I was wondering what guys have stock automatic transmission in their FD, drag or street race what type of mods and how the transmission are holding up.can a trans brake be installed in a stock tranny?

I was thinking of going manual then I learned about the Th350/w Trans brake but before I make a decision I would like to know what has been done out there with the stock tranny.

 

From what I've been reading, it's a toss-up when you puch the hp past 300hp. That being said, I'm not sure about the TH350. Sorry.

 

no need fo a swap now that banzai racing has developed the auto ecu harness. it let you use the auto trans at stock functions while upgrading the ecu. I now use the pfc and the trans works the same as stock. you can upgrade to a level 10 trans for the stock unit or go with the TH350 but that will require some mods.

What are your mods now?. if your not going over 300 HP just get the stock trans serviced with synthetic oil and don't power brake or speed shift the trans and it should hold up for a while.

with all the bolt on's and a dyno tuned pfc 280-300 rwhp is about max you will get on stock ports and injectors. I will post some numbers after I get my car tuned in a couple of weeks.

Jeff

 

no one makes a transbrake for the stock rx7 transmission.

 

The stock mazda auto transmission will not take much over 300 hp. It WILL burn up. I know from experience. Exactly why I went manual transmission. so if you stay under the 300 range and watch those tranny temperatures, you'll be alright. But when the mod bug hits, watch out.


Later

 

I have a TH350 w/transbrake tranny in my car. gotta say... trans brake is insane, one push of a button and crazy g-force pushing u back in your seat. KDR did the conversion.. unfortunatly i think i blew a coolant seal so its back there right now. got ne questions about it just ask

 

The one mod you can do to help any automatic transmission from premature failure is the addition of a transmission cooler. The automatic FD transmission can be upgraded to take the abuse of 700RWHP with no problem, it's all about the $$$. Upgrading to a slightly higher stall converter will help with launches as well. No transbrake is available though for this transmission.

 

I guess you mean upgrade the trans cooler as the auto rx7 already has a stock trans cooler located on the passenger side oil cooler mount. Stock stall is around 3-3.5K. Any higher wouldn't be streetable.

I had modded/rebuilt my stock tranny with level 10 components. It served me well and I sold it when I swapped to a 5 speed. But the guy that bought it after me broke it at the drag strip. Nowhere near 700hp either.

 

track only car?

 

in all my research, the auto rx7 tranny is still grossly unexplored. banzai's harness is the first step in really seeing where the breaking point is. without the harness it appears (from a few that have pushed the transmission) to lie in the 300-350 range; however, no one has really came up with any solid list of transmission modifications done to these "failed" transmissions.

in my book an additional/better transmission cooler is an absolute must on any modded auto car. I'm currently running both the stock cooler, an aftermarket, and the banzai harness. still got a few other pieces to put on the car before getting it over to tuning.

 

these cars stock have about 210 rwhp. so moving up to 300 rwhp is a big jump for a stock trans. thats why adding synthetic oil and an aftermarket cooler will add longevity. even now with the banzai harness I think 350 rwhp will kill the stock trans. so if your going to have numbers over 300 rwhp a level 10 or better upgrade will be needed or the trans will be short lived. we need someone with a one owner low mileage well maintained trans to do the testing.

my car was purchased used so I have no idea how well the car was cared for. so my results will not be accurate.

Jeff

 

Na, I drive it everywhere, havent even had a chance to take it to the track. gearing is shorter then what i would like it... tops out about ~125mph. I do wish I had a 4thg ear or overdrive cause im at about 3500rpms going 60 mph on the highway. great acceleration though.

 

The reason I know about the th350 on an FD is because I read one you your threads so from your experience would you have rather go manual or stay th350?

 

Did you keep the auto 3.9 rear end?

 

This is a link to mods I've done on my datsun jatco 3n71b. I also have a zip file with the rebuild info for nissan jatco's from keas. You might be able to apply it to the mazda trans. PM me with an email address to send it to if you want/need it.

http://www.z31performance.com/forum/....php?f=3&t=889

 

While we are on this subject...yet again....I have always wondered one thing: What EXACTLY 'fails' on the transmission as you go up in hp? Gear sets? Clutch packs? Torque converter? Combination of things? And so...what EXACTLY is done by shops like Level 10 to make these 'bulletproof' trannies?
In all the 'muscle car' playing around I did in the '70s, most people were running TH400s in REALLY modded, big block cars or dual-plate clutches if they stayed 4 speed. A stock TH350 would run forever with engines pushing 400 hp and cars weighing two tons. Shoot....one of the fastest, most reliable combos I'd seen was a friend's '62 Chevy running a 283 with a two speed Powerglide...that car ran in the 12s at the track and was his grocery getter/work car too.
There are some excellent transmission shops in my area, I've been tempted to purchase one of the many stock FD transmissions seen for sale here or go to a salvage yard and get a MPV tranny and take it to Neil Chance here in Wichita and let them play with it.

 

My planetary set grenaded. My trans also slipped like crazy until I did vb modifications. The 2-3 shift flareup was terrible. A jatco with the 4 gear planetary will hold as well as a c4 according to Keas.

 

bajaman- thats awesome that you are looking into the auto tranny.i would love to make 400HP and still rely on my auto transmission it would be even better if some made a trans brake for it.i my self will be looking and asking questions to the automatic gurus to see what can be done

 

When I pull my auto, we can figure out a way to get it to you, but the shipping probably outweighs the free transmission. I'm figuring if they can take a 200r4 out of a GN and make it run in the 10's, they can do the same to the rx-7's trans. Just upgrade the internals to billet, have good clutch packs, springs and a shift kit to firm it up some. Some might be willing to pay $1500 or so for a built reliable auto trans that can hit the drag strip (transbrake?) and then auto cross and drive home...Heck, I would if it was available.

 

Shipping these days IS outrageous but if you get to the point of really wanting to give it away....I'd be willing to work something out with you perhaps.

And yes, I can speak for myself and probably others in saying $1500 would be considered very reasonable. Heck, Level 10 wants a grand for the torque converter and $3,300 for their 'bulletproof' tranny.

http://www.levelten.com/store/mazda.htm

 

It ain't bulletproof.

 

I'm definitely serious. Would love to contribute in some small way. If it's the trans and later, a few dollars, would be willing. Hopefully I'll get my longblock soon from Jerome (djseven), still trying to get a 5-speed and when I get the automatic out, I'll contact you in trying to get it over there.
Meanwhile, I can try to contact the GN guys and see if they can do something about it. Aloha. Robbie.

 

C4 $50
$300 to build it
$500 converter from www.DirtyDogPerformance.com
$50 2nd Gen Auto Bellhousing, Starter and Flexplate
$200 driveshaft
$100 Manual Valve Body
$250 Transbrake

Much cheaper than a TH350, Levelten or KEAS

 

Where did you find a manual valve body for 100.00?

 

That is why I put it as 'bulletproof'....lol!