3.73 to 3.31 pumpkin swap, durability question....

Tammaro21 · May 22, 2017

I have a pp gt that has a Paxton blower on it and I found someone who is willing to swap pumpkins with me here in town. I am dropping my car off to my mechanic a couple days prior to the other guy so I won't be able to test drive his car before I do the swap. His car is a manual like mine and his has just normal bolt on's and has only 7 k miles on it. He has approx 10 passes at the strip. What my question is, how is the durability on these pumpkins? Are they usually pretty solid or should I try to make it down there to test drive the car prior to doing the swap. We have been trying to get this done for a couple months and he seems like a standup guy from what I know. He has tried to meet up with me prior in past weeks to have me drive his car to check it out but my schedule didn't permit. What are your guys thoughts on the durability of these pumpkins? Thanks!

whatsup62 · May 22, 2017

Tammaro21 said:
I have a pp gt that has a Paxton blower on it and I found someone who is willing to swap pumpkins with me here in town. I am dropping my car off to my mechanic a couple days prior to the other guy so I won't be able to test drive his car before I do the swap. His car is a manual like mine and his has just normal bolt on's and has only 7 k miles on it. He has approx 10 passes at the strip. What my question is, how is the durability on these pumpkins? Are they usually pretty solid or should I try to make it down there to test drive the car prior to doing the swap. We have been trying to get this done for a couple months and he seems like a standup guy from what I know. He has tried to meet up with me prior in past weeks to have me drive his car to check it out but my schedule didn't permit. What are your guys thoughts on the durability of these pumpkins? Thanks!

Chances are there are no issues...they are pretty durable. You will be losing the torsion rear however in the trade.

Tammaro21 · May 23, 2017

whatsup62 said:
Chances are there are no issues...they are pretty durable. You will be losing the torsion rear however in the trade.

Thanks for the response, yeah, I hear they are pretty durable and I'm figuring it should not be an issue but I didn't know what everyone's thoughts were on the topic. I hear the Torsen dif better for road racing though... first and second gear in my car are absolutely pointless right now. it revs up so fast. The car may see the strip once or twice but most of my fun will be had on the freeways so I think the 331's will be better. The car put down 650 and 530tq so the 373s are no bueno anymore lol

EastTNMustang · May 23, 2017

Tammaro21 said:
Thanks for the response, yeah, I hear they are pretty durable and I'm figuring it should not be an issue but I didn't know what everyone's thoughts were on the topic. I hear the Torsen dif better for road racing though... first and second gear in my car are absolutely pointless right now. it revs up so fast. The car may see the strip once or twice but most of my fun will be had on the freeways so I think the 331's will be better. The car put down 650 and 530tq so the 373s are no bueno anymore lol

Me personally, I'd keep the Torsen 3.73 gearing and just upgrade to some 20" wheels. This would allow you to effectively change the gearing closer to a 3.50ish equivalent and you keep the Torsen performance. I definitely wouldn't do a straight swap with someone...they would have to throw in some cash to get a Torsen if I was set on trading.

Davepurp · May 23, 2017

I was in the same boat considering a rear pumpkin swap on my GTPP w/ a procharger.

But before I dive into that it seems swapping trannys to a TR6060 makes the most sense since it will be a weakpoint from here on out and adjust the gearing correct?

and if I swap to a larger radius tire that will buy me a little time?

EastTNMustang · May 23, 2017

Try this link to see how tire size affects your gear ratio.

https://tiresize.com/gear-ratio-calculator/

jasonstang · May 23, 2017

EastTNMustang said:
Me personally, I'd keep the Torsen 3.73 gearing and just upgrade to some 20" wheels. This would allow you to effectively change the gearing closer to a 3.50ish equivalent and you keep the Torsen performance. I definitely wouldn't do a straight swap with someone...they would have to throw in some cash to get a Torsen if I was set on trading.

Bigger diameter tires will give better traction too.
Not uncommon for cars to run different tire sizes in the back.

Tammaro21 · May 23, 2017

EastTNMustang said:
Me personally, I'd keep the Torsen 3.73 gearing and just upgrade to some 20" wheels. This would allow you to effectively change the gearing closer to a 3.50ish equivalent and you keep the Torsen performance. I definitely wouldn't do a straight swap with someone...they would have to throw in some cash to get a Torsen if I was set on trading.

I currently have 20's on the car as it sits. Im running 285/35/20 toyo proxies. If i go with a 305/35 (28" inch tall tire) do you think with the extra grip and height that would be better than swapping pumpkins?

Tammaro21 · May 23, 2017

EastTNMustang said:
Try this link to see how tire size affects your gear ratio.

https://tiresize.com/gear-ratio-calculator/

I just did the calculation and it would change it to a 3.63 gear ratio with a 305/35/20 in the rear. My car is putting down 650 to the ground, in your opinion would you swap pumpkins or would you just change to a bigger tire in the rear? My car probably will never see the strip and it's just a fun street car. What would you do because as it sits first and second gear are completely useless with the tire setup that I have now

whatsup62 · May 23, 2017

Tammaro21 said:
I hear the Torsen dif better for road racing though... first and second gear in my car are absolutely pointless right now. it revs up so fast. The car may see the strip once or twice but most of my fun will be had on the freeways so I think the 331's will be better. The car put down 650 and 530tq so the 373s are no bueno anymore lol

Been there done that...here is my experience. I haven't seen anyone break a torsion yet..love mine and wouldn't trade it for the world. There are members on here that are now replacing the clutches in their non-torsion rears from drag's. I assume you are a straight line racer by your comments...me too. Although I like going from a dig I find most of my races happen at a roll... kids nowadays... anyway tires are a big deal. 1st and 2nd were worthless on my car as well with NT05's, when I switched to MT S/S's that changed everything...but with a FI car 3:31's are the way to go. I was going to do a 3.31 gear change in my torsion before I decided on the 6060 swap. See my next quote answer.

Davepurp said:
I was in the same boat considering a rear pumpkin swap on my GTPP w/ a procharger.

But before I dive into that it seems swapping trannys to a TR6060 makes the most sense since it will be a weak point from here on out and adjust the gearing correct?

and if I swap to a larger radius tire that will buy me a little time?

So the MT82 isn't so bad unless you are/plan to run the RXT or a ceramic type clutch disc. The MT82 will break using those under a higher HP/TQ load. If you plan to do a TR6060 swap...you definitely want to keep 3.73's as the rear gear. The gearing in the Tremec is such that the 3.73's is more like a 3.15 in the MT82 cars...barely enough.

Tammaro21 · May 23, 2017

whatsup62 said:
Been there done that...here is my experience. I haven't seen anyone break a torsion yet..love mine and wouldn't trade it for the world. There are members on here that are now replacing the clutches in their non-torsion rears from drag's. I assume you are a straight line racer by your comments...me too. Although I like going from a dig I find most of my races happen at a roll... kids nowadays... anyway tires are a big deal. 1st and 2nd were worthless on my car as well with NT05's, when I switched to MT S/S's that changed everything...but with a FI car 3:31's are the way to go. I was going to do a 3.31 gear change in my torsion before I decided on the 6060 swap. See my next quote answer.

So the MT82 isn't so bad unless you are/plan to run the RXT or a ceramic type clutch disc. The MT82 will break using those under a higher HP/TQ load. If you plan to do a TR6060 swap...you definitely want to keep 3.73's as the rear gear. The gearing in the Tremec is such that the 3.73's is more like a 3.15 in the MT82 cars...barely enough.

I have the rst in the car right now along with the mgw shifter and the mt82 shifts like butter. I have never had any issues. If I do I will get it built by Ben calimar but I don't have any intentions of doing a tr6060 swap or a Tremec

EastTNMustang · May 23, 2017

Not sure how you got 3.63, going from the stock PP tire size of 275/45R19 to your current setup of 285/35r20 gives an effective gear ratio of 3.85, using 3.73 stock PP rear end gear ratio...and if you change to the 305/35r20 the effective gear ratio goes to 3.77. If you go to a 285/45r20 you have a ratio of 3.56 or go to a 305/45r20 gets a ratio of 3.48

For what you've indicated how you will use the car, I would keep the Torsen and change tire size slightly to improve overall performance.

Tammaro21 · May 23, 2017

EastTNMustang said:
Not sure how you got 3.63, going from the stock PP tire size of 275/45R19 to your current setup of 285/35r20 gives an effective gear ratio of 3.85, using 3.73 stock PP rear end gear ratio...and if you change to the 305/35r20 the effective gear ratio goes to 3.77. If you go to a 285/45r20 you have a ratio of 3.56 or go to a 305/45r20 gets a ratio of 3.48

For what you've indicated how you will use the car, I would keep the Torsen and change tire size slightly to improve overall performance.

I dont have a stock pp tire set up. Currently in the rear I have a 20 x 10 wheel and I am running 285/35/20 so I put that in the top section and then I put 305 35-20 which is what I would be switching to

EastTNMustang · May 23, 2017

When it's time to change my tires I'm probably going to 285/45R20 which will give me an effective gear ratio of 3.56... which I think is a good compromise of quickness and highway cruising.

Tammaro21 · May 23, 2017

EastTNMustang said:
Not sure how you got 3.63, going from the stock PP tire size of 275/45R19 to your current setup of 285/35r20 gives an effective gear ratio of 3.85, using 3.73 stock PP rear end gear ratio...and if you change to the 305/35r20 the effective gear ratio goes to 3.77. If you go to a 285/45r20 you have a ratio of 3.56 or go to a 305/45r20 gets a ratio of 3.48

For what you've indicated how you will use the car, I would keep the Torsen and change tire size slightly to improve overall performance.

Would you reccomend getting a 285/45/20 and get more sidewall rather than a 305/35 and getting more width?

3.73 to 3.31 pumpkin swap, durability question....

Tammaro21

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whatsup62

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EastTNMustang

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Davepurp

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Tammaro21

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