What determines the mid engine adder?

[quadzjr]

I am not beating up on Andy.. he is just the only person that has responded to my question. In all sinserity.. I appreciate his response. I had a question.. he answered it.

I believe IIRC the MK1 weight % is 44.5/55.5 +/- a perecent or so.

I think we are finally coming to some sort of a conclusion.. To re-iterate the adder is subjective based on weight distrubtion that is provided by the MR layout to provide better braking stability.

However that weight distrubtion is a hindernace on other parts on the track. If by chance that it is found that the cars really dont' have an advantage, does the adder go away? I guess that would be hard to prove, many times it has been stated on this site before that on track results are a weak excuse at best.

[ekim952522000]

Let's start by listing all of the mid-rear cars in IT factory weight balance. Let me know if I missed any. I don't know much about Porsche I may have missed a few of them.

Toyota MR-2 (90-94) ITA

Toyota MR-2 1.6L (85-89) ITB

Porsche Boxster (97-99) ITR

Porsche 914-4 1.8 (74-75) ITB

Porsche 914-4 2.0L (73-76) ITB

Porsche 914-4 1.7 (70-73) ITC

If you can find these online please post a link to the results I will look aswell.

Then after we find the weight balance for all of these we need to see if there are other cars in the same class as these that have the same, or more of a rearward weight bias.

We need to check against the rear engine cars as well.

I think that will be a good first step. Then we will have to discuss if we think it should get applied to all of these cars equally, or none of them.

[quadzjr]

Fiat X1/9 roles in at 41/59 I believe.

But I am a for of getting rid of it entirely.. do to the fact that where it's weight distubtion may help in one area, it is a hinderance in another.

However it is hard to remain un-biased when I am building one currently.. But it is because of that fact that I even thought about this in the first place. another point as a continuation of the FWD adder conversation, is that if and when it is applied why is it a flat 50lbs.. when weight plays such a higher roll in slower class cars.

[ekim952522000]

I also understand the adder but do not agree with it either.

It "seems" like no one agrees with it. Is there anyone on the forum who thinks we should include weight bias in the process?

My biggest problem with it is that we remove so much stuff from the cars and then add a cage I am not sure the stock weight balance number is really a reflection of what the cars end up.

[Knestis]

... My biggest problem with it is that we remove so much stuff from the cars and then add a cage I am not sure the stock weight balance number is really a reflection of what the cars end up.

A good question. We need to remember that we start at "stock" in all instances but go from there.

On anecdote, I'd initially *think* that if anything, balance would tend to go more in whichever direction it starts. When we cleaned out the Golf shell, it ended up being a big box of air in the back. We couldn't take much at all out from the dash forward.

K

[quadzjr]

On anecdote, I'd initially *think* that if anything, balance would tend to go more in whichever direction it starts. When we cleaned out the Golf shell, it ended up being a big box of air in the back. We couldn't take much at all out from the dash forward.

K

That is pretty much I think happens to most vehicles. Having a longer wheelbase would lessen this effect a bit.

[ekim952522000]

OK so I know some of you guys don't like LapSim but I decided to run some simulations with a 2500lb RWD car.

Here are the results.

Watching the simulation it looked like the rear weight biased cars had slightly slower mid corner speeds but later breaking and were able to get back on the gas sooner.

[ekim952522000]

.....

I believe IIRC the MK1 weight % is 44.5/55.5 +/- a perecent or so.

....

ok are there any front or rear engined cars in ITB that have as much or more rear bias. I am asking because if it is a weight balance adder the first thing to figure out is if it is being applied equally regardless of engine location.