I have an 09 G37S RWD with a 7 speed auto that I'm planning to turbo charge. I know that the car will make around 650 RWHP once I'm done. Therefore I'm looking to first to modify the 7 speed automatic transmission to handle the power as well as modify the torque converter for a higher stall speed and install a transmission cooler. Does anyone on this forum have any experience with a 7 speed automatic that was modified for higher HP levels? If so, what exactly was modified in the transmission? How does the transmission shift in comparison to the stock one in the D and DS positions? Is there still a delay at times with the steering wheel paddle shifters? What HP level is your car at? How many miles do you have on it with the modified transmission? Any issues with it? Etc. I can't start turboing the car without addressing the transmission first so I'm asking anyone out there with a modified 7 speed to please post your experiences on this thread. Thanks in advance.

 

Im pretty sure you will get a answer. GTM supplies almost everything you need as far as the transmission requirements.

 

Due to not seeing any responses as of yet, I'm going to assume that either #1 There are no modified 7 speed automatics out there OR #2 No one with a modified 7 speed automatic transmission wants to share any info. Crickets so far....

 

This morning I had a conversation with Pat at Level Ten. He says, yes, they are new, but he's worked on them for clients in Dubai with Nissan Patrols. Same trans, apparently. He does a brisk business with the royalty vehicles in the Middle East.

Coop

 

Try the search option. Maybe you will find out more infos about it.

 

take a look at the GTM stage 2 SC press release document, that's all that i have seen so far

 

I looked at that thread and still NOTHING with anyone stating any experiences they have had at all with the 7 speed AT. I know that GTM sells modifications for that transmission but has anyone bought any?

 

I know there's a guy either on here or on the370z.com with the GTM torque converter. but that's the only upgrade I'm aware of that anyone has.

 

I think a few have put in their orders, but as far as i know, no one have it installed. Shumby is the one who sent GTM it's R&D unit, and he hasn't even got it back yet.

 

If that's the case then I don't understand how anyone selling any modified 7 AT transmissions can make any claims of TQ/HP limits of the transmission yet. Hmmm....

 

We have couple 7 AT build transmissions on the road for while know with grate results, one off them is a twin turbo pushing over 500 RWHP .

If you are looking for a unit that can handle 600 to 700 RWHP then i would recommend our stage 4 trans, Here is a list of what improvement we made in our stage 4 transmission .

-Increase Heat capacity resistance by upgrading OE friction material from OEM D-0530-31 to GTM D-0880-88. (35% Over Stock)
-Increase Clutch Friction Plate Surface Area By increasing amount of clutches used (from 32 clutches to 44)
-Increase Torque holding capacities by 40% By using different friction materials and adding more clutch plates
-GTM Separator Plates are used specially-made from high-quality steel to ensure durability,and are done in several processes to control surface finish to meet friction requirements
-GTM Stepped pressure plate
-All Separator and Pressure Plates are Surface treated to increase durability and reduce frictions
-GTM Lube Modification
-GTM Apply Pistons
-GTM shift point and speed Modification

 

Thanks for your response. Is it possible for you to ask any of the customers that have your modified 7AT transmissions to post feedback on this thread with their experiences? Any videos of these cars at a racetrack? Thanks in advance.

 

so far i think there's only 1 person that i know of has some of those mods and he does take them to the track and beat on it. let me try to find you those links.

not a whole lot of info but for sure this guy has a modded 7at. you can PM him over there and ask him about it.

http://www.the370z.com/1554343-post9.html

 

Thanks Weiboy718, I PM'd that guy on the forum to ask and also asked him if he could post on this thread as well. Let's see what happens.

 

In general an automatic transmission is modified to handle more torque and have the transmission shift at a faster pace by altering shift points, raising line pressure, adding stronger clutches, separator plates, bands, pressure plates, pistons, etc.

The intent of starting this thread was to get more information and opinions on modifying the JR710E transmission because there doesn't seem to be much out there as far as specifics go. I don't mind paying for a shop to modify my JR710E but since it's my transmission that's being modified I should be told exactly what's going to be done, why and how. I called two different shops and asked a few questions because I like to be informed as much as possible before making a decision. Here's feedback I got from some of the questions I asked them:

Shop#1: I asked this shop if I could buy the parts from them and modify the transmission myself since I have access to a transmission shop and tools. They stated that I could do that but it was not cost effective because there was also some machining that had to be performed and by the time it was all said and done, it would end up costing the same or more than just having them build it. I crunched the numbers of how much the parts were from what they told me and I agreed with that statement. I also asked how the electronics played into the shifting of the transmission and they stated that this was changed inside the transmission by the modifications performed by them, whether this was the only thing performed to alter shifting or not, I don't know. There is a 4 week wait to get this transmission built by them.

Shop# 2: I asked this shop what parts they changed inside the transmission, etc. They weren't too willing to tell me what exactly would be replaced inside the transmission, only that the transmission would handle my HP goal. I also asked this shop about how the electronics played into the shifting of the transmission and they stated that changes would be done through the Uprev software because there's a section in the tuning map where you can change the torque values on the transmission. I'm not sure exactly what that controls but it sounds like the line pressure in the transmission, this is just my speculation at this point. Once again, whether this was the only thing performed to alter shifting or not, I don't know. This shop stated that the wait to modify the transmission is 3-5 days.

I also called Uprev Engine Management Solutions to ask if there was such a parameter in their software that allowed changes to the transmission and they confirmed that there is a screen where you can adjust these settings.

From the responses I received there are a few things I'm questioning:

Question #1:

I know that in traditional/older cars, the valve body is what controlled how the transmission shifted. Shop#1 is telling that they modify the transmission internally to do this, is this done by modifying the valve body?

Questions #3&4:

Shop#2 is saying that they modify the way the transmission shifts by making changes in the Uprev software. Which shop is right? OR are both shops right in some way?

Questions #4&5:

If Shop#1 does just change something internally inside the transmission, would it also benefit more so from making changes in the Uprev software for the transmission? If Shop#2 just makes changes in the Uprev software would it benefit from what Shop#1 modifies inside the transmission?

Question #6: Shop#1 mentioned that there would be some machining performed inside the transmission when being modified, does anyone know exactly what this consists of?

I do understand that a lot of R&D goes into modifying a new car. Especially in a transmission like the JR710E that is still considered fairly new as far as modifying goes. There are certain things that these shops keep to themselves due to the fact that they spent the time, money and R&D getting their products ready for sale. I hope that no one takes offense to anything I've stated or asked.

Thanks to the both of the shops I called today for their time in speaking with me, I know your time is precious when running a business these days and I thank you for taking your time out in speaking with me.

Also thanks to Uprev for speaking to me and answering my questions as well.

So can anyone out there educate us by answering the questions above? This isn't my first time down this road by any means and I just want to make sure on what exactly it is I'm buying and how it works. Thanks again in advance.