Spooled 4.56 rear build

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majorownage

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Well, I convinced my buddy to give me his IRS out of his parts car, so I'll be stripping it apart and building up a mark viii rear.

The highlights are a 4.56 spool, delrin bushings, new shocks, and springs.

I think this will let me rationalize further mods. (short runner intake, stall, etc)

Anybody able to hit 12s with a mark yet? lol:shifty:
 
Strip car only? The axles are not going to "like" the full spool. There are alot of marks in the 12,11 and couple in the 10's. But stock N/A record is 13.11 by Driller.
 
majorownage said:
stock n/a?
Click to expand...
Fo fi six is not stock. Nor is stall. Short runner is far far far from stock.
Stock is stock, changes are mods.

Anywho, 4.56 wont put you into the 12's.

Forged stroker, steep gears, stall, exhaust and tune is good for NEAR 12's but not quite in them. 4.56 will just put the car into overdrive sooner and kill the trans. WOT shifts to 4th are bad mkay.
 
majorownage said:
why not?
Click to expand...
When you take any corner the outside wheel has to travel father hence faster. Now since the axles are now locked together with a spool there is no"give" bending one axle. It can be dangerous also as one tire will HOP going around corners.
 
LaserSVT said:
Fo fi six is not stock. Nor is stall. Short runner is far far far from stock.
Stock is stock, changes are mods.

Anywho, 4.56 wont put you into the 12's.

Forged stroker, steep gears, stall, exhaust and tune is good for NEAR 12's but not quite in them. 4.56 will just put the car into overdrive sooner and kill the trans. WOT shifts to 4th are bad mkay.
Click to expand...

ok n/a 4.6 STOCK engine.

And there is no way I'll be breaking into the engine.

The reason for gears is to bring the 60' time down.
At the 1/4 mile I'll never go into overdrive with 4.56.
 
Right on the Mark said:
When you take any corner the outside wheel has to travel father hence faster. Now since the axles are now locked together with a spool there is no"give" bending one axle. It can be dangerous also as one tire will HOP going around corners.
Click to expand...

Ok, I knew that...I thought you were implying there was some sort of wierd problem because the axles have cv-joints or something.
 
majorownage said:
ok n/a 4.6 STOCK engine.

And there is no way I'll be breaking into the engine.

The reason for gears is to bring the 60' time down.
At the 1/4 mile I'll never go into overdrive with 4.56.
Click to expand...

Do you have a high stall converter? If you don't 4.56's still won;t help ya. FYI I 60fted 1.810 with 4.10's all calculators says thats pretty max 60ft with weight and hp of car.
 
Right on the Mark said:
Do you have a high stall converter? If you don't 4.56's still won;t help ya. FYI I 60fted 1.810 with 4.10's all calculators says thats pretty max 60ft with weight and hp of car.
Click to expand...

I'm reasoning that 4.56s will help with a short runner because the loss of torque when launching.

I have a stock converter right now, but I plan to stick one in while I have the car apart. (4k-4.5k ish)
 
majorownage said:
At the 1/4 mile I'll never go into overdrive with 4.56.
Click to expand...

Wanna bet? Actually you may not with the partial tune you have and the full spool. I hope you know how and where to make adjustments in your software to make the trans properly shift. With 4.56 and no trans tune AND your knock sensors being turned off you will prolly pop the motor when it bounces off the rev limiter trying to change to third.

The last Mark I built had 3.73s and a blower. In the quarter I came within a hair of shifting to 4th so no doubt 4.56 would be well into fourth.

Now it can be done, I am not discouraging you BUT the trans needs to be programmed properly and the engine management needs control over the motor. You need your knock sensors back on. If they are getting false readings then stop modding the car and save for a rebuild.
If its not actual knock that makes them think there is knock you have bad rod bearings or bad tensioners or a broken crank keyway. Need to inspect that motor. My first blown motor poped on Gearheads dyno due to a bad keyway and me limiting the knock sensors controll too much.

In the software you should (I assume, I use SCT and it can) be able to set the knock sensors range and ammount of timing they can add or remove. After you get that down then you can play with your tip in timing and that will really make it snappy.


Anywho back to the issue at hand. Stock axles are not that strong and a spool with 4.56 on the street WILL break one of them. Prolly the passenger side. You have 4.30s already, just get a TL for the diff and call it a day. Work on power addition cause the trans will not like using 4th as a pulling gear and it will fail. Trans cooler, J-mod and proper tune will help it last longer but it will still be at risk.
 
majorownage said:
I'm reasoning that 4.56s will help with a short runner because the loss of torque when launching.

I have a stock converter right now, but I plan to stick one in while I have the car apart. (4k-4.5k ish)
Click to expand...
4500 stall, spool, short runner and fo fi six ...... ueah, thats gonna SUCK on the street. You would be WAY better off selling the car and getting a 96-98 Mustang and dropping a used Mark motor in it. Will be cheaper and hit 12's no problem with 4.10s, tune, exhaust and a man pedal.
 
LaserSVT said:
Wanna bet? Actually you may not with the partial tune you have and the full spool. I hope you know how and where to make adjustments in your software to make the trans properly shift. With 4.56 and no trans tune AND your knock sensors being turned off you will prolly pop the motor when it bounces off the rev limiter trying to change to third.

The last Mark I built had 3.73s and a blower. In the quarter I came within a hair of shifting to 4th so no doubt 4.56 would be well into fourth.

Now it can be done, I am not discouraging you BUT the trans needs to be programmed properly and the engine management needs control over the motor. You need your knock sensors back on. If they are getting false readings then stop modding the car and save for a rebuild.
If its not actual knock that makes them think there is knock you have bad rod bearings or bad tensioners or a broken crank keyway. Need to inspect that motor. My first blown motor poped on Gearheads dyno due to a bad keyway and me limiting the knock sensors controll too much.

In the software you should (I assume, I use SCT and it can) be able to set the knock sensors range and ammount of timing they can add or remove. After you get that down then you can play with your tip in timing and that will really make it snappy.


Anywho back to the issue at hand. Stock axles are not that strong and a spool with 4.56 on the street WILL break one of them. Prolly the passenger side. You have 4.30s already, just get a TL for the diff and call it a day. Work on power addition cause the trans will not like using 4th as a pulling gear and it will fail. Trans cooler, J-mod and proper tune will help it last longer but it will still be at risk.
Click to expand...

I don't use SCT. I've already raised my rev limiter and changed several tranny settings. (Lowering the amount of torque to the trans to firm up the shifts) I've talked to several experienced tuners and b-head guys. They all say to turn them off.

I do plan a J-mod in the near future.

TL?

Why do you insist that if I hit the rev limiter with the knock sensors off I'll blow my motor?
 
Right on the Mark said:
"fo fi six" what is this????????
Click to expand...
4.56 :lol:


Sorry, on DFWMustangs there is a kid with a 96 Cobra that always said he had "fo fi sixes yo" :lol: He also had a spool. After snapping an axle he fixed it then tore out his tourque boxes. After fixing that he went back down to 4.10s and a trac lok. I forget what his times were but I do remember him being a tenth faster when he droped the gear ratio back to 4.10s
 
LaserSVT said:
4.56 :lol:


Sorry, on DFWMustangs there is a kid with a 96 Cobra that always said he had "fo fi sixes yo" :lol: He also had a spool. After snapping an axle he fixed it then tore out his tourque boxes. After fixing that he went back down to 4.10s and a trac lok. I forget what his times were but I do remember him being a tenth faster when he droped the gear ratio back to 4.10s
Click to expand...

His cobra had problems already.

4.56s are THE best gear for a b-headed n/a cobra
 
majorownage said:
I don't use SCT. I've already raised my rev limiter and changed several tranny settings. (Lowering the amount of torque to the trans to firm up the shifts) I've talked to several experienced tuners and b-head guys. They all say to turn them off.

I do plan a J-mod in the near future.

TL?

Why do you insist that if I hit the rev limiter with the knock sensors off I'll blow my motor?
Click to expand...
I dont insist, I merly point out that it is a real possibility. Now granted I have only built a dozen Cobras and a few Marks but I have never and would never turn the knock sensors off. They serve a very important purpose. I have no clue who you are talking to but if you ask Travis (owner of Gearheads) anout it he will tell you not to turn them off. Take a look at his yard. There are no less then 30 DOHC 4.6 cars in his shop. I have many friends in Dallas and Houston running 600+ RWHP Cobras and not a single one would EVER say to turn the knock sensors off.

TL stands for Trac Lok. Its Fords LSD. Its a very good design and has excellent properties if you rebuild it with 4 clutches instead of the standard 3. Had one in a couple Stangs and in my blown Mark. That car could lay dual stripes untill you let off the gas and the tail never tried to wag when taking tight turns. Its also very quiet unlike mechanical LSDs.

I know you dont use SCT, you use Quarter Horse. I have zero experience with QH and thus is why I stated it could be done in SCT but wasnt sure about QH.

Now I hope you didnt raise the limiter too high. Anything past 6500 and you will start to bind the valve springs. Factory tune pulls apx 30% TQ on WOT shifts so you really dont need to take that down more but a trans cooler is a MUST HAVE for a modded Mark.
 
majorownage said:
His cobra had problems already.

4.56s are THE best gear for a b-headed n/a cobra
Click to expand...
Whats the key word there?

You have one less gear.
You have a TC, not a clutch.
You have 500+ more pounds.
You have a couple joints in your axle shafts.
You have an aluminum diff case thats prone to cracking its cover.
Your intake does not flow as well.
Your intake cam does not flow as much.


While a COBRA thats track only may do better with 4.56 gears a Mark that you expect to use on the street wont do better. The gear needs to be chosen for the application, not cause it kinda works for a completly different application.
 
LaserSVT said:
I dont insist, I merly point out that it is a real possibility. Now granted I have only built a dozen Cobras and a few Marks but I have never and would never turn the knock sensors off. They serve a very important purpose. I have no clue who you are talking to but if you ask Travis (owner of Gearheads) anout it he will tell you not to turn them off. Take a look at his yard. There are no less then 30 DOHC 4.6 cars in his shop. I have many friends in Dallas and Houston running 600+ RWHP Cobras and not a single one would EVER say to turn the knock sensors off.

TL stands for Trac Lok. Its Fords LSD. Its a very good design and has excellent properties if you rebuild it with 4 clutches instead of the standard 3. Had one in a couple Stangs and in my blown Mark. That car could lay dual stripes untill you let off the gas and the tail never tried to wag when taking tight turns. Its also very quiet unlike mechanical LSDs.

I know you dont use SCT, you use Quarter Horse. I have zero experience with QH and thus is why I stated it could be done in SCT but wasnt sure about QH.

Now I hope you didnt raise the limiter too high. Anything past 6500 and you will start to bind the valve springs. Factory tune pulls apx 30% TQ on WOT shifts so you really dont need to take that down more but a trans cooler is a MUST HAVE for a modded Mark.
Click to expand...

I have TL with the upgraded ford racing clutches already. That piece is an easy 20 pounds. With a spool it'll cut lots of rotational weight off.

What do you mean valve bind? Do you mean float? I have a 98 and I assume they have the beehive springs like 98 cobras.

I decreased the torque supplied to the tranny because I'm running 30* of timing. The EEC decreases torque by decreasing the timing, so more engine torque limiting is needed. (The value is a scalar)
 
Actually even better if 12's and a street machine is your goal then sell it and put the cash down on a 2011+ GT. I just watched my buddies completly stock 2012 GT with an auto and 3.31 gears run a 12.5@112mph and at the Texas Mile it hit 154.5MPH.

Hell in his stick 2011 he ran 11.03 with only an exhaust, intake, tune and control arms with the stock 3.73 rear end. :)
 
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