Spooled 4.56 rear build

majorownage said:
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)
Click to expand...
If you had your KS properly set then you could back it down to a proper 24* and allow the KS to ramp to 30* as needed and then it would pull that timing back out during the shift. Thats the proper way of doing it. It would get back on power quicker and complete the shift quicker as well.

And yes they are beehive and I did meen float. My bad. B head Cobras can run a few hundred more RPM but there are many factors that allow them to do that. They have less weight and more air flow so they are not taxing the motor as much and the motor spends less time above 6500 rpm.

Talk to the few people on here that actually spin their motors to 7000 RPM, they (most anyway) have aftermarket springs. Then again they also have built bottom ends.
 
LaserSVT said:
If you had your KS properly set then you could back it down to a proper 24* and allow the KS to ramp to 30* as needed and then it would pull that timing back out during the shift. Thats the proper way of doing it. It would get back on power quicker and complete the shift quicker as well.

And yes they are beehive and I did meen float. My bad. B head Cobras can run a few hundred more RPM but there are many factors that allow them to do that. They have less weight and more air flow so they are not taxing the motor as much and the motor spends less time above 6500 rpm.

Talk to the few people on here that actually spin their motors to 7000 RPM, they (most anyway) have aftermarket springs. Then again they also have built bottom ends.
Click to expand...

I'll try that strategy out. After I j-mod, I plan on removing all torque limiting.

Before I settle on 4.56s I'll talk to Dirty Dog and find out how much slip to expect at 7000. I want to be trapping at my redline (7k).
 
There is a ton of give in an irs cv rear. The cv's have a TON then the entire torsional slack is HUGE compared to a straight axel car.

I have had a spool in the Plymouth with 3.90 gears and hardened Strage 35 spline axels (another recommended no no by people that have never run them on the street) and have never had a problem. In my case Im in a little better shape with the MT ET Streets at 20lbs, they give and wrinkle alot on turns. If I park with the wheel cut in a turn position one tire is wrinkled like Im launching on NOS.

I actually have run spools MANY times in MANY cars in the past 25 years and never once had a spool related issue.

Plenty of Marks run 4.56's, can't remember the Guys name from the Pacific Northwest I think on LOD site. I mean WAYYY back, it was a black Mark if I remember correctly. He had just 4.56's and exhaust/chip and went 13.50's I think.

As long as you have the correct combo and a built trans your fine.
 
LaserSVT said:
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. :)
Click to expand...

Yeah there sick, easy to mod cars, look killer too.
 
ONEBADMK8 said:
Yeah there sick, easy to mod cars, look killer too.
Click to expand...
And uber comfertable. When I drove it I was amazed! Lots of room, superb seats, nice materials and the cars ride was amazing for a muscle car. Ford really has a winner there.
 
ONEBADMK8 said:
There is a ton of give in an irs cv rear. The cv's have a TON then the entire torsional slack is HUGE compared to a straight axel car.

I have had a spool in the Plymouth with 3.90 gears and hardened Strage 35 spline axels (another recommended no no by people that have never run them on the street) and have never had a problem. In my case Im in a little better shape with the MT ET Streets at 20lbs, they give and wrinkle alot on turns. If I park with the wheel cut in a turn position one tire is wrinkled like Im launching on NOS.

I actually have run spools MANY times in MANY cars in the past 25 years and never once had a spool related issue.

Plenty of Marks run 4.56's, can't remember the Guys name from the Pacific Northwest I think on LOD site. I mean WAYYY back, it was a black Mark if I remember correctly. He had just 4.56's and exhaust/chip and went 13.50's I think.

As long as you have the correct combo and a built trans your fine.
Click to expand...

Come on your comparing aftermarket 35 spline axles.
 
majorownage said:
If guys can run 10s quater miles on a stock 28 spline...a stock n/a with 4.56 should be just fine
Click to expand...
Big difference going in a straight line with an IRS on stock half shafts with 4.56 gears and a spool then there is making a simple right turn on a street. Being one tire is moving faster and they are now locked together then something has to give. Its gonna be a twisted shaft, exploded rear, blown CV or a ripped out control arm bushing after the tire is done giving up traction.
 
LaserSVT said:
Big difference going in a straight line with an IRS on stock half shafts with 4.56 gears and a spool then there is making a simple right turn on a street. Being one tire is moving faster and they are now locked together then something has to give. Its gonna be a twisted shaft, exploded rear, blown CV or a ripped out control arm bushing after the tire is done giving up traction.
Click to expand...


Have you even driven a car with a spool?
 
majorownage said:
Have you even driven a car with a spool?
Click to expand...
Driven? Not many, prolly less then 20. Owned one but it was an F body and the second time I took it out it snapped the axle in the pumpkin and the chards went into the gears and locked up the rear end and cracked the tail shaft on the T-56. Granted I was going to fast entering a driveway at 15 mph and on drag radials at 25lbs. :rolleyes:


Look dude, this aint my first rodeo and I (as well as others) are trying to give you sound advice. I realize you are young and fairly new to all this. Drove one or two cars with spools and read various tidbits posted by people on forums and left behind what you didnt like or didnt believe but fact of the matter is I know Cobras and Marks. There are many on here (ONEBAD, Jamie, DLF etc) that know more then I and I am no guru but I work on these cars all the time. I have worked on 4V cars for 15+ years and have had many failures and sucesses. I go to SVT meets and have been part of many high HP builds and have many many friends with high HP modular based cars. I help some wrench and I help some find parts. I have seen many failures with my own eyes, not just read about them online.

I am trying to help a n00b that seems to show some smarts from having a heavy failure and wasting cash when its not needed.

You seem die hard on this though so go for it. I wont even say "I told ya so" when the car breaks the rear end while you go to In and Out Burger.

BTW, 4.56 with short runner intake and a 4.5 stall I will make a guestamate your car will run a 13.9 to 13.8 at best. And if the car is trailored and a track only car then you will prolly never have rear end issues at that power level. Your trans will prolly even last a little bit with a trans cooler and some cool down between runs.
The real world on the streets, well thats a different story.
 
LaserSVT said:
And uber comfertable. When I drove it I was amazed! Lots of room, superb seats, nice materials and the cars ride was amazing for a muscle car. Ford really has a winner there.
Click to expand...

100% agreed. This is THE only latter Mustang I would even consider, they "NAILED IT".
 
ONEBADMK8 said:
Spline doesn't have ANYTHING to do with the spool issue point. I made the point meaning I have HARDENED race axels and a spool and NEVER had ANY problems ever. Same with all my old spool cars.
Click to expand...

Spline count comes down to dia. I have never had any problems with my MW 35 spline axles and spool either. These are on the tank level of strength. You never had any problems because 35 spline axles are huge dia hence stronger.
 
majorownage said:
4.56s are THE best gear for a b-headed n/a cobra
Click to expand...

I agree, I have them in my Cobra. :cool:

You, however, don't have a Cobra, you have a Mark VIII, and it's an entirely different animal, I assure you.

To hit 12's you'll need a trap speed around 104-105 MPH and 60's in the high 1.7 range. With 4.56's and a 25" tire (275/40-17 DR's) you'd make the traps in 3rd at right around 6,500 RPM and 105 MPH, IF you have the motor. A 26" tire is good for about 110MPH @ 6,500 RPM.

I'd skip the spool and get a True-Trac diff, I have them in all of my cars, and pull mid 1.7's with my Cobra and SC, so they're up to the task.

You've been posting quite a bit about tuning and performance, but I have yet to see recent track numbers, it'll be interesting when you post some.

Good luck with your project.
 
Last edited:
LaserSVT said:
If you had your KS properly set then you could back it down to a proper 24* and allow the KS to ramp to 30* as needed and then it would pull that timing back out during the shift. Thats the proper way of doing it.
Click to expand...

I already tried telling him that in another thread, but he isn't listening, so let's see what results he can manage doing it his way....
 
Right on the Mark said:
Spline count comes down to dia. I have never had any problems with my MW 35 spline axles and spool either. These are on the tank level of strength. You never had any problems because 35 spline axles are huge dia hence stronger.
Click to expand...

I have herdened race axels which I was told by MANY people that these would break, first pothole and or hard turn, they haven't. Thats the point I am trying to make. They are tank strong in a straight line.
 
attachment.jpg
 
You must log in or register to reply here.

Members online

Total: 236 (members: 1, guests: 235)
Back
Top