the track flattening out toward the end of turn 4.

Whatever you do, don't put a spacer in the RF spring if you don't want it to push. That increases the spring rate and will therefore cause it to push more. You want it to roll over on that side giving you bite. The stiffer the RF, the tighter the car will be (causing the push). If you want to promote more rollover on the right front you could put the spacer in the LF spring or the LR sprint.

I think your biggest thing will be driving style. I notice that the faster guys at the track will go really hard and fast into the turn but off the throttle. Let the car start turning before you get back into the gas. And ease into the throttle, don't stomp it. The drawback of a FWD car is the front tires are used to both steer and accelerate. Tires can only handle so much of it at once. The cars I see push the most are the ones that as soon as they start turning they try to stomp the gas and the car then just slides up.

I'm not sure about the tire brands though.

[itunes gift card]

Thanks for the good post.

[Egoracing]

Something to keep in mind, a RWD car drives off of the LR and RF and a FWD car drives off of the LF and RR.

[warriorautotech]

I am not sure what you are talking about in that last post, about lf and rr, could you explain that ?

[BleedingOrange]

I am not sure what you are talking about in that last post, about lf and rr, could you explain that ?

Usually (most commonly), rear wheel drive race cars will have a heavier RF than LF and a heavier LR than RR. So, your cross is created between the RF and LR. On a FWD car, your cross will be between your LF and RR. So, heavier spring rates in those corners (LF and RR) are preferred on a FWD race car.

I've heard many people say, the outside drive tire is more for steer/control and the inside drive tire is for bite/acceleration. So, in your case, let it roll on the RF for steer while you stiffen the LF to keep it planted for proper acceleration out of the turn. The stiffer the RR spring is, the more cross you will have on the LF as well.

Hope this makes sense.

[be11]

alright man look idk how ur rear bars are but in some way i know u can put rear steer which means (not a nice word)(not a nice word)(not a nice word)(not a nice word) the right rear tire out in the front which will make it look like a nascar going straight and when u turn it it will allow the rear of the car to try and pass its self up but wont do so because the front wheels r pulling that will give u ur sidways and bottom corner u want... then on ur tow dont tow it out 1/4 tow it in 1/4 on the rf,,and bump ur rear tire press to about 55psi and see how that maks the car turn just try it..it whats i do here in indiana and kentucky.. Blayne Ellis#11

[warriorautotech]

Thanks for the tips.

[te33]

Man I must be out to lunch ! I run a spring rubber in the rf,2 when it rubbers in and gets fast,Don't have over 18lbs of air in ANY tire,run a TON of stager across the front.No tubes,you know how much those thing weigh ? Get rid of the steel wheels,to much unsprung weight,go get NEW OEM springs,some new decent struts,check all your front end parts for wear and replace anything you might THINK is bad.Lose that 1/4 inch of toe out,set it straight up,a fwd toes out a bit under load .Get light on everything you can ! Don't toss it in the corners ,arc it in ,keep it straight.imagine an egg under gas pedal,gentle.You will gain so much speed in the middle of the corners that your corner exit speed will be so much quicker they will think you bolted on 25 h.p.JMHO,It works for us.