help me brainstorm about IRS
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help me brainstorm about IRS My 7 replica has a solid rear from a 1980 supra. I think this car had something like 90-110 horses. The rear does have a TruTrac diff, which is a Torque sensing design.
The rear suspension is a 4 link design, with 2 radius arms, 2 torque arms and a panhard rod.
So far, it has held up with the LS1, mostly because (I think) 225 tires are easily blown away on a 1650 lb car. I'm somewhat worried about increasing traction. I am suffering from axle hop, and have broken a panhard rod as a result...
I know RX-7 LS1 conversions are pretty popular. Do those guys normally stick with the RX-7 IRS setup, or switch to a solid rear?
I'm kind of thinking about the possibility of replacing my solid rear with a subframe to support a IRS setup.
The car's handling is very good right now, so I'm almost guaranteed to screw that up as I sort out the IRS setup.
My gut tells me when it's all said and done, the IRS may end up heavier than the solid axle setup I have now.
I'd apprecieate thoughts, pics, pros and cons, etc... from any of you who have some input.
The rear suspension is a 4 link design, with 2 radius arms, 2 torque arms and a panhard rod.
So far, it has held up with the LS1, mostly because (I think) 225 tires are easily blown away on a 1650 lb car. I'm somewhat worried about increasing traction. I am suffering from axle hop, and have broken a panhard rod as a result...
I know RX-7 LS1 conversions are pretty popular. Do those guys normally stick with the RX-7 IRS setup, or switch to a solid rear?
I'm kind of thinking about the possibility of replacing my solid rear with a subframe to support a IRS setup.
The car's handling is very good right now, so I'm almost guaranteed to screw that up as I sort out the IRS setup.
My gut tells me when it's all said and done, the IRS may end up heavier than the solid axle setup I have now.
I'd apprecieate thoughts, pics, pros and cons, etc... from any of you who have some input.
I believe that the FC RX7 guys use the Turbo II rear which is stronger than the non-turbo rear. Depending on the width of the car, what about using C4 Corvette parts? They're very popular among those updating older Corvettes (and other full-size GM cars) to a newer style suspension. The 6 speed cars had a Dana 44 (I think?) which is supposed to be stronger than the one in the automatic cars.
Just a thought.
-Matt
Just a thought.
-Matt
The 93 and newer rx7 rear end's are not to bad all the weight comes from the center section the housing. Its a giant cast Iron thingiee. That's why they get a center section from a 99+ IRS cobra. Its aluminum, and theres more gear ranges, and stuff.
There is a bunch of IRS setups out there you could look into: jaguar, RX7, Thunderbird, GTO, C4 Corvette.
I am most familiar with the C4 IRS. I have one and will put it in the next 70-73 camaro I get. It is all aluminum and the shocks and monoleaf can be replaced with coilovers. I don't know how much it weighs but I would not describe it as a heavy unit.
The dana 44 out of 84-96 6sp cars is the way to go. The reason I am going to use this rear end is because it more adjustable than a factory leaf spring setup and minimizes axle wrap and wheel hop which translates to better handling.
With a properly installed C4 IRS, you can maintain the good handling and it can handle more power than your current setup. Here is one on a chevelle. The coilovers are not installed yet.
On the other hand, you could just beef up your current setup and be done with it since it already handles good.
I am most familiar with the C4 IRS. I have one and will put it in the next 70-73 camaro I get. It is all aluminum and the shocks and monoleaf can be replaced with coilovers. I don't know how much it weighs but I would not describe it as a heavy unit.
The dana 44 out of 84-96 6sp cars is the way to go. The reason I am going to use this rear end is because it more adjustable than a factory leaf spring setup and minimizes axle wrap and wheel hop which translates to better handling.
With a properly installed C4 IRS, you can maintain the good handling and it can handle more power than your current setup. Here is one on a chevelle. The coilovers are not installed yet.
On the other hand, you could just beef up your current setup and be done with it since it already handles good.
A vette rear would be pretty easy to work with. You can get a Dana 36 for about $300-500 end to end and start working on it. The D36 might hold in your car since its 1/2 the weight of a stock vette. Later on you could step up to a D44 center... all the other parts are the same. You can see from the pics that it could be narrowed easily if required. Just shorten the half shafts, swap to rod end camber rods (the lower rods in the pic) and swap in rod end toe bars and you'd be set.
The C4 also uses two trailing arms per side that are very short due to the driverseat location right in front of the bulkhead. In your car you want/need a very compact system too. Might be a very good choice for you.
AND its got that sweet chevy lug pattern that we all love... if that matters to you
The C4 also uses two trailing arms per side that are very short due to the driverseat location right in front of the bulkhead. In your car you want/need a very compact system too. Might be a very good choice for you.
AND its got that sweet chevy lug pattern that we all love... if that matters to you
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I just saw a vid of a Z06 doing a 8.46 1/4 mile. IRS has gotten a lot stronger.
I'm using Porsche 930 CVs with chromemoly cages and chromemoly stub 28 spline axles. The BMW rear I'm using is good for 580 Ft Lbs of torque.
I'm partial to the german stuff as it is usually over engineered, much stronger than the stats they publish.
I'm using Porsche 930 CVs with chromemoly cages and chromemoly stub 28 spline axles. The BMW rear I'm using is good for 580 Ft Lbs of torque.
I'm partial to the german stuff as it is usually over engineered, much stronger than the stats they publish.
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Originally Posted by CHarris
A vette rear would be pretty easy to work with. You can get a Dana 36 for about $300-500 end to end and start working on it. The D36 might hold in your car since its 1/2 the weight of a stock vette. Later on you could step up to a D44 center... all the other parts are the same. You can see from the pics that it could be narrowed easily if required. Just shorten the half shafts, swap to rod end camber rods (the lower rods in the pic) and swap in rod end toe bars and you'd be set.
The C4 also uses two trailing arms per side that are very short due to the driverseat location right in front of the bulkhead. In your car you want/need a very compact system too. Might be a very good choice for you.
AND its got that sweet chevy lug pattern that we all love... if that matters to you
The C4 also uses two trailing arms per side that are very short due to the driverseat location right in front of the bulkhead. In your car you want/need a very compact system too. Might be a very good choice for you.
AND its got that sweet chevy lug pattern that we all love... if that matters to you
If you are fabbing everything up a C5 IRS with a Ford Cobra 8.8" chunk might work.
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Brett Foote Thread Starter
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Originally Posted by CHarris
A vette rear would be pretty easy to work with. You can get a Dana 36 for about $300-500 end to end and start working on it. The D36 might hold in your car since its 1/2 the weight of a stock vette. Later on you could step up to a D44 center... all the other parts are the same. You can see from the pics that it could be narrowed easily if required. Just shorten the half shafts, swap to rod end camber rods (the lower rods in the pic) and swap in rod end toe bars and you'd be set.
The C4 also uses two trailing arms per side that are very short due to the driverseat location right in front of the bulkhead. In your car you want/need a very compact system too. Might be a very good choice for you.
AND its got that sweet chevy lug pattern that we all love... if that matters to you
The C4 also uses two trailing arms per side that are very short due to the driverseat location right in front of the bulkhead. In your car you want/need a very compact system too. Might be a very good choice for you.
AND its got that sweet chevy lug pattern that we all love... if that matters to you
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Originally Posted by 93Polo
I agree. How much power are you planning on running? The D36 maybe a good option.
If you are fabbing everything up a C5 IRS with a Ford Cobra 8.8" chunk might work.
If you are fabbing everything up a C5 IRS with a Ford Cobra 8.8" chunk might work.
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From: Austin, TX
Originally Posted by 99c5vert
My car will not require much power (400 horses will be plenty in the future).
Regards, John McGraw
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From: Elizabeth City, NC
Originally Posted by Schitzo
There is a bunch of IRS setups out there you could look into: jaguar, RX7, Thunderbird, GTO, C4 Corvette.
I am most familiar with the C4 IRS. I have one and will put it in the next 70-73 camaro I get. It is all aluminum and the shocks and monoleaf can be replaced with coilovers. I don't know how much it weighs but I would not describe it as a heavy unit.
The dana 44 out of 84-96 6sp cars is the way to go. The reason I am going to use this rear end is because it more adjustable than a factory leaf spring setup and minimizes axle wrap and wheel hop which translates to better handling.
With a properly installed C4 IRS, you can maintain the good handling and it can handle more power than your current setup. Here is one on a chevelle. The coilovers are not installed yet.
On the other hand, you could just beef up your current setup and be done with it since it already handles good.
I am most familiar with the C4 IRS. I have one and will put it in the next 70-73 camaro I get. It is all aluminum and the shocks and monoleaf can be replaced with coilovers. I don't know how much it weighs but I would not describe it as a heavy unit.
The dana 44 out of 84-96 6sp cars is the way to go. The reason I am going to use this rear end is because it more adjustable than a factory leaf spring setup and minimizes axle wrap and wheel hop which translates to better handling.
With a properly installed C4 IRS, you can maintain the good handling and it can handle more power than your current setup. Here is one on a chevelle. The coilovers are not installed yet.
On the other hand, you could just beef up your current setup and be done with it since it already handles good.
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Originally Posted by JD_AMG
You have an LS1 in a 7 replica!? Dear god! Pics now!
here you go... couple of pics, followed by a short vid...
This is from the first drive in February after the engine conversion... I think the tires were trying to tell me something
http://filebox.vt.edu/users/arebrahi...ioncropped.wmv
Originally Posted by badtexasZ28
just to clarify, the 84 vette was only optioned with a D36 in it....i found out the hard way since i bought the rear out of one for my styleline conversion
Yo 99c5vert, cut the tires some sluck
Originally Posted by John McGraw
400 horsepower and a manual transmission will prove to be too much for the D36 rearend. With this level of power, a D44 rear will be a much better choice. The D36 will live real well with this much power on an automatic, but the shock loading of the gears with a clutch type trans is just to much for this rear to live with long term.
Regards, John McGraw
Regards, John McGraw
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That's true... if it can live in a 3000 lb car into the 11's, I'll never break it.
One question I have though... currently I have a TrueTrac diff, which is similar to a Torsen or Quaife type differencial. Do they make that for the C4 rears? I have never had the opportunity to do a side by side comparison, but from what I've heard, torque sensing diffs are better for autox applications. Also, there are no clutch packs to wear.
One question I have though... currently I have a TrueTrac diff, which is similar to a Torsen or Quaife type differencial. Do they make that for the C4 rears? I have never had the opportunity to do a side by side comparison, but from what I've heard, torque sensing diffs are better for autox applications. Also, there are no clutch packs to wear.
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You may be right, but I tend to allways lean to the cautious side. I have used D36 rears on 400 hp cars with automatics, but using them in manual transmission cars never left me with a warm fuzzy feeling. In any case, the D44 is a lot more durable center section even though they are more bucks at the junkyard.
Regards, John McGraw
Regards, John McGraw