josh99ta

iTrader: (1)

I'll soon be getting some dyno time as part of a club discount day, and I have no way to lock the converter. I've read before that unlocked numbers are irrelevant, but under real world conditions, when you're going full throttle through the gears, the converter isn't locked anyways, so why would these numbers be irrelevant? Also, without being able to lock the converter, what am I going to see anyways? I'm assuming a torque spike and some lost HP, but how much of a spike and how much of a HP loss on average?

Last time I dynoed was stock and the car put down 282/304, so with the intake (SCC ram air good-for-nothing dealy :p), exhaust (Hooker catback), free mods, etc I'd hope to be around 300 rwhp, but taking into account that dyno was around 50,000 miles ago I'm probably down on power anyways, and with the built tranny and converter I'm assuming I'll lose some there too, not to mention not being able to lock the converter and the fact that those stock numbers were with the stock 16x8 chrome wheels and I'm now on 17x9 ROH Snypers, what kind of basic numbers am I looking at here? Will I be below the initial 282/304 numbers you think (for some reason I see this as a very real possibility)? Or despite the mileage (which were 50k HARD miles), should I still be about where I should be given my minor mods? Thanks for any help guys.

Ragtop 99

iTrader: (7)

The peak HP numbers aren't irrelevant. However the TQ reflects the converter at lower rpms and rpm readings are skewed by the converter's flash & shift extension. It makes it more difficult to accurately tune becuase of the error introduced by the converter. The dyno is for tuning; the track is for racing.

If you're there just for the fun it, don't work about it. If you are there to tune A/F and timing, use Edit to lock the converter.

JS

iTrader: (4)

Ragtop I dissagree,A T400 doesnt have a lockup verter but u can tune it just fine on a dyno?Granted the 4L60E in unlocked runs will peak alittle higher than if it were locked but dont tell people u cant tune a car thats not locked.

Mikey from Rapid does it all the time....
JS

josh99ta

iTrader: (1)

Interesting discussion and points made by both Ragtop and JS. Any other input?

Also, this is for a group dyno, and it's only $35 for 3 pulls, so I'm not really worried about it, but I was just curious if I'm going to see higher or lower numbers, or if it's even a possibility that I'll dyno lower now than what I did stock. LoL

jfm

iTrader: (4)

With my Yank 4400 I saw 10 more HP locked over unlocked.The first time at the dyno I had no lock up switch so I called ThunderRace and spoke to [Geoff/Paul?]and he told me with a Yank expect about 10 more HP locked,second dyno we locked it and unlocked it and damn TR was right on the money,10 hp diff.

N.Y. LS1

Here's my dyno sheet with unlocked and locked #'s. We couldn't get an acurate Tq # on the unlocked pull because of the converter.

http://www.hpphoto.com/servlet/LinkP...1109&size=

Ragtop 99

iTrader: (7)

JS:
Read what I said. I did not say you can not tune an unlocked converter car, I said:
"It makes it more difficult to accurately tune becuase of the error introduced by the converter."

That is 100% correct. If you are there to tune A/F and Timing with Edit, you should lock the converter to make your job easier.

Lets look at what happens when you tune a 4000 stall unlocked converter and punch it from say 70 mph on the dyno. You and I both know that the moment you go to WOT that the engine jumps up to at least 5000 rpm and stays there a bit before climbing to redline (let's say 6500 rpm redline with 6700 rev limiter for this example). When you look at the dyno graph, the dyno will give you a read out with torque and HP starting at 4000 rpm (or even lower) and probably shows HP all the way to 7000 rpm. Now you know that the car was never at 4000 rpm nor was it at 7000 rpm, yet you have readings for these (You can confirm the true rpms with the ATAP log you should have going while doing the dyno pull). If you change your 4000 rpm P/E table based upon the dyno data you are just guessing. Its better than a shot in the dark, but it is a guess. For tuning at 5000 rpm and above in this example, there is rpm skewing, but typically a 5% - 10% correction factor gets back you in the ballpark.

scalemaster

iTrader: (3)

when do u know when its lock or unlock I just got mine install so I need some pointers on how to operate

Pro Stock John

iTrader: (34)

Dynoing locked and locked can be useful since you can see how effecient your converter is.

I have seen a difference of 25rwhp for a lot of my dyno sessions. I would dyno 25rwhp more locked up. If you see a really big increase by locking it up you might look into manually locking it at the track to help your mph. When I did 350rwhp unlocked and 375rwhp locked back in 2000 it was a difference of 2mph until I changed from the PI3600 over to the Yank 4400.

Ed Blown Vert

iTrader: (2)

Interesting. Will have to try that on a dyno and at the track.
Has anyone done this with EDIT?

Ragtop 99

iTrader: (7)

I did that last time I dynoed, just for curiousity. If you set the shift points so the car won't downshift, you can punch it from a low rpm (i.e. low mph) and see the amazing amount of torque a 4000 stall generates.

Ed Blown Vert

iTrader: (2)

Nice, something else to try.