TurboAv

iTrader: (6)

For example:

If a six speed guy is making 1000rwhp what would a TH400 guy with a good converter be making assuming the same engine is used?

I'm trying to figure out my realistic power goals for my car to size my turbos correctly. I'm on a stock gm ironblock, 370 with forged internals, and 243 heads. What horsepower level at the motor and I safe to? Then what RWHP does that translate to?

smokinHawk

iTrader: (48)

Well the th400 will put more to the ground so that is worth any loss

TurboAv

iTrader: (6)

I know it will be faster for sure. I'm trying to figure out what the safe max is on my engine and what that will translate to in RWHP.

BlwnTA

iTrader: (18)

My guess would be 925-950ish.

Zombie

iTrader: (2)

depends on the dyno, converter, planetary alignment and moon phase. For example, my 3840lb race weight car with Th400 dynos 520 rwhp and goes 10.0-10.2 @ 135-136. The math says it takes 740 average RWHP to do that so the dyno is off by 200ish rwhp in my case. According to my fuel flow (100% DC on 95lb/hr injectors running e85) I'm making around 900 HP at the crank which is in line with my 740 average rwhp.

So according to the dyno, I'm losing 380ish HP through the TH400 LOL.

Nothing wrong with the dyno either, stockish LS1's dyno right around 280-300 rwhp stick or auto.

Moral of the story DYNOS ARE TOOLS FOR TUNING

SPRAYED 01

iTrader: (22)

I would say 850. You lose alot on a dyno through an unlocked trans.

ninetres

iTrader: (35)

+1


But like Zombie said. THEY ARE JUST NUMBERS for tuning. WHO CARES. The TH400 car would put busses on the M6 car at the track.

mike13

iTrader: (27)

Don't get me started on convertors and horsepower, there is absolutely no correlation between the two. 18mths ago I installed a STS t-67 kit dynoed 330rwhp with 8psi 3200 stall 700rpm loss in the convertor, similiar car with stock convertor, same tuner dynoed 424rwhp. My friends teased me that I had the fastest 330rwhp car they'd ever seen.

IT_SS

iTrader: (5)

that sounds sounds odd...

mike13

iTrader: (27)

Not really, the load and resistance placed on a set of drive wheels by a dyno doesn't neccesarily match the same load and resistance that a torque convertor sees when pushing the car.

Turbo LS1 SS

iTrader: (7)

i can tell you with 17psi (VERY conservative tune), my car only put down "776rwhp" on a mustang dyno (408ci S88). Two days later it trapped 150 at over 3700lbs race weight. When the car was a M6 making siginificantly less power with a 365 and 76GTS, it made 749rwhp at 14psi on a dyno dynamics.

Never had my current setup on the dyno when it was with the M6, but i can tell you it feels exponentially faster with the th400. cars with the same setup have made over 1100rwhp through th400's

TurboAv

iTrader: (6)

Maybe I'm asking my question wrong. I'm building my car on a stock GM ironblock with ported stock 243 heads. What's the limit at the crank I should take it to and what will that number translate to in RWHP through my TH400?

SPRAYED 01

iTrader: (22)

I would say if you get up to around 900whp through the th400 your at the limit. Thats probably aroound 1100 flywheel hp. Im sure you can run more power than that but its pointless on a street car and it might not last as long.

TurboAv

iTrader: (6)

Ok. So my target of 750-800rwhp is going to be a safe guestimate on what is safe on my engine. Thanks.

engineermike

A couple years ago, INTMD8 and I were both pulling nearly the same mph (146-148). His was a T56 and made 850 rwhp, while mine was a TH350 making 700 rwhp. So, I'd say that a stick making 1000 rwhp is equivalent to an auto making 800-850 rwhp.

TurboAv

iTrader: (6)

That's some good info. Thanks.

Cliff

iTrader: (19)

I don't believe there is a clear answer. The general rule of thumb everyone seems to go by is, for a th400 you will loose around 20 to 25% hp over a M6.

TurboAv

iTrader: (6)

I just want to make sure I'm not pushing my motor to hard. I'm going to shoot for 750-800rwhp MAX and leave it there. Then start saving up for a 6 bolt setup because I know I will want more power eventually, lol.

stangeater01

iTrader: (125)

i made 558rwhp with my 6 speed was going 11.0's put the th400 made 491rwhp but went 9.9's i am sure some was driver error

Elite_Hot_Rod

15 to 20% HP lose thru an auto as compared to a manual. Probably close to 800 RWHP.