letsrunem

iTrader: (15)

I've gotten to the point where I know my T56 is holding me back. I have never stepped foot in this forum and I never thought I would, but here I am. My current setup is a forged 347 LS1, ported 317 heads, TC78 turbo, stock T56, Monster Lvl 5, 3.73s. High boost should be close to 800rwhp.

I do alot of street driving, and go to the track 5+ times a year. I want to get fast at the track.

I would like to see what my options are and what you'd recommend. Thanks!

novaflash2002

iTrader: (51)

id say a 4l80 with around a 3600 stall. be sure and buy a bad *** converter. (triple disk)

MY99TAWS6

iTrader: (3)

I am going to RPM 4l80e basically their top of the line trans and have a PY3400e yank converter. I researched the swap a lot and have everything else I think needed to do it.
Got flexplate from speed inc,arp bolts,lokar firewall dipstick,t56 to 4l80 wiring harness, my hptuners is setup for the 4l80 now,got big b and m trans cooler,got pedals and stock auto shifter and upper auto console,bmr relocation crossmember,think normal trans mount works. My 4l80e should be here in a couple of days its been shipped and will be getting on the swap asap.Hoping to get a week or two of driving the car with the new auto setup before winter storage.
Should have maybe went to 3600 yank but guess see how the 3400 works out.I didn't get trans brake as car isn't a track car might see track a few times. I did get shift kit in the trans.

MY99TAWS6

iTrader: (3)

If you don't want overdrive and want to do it a lot cheaper than a good turbo 400 would be fine then maybe go with 3.08 rear gears so its not so bad on the highway.
I can't go under 3.54 gears with my dana so overdrive is more important to me.

slow67

iTrader: (2)

3.00 gears and Overdrive is nice with a 4L80E, 2050 rpm at 70mph.

letsrunem

iTrader: (15)

Hmm I like the idea of light weight with a TH400, but I might miss OD. But I can keep my M6 ECU. And it's cheaper. I see so many different types of auto shifters, what is actually necessary?

INTENESS

iTrader: (4)

Im in the same scenario as the OP my t56 has been fighting for too long broken this broken that you name ive broken it.I have 402 on the spray on 150 shot should put close 700 to the wheels.Im going with th400 and hughes converter and manual valve body tranny.Will make driving the car alot more intresting then sticking it in d and going.

MY99TAWS6

iTrader: (3)

I don't think a 4l80 is much heavier than a turbo 400..anyone know exact weights?
Manual turbo 400 could be fun. I wanted as said overdrive and like higher gears like 3.54 off boost which is where my car is around town most of the time.You dont' go into boost much on a built 408 in town.Unless you like jail..! LOL

Also computers are better at shifting than humans these days.So nice to leave it in
drive and just concentrate on driving. But would have maybe went with paddle shifting auto if the 6l80 would handle as much power as 4l80 have.

TCI has nice paddle shifting 6l80 option.

jakeshoe

iTrader: (14)

TH400 is 135 lbs, Chevy short tail with OEM deep pan dry.

4L80E is 178 lbs.

01ssreda4

iTrader: (96)

I vote 4L80e. Congrats on the future swap.

Avengeance

iTrader: (4)

Another vote for 4L80.... just finished my swap... just have to do a little wiring and install the new Moser 9". Good luck... any Qs feel free to PM me.

FWIW I went with a FLT 4L80 lvl 4, Circle D 4C billet multi disc converter, Rossler trans brake. For the hell of it I upgraded my driveline to a Dennys Nitrous ready with Mark Williams billet slip yoke and ditched my Moser 9" with trutrac and 31 splines for a complete new unit with 35 spline and spool.

letsrunem

iTrader: (15)

Manual valve body- this makes it full time manual correct?

Also, I was reading something about if you do a 'brake on a 400 you can't downshift unless you're stopped. True?

I'm not going to ask if it's "better" to run a manual valve body but when would one want to?

letsrunem

iTrader: (15)

Thanks, just worried about fitment since it's going in a mustang.

Would I need an auto harness/ECU for a 4L80e?

Avengeance

iTrader: (4)

You can convert a M6 ECU (99+ years) to run a 4L80E. Check out LSXtune for the harness for the conversion.

FMS_FTW

Well for starters I would suggest going to the track more than... alot more than 5 times a year.. plus try building that stock T56 of yours up and getting an aftermarket master cylinder. The thing about the potential of 6-speeds is that they are more dependent on the ability of the driver than an automatic.. but if you feel like you can't drive a 6-speed turbo car than this is the place.

Anyways.. If you plan on street driving and are dead set on getting an automatic than I would recommend getting a 4l80 and a converter spec'd to what you want after talking to Chris at Circle D.

letsrunem

iTrader: (15)

So everyone is in here because they can't drive a 6-speed car well enough? Nothing to do with the fact that autos are faster in the 1/4?

I'm actually leaning towards a 400 now so more questions:
When would one want to use a manual valve body?
It has no connection to the ECU correct?

FMS_FTW

While the OP plans to make a good amount of power, 800 is nowhere near uncontrollable at a track and a 6-speed could still get very impressive times with practice. Now of course automatics are more consistent but again at the OP's power levels there are a good amount of 6-speed cars making very fast passes. I'm not trying to bash everyone in this section but from his post about how many times he has been to the track it is obvious that there is still a good amount left in the car with the T-56.


edit: didn't pay attention that you are the OP but I don't feel like re-wording my post.

letsrunem

iTrader: (15)

Yes I know it's possible but I want to go auto. I used to hate on auto cars all the time and even swore I'd never put one in mine. If I was going to drive on the street more, I'd keep it the way it is but I want to hit the track hard next year and get consistent.

letsrunem

iTrader: (15)

Also will be selling my T56 and <1000mi clutch/flywheel soon in case anyone wants to go to the darkside.

INTENESS

iTrader: (4)

I was the same with his thinking about automatic,but when you want to go faster and enjot the car more auto is the way to go,I wont miss the hydralics always playing havoc with the 6spd car goood riddance 6spd,As far as the TH400 maual valve body im not to informed on it yet just getting into myself.But from what I see people love the manual valve bodt feature you basically shifting the car almost like a 6spd,I think there has to be some interaction from the driver to drive the car cause just sticking into D is boring and no fun at all.