IRS vs live

[Selo]

After much research just made arrangements to purchase a Mk IV Roadster. Very excited, only reservation is no IRS. Does anyone care to comment, or is this seen as flogging a dead horse?

[Ron61]

It has been discussed a lot but no problem with asking. I have had both types of rear end suspension and raced them. The IRS does give a little better traction when cornering but the straight axle is just fine, especially if you aren't going to race it. Tell us a little bit more about your new toy and post some pictures. And don't let the no IRS bother you at all.

Ron

[Selo]

Thanks for the input! I'm purchasing from an aerospace engineer in Florida who built the car a couple years ago. It's a FFR unit with a small block making slightly north of 300 hp that favors driveability over intense hp. It has numerous thoughtful touches and modern conveniences that I believe will make it a great driver as well as a showpiece.
It's not in my possession yet, but as soon as I have it I'll post pics.
By the way, the rear suspension has a Panhard bar - not just a live axel, not sure if that's standard fare or not.

[jhv48]

My first FFR had the live rear axle. My current SPF has the IRS.
The solid axle rode a bit harsher until I massaged the springs and shocks to suit my taste. Seemed to handle better too.
You’ll have no problem with the solid axle. If the car comes with Bilstein shocks (they were used up until a few years ago when they began to fail and were replaced with adjustable Koni’s) replace them with adjustable shocks and you’ll notice a very drastic improvement in ride comfort.
Don’t sweat not having IRS. It's definitely a more comfortable ride, but not enough to worry about.
Enjoy the FFR.

[patrickt]

Originally Posted by jhv48

MDon’t sweat not having IRS. It's definitely a more comfortable ride, but not enough to worry about.
Enjoy the FFR.

I agree. An IRS is better on bumpy streets, but I wouldn't skip a nice car that I really wanted just because it didn't have it. Now, having an LSD will help you a bit. Probably the most dangerous condition you can encounter in these cars is the unexpected "snap oversteer" condition on hard acceleration. Even just 300HP can get you in to trouble real, real fast with these cars.

[saki302]

If it has a panhard bar it's probably the 3-link setup.

Street ride will be rougher, but they handle well with the Konis. I added swaybars to my old car, it handled (and rode) like a go kart ��

[undy]

Not that it applies to the OP, but a sturdy live axle will survive high HP/TQ applications better than an IRS setup will.

[Selo]

I haven't driven the vehicle - buying sight unseen. Seller assures me car will break tires loose in 1st and 2nd gear for sure. If I do want to add hp, what is the easiest way?

[olddog]

The easiest way to add Hp, is a bottle of laughing gas. It works. It can be hard on an engine if too much or not done right. I wouldn't recommend it, but it is easy.

[Selo]

Originally Posted by olddog

The easiest way to add Hp, is a bottle of laughing gas. It works. It can be hard on an engine if too much or not done right. I wouldn't recommend it, but it is easy.

What's the next easiest, and hopefully safer way to add horsepower?

[patrickt]

Originally Posted by Selo

What's the next easiest, and hopefully safer way to add horsepower?

Not knowing what you have under the hood, I would vote for a different camshaft and head work.

[Selo]

How expensive is it to pull out the Fox 302 and out in a nice small block/hipo crate motor?

[patrickt]

Originally Posted by Selo

How expensive is it to pull out the Fox 302 and out in a nice small block/hipo crate motor?

Call up Brent Lykins, a member here, chat with him for about an hour first, and then he'll give you a quote that will be quite competitive and the engine will be as solid as a rock. You can pull your own engine out, and swap a new one in, in your own driveway with a little help from a strong son or buddy.

[120mm]

If you have a 302, the easiest way to get more power is to drop a 347 in there, or have the 302 stroked to 347.

A well set up 347 should give you 400 crank HP easy and still be driveable. It will also bolt right in without changing anything.

The next easiest is to go with a 351W or a stroker based on it, such as 408W. Running this requires new headers at a minimum.

[patrickt]

But, to be honest with you, unless you've owned one of these cars before, I wouldn't do anything until you've driven it for a year. There's a decent learning curve involved....

[Selo]

I'm not planning on doing anything for awhile. Just a little concerned as we do lose some power at high altitude - supposedly about 3% for every 1000ft above sea level. We're at about 5000 ft, so theoretically starting at a 15% deficit. Just need to see how it feels, and how the EZ fast injection system works up here.

[Selo]

Need some quick advice:. Side pipes are stainless without heatshields. Should I put on ceramic or chrome heatshields, neither of which will be a perfect match?

[patrickt]

Originally Posted by Selo

Need some quick advice:. Side pipes are stainless without heatshields. Should I put on ceramic or chrome heatshields, neither of which will be a perfect match?

Neither. Stepping over the hot pipes is part of the learning curve.

[Selo]

Originally Posted by patrickt

Neither. Stepping over the hot pipes is part of the learning curve.

That's just not gonna fly with my wife. One pink leg on my kid and the car's gone I'm afraid!

[patrickt]

Originally Posted by Selo

That's just not gonna fly with my wife. One pink leg on my kid and the car's gone I'm afraid!

The burns rarely leave a long lasting scar. Here, read this thread, it's what I've done for over a decade: Rick Lake - Thanks for this Tip!