Jump to content

Recommended Posts

Hi

 

According to the swap calculator a 2006 Miata weights 2248 lbs. What is the definition of this weight? Full of fuel ready to race without drive

 

I would take 2248 lbs anyday! Ours weighted in 2366 at WRL. We have a super light top, 5lbs battery, fancy wheels and normal gutting (still looks like a car, no ac, etc)

 

 

Link to post
Share on other sites
1 hour ago, turbogrill said:

Hi

 

According to the swap calculator a 2006 Miata weights 2248 lbs. What is the definition of this weight? Full of fuel ready to race without drive

 

I would take 2248 lbs anyday! Ours weighted in 2366 at WRL. We have a super light top, 5lbs battery, fancy wheels and normal gutting (still looks like a car, no ac, etc)

 

 

Factory weight -10%=swap weight

Link to post
Share on other sites
1 hour ago, turbogrill said:

What is the definition of this weight?

It's a fudge factor. The formula assigns swap points based on a PWR formula, so weight is part of that. They started with 90% of curb weight for each car and then ran a bunch of engine swap options in a spreadsheet for each car at that 90% weight. But because it's a 1 size fits all formula, the resulting points didn't quite match what they thought was "appropriate points" for each car. Therefore, they changed the "weight" factor for each car until the formula spat out "appropriate points" values for that car.

Edited by enginerd
  • Like 1
  • Confused 1
Link to post
Share on other sites

I see, then I guess something is wrong with the weight. I get 9 points extra if I swap in my OEM engine:

 

Make: Mazda
Model: Miata
Year: 2006
VPi: 400
Car Weight: 2248
Original HP: 167
New HP: 167
Points Added to VPi: 59
--->NEW VPI: 459

 

 

Link to post
Share on other sites
2 minutes ago, collinskl1 said:

There is more to the whole consideration of VPI and swap formula than just PWR though. Some cars from the factory have a favorable PWR, but are limited in other areas, so if the factory engine was "swapped" they would incur points.

 

That is a good point, I think in my case it's fuel. So maybe I get a 9 pts "discount" due to that.

 

I am looking into swapping in a 167 hp engine into my car (rated exact same as OEM):

 

But it's a little strange since a horse power reduction gets 50 points.
Swap in 166 hp = 450 pts

Swap in 167 hp = 459 pts

 

 

Also what is the best official HP number? I did find a source saying 170hp for my car, that would make my swap cheaper (since I would do horse power reduction).

 

Link to post
Share on other sites

It's a 9 pt reduction for anything less than stock hp because that is how the calculator works.  If you swap in less hp, or the same, it's a 50 pt hit.

 

Some cars have better pwr stock than the calculator would like to see.  For example, I believe the newer Nissan Altima make a good but more power than the swap calculator allows.

 

Fuel has nothing to do with it.  Neither does original hp (unless swapping in stock or less hp)

 

It is all about power to weight.  

  • Thanks 1
Link to post
Share on other sites
39 minutes ago, turbogrill said:

 

That is a good point, I think in my case it's fuel. So maybe I get a 9 pts "discount" due to that.

 

I am looking into swapping in a 167 hp engine into my car (rated exact same as OEM):

 

But it's a little strange since a horse power reduction gets 50 points.
Swap in 166 hp = 450 pts

Swap in 167 hp = 459 pts

 

 

Also what is the best official HP number? I did find a source saying 170hp for my car, that would make my swap cheaper (since I would do horse power reduction).

 

Sounds like your official hp is 166 by your numbers.

 

Edmunds.com is what I believe the initial official numbers came from.

Link to post
Share on other sites

Now one has ever lost a race for being to light!  If you do a engine swap it +50 point even if you go down on HP. My TT is a 225 HP with the TDI 140 HP engine swap its +50 points.

Champ dos not weigh the cars after a race. www.DRVOLKS.com

 

Link to post
Share on other sites
19 minutes ago, DRVOLKS said:

Now one has ever lost a race for being to light!  If you do a engine swap it +50 point even if you go down on HP. My TT is a 225 HP with the TDI 140 HP engine swap its +50 points.

Champ dos not weigh the cars after a race. www.DRVOLKS.com

 

 

I wish I could reach the champcar weight, it's over 100 lbs lighter than what we have. That would require some mad max chopping...

Link to post
Share on other sites

So the 2006 NC is 170hp, this is according to Mazda:

 

https://www.miata.net/faq/brochures/2006/veh_specs_MX5.pdf

 

image.png.a83f29454a3ac7dbf9442c73c3ea8876.png

(.....the 2007-2015 NC Miata is 166/167 hp according to mazda, so when you swap in your 167 HP 2.5 engine from a Mazda3 you obviously went from a 2006 NC engine. That gives you 50 VPI increase instead of 59 VPI)

 

 

Edited by turbogrill
Link to post
Share on other sites
10 hours ago, enginerd said:

It's a fudge factor. The formula assigns swap points based on a PWR formula, so weight is part of that. They started with 90% of curb weight for each car and then ran a bunch of engine swap options in a spreadsheet for each car at that 90% weight. But because it's a 1 size fits all formula, the resulting points didn't quite match what they thought was "appropriate points" for each car. Therefore, they changed the "weight" factor for each car until the formula spat out "appropriate points" values for that car.

As far as I know there has never been any "factoring" of the weights. Do you have any proof that there was? 

 

The only variations of the swap weights came from when someone decided that the heaviest curb weight found somehow was a good basis for the swap calculator weight. This tilted the balance even more to the luxury cars, whose -10% was already shy of a typical race weight of much closer to 20% less than the curb weight. In some cases, the difference between the curb weight and a typical race weight is over 30% (3034 lbs used, 2300 lbs actual race weight for E30s). Other examples abound in the swap weights.

 

 

 

 

Link to post
Share on other sites
1 hour ago, turbogrill said:

 

I wish I could reach the champcar weight, it's over 100 lbs lighter than what we have. That would require some mad max chopping...

There is nothing to be gained from the swap weight other than it being advantageous to have an artificially high curb weight that allows a much better engine and PWR to be used than a more reasonable swap weight would. 

 

Your case just emphasizes that the Champcar weights for small econocars are much lower than that allowed for luxury/sport sedans. Don't feel bad that you didn't get to it if you're not swapping.  

Link to post
Share on other sites
12 hours ago, turbogrill said:

Hi

 

According to the swap calculator a 2006 Miata weights 2248 lbs. What is the definition of this weight? Full of fuel ready to race without drive

 

I would take 2248 lbs anyday! Ours weighted in 2366 at WRL. We have a super light top, 5lbs battery, fancy wheels and normal gutting (still looks like a car, no ac, etc)

 

 

Do you have only skins for your doors, hood, trunk, etc?  I assume no dashboard, unnecessary wiring removed, etc.  All brackets shaved off that you don't need.

 

The reason I ask, is because that seems a bit heavy for a miata.  I know that the nc was the heaviest miata, so that may well be where it ends up.  Just curious is all.

Link to post
Share on other sites
1 minute ago, wvumtnbkr said:

Do you have only skins for your doors, hood, trunk, etc?  I assume no dashboard, unnecessary wiring removed, etc.  All brackets shaved off that you don't need.

 

The reason I ask, is because that seems a bit heavy for a miata.  I know that the nc was the heaviest miata, so that may well be where it ends up.  Just curious is all.

 

There is absolutely weight to be removed but I not sure what the norm should be. All the easy weight is removed.

 

For reference:

An NC Miata with plenty of carbon fiber is 2126 ready to race (https://www.good-win-racing.com/mazda/miata/projectcar/1/2006 'NC Light'.html)

There is a another NC Miata without carbon fiber but with a lot of weight reduced that is in 2150-2200 lbs ready to race. But that is with no a pillars and extreme weight reduction.

 

Link to post
Share on other sites

I think Troy from biohazard went as far as to cut or replace every fastener in his car with only the shortest length that still had full strength.  I know he ended up losing a bunch of weight while the car basically looked unchanged.

 

Weight reduction is your biggest performance enhancement over anything else.  It's also cheap for the most part.

  • Like 1
Link to post
Share on other sites
2 hours ago, mender said:

As far as I know there has never been any "factoring" of the weights. Do you have any proof that there was? 

 

The only variations of the swap weights came from when someone decided that the heaviest curb weight found somehow was a good basis for the swap calculator weight. This tilted the balance even more to the luxury cars, whose -10% was already shy of a typical race weight of much closer to 20% less than the curb weight. In some cases, the difference between the curb weight and a typical race weight is over 30% (3034 lbs used, 2300 lbs actual race weight for E30s). Other examples abound in the swap weights.

The text in the rulebook changed. It used to say "curb weight -10%" or something like that. I will find the documentation which went along with this change.

4.5.2.1. “weight” refers to the ChampCar Swap Performance Value of that make and model, as determined by ChampCar

 

Those aren't the only variations... for some cars I can't even tell where the weight numbers came from. It isn't just a "luxury trim" weight.

  • Like 2
Link to post
Share on other sites
3 hours ago, wvumtnbkr said:

I think Troy from biohazard went as far as to cut or replace every fastener in his car with only the shortest length that still had full strength.  I know he ended up losing a bunch of weight while the car basically looked unchanged.

 

Weight reduction is your biggest performance enhancement over anything else.  It's also cheap for the most part.

 

It's not cheap in terms of time, and if you don't have time you have to pay someone to do it. And at $40-80 bucks an hour it gets expensive fast...

 

Buying a set of $1500 coilovers takes 2 hours to install.

 

 

Link to post
Share on other sites
3 hours ago, mender said:

As far as I know there has never been any "factoring" of the weights. Do you have any proof that there was? 

 

The only variations of the swap weights came from when someone decided that the heaviest curb weight found somehow was a good basis for the swap calculator weight. This tilted the balance even more to the luxury cars, whose -10% was already shy of a typical race weight of much closer to 20% less than the curb weight. In some cases, the difference between the curb weight and a typical race weight is over 30% (3034 lbs used, 2300 lbs actual race weight for E30s). Other examples abound in the swap weights.

Found it  (43:12) :

 

Edited by enginerd
Link to post
Share on other sites
4 hours ago, enginerd said:

The text in the rulebook changed. It used to say "curb weight -10%" or something like that. I will find the documentation which went along with this change.

4.5.2.1. “weight” refers to the ChampCar Swap Performance Value of that make and model, as determined by ChampCar

 

Those aren't the only variations... for some cars I can't even tell where the weight numbers came from. It isn't just a "luxury trim" weight.

Oh, I agree that the intent and wording was changed this year but were there any of these spreadsheets and subsequent factoring done? Or is it an escape clause to get people like me to stop bringing up the erroneous weights being used?

Link to post
Share on other sites
3 hours ago, enginerd said:

Found it  (43:12) :

 

The original intent from what I understood at the time was strictly power to weight. The math is fine, and adjusting the VPI to compensate for any of the other things Mike mentioned can be done directly via changing the VPI points.

 

I disagree with the decision for the change.

Link to post
Share on other sites
3 minutes ago, mender said:

Oh, I agree that the intent and wording was changed this year but were there any of these spreadsheets and subsequent factoring done? Or is it an escape clause to get people like me to stop bringing up the erroneous weights being used?

It's not erroneous when it's a BOP factor. Just look at the e30 number, that's all the evidence you need that a 189 HP swapped e30 at exactly 500 points is what they want. Whatever weight BoP factor was needed to make that happen was used.

Link to post
Share on other sites
1 hour ago, enginerd said:

It's not erroneous when it's a BOP factor. Just look at the e30 number, that's all the evidence you need that a 189 HP swapped e30 at exactly 500 points is what they want. Whatever weight BoP factor was needed to make that happen was used.

As I said, I disagree with calling it a balance of power when it should be power to weight. Conflating the two is a mistake.

 

If I remember correctly, that's where the "heaviest model" came into being; it allowed the 189 hp swap for 500 points but the weight itself wasn't factored. Allowing that opened yet another can of worms which I feel led to this year's severing the tie between searchable curb weights and a fictitious number that Champcar decrees. 

 

In my mind, this takes the swap calculator completely away from the original intent. Those benefiting from this escape from reality will likely disagree with me.

Edited by mender
  • Like 2
Link to post
Share on other sites
On 4/5/2020 at 11:06 PM, Ronh911 said:

Factory weight -10%=swap weight

Is that from the highest weight or an average between all available models? We'd be hard pressed to get our car (88 F-bird) under 3000 w/ gas and driver, no way. The cage itself is heavy AF. 

Link to post
Share on other sites
23 minutes ago, TiredBirds said:

Is that from the highest weight or an average between all available models? We'd be hard pressed to get our car (88 F-bird) under 3000 w/ gas and driver, no way. The cage itself is heavy AF. 

My old gbody was 2700# as raced with a 350 and Saginaw 4 speed.

 

Is the camaro really that much heavier with a similar drivetrain and being a unibody?

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...