Hey guys,

This is my first post on the forums because I've been searching and reading deciding on the right path for my goals over the past few months and most of my questions have been answered in reading except for one. I haven't really found a consensus of what kind of power the 7AT can handle with a valve body upgrade and upgraded torque converter before experiencing unwanted issues? So, I was hoping some that have experience here could chime in.

-thanks

 

Welcome to the forum!
I was in The same place not too Long ago!
First things first, you will always have some type of issues to deal with at some point if you go forced induction. For example (shifting will be different, engine tune will never be as "perfect" as the factory tune (engineers spend THOUSANDS of hours perfecting a production tune). Tuners haven't cracked the auto transmission tuning code, so you still have a computer setting shift points for roughly 300whp when you have well over that.
This means you'll likely be hitting rev limiter every time you punch it from a stop unless you shift manually, well in advance of shift point.
Lastly, your car will ALLWAYS be a project! Once you crack that baby open you will ALLWAYS be listening/feeling for sounds, creeks, taps and other issues.

Once you accept all this you can think about how much power you want.
In my case, a Twin Turbo setup with 500+whp and a valve body upgrade, I know I am putting too much strain on my auto tranny at full torque. My trans takes a beating every time I floor it. I think about it every time!
Supercharges offer great power with less torque and a more even power curve. You could be north of 400whp and have a very fast G.

It's a trade off of how much power you want vs. the strain on your "stock" parts.
Good luck with your decision. PM if I can help.
Cheers

 

Thanks for the info, Wattles. Oh, I know they are always projects, I have an 04 GTO with a 407, APS Twin Turbo and built 4L60 that has been an ongoing project since 2008. I've been a domestic guy most of my life, but the G37 really caught my eye, so I purchased one to venture in to something new and more fun to drive having moved from Missouri to Georgia where there are a lot more interesting places to go for a drive . With what I've read about the options available, I've decided the GTM TT is the best option for me with the goal of 450-500whp. Main goal for the car is to have modest power to play around and toy around on tail of the dragon with co-workers that venture up that way. Previous experience 'growing up' taught me not to do excessive hull shots in a car not built for drag racing with such an increase in power (twisted the drive shaft and grenaded the rear-end in my GTO when a pinion locked up) so this car won't see much time at the drag strip. That being said, my main concern for the car is how the 7AT will handle my power goals with the valve body upgrade. How many miles have you put on your car with the power you are running and have you noticed any issues other than hitting the rev limiter from a stop when not manually shifting?

 

The car has about 5k miles on the TT setup. It's still pretty much brand new (2012). I have enjoyed the great power to weight ratio.
The car burns rubber thru 3rd gear. That being said, the trans gets confused sometimes when to shift. I think this may be a function of the valve body, or possibly just the increased power.
My acceleration isn't perfect at low RPMs but I think an update to my tune should fix that (hopefully).
I'm still waiting on a tweak to the manifold to eliminate a spacing/rubbing issue I'm having.
Not havin a windshield wiper resevior is a pain as well, although I'm trying to work out something with GTM to install that works & looks good.

If I can get those issues ironed out (and not have new ones develope) my daily driver will be complete (in my opinion)

 

Thanks again for the info! I was doing a lot of thinking last night at work and decided it would probably be better in the long run for me to just save for another month or two and get the transmission built when having the turbo installed. I say my power goal is 450-500, but we all know how addictive boost is and that desire to turn it up at later points lol. My delima now is where I want to get the work done...send it to GTM or Forged Performance (I live about 15 miles from their shop). While reading and hunting info needed on 350/370z forums and here I see that Forged did a lot of great things for the 35, but haven't read about much coming out of their shop for this car.

 

Bassmechanic12 congrats on your new purchase. I cannot give you advice on the 7AT transmission since I don't own one, but I can tell you about the positive experience I had with GTM. My car started out with a Stg One GTM Supercharger. My Stage one kit was installed by a subpar shop in Hawaii which resulted in boost leaks, oil leaks, and a bad tune. After trying to fix some of the mess myself I decided I was going to get it right the next time around and send it to GTM for any future upgrades. To make a long story short I sent my car to GTM to fix some of the issues I was having and install a Stg 1.5 upgrade. After all was done and said, my issues were resolved and my car was finally running like a supercharged beast was supposed to. I'm sure Forged is a great shop, but
I feel that if you plan to go with a GTM FI kit it would not be a bad idea to have them install as well.

 

I'd stick with GTM or Z1 locally.

 

Thanks for the info guys. Cereal, I see you're in GA, have you dealt with Z1 (if so, how is their work/customer service?)? I just looked up the location of their shop, that's not that bad of a drive (I live between Roswell and Sandy Springs) I may make a drive down there this weekend now that I finally have weekends off at work lol. Going to fly back to Missouri next week for the holiday and drive my Tahoe back down so I can put the G under the knife this winter when I decide on which shop.