Jump to content

FWD transaxle/final drive swap clarification


 Share

Recommended Posts

I have dug into the rules and forums and I’m looking for clarification on if something is points or not. Here’s the scenario… We are racing a FWD car (Neon) with the base transmission that has a 3.55 final drive (aka axle ratio). In a RWD application my understanding is you can run any factory ratio available. This is as simple as unbolting one axle and dropping in another from the same model with the desired ratio.  On our Neon there are a few transaxles available and one of them has the exact same ratios for all 5 forward gears and open differential but has the more optimal 3.94 ratio. If we swap this transaxle would we be paying points for a transmission swap?  There are other transmissions (2nd gen) that are stronger and have a shorter 5th gear that make more sense if we are paying points just to swap axle ratio. To be clear, it is possible to swap the final drive in the transaxle but it’s beyond my comfort level in my wrenching abilities.  We’ll just pay the points and get the best one if this is a no-go. 
 

To show which two transaxles I’m talking about I’ve attached an image listing them all and marked which two are in question. 
 

Thanks,

Tyler

 

1995-2005 Dodge Neon Transmission Gear ratio breakdown – ModernPerformance.com Blog.pdf

Edited by Lackluster
Wrong screenshot
Link to comment
Share on other sites

"• Final drive ratio is open to all factory offered ratios for that body style or chassis generation. If that body style or chassis generation was offered from the factory with an LSD, its use is permitted. Specialty high performance models not listed on the VPI table are excluded."

 

If the final drive ratio came in the same transaxle case (T350) as the original and it's not from a specialty high performance model not listed ((column #4 as you indicated, "non-ACR and RT") it should be 0 points.

Edited by mender
Link to comment
Share on other sites

2 minutes ago, mender said:

"• Final drive ratio is open to all factory offered ratios for that body style or chassis generation. If that body style or chassis generation was offered from the factory with an LSD, its use is permitted. Specialty high performance models not listed on the VPI table are excluded."

 

If the final drive ratio came in the same transaxle case (T350) as the original and it's not from a specialty high performance model not listed ((column #4, "non-ACR and RT") it should be 0 points.

My question is can I swap the whole transaxle for 0 points since it’s otherwise identical. 
 

I’m just trying to be 100%, rock solid, idiot proof, crystal clear.  A Neon with penalty laps is a bad place to be. :)

Edited by Lackluster
Link to comment
Share on other sites

1 minute ago, mender said:

The BMW teams swap the entire differential case for 0 points to get their desired final drive so I see no reason for your situation to be any different. 

Thankfully the transmission tag is in a very easy to see spot so there should be no accusation of shenanigans!

Link to comment
Share on other sites

I and almost all of the other neon teams run the ACR (all years)\95 DOHC neon trans ratios (3.94 final and .81 5th). We run this as a zero point item, that was an option available for both SOHC and DOHC cars of all years in the ACR package (and others). With the .72 5th it is going to be a dog when you shift to 5th. So yes you can make that swap, but neither is really the trans you want.

 

Technically if you run the "HD" trans those ratios were not offered in the gen 1 cars and it should be points. In reality the ratios are so close it would be hard to tell, but you will have to do some work to swap on a non hydraulic clutch bellhousing and there really isn't a performance reason to go through to effort (i never bothered to mess with them). Other people have used the HD trans as a crutch to try and address the damage a stiff clutch will do to these gearboxes, only to continue to break them anyway. On a stock PT clutch we have had good success with bone stock trans. Some of the rebuilders in the neon world may be able to find you one of these trans, they pop up but take a little searching. Every spec neon and the neon scca road races cars in IT all used this.

 

You can also find 3.94 .81 transmissions in 01 and 02 pt cruiser in "HD" variety and the same internals were used in some gen 2 mitzu eclipse trans for the 420. The housing will be the wrong shape, but you can use the parts in a neon trans core. 

 

The only real year specific item on the neon from a rules point would be that to run the 95 SOHC cam and engine ( a little better)  you would technically get the early neon fuel capacity of the steel tank. In reality since you will be motor swapping the car to run well (speed) reliably this doesn't matter and you would be claiming the late neon 12.5 fuel capacity. 

 

  • Like 2
Link to comment
Share on other sites

  • Technical Advisory Committee
On 7/20/2022 at 10:06 AM, mender said:

The BMW teams swap the entire differential case for 0 points to get their desired final drive so I see no reason for your situation to be any different. 

Not correct nor relevant to this question whatsoever.   If your going to troll at least attempt to be informed first.

 

 

 

i think Drew has sorted OP’s question with a detailed answer but my advice is if you are planing anything outside of the “ordinary” or something is unclear please get an Official answer via the tech desk before spending any cash.  Ray has been doing a fantastic job staying on top of technical questions.

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

22 hours ago, Chris Huggins said:

Not correct nor relevant to this question whatsoever.   If your going to troll at least attempt to be informed first.

"The BMW teams swap the entire differential case for 0 points" - meaning that very few teams go to the trouble of keeping the original vin number correct differential case (typically a medium or 188 mm case) and only swap the gears but instead exchange it for another medium case diff that already has the desired gear.  Swapping to a 210 mm case requires mods and points, so hopefully no one is doing that.


 Go back and read the sequence of his questions and my replies for context, Chris. To quote someone, "If your (sic) going to troll at least attempt to be informed first."

Edited by mender
Link to comment
Share on other sites

On 7/23/2022 at 9:42 AM, mender said:

"The BMW teams swap the entire differential case for 0 points" - meaning that very few teams go to the trouble of keeping the original vin number correct differential case (typically a medium or 188 mm case) and only swap the gears but instead exchange it for another medium case diff that already has the desired gear.  Swapping to a 210 mm case requires mods and points, so hopefully no one is doing that.


 Go back and read the sequence of his questions and my replies for context, Chris. To quote someone, "If your (sic) going to troll at least attempt to be informed first."

The 4.10 LSD and the 3.73 LSD use the same 188mm "medium case". Nobody swaps to a the large case diff.

  • Like 2
Link to comment
Share on other sites

29 minutes ago, Team Infiniti said:

Don’t know what you’re getting at, the vin is not on the case, I have collected 6 e30 differentials, a couple 373 another couple 410 both Posi and open, they’re all the same case.

I don't have an E30 so have no idea whether there is a particular casting number or letter on the diff case that identifies it as the one that came with the car originally (some might call that a vin correct or numbers matching diff but apparently BMW owners don't) or whether it had a part number or letter stamped in to the case, or a tag or a paint stamp, etc. but hopefully it's clear enough what I intended so people can relax. If not, feel free to flail away.

 

As I said a while back, BMW teams don't keep the differential case that came with the car and change the gears, they take out the original case with the unwanted gears and put in a different case from another E30 with the desired gears. This was in direct response to lackuster's question of whether he could exchange the whole transaxle case because he didn't feel comfortable changing out the final drive gearset. 

 

Got it now?

 

Edited by mender
Link to comment
Share on other sites

11 hours ago, mender said:

As I said a while back, BMW teams don't keep the differential case that came with the car and change the gears, they take out the original case with the unwanted gears and put in a different case from another E30 with the desired gears. This was in direct response to lackuster's question of whether he could exchange the whole transaxle case because he didn't feel comfortable changing out the final drive gearset. 

 

Got it now?

The confusing part is that you said "BMW teams do this" rather than saying "it is accepted per the rules (4.7.1) that you can replace any part with newer/not broken/other identical parts. You do not need to retain the factory original diff case / factory original engine block / etc."

By saying "BMW teams do this", you are implying (intended or not) that there is a practice of replacing parts which wouldn't be allowed per letter of the rules, but is nonetheless permitted and BMW teams take advantage of it.

Edited by enginerd
  • Like 2
Link to comment
Share on other sites

On 7/23/2022 at 10:42 AM, mender said:

vin number correct differential case

 

12 hours ago, mender said:

flail

 

 

 

What is this, Barrett Jackson?  12 years running the same car, the only VIN match parts original stuff we have left are the dash pad,  roof and trunk lid. 
 

VIN goes along with weight, all trumped by performance modifiers and platform/generation.  

 

  • Like 1
  • Haha 1
Link to comment
Share on other sites

2 hours ago, Team Infiniti said:

What is this, Barrett Jackson?  12 years running the same car, the only VIN match parts original stuff we have left are the dash pad,  roof and trunk lid. 
 

VIN goes along with weight, all trumped by performance modifiers and platform/generation.  

 

 

Unless if you run a Fox platform, then it is special rules and the platform is further trumped by the quarter panels, hood, and nose.  https://en.wikipedia.org/wiki/Ford_Fox_platform

Link to comment
Share on other sites

2 hours ago, Ron_e said:

Unless if you run a Fox platform, then it is special rules and the platform is further trumped by the quarter panels, hood, and nose.  https://en.wikipedia.org/wiki/Ford_Fox_platform

Nobody cares about your "platform". The quarter panels, hood, and nose need to match the car MODEL. Just like every other car. If it doesn't match the model, then it's a non-stock part.

4.4.1. ALL non-stock components, parts, assemblies, or systems MUST be declared to Tech Inspection and declared and accounted for in the total points of the vehicle.

Edited by enginerd
  • Like 1
  • Thanks 1
Link to comment
Share on other sites

4 hours ago, enginerd said:

Nobody cares about your "platform". The quarter panels, hood, and nose need to match the car MODEL. Just like every other car. If it doesn't match the model, then it's a non-stock part.

4.4.1. ALL non-stock components, parts, assemblies, or systems MUST be declared to Tech Inspection and declared and accounted for in the total points of the vehicle.

 

Sure, so uhhhh how many points is a quarter panel that is the exact same material, exact same thickness, and overall dimensions?  You sure seem to care about my "platform", if nobody cares about "platforms" then why is this in the rulebook "4.6. PLATFORM SWAP"?

 

😆😆"platform"😆😆

Link to comment
Share on other sites

42 minutes ago, Ron_e said:

Sure, so uhhhh how many points is a quarter panel that is the exact same material, exact same thickness, and overall dimensions?

Well, if it was actually identical, then you wouldn't have asked. So I assume it has a different shape. And if it has a different shape than factory, then it's a non-stock part, and the points would be: not zero. It's a simple concept.

 

Link to comment
Share on other sites

Once again, a couple of posters have taken a very specific question by a member that is racing with us and have attempted to make it about them or their pet crusade that has been hashed over many times.  Please stop.  There are multiple threads discussing your beef with the rules or interpretation of your specific issue you seem to have.

  • Like 4
  • Thanks 2
Link to comment
Share on other sites

12 hours ago, enginerd said:

The confusing part is that you said "BMW teams do this" rather than saying "it is accepted per the rules (4.7.1) that you can replace any part with newer/not broken/other identical parts. You do not need to retain the factory original diff case / factory original engine block / etc."

By saying "BMW teams do this", you are implying (intended or not) that there is a practice of replacing parts which wouldn't be allowed per letter of the rules, but is nonetheless permitted and BMW teams take advantage of it.

"Up to 40% of the field appears to be allowed to swap the main component case with internals rather than being forced to change only the internals, therefore to the best of my knowledge though transaxle cases are not specifically mentioned in the rule that says you can replace worn, impaled, defective, etc. parts, it would appear that tech would accept a transaxle with the desired final drive gear set that is otherwise otherwise identical."

 

Happy?

Link to comment
Share on other sites

11 hours ago, Team Infiniti said:

What is this, Barrett Jackson?  12 years running the same car, the only VIN match parts original stuff we have left are the dash pad,  roof and trunk lid. 
 

VIN goes along with weight, all trumped by performance modifiers and platform/generation.  

More flail. Stop any time, Ed.

Link to comment
Share on other sites

3 hours ago, enginerd said:

Well, if it was actually identical, then you wouldn't have asked. So I assume it has a different shape. And if it has a different shape than factory, then it's a non-stock part, and the points would be: not zero. It's a simple concept.

 

 

🤣

Link to comment
Share on other sites

On 7/20/2022 at 1:37 PM, Black Magic said:

I and almost all of the other neon teams run the ACR (all years)\95 DOHC neon trans ratios (3.94 final and .81 5th). We run this as a zero point item, that was an option available for both SOHC and DOHC cars of all years in the ACR package (and others). With the .72 5th it is going to be a dog when you shift to 5th. So yes you can make that swap, but neither is really the trans you want.

 

Technically if you run the "HD" trans those ratios were not offered in the gen 1 cars and it should be points. In reality the ratios are so close it would be hard to tell, but you will have to do some work to swap on a non hydraulic clutch bellhousing and there really isn't a performance reason to go through to effort (i never bothered to mess with them). Other people have used the HD trans as a crutch to try and address the damage a stiff clutch will do to these gearboxes, only to continue to break them anyway. On a stock PT clutch we have had good success with bone stock trans. Some of the rebuilders in the neon world may be able to find you one of these trans, they pop up but take a little searching. Every spec neon and the neon scca road races cars in IT all used this.

 

You can also find 3.94 .81 transmissions in 01 and 02 pt cruiser in "HD" variety and the same internals were used in some gen 2 mitzu eclipse trans for the 420. The housing will be the wrong shape, but you can use the parts in a neon trans core. 

 

The only real year specific item on the neon from a rules point would be that to run the 95 SOHC cam and engine ( a little better)  you would technically get the early neon fuel capacity of the steel tank. In reality since you will be motor swapping the car to run well (speed) reliably this doesn't matter and you would be claiming the late neon 12.5 fuel capacity. 

 

I agree with all of this, swap in a 1st gen complete neon trans with the .81 5th and 3.94 final, no points. Don’t waste your time with the .72 5th and 3.94 final even at Daytona (2.4 swap) is was a dog. I have some new in the package DCR LSD inserts if you really get into neons. 

  • Like 1
Link to comment
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.

 Share

×
×
  • Create New...