LM vs. EM Debate.

[bbodie52]

Race-Bred: A Brief History Of The Chevrolet 409...
http://www.roadkill.com/race-bred-brief ... t-409-409/

I guess the 1962-1963 Chevrolet is where the 1965-66 Corvair Corsa silver cove area came from...

[Deadwolf]

Actually, building a 409 for my 63 Convertible right now, or should I say 438 as it is actually a 348 that has been stroked and bored 30 over. Going with Aluminum heads and dual 4 barrels and all the stickers to make it look like a 409/425 hp engine to anybody that doesn't know how to read block numbers.

Dang I have too many irons in the fire!

[mdh157]

While we are on the subject, who here currently owns or has owned both EM and LM vairs? Interested in hearing the differences in handling and which you prefer.

[joelsplace]

I have a few. LMs definitely handle better but are flimsy and poorly constructed compared to EMs. I prefer EMs because you can drive them at the limit without getting into as much trouble. The less flexible bodies feel better also.
The LM tends to push in tight low speed corners more than the EM and I hate push.

[mdh157]

The LM tends to push in tight low speed corners more than the EM and I hate push.

What do you mean by 'push'?


I will have to find one of each close by to drive before I make my decision. Nothing closer than 90 minutes away right now.

[bbodie52]

Four stages of oversteer

1. The car has turned in normally and is aiming towards the apex.
2. The rear wheels have started to lose adhesion, the driver compensates by steering left to keep steering aligned to the desired driving line (counter steering, explained below).
3. The driver has maintained control of the car and continues to follow the desired line.
4. The car is at the limit of left hand lock, a spin is likely at this stage unless dramatic corrections are made.

Oversteer is more exciting than understeer and like most exciting things (such as jumping off cliffs) there is an element of risk involved. Most ‘driver’s cars’ have a tendency to oversteer when on the limit around corners, and this property can be found in a variety of vehicle layouts and drive formats.

https://drivingfast.net/oversteer/

Thu Dec 17, 2020 11:57 am
The LM tends to push in tight low speed corners more than the EM and I hate push.

What do you mean by 'push'?

Perhaps he meant that he enjoys the oversteer handling nature of a rear-engine Corvair, and that oversteer is more-easily induced in the swing-axle EM Corvair than it is in a LM Corvair, because of the improved rear traction in the redesigned LM rear suspension.

Rear engine, rear wheel drive

Causes, and likelihood of oversteer for a rear wheel drive, rear engine car
Cause of oversteer — Likelihood of oversteer

• Entering the corner too fast — High
• Accelerating early or aggressively — Medium
• Lifting off the throttle — High
• Braking — High

Rear engine, rear wheel drive vehicles such as the Porsche 911 can oversteer for different reasons to front engine varieties. In this case most of the vehicle weight is over the rear wheels, leading to greater levels of natural grip at the back, which should lead to an inherent low risk of oversteer. However, there is another force at work here – momentum. Objects with greater mass carry more momentum and are harder to change direction at speed. In the case of rear engine cars, the rear has more momentum than the front which can lead to a greater risk of oversteer as a result of braking or lifting off mid corner.

In a high-horsepower front engine performance car, oversteer can be induced by applying excess horsepower to the rear wheels, to break rear traction intentionally with horsepower (inducing oversteer). This is not easily done in a relatively low-horsepower small engine Corvair, and it is also not necessarily desirable to back-off the throttle or apply the brakes in a turn to induce oversteer in a turn, since the Corvair lacks horsepower to make up for speed lost by braking or backing off of the throttle in a turn when exiting out of the turn. The swing-axle EM Corvair, with its relatively poor rear camber control, is easier to induce oversteer in a hard low-speed corner, which may be the fun referred to when driving an EM Corvair. A front-engine car tends to "push", or "plough" as the heavy front end tends to resist a direction change in a turn.

Four stages of understeer

https://drivingfast.net/understeer/

Ploughing into a corner too fast
If you have attempted to take a corner too fast, have turned the steering wheel, and find yourself running wide, you my friend are in a spot of bother. But before you close your eyes and hope for the best, all may not be lost. You’ve exceeded all of the available grip, yes, but it may be possible to actually increase the level of grip by the slightest, smoothest dab on the brakes. “The brakes?!”, I hear you shout, “but surely that is adding to the demands of the tyres, not reducing them?”. This is very true, but if you’re not totally out of control by pressing the brakes you’re causing the weight to transfer to the front, and thus artificially increasing the levels of adhesion at the wheels. This may, however, not work. The moral is to enter the corner at a slower speed, then get on the power early on the way out.

[joelsplace]

Good info Brad. Yes, push = understeer. I hate the feeling of not being able to steer when the front tires slide.

[Rick's 65 turbo]

"oversteer scares passengers,

understeer scares drivers...."

[gbullman]

"oversteer scares passengers,

understeer scares drivers...."

Yes, I agree with that! Controlled oversteer is a blast!

[manofsteel]

must what Re we talking about....lm. em??

[bbodie52]

With the rear wheel camber changes that typically occur as the wheels move up and down with swing axle-based vehicles like the 1960-1964 Corvairs, rear tire traction is somewhat unpredictable. There was some improvement with the 1964 enhancement, but the 1965 redesign made rear tire stability and predictability much-better. Oversteer was still present in the Corvair, with its rear-engine weight bias — but driver control of the oversteer characteristics was greatly improved! (The new 1965 Corvair rear suspension design was copied from the 1960s Corvette Stingray generation, while substituting coil springs on the Corvair in place of the transverse leaf spring design used on the Corvette — which was needed due to the Corvette fiberglass body that lacked solid coil spring mounting points).

Tech Article: VW Swing Axle vs. I.R.S. (Independent Rear Suspension)











https://www.jbugs.com/VW-Tech-Article-S ... s-IRS.html





http://www.corvaircorsa.com/handling02.html

[Scott H]

I've only owned late models up to this point. Now I have the earliest one. lol.

[joelsplace]

Swing axles are IRS.

[808kicks]

Love it! Stance and wheels are awesome!

[808kicks]

Show these guys some EM coupes with wide wheels, fat tires, and an aggresive stance. That is what changed my mind about earlies. Kinda wish it didn't, then I wouldn't have to find myself a spyder coupe to restore!

Gotta say, I really like having one early and one late in the garage =)

Goals!!! Got the 64 in garage just need the 65 CORSA next

[66vairguy]

I like both the EM and LM cars for different reasons. That said, the 64 had so many improvements, especially the rear suspension, that I consider the 64 models in a class of there own.

As for Joel's "push" or understeer, just add 10PSI to the front tires and you'll have plenty of oversteer. BTDT. On the LM's I use a higher front tire pressure vs. stock and keep the back in check with wider rear tires.