mikemodano9c

hey guys...

i was wondering what you guys saw with your converters on the dyno locked opposed to unlocked...specifically a midwest stall...

i made 400 unlocked...and i just wondered how much i should expect to gain with the converter locked...

it seems there is a big difference with different brands, stall speeds, etc...

thanks

SDB

iTrader: (7)

I had my car dyno tuned at Livernois Motorsports on a Mustang dyno (403 rwhp) with a Vig 3400 multidisc. I wanted the car to lock up the converter in 2nd at WOT, but Greg Banish talked me out of it. He said it would gain up to 3 mph or so in the 1/4, but is very very hard on parts. I don't know how much more I would have dyno'd if I had it locked. Seems people do this just to post good numbers (i.e. tuners). Dyno it as your going to drive it (unlocked).

SDB

mikemodano9c

it was dynotuned unlocked...i just wanted to know because i made 397 unlocked and wondered if anyone had a midwest locked/unlocked dyno to compare it to...

Ed Blown Vert

iTrader: (2)

I thought you had to tuned it locked?

mikemodano9c

no it was tuned unlocked...

he was going to lock it for the final #'s, but i blew up another tranny housing before that run...

if possible as i understand it...it is better to tune unlocked because that is how the car is run WOT in the real world...

of course if you have a 4400 stall it might not be possible to tune unlocked since your starting at such a high rpm...

either way...the final numbers should be locked up to 1. get an idea of what efficiency your converter is providing and 2. to get some real numbers on what power you are making.

the efficiency of different converters is too wide of a spectrum to measure comparing unlocked numbers...

Tom's_03SVT

i saw a 15RWHP difference.......

Sunset01

Tom'sSS, was this with a Midwest converter? Which one?

I dynoed today for this first time & I show 30hp unlocked/locked
with my Midwest 3200/2.0. I was expecting more like 20hp.
Dissapointed and tempted to consider a more efficient converter.
Trying to also understand how any high stall converter can help
but lose more like 20+ hp doing the slipping to higher RPM thing-- i.e.
if the converter measures super efficient, is it really getting you higher
in the rpm's compared to a converter that measures less efficient.

Mike, have you run locked yet ?

mikemodano9c

i posted in your thread...no i havent done a locked run because of my tailshaft housing breakage problem, but after i get that taken care of i do some locked pulls and post the results...

im running a midwest 3200 steel stator 3200 2.0 str

if i pick up 20-30rw locked ill be happy that my motor is making more power than i thought, and if that is the case i will probably make a lockup switch as well...

like you said in your thread, you might consider a multidisc vig...they seem to hold very well in the upper rpms

i didnt figure a 3200 stall would loose that much up top...something like a 4200+ stall i could see a 30rw hp drop, but not a stall under 3500 rpm...we'll see what happens

Sunset01

I have yet to find a good graph with anybody's locked/unlocked #s with one of the higher (20+ ) losing torque converters. I only got one high rpm run, but I really don't like the trend of that torque line unlocked in my graph.

http://www.vettecaliper.com/ls1/scan.jpg


Dean

DEEZ98Z

iTrader: (5)

I have a Vig 3600... and I saw a 18hp difference between locked and unlocked.

Sunset01

Given my findings Mike, your loss is hopefully much less, assuming your
converter was made for your power level.
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I've my converter figured out & I think possibly my short shifting issue. I didn't have the cam planned when I first ordered the converter. I am 'blowing through' the converter with the torque/power I am now making. 'verter coming out this weekend and Midwest is restalling for free. Some of my old scanner logs showed how loose this converter acted with my hp- at the top of 2nd gear, my actual mph is about 10% less than predicted by pure tire/gear calculator. It is worst around 5000rpm & slightly better toward 6000rpm- just like the unlocked dyno, which makes perfect sense, torque is dropping off at that point & I am blowing through the converter 'less'. I am confident that my short shifts will clear up too- thinking the computer was confused with almost 10% slippage.

mikemodano9c

i replied in the other thread...

i dont think there should be any "blow through" at your or my power level with a regular midwest converter...

i think the normal midwest's are rated to 500hp...

Sunset01

I'll put my same response here to:

I did tell them at the time, basically full bolt ons... I think John at HPA related that to 330hp. No steel stator/stator quality has more to due with physical parts durability, not how the converter is going to operate.

I don't pretend to fully understand this stuff. But I do know that the same converter is going to act very differently with different hp.. I didn't expect 30-40hp to make this much difference, but it may have been leaning on the wrong side of even my lower hp estimate. The 'blow through' is not due to physically inferior parts- Dennis at Midwest said they use 12 different stators and that each one can represent 30-40 hp range (or more properly ft-lb torque). I believe that my exact converter on a stock to light bolt on car would show more like the 20hp loss.

mikemodano9c

i dont buy any of that...

from my understanding...and some common sense i would think...

why would you put a stator in a car that cannot support the power the motor will make, when you have access to a better stator that will handle the power? the only reason i could see to do this is to increase the stall of the converter...correct?

my point is...even if that were true...

with only a 3200 stall speed midwest should be able to make a converter that doesnt loose 30+ hp at only a 3200 stall speed...for that to make sense, the stall of the converter would have to be higher than it is spec'd for...probably way higher (4000+)

im not sure if that is clear, but in the end midwest should be able to make a true 3200 stall that looses only maybe 10-15 hp (if that) in a cam only, bolton car.

if what they are saying is true, i think they just skimped on the internals...plain and simple...

if they sold you a 3200 stall it should stall at 3200 and be able to handle power up to 500hp (as per their rating)...

if you increase your power output (up to but not over 500hp) then the stall speed might decrease (ie 3000 or 2800) but it should still handle the power. if you paid 450-500 bucks then you should have gotten what you paid for...what they advertised...