darrensls1

Let me quote what I read in a thread from early this year:

I just don't get it. I don't think the difference between a a4 to m6 is that big. Anyone got any input?

I am having a 408 built with ETP LS7 heads, LS7 intake, custom cam, ect. I was going to keep the TCI 3500 for awhile. Lets say I make 475 rwhp. Going to a Pro Torque converter will actually bump that up to 550 rwhp?

It just sounds too good to be true.

05gto60

iTrader: (3)

maybe they had a bad converter to begin with? i dunno. ive always been told that bigger stall converters loose power on the dyno. maybe somebody that knows transmissions can chime in

BlackHawk T/A

iTrader: (3)

It is...

Numbers can get very skewed with a converter that "stalls" or slips to a higher RPM. They are not telling the whole story.

performabuilt

iTrader: (25)

Converters change the way and at what rpm torque is applied , in this was yes you could get higher HP and T numbers at various rpm ,However overall they cannot add hp and there is actually some loss through them , As stated above numbers can be skewed to look a certain way, Im sure with the sheets and all the info it would tell a diferrent story

FLT

iTrader: (1)

Ok let me throw a bump in this thread. I have talked to alot of customers that call up complaining that on the dyno they had lost rwhp when they did a TC swap. Although at the track their vehicle had picked up mph and et's. I guess what I'm saying here is that Dyno numbers are just what they are, numbers. The truth is told at the track. The Dyno is a tuning tool and truth is told at the track. Vince

performabuilt

iTrader: (25)

Agreed converter affect how the power is applied which means everything at the track in most cases way more than the actual numbers

Ragtop 99

iTrader: (7)

The only way it gained 75 rwhp is if it was broken. The worst of the inefficent converters I've seen have cost roughly 40 rwhp locked v. unlocked on a bolt-on LS1. The best I've seen is around 9 hp unlocked loss. So any delta over 30 rwhp is probably a mechanical problem. Even accounting for a 408's extra torque, it would have to be mechanical or so totally the wrong converter that it was just luck that it fit on the input shaft.


I have seen some big torque differences between converters on the dyno. You can get a bigger torque number by going to WOT at lower mph so that you are riding the converter more. Also, the big stalls played havoc with the dynojet software in the past. Supposedly dynojet fixed that a year or two ago.

ls1408cp

iTrader: (37)

my 408 dynoed 490rwhp and went 10.30s on its first pass dont dyno race with an auto you will lose

darrensls1

That's impressive. I spend a lot more time at the track then at a dyno so I'm not caught up on dyno graphs. But I'm also not stupid and would rather have 550 rwhp instead of 475 rwhp (auto or not). I understand about converter effiency so when I read that comment, saw it was backed up by another poster and further saw no one disputing it I got a little curious as to how this could be possible.

It appears to be another case of something sounding too good to be true and thus it isn't. Looks like I'll stick with my TCI 3500 for awhile longer.

Thanks for the replies

GXPPOWER

indeed their is a guy who only has slp lid and exhaust. and a 3500 ish stall.

he ran 13.6 before the stall at 102. and after the stall went 12.9@104 dont let a dyno trick you. who cares if you dyno less. a stall keeps you in the power band long. your not actually making more HP your just Utilizing more of the Peak HP that is already their.

Sean Collins

Are we talking peak or Avg HP. If i saw a converter pickup 75avg HP then i do agree with sevral of the folks here. Something was wrong with it or it was a total POS.

Converter Vs dyno arguments. the dyno is not the issue. the problem is HP vs ET. its only takes about 490whp to run 10.30's in a 3000lb car in fact i have seen sevral vehicles making mid 500's run mid 9's. the secret to why exactly a higher stall converter makes a car faster is that it add's avg HP by keeping the engine in its power band. It may dyno lower but will be faster to a point. If you have a crappy converter IE fuddle its very easy to have your car slow down alot simply becuase the converter is so infficient.

MNR-0

I lost 20rwhp peak with a converter swap, but gained 20rwhp average! Not to mention 0.5s and 2mph faster at the track.