1 year after th400 swap

[Bo White]

Still lovin it!
Since the swap Ive changed the 3.45 gear out for 4.10s and swapped the 10" 4000 stall out for an 8" 5000. Its a real fun daily for me. Exactly what I wanted ever since I bought this car.

[Rob10CamaroSS]

T400 w/4.1's & 8" 5000 RPM Convertor must be SICK
I would imagine the 1 2 shift is INSANE

[BradySS]

Sounds close to my setup which has a RMVB and brake 400. Stall was supposed to be 5500 but ended up coming in at around 5300 when I'm on the brake. Went from stock gears to 3.91s and I'm running a 29.10.5W/15 Hoosier. Stalls an 8" billet from Circle D and has done well. I'm spraying the car now and a 75shot that I was using to test its fine but the 200shot it immediately is on the limiter its just blowing right through the stall. Pulled the converter out to send in and I'm going to knock 1000rpm out of it.

[Bo White]

Yes. The more power you put against a converter the higher it will stall. I was running a mvb but pulled it out. Too much wear on the pump for a daily.

[gmcvt]

Bo, please forgive my ignorance here. I've been reading through your swap threads and Diet Cokes...bouncing back and forth between a TH400 and 4l80. Each one has its benefits and drawbacks. (like everything else) My question would be this: Does not having lock up negatively effect your ET? My understanding is that at some points, say during a pass on the strip, your converter will go into lockup which increases your wheel hp, because you are now 1:1, correct? So if that is true is the loss of ET negligible if you do not have that ability? I assume it must not be a huge issue since you decided to go TH400.

[Bo White]

Usually locking the converter will give you another tenth depending if the engine is in the meat of the power when your at that point on the track. Thing is the th400 is lighter than the 4l80 and 6l80 so its a wash most of the time. We found that out at CamaroFest7.

[gmcvt]

Originally Posted by Bo White

Usually locking the converter will give you another tenth depending if the engine is in the meat of the power when your at that point on the track. Thing is the th400 is lighter than the 4l80 and 6l80 so its a wash most of the time. We found that out at CamaroFest7.

What happened there? Are you just talking about the overall physical weight of the trans or less reciprocating weight? Only reason I ask is I didn't think that the overall difference in the physical weight between the th400 and 4l80 would make any measurable difference in ET.

[Bo White]

The transmission is lighter and rotating mass is lighter from lockup to nonlockup.

[bct10985]

Overdrive and lockup are nice @ 65mph

[Bo White]

I drive 70 most of the time.

[EV1L SS]

So what are your rpms like driving at 70? I also wanna swap to the th400 . I'm just concerned if I'll be able to cruise at like 65 with my 3.91s and 28" tire...

[EV1L SS]

Also what would you say the total cost to swap from a m6 to the th400 is ? Thanks

[Bo White]

I cruise at 3500rpm at 70
Youcan do the swap for around $3500 nicely

[faSSteddie]

Originally Posted by gmcvt

Only reason I ask is I didn't think that the overall difference in the physical weight between the th400 and 4l80 would make any measurable difference in ET.

Best that I can tell, the difference in weight between the two is about 100 pounds. ( TH-400 roughly 140 lbs and the 4L80 about 255 lbs). A very good rule of thumb is every 100 pounds is worth 1/10th of a second in a quarter mile for street-type cars or non-dragsters (all else being the same).

This certainly backs up Bo's experience as he lost 1/10th from no lock up but gained 1/10th from shedding 100 lbs of weight... thus no net loss or gain.

I love it when theory and the real world coincide!
faSSteddie