Ticket received: VPI request FWD Nissan SR20DE GA16DE

[jWashburn]

I submitted a ticket, just starting a forum thread for transparency and open discussion.  I think that there may be other FWD platforms with similar performance may want to follow the same logic.

 

Hello,

 

Apologies in advance for the long email, somewhere contained in the ramblings a point will be made.  Jumping straight to the point the SR20DE powered Nissan NX2000, Sentra SE-R and 200SX SE-R VPI are grossly too high compared with direct competition (SCCA ITA level cars; EF CRX / Civics, EG Civics, NA Miatas).  Starting on page 420:  https://www.scca.com/downloads/66880-april-updated .

 

Performance:  I have been casually racing these platforms for over 20 years.  Yes, I understand that SCCA rulesets do not directly apply endurance racing.  But, it should be noted that power to weight should not be the only determining factor, especially considering that the lower weight vehicle will turn better, brake better, and have better fuel economy.  Secondly, 90’s Civics have a superior double wishbone suspension, and Miatas inherently have better weight distribution, again emphasizing power to weight is not everything.  As a result, CRXs, Civics and Miatas performance, on average are better than equivalent Neons, NX2000, Sentras and 200SX.  A quick search of track records show out of 13 track records 6 are Miata, 5 are CRX, 1 Integra, and 1 NX2000:

https://www.nediv.com/index.php?option=com_content&view=article&id=91&Itemid=282

https://www.scca.com/downloads/50085-midohio-2

https://www.mcscc.org/results/trackrecords/MC.WW.2018.TrackRecords.GingerMan.pdf

The big exception would be Greg Amy’s run to the SCCA runoffs https://kakashiracing.com/reports/2006arrc.html , but even then the 1.6 liter non VTEC CRX was on par. 

 

 

Fuel:  Yes, the Nissans have a 13.2 gallon tank compared to 11.9.  That 1.3 gallon advantage might lead to (1) 5 minute pit stop advantage.  MIGHT.  Considering a 2:00 lap time that might be 2.5 laps, or 25 points.

 

LSD: In most cases the SR20DE cars did come with a Viscous Diff, but these definitely are not worth 25 points (call it 15 points?)

 

 Proposal 1:  All the “ITA” level cars should be 250 points.  This means that the CRX, EG Civic and Integra B18B increase to 250 points.  DOHC Neon remains at 250 points.  SR20DE cars, NX2000, Sentra SE-R and 200SX SE-R decrease to 250 points.  GA16DE Cars go to 200 points.

 

Proposal 2: the CRX and EG Civic and Integra B18B remain at current level. DOHC Neon decreases to 200 points.  NX2000, Sentra SE-R and 200SX SE-R also decrease to 200 points. GA16DE Cars go to 125 points.

 

 

See attached excel.

 

Fuzzy logic (and other terrible maths), for arguments sake can we quantify the differences between chassis?  Comparing the 1.6l vs 1.8l NA Miata establishes that 19 horsepower = 50 points = 2.6 point per hp.  SCCA deals with the 1.6l and 1.8l with a 205 pound weight penalty = 50 points = 4.1 lbs per point.  Suspension advantage is 10 points per corner.  Fuel advantage is 25 points, VLSD 15 points.  Not perfect, but the SR20DE cars come out to 192 points using the EF and EG as a baseline “hunk of fwd metal” that can be built off.

 

 

Probably some flaws with logic, but no way, no how is the NX2000, Sentra SE-R, and 200SX SE-R are 350-375 point cars when track record setting CRXs are 150 points as it is under the current VPI table.

[55mini]

Well this will be interesting to see how this moves thru TAC.

 

A couple things to point out for you, check the swap weight used for the honda as everything is based on power to weight.

It allows a monster swap to happen with a frankenstein motor.

 

Keep us all posted with your reply and good luck

[turbogrill]

375 sounds high! Maybe someone never complained?

 

I had a rare car with high VPi that got down a little, just because nobody had ever cared about it.

 

I think that is fair

[jWashburn]

Yes, I was looking at that too, but want to correct one blatant mathematically issues at a time:

 

 

I don't think I'd swap in a QR25DE anyways?, but still, over 600 points and not anywhere close to the power to weight of a swapped CRX.

[MMiskoe]

Without trying to be a pain I see a couple of things in your logic that might be flawed

 

So proposal 1 says move all ITA cars to 250.  Was the 1.8NA Miata going to come down to 250?  If so, then the NB1 & 2 cars can come down 50 points too?

 

I think using IT as an example isn't a bad idea, but I wouldn't hold your breath for it to be used as a direct classing option.  It opens a lot of doors that are probably not easily closed.  

 

You should add the NB1 & 2 Miatas into your spreadsheet for comparison.   There is a small change in HP but otherwise the other numbers remain the same, but 50 points more on the VPI.

 

Not sure your fuel capacity for the 1995 miata is right, I think you've got the 1.6L number carried.

 

Don't discount the fuel capacity.  Taking the Nissans or the Acura at 13.2 gallons sounds pretty sweet.  It allows you a much better chance of using the full capacity of the motor for 2 hours.

[Chris Huggins]

The CRX should not be used as the baseline or justification for changing a value as its value is a point of contention.

 

I also think you may have mixed up some of your current values.  IE the GA16 sentras are 200 points already?

 

Theres a lot going on here to unpack, I'm concerned your intent may be a bit muddied in the details you have provided.

 

Which specific years, models, or chassis codes do you want re-assessed for lower points?  Which Years do you want assessed for a VPI increase?

 

 

 

[jWashburn]

20 minutes ago, MMiskoe said:

Without trying to be a pain I see a couple of things in your logic that might be flawed

 

So proposal 1 says move all ITA cars to 250.  Was the 1.8NA Miata going to come down to 250?  If so, then the NB1 & 2 cars can come down 50 points too?

 

I think using IT as an example isn't a bad idea, but I wouldn't hold your breath for it to be used as a direct classing option.  It opens a lot of doors that are probably not easily closed.  

 

You should add the NB1 & 2 Miatas into your spreadsheet for comparison.   There is a small change in HP but otherwise the other numbers remain the same, but 50 points more on the VPI.

 

Not sure your fuel capacity for the 1995 miata is right, I think you've got the 1.6L number carried.

 

Don't discount the fuel capacity.  Taking the Nissans or the Acura at 13.2 gallons sounds pretty sweet.  It allows you a much better chance of using the full capacity of the motor for 2 hours.

 

In SCCA land this difference is addressed with a 205lb weight penalty.  ChampCar does not monitor weight, therefore a 50 point penalty is used.

 

You are correct, 12.7 gallons for 1995 Miata.

 

I'm not discounting fuel capacity, I already stated that the 1.3 gallon might lead to a single pitstop advantage.  Since 10 points = 1 lap, 25 points is appropriate.

[jWashburn]

4 minutes ago, Chris Huggins said:

The CRX should not be used as the baseline or justification for changing a value as its value is a point of contention.

 

I also think you may have mixed up some of your current values.  IE the GA16 sentras are 200 points already?

 

Theres a lot going on here to unpack, I'm concerned your intent may be a bit muddied in the details you have provided.

 

Which specific years, models, or chassis codes do you want re-assessed for lower points?  Which Years do you want assessed for a VPI increase?

 

 

 

 

The CRX Si has a document race history of being able to set track records.  My first proposal is to increase the CRX Si value.  EG Civic and Integra B18B1 is very similar that is why I also included that.

 

The GA16DE NX1600 is 300 points.

 

1991 - 1993 NX2000 (should share same VPI line as 1991-1993 Sentra SE-R, there was no 1994 NX2000)

1991 - 1994 Sentra SE-R (B13)

1995 - 1998 200SX SE-R (B14)

 

1991 - 1993 NX1600 (should share same VPI line as 1991-1993 Sentra, there was no 1994 NX1600)

1991 - 1994 Sentra (B13)

1995 - 1998 200SX / Sentra (B14)

[Chris Huggins]

SCCA track records and performance are not relevant to Champcar performance.

 

so your saying the nx1600 is the same as a b13 Sentra 1.6

 

and the nx2000 is a b13 ser?

Edited April 19 by Chris Huggins

[jWashburn]

Yes, I believe that I addressed that in my original post disclaimer, no? 

Historical data of performance is a lot more representative than CRX Si = 150, NX2000 = 375.

 

Yes, NX are extremely similar to B13, same engine / transmission / suspension / axle / brake / hub interchange.

[petawawarace]

Your trying way too hard for this, and making it alot more complicated than it needs to be.  Your never going to get a bunch of different cars VPI changed to make them equal to ITA specs.  That would throw off the balance they have with other non ITA cars. 

 

Just focus on getting the VPI changed that you want. (I'm guessing thats the Nissan Se-r).  I think its likely just that it hasn't been raced, and the VPI has remained high because no-one has challenged it.  Use other cars that have actually raced to compare it to, and suggest a new VPI based on that.  My guess is it should end up in the 250-275ish range.

[jWashburn]

ITA records establishes a reasonable performance ballpark.  I'd be more than happy to discuss the nuances between SCCA rulesets and ChampCar rulesets, but no one has gone into these specifically other than to say "they're not the same".

 

Sure I can keep it simple:

 

 

 

225:

 

Integra has superior suspension easily worth 10 points per corner.

NX2000 has crappy VLSD, but hey let's call it a 25 point diff anyways.

 

I guess 70lb is worth over 150 points?

[petawawarace]

ITA is essentially useless here.   Just ask for the VPI of the Nissan to be re-evaluated and provide some comparisons. 

 

What is your goal here?  Do you have a Nissan that you want to race with Champ? 

[jWashburn]

Primary goal, as it should be every member of this series goal, is to have mathematically correct VPI evaluations.

 

Second goal is to stop getting pulled by B series and K series swapped Hondas because the weight for the swap calculator is incorrect.

[tommytipover]

My annual declaration that as long as the MR2 is 200 points every 4cyl. FWD car on the list should be lower...

 

[petawawarace]

1 hour ago, jWashburn said:

Primary goal, as it should be every member of this series goal, is to have mathematically correct VPI evaluations.

 

Second goal is to stop getting pulled by B series and K series swapped Hondas because the weight for the swap calculator is incorrect.

Im confused.  Are you trying to lower the VPI of the Nissan so you can make it faster? Or try to slow down the swapped CRXs etc? 

[MMiskoe]

4 hours ago, jWashburn said:

ITA records establishes a reasonable performance ballpark.  I'd be more than happy to discuss the nuances between SCCA rulesets and ChampCar rulesets, but no one has gone into these specifically other than to say "they're not the same".

 

Sure I can keep it simple:

 

 

 

225:

 

Integra has superior suspension easily worth 10 points per corner.

NX2000 has crappy VLSD, but hey let's call it a 25 point diff anyways.

 

I guess 70lb is worth over 150 points?

This does a better job of pointing out why the NX is over valued.

 

Using the SCCA results is good to show how two cars prepped to the same standard fair out on the track.  It should not be (nor do I think it was the goal) to do a cross reference that an ITA car is worth XXX points in Champ. 

 

The record holder ITA cars you are referring to were full-tilt cars too.  I remember some of them.  At least one got demolished.

[Ian]

On 4/19/2023 at 12:50 PM, Chris Huggins said:

so your saying the nx1600 is the same as a b13 Sentra 1.6

 

and the nx2000 is a b13 ser?

 

They're basically the same car underneath.  The NX is just a hatchback sentra with funky headlights.

[55mini]

So its been a couple weeks any news or progress?

[jakks]

TAC and BOD working on petitions. Also changes are not approved/made until Jan 1.