Cobra IRS Swap

DropTopPony

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What do you guys think about an IRS swap? Since i have a vert i'll never set it up for 1/4 mile and i mostly just joy ride it. Ride is rough and i;m thinking about maybe putting in an IRS.


Pros?
Cons?
 

NERD

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Pros is it's the best riding rear end.

Cons, none.

You guys all know how I go back and forth with my car so....: If I keep my car I will have an IRS next summer.
 

dafizuck

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I love mine... the install isnt bad at all. Steppin on it does suffer but the handling is far superior, from the springs and shocks I had. I say go for it.
 

dafizuck

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OnyxCobra said:
sxynerd said:
Cons, none.

what about a lot of extra weight, wheel hop, the need for a new catback, etc?

hes not racing it (takes care of 1 and 2), new catback = new parts and new sound! (takes care of 3)
 

NERD

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OnyxCobra said:
sxynerd said:
Cons, none.

what about a lot of extra weight, wheel hop, the need for a new catback, etc?

The weight is unsprung which helps the achieve a better 50/50 distribution. The extra weight is what all the extra parts would weigh if you built a SRA to handle the curves.

Wheel hop is taken care of "Mostly" by delum bushings and correcting the camber when lowered. Who cares if you have to buy a new catback? Stainless pipes under the car look sick.
 

idro

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Theres better things you could spend the cash on suspension wise instead of an IRS.
 

NERD

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idro said:
Theres better things you could spend the cash on suspension wise instead of an IRS.

Truthfully, if you're talking about "Race Use Only" (twisties) an SRA can be built to handle just as well as an IRS. BUT, if you're talking about street manners local track days and all around feel of the road, IRS can not be beat.
 

OnyxCobra

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sxynerd said:
OnyxCobra said:
sxynerd said:
Cons, none.

what about a lot of extra weight, wheel hop, the need for a new catback, etc?

The weight is unsprung which helps the achieve a better 50/50 distribution. The extra weight is what all the extra parts would weigh if you built a SRA to handle the curves.

Wheel hop is taken care of "Mostly" by delum bushings and correcting the camber when lowered. Who cares if you have to buy a new catback? Stainless pipes under the car look sick.

so all you did was make excuses for what i posted, which i suppose you could do for pretty much any questionable mod. The cars have nasty wheel hop in stock form, so being lowered is rather irrelevant. If it was a direct bolt in swap i could see it being a lot more worth it but from what i've seen on the forum it's a little involved.
 

Steven

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OnyxCobra said:
sxynerd said:
OnyxCobra said:
sxynerd said:
Cons, none.

what about a lot of extra weight, wheel hop, the need for a new catback, etc?

The weight is unsprung which helps the achieve a better 50/50 distribution. The extra weight is what all the extra parts would weigh if you built a SRA to handle the curves.

Wheel hop is taken care of "Mostly" by delum bushings and correcting the camber when lowered. Who cares if you have to buy a new catback? Stainless pipes under the car look sick.

so all you did was make excuses for what i posted, which i suppose you could do for pretty much any questionable mod. The cars have nasty wheel hop in stock form, so being lowered is rather irrelevant. If it was a direct bolt in swap i could see it being a lot more worth it but from what i've seen on the forum it's a little involved.

Brake lines and two brackets. It's really not that hard. I would define and involved swap, as say putting an intake on the car. This is bolt on, fairly simple. I'm still considering it myself. Simply because I drive so much, have no dragstrips locally, and don't race much at all.
 

OnyxCobra

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i don't define bolt on's as something that you need to drill holes for, seems like an intake would be a lot more straight forward. I recall hearing you have to drop the gas tank too...
 

Steven

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Two bolts. I really don't see why your making it to be such a big deal. Raise it up, mark bracket locations, weld/bolt them on, raise it back up, bolt it in, make your brake lines, put in the DS and finish up the brakes. Throw the wheels on. Your done. If I can take a rear end out by myself in an hour then this is cake.
 

OnyxCobra

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i'm not making it out to be any kind of deal, everyone might not be as comfortable with doing that as you are...
 

dafizuck

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It was quite an ordeal for my install... but I put some massive bolts in there. Otherwise, not a walk in the park, but still not bad.
 

Steven

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We've put fire walls and frame rails in cars before. Compared to an IRS swap it's involved. A phb install is a pain because of the geometry getting set but it's not hard. Time consuming I would say
 

ReplicaR

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Ok, lets clear up a few things real quick, as there seems to be a quite a bit of incorrect information.

1. Cobra IRS is not a performance built suspension. It's a modified Thunderbird rear end, which was installed into thunderbird in the first place to give it a better ride. No one cared how the thunderbird handled. When you install the same rear end into a car that was never supposed to have it in the first place, and make it cope with twice the power, there will be some shortcomings. Wheel hop, cradle deflection, among a few to mention. People say that installing harder or zero deflection bushings will cure everything, but in process it takes away A LOT of compliance, making the car much harsher, and putting you almost back to square one. Kinda goes against the point. If you want to see a well designed rear suspension, look at BMW. They manage to achieve excellent traction, and they don't do it with solid bushings.

2. Cobra IRS is not faster around the track than a Torque Arm car. I know a few people who have a very well setup IRS equipped cobras, and all of them say that while IRS is nice on the street and all, it does not compare to a well setup 3rd link / Torque Arm car. Those cars always have more traction.

3. Cobra IRS also needs a cooler, if it will be driven hard. Ford underestimated how much heat the differential produces, and made everything plane jane. If you look at most of the powerful IRS cars out there, most of them will have a finned differential to help keep the temps of the fluids down. Ford solid has a lot more surface to cool, but IRS has just the pumpkin, and no fins. High temps will cause premature differential failure, gear oil spills.
 

idro

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sxynerd said:
idro said:
Theres better things you could spend the cash on suspension wise instead of an IRS.

Truthfully, if you're talking about "Race Use Only" (twisties) an SRA can be built to handle just as well as an IRS. BUT, if you're talking about street manners local track days and all around feel of the road, IRS can not be beat.

The cash you would use to install/buy the IRS/components you could have a nice SRA setup. Just not very economical IMO. But hell if i had an IRS *GIVEN* to me, i would install that bastard. LOL.
 
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DropTopPony

DropTopPony

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I'm still on the fence. :sad5:

Current set up is

Auburn Pro rear diff w/3.73's
31 spline forged axels
Steeda alum upper/lower CA's
Steeda Springs

I might just go with a Coil Over kit at all 4 and be done with it but a new day brings new ideas.
 

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