Before the stall and Z06 wheels I put down 343hp/364tq on a DynoJet unlocked. Now with the 3600rpm 2.1str hp/street stall and wheels it's down to 288hp/282tq unlocked. When locked it put down 331hp/341tq. And unlocked on the spray it put down 389hp/377tq. So from unlocked to locked thats a difference of 43hp/59tq which isnt sitting too well with me. But the car did drop 5 tenth's at the track and still went through the traps at the same speed and I think theres more in it with a better 60ft. For all the dyno runs the timming was about 26* and the A/F stayed around 13.0

The mods I have are a lid, filter, lt's, ory, loudmouth, 160* stat, Predator tuner, DynoTune wet kit, and stall.

 

a4 are no dyno queens...but hey it droped at the track and thats what counts right?

 

Yep your right. Oh the bottle pressure was about 825-850 with the 150hp jets in.*rated at the crank* So I got 101hp out of that, which I dont think thats too bad after seeing what the stall eats unlocked and the low psi.

 

I noticed a couple things with this.
1. When a converter is locked, it is completely taken out of the equation. The converter is gone and the engine is delivering 1:1 to the rear tires. If you created more power unlocked stock then locked with the new converter, you have lost power somewhere else
2. MPH equals efficiency Your mph didn't change a tall. That is pretty impressive for a 3600 stall.
3. Check this out from PI...http://converter.com/whatsnew_dynamometer.htm
Dynos really don't tell you much about high stall converters and their efficiency. MPH does.

 

Seems like something else is amiss here. Environmental conditions, dyno operator, incorrectly set dyno parameters etc. can all fudge your final figure. But a loss even with it locked indicates something else went amiss there, and it wasnt the converter. Perhaps an inflated initial power figure?

I lost only 15rwhp unlocked with my Fuddle 3200 compared to my stock converter. Ive never locked mine cause I currently dont have the "mondo" clutch. With the 3600/2.2 I expect it will lose another 5rwhp but who gives a toss about that.

 

43 hp loss locked to unlocked is alot. The last time I saw a converter loose that much was on JS `s car when he lost 40 hp locked vs unlocked on his vig 4000 and he had over 400 hp. Ofcourse dyno numbers dont mean much but I think at some point you would have to take into account how efficient the converter is. Anyway take it to the track i bet its alot faster either way.

 

With the stock stall unlocked with stock wheels/tires it put down 343hp. With the Fuddle locked it was 331hp so thats 12hp short. I would guess running less timming, the bigger wheels and tires and the difference in weather could make up for that 12hp so im not too worried there. I just thought it was weird to lose 43hp going from locked to unlocked.

transsam- Have you put your car on a dyno? I see your running a Fuddle also.

 

Also on the dynographs the unlocked n/a one went from 4650rpm-6250rpm.*im guessing to keep it from downshifting or would the verter have unlocked then went up to around shift extension then pulled from there?* The locked n/a was from 3500rpm-6300rpm. And the unlocked spray went from 5100rpm-5900rpm. Im not sure what all was up with that. I know the time on the bottle he said he would make it lock into 3rd gear so it wouldnt down shift.*not lock the verter though by my choice* So if the graph doesnt start till 5100rpm does that mean the spray made it flash that much higher or what is going on?

Sorry for all the questions just trying to learn more about these things.

 

How efficient the converter is? Thats funny, he said he is running the same mph as he was before the converter. That folks, is efficiency. Dyno numbers don't mean anything. MPH=efficiency.

Also, I actually have averaged about 1mph gain with my fuddle 3600. No real dyno time, but +1 where, according to PI, efficiency is best tested.

 

Agreed. Different dynos load stalled A4s differently and can greatly mask the actual power output. Infact, if the dyno is not configured for the converter slip the power figure at RPM is a waste of time.

If you maintain MPH, or even gain MPH at the track, then its a good verter. Converters DO NOT create horsepower - they either leech it out via efficiency losses or preserve it due to the internal design. NO high stall that I have seen designed to slip more than stock CAN EVER dyno more horsepower on the dyno.

Now a dyno that loads an engine is infact creating a bogus figure for an A4 in that there is significantly less resistance load on the road. The more you load the dyno, the more the converter will slip and so the more power you will "lose". Diff gearing also plays a big part for a stalled A4, more so than for an M6. Higher diff ratios will decrease the torque required from the engine to drive the wheels at the same RPM, much like the windmill effect. The higher the diff gears, the tighter the converter will behave and hence the more "efficient" it will "seem" to be. A converter will exhibit less slip in 1st and 2nd than 3rd too. Wanna gain MPH with a stall? Lift the diff ratio. Alternatively, buy one with a full WOT lockup feature.

Ive logged my converter both on the road and the dyno and I can tell you it behaves very differently on the road.

Over here in OZ it has been shown that a locked converter in 3rd will gain 2mph and 0.2s over the qtr. Match that with the kick-*** 60' and you should kill any M6 with equal mods and power from a standing start. Stalls arent good for rolling starts, especially from anywhere above 30MPH.

A stalklked A4 will never behave like an M6. So don't fool yourself. If you are getting close to locked HP with an unlocked converter, you may well be experiencing some converter apply.

End rant.

 

Thanks guys. Yeah im still happy with the converter and belive its works right. I was just shocked by the drop in the #'s I guess.

 

Im glad all the experts chimed in. If hes loosing 43 hp unlocking the converter at 331hp I wonder how much he would will lose at 400hp. Did he get 5 tenths faster sure he did. The car is faster for sure as it should be with a loose converter. But this isnt a 4400 stall this is a 3600rpm 2.1str hp/street stall. To me thats alot of lose.

BTW I am not an anti fuddle guy. I have spoken to john and he seems to be a great guy who knows his stuff. So I dont need all of the fuddle nut huggers jumping in here to try to tech me in. I have had 9 different converters and alot more hp than 331 and never lost anywhere close to 43 hp. Is it possible he got a looser converter or something is wrong?

 

Did someone say they did create hp? I think his converter leeches alot of hp.

This is a street converter with a 2.1 str in his car.

 

offaxis- Thanks for the info thus far. I did actually find a sig last night were a guy had my mods plus a pulley, 3.73's, and a dyno tune and he put down 298. So im thinking Fuddles may just not be for the dyno which I can live with as long as it puts down the times at the track.

 

Devon

Im not trying to get down on you or fuddle. Trust me I am not that guy.

BTW on the dyno the converter looks like its only 87% efficient compaired to locked when unlocked so if thats a good number then Im way off base.
Ofcourse the track/street is different than the dyno.
Can you post the info from you full time slips before and after your converter?

60ft

1/8 et and mph

1/4 time and mph


BTW if you made 400 hp locked you would loose 52hp unlocked

 

My slips are home ill check those later. I didnt take it as you bashing Fuddle at all. And I made 331 locked 288 unlocked n/a. The 389 was on the the spray unlocked.

If I remember right track times were. I post up though later once im home with the slips.
60ft: 2.0x
1/8th: 8.4x @ 86
1/4qt: 12.9x @ 108
Stalled
60ft: 1.79
1/8th: 7.9x @ 86
1/4qt: 12.4x @ 107.5x

 

**** if i could get my bolt on only car to run high 7s in the 1\8 i would **** a brick!lol good #s

and as said b4 a4 are no dyno queens if it gained at the track then im sure you didnt lose any hp...

 

I'm a bit confused but I would like to see images from these pulls and
line up the locked / unlocked, same-basis ones for my "Efficiency dyno"
series of Excel sheets.

I have done a little logging on my new converter and see it just get to
95% at 6000RPM. But this is past my HP peak I'm pretty sure, stock
cam.

The MPH speaks less to peak HP /efficiency, than the total efficiency
across the powerband. You could have the same trap off a converter
that was slightly less efficient at peak, but got up to efficiency sooner.
Or not. It's really integral HP*eff@RPM that rolls up to the trap speed.

I think you have to check all of the "setup inputs" that went into the
dyno machine, I gather that things like wheel size, gears, etc. can
really throw off the numbers that all the "data massaging" comes to.
Locked/Unlocked, same day, same spray, that should tell the tale
as far as efficiency. Too many variables in separate-session dyno
results, I suspect, to put much weight on that comparo.

 

Ill get some pics up of the graphs in a few days.

 

No-one did. Its just that I read all the time about how much power is lost on the dyno with a stall and it seems to me it shades a lot of peoples opinions on how they actually perform.

And yes, as 93% efficient converter is getting a little too loose in my opinion. To get a truer measure of performance in a car, efficiency must be measured on the road/track by logging input/output shaft RPM and TCC slip RPM.

Note however that while being looser, it may well show greater efficiency by way of torque multiplication up until hydraulic lockup, then show less efficiency afterwards, the nett effect being greater average power delivered to the wheels hence faster MPH and lower ETs. Thus, there is something to be said for matching the right converter to the cam. The wrong converter may show less MPH in one car and more MPH in another.