Sunset01

Scan of graph, unlocked & locked :
http://www.vettecaliper.com/ls1/scan.jpg

The skips in the graphs are the rpm pickup being flaky at this dyno.. Locked
actually skips out right at the hp peak at 6100. This is after trying to tune fuel and spark; more on that below.

I am unhappy with the 30hp drop unlocked. Actually studying the #s,
I get as much as much as 35hp and as little as 10hp loss at 4500 rpm. By 5000rpm, unlocked is down 34hp. I have had a short shifting problem with my combo and I am somewhat supsicious of the converter now, given the inefficiency.. I'm going to make a separate post on this subject in trans section. I'm tempted by the new multi-disc Vig converters.

Very satisfied with locked results. SAE correction was 1. In my favor are still through 10 bolt, CF driveshaft. Against me are no dyno fan in front of the car whatsoever (thinking engine airflow more than cooling) and didn't allow any real cooldowns other than reflashing the computer.

I also screwed up on tuning the timing. On the street, and in cooler weather, I was hitting .8 gms/cyl when WOT, so I got in the habit of tweaking spark from about .7 or so on up. My gms/cyl were about .68 today, so my timing changes weren't affecting WOT timing (verified in my scan logs after the fact).

Also, the innovate wideband is a piece of crap. (maybe the bosch sensor is) I had in running 13 AF and the sniffer at the dyno was reading 15. The dyno sniffer was in the tailpipe, after cats, but still. And the car responded big to richening up to what was around 11.8-12.0 afr on innovate. At stoich, the kit is dead nuts accurate, as I read 14.6 -14.7 at idle warmed up and part throttle.

chief455

iTrader: (21)

I had a similar graph and peak with a TR224 112 cam AND heads!
I also had around 35 hp/tq loss unlocked with a Vig 3200
Some tuners feel this is poor and others go by track numbers. Seen the big loss unlocked graph cars e.t./mph just as well as the locked number at the track.
In my case I am leaving the converter, making some passes to get e.t. and mph.
Then I'm going with a Midwest 4000/2.5 str and dyno again plus track again. Test and tune is all we can do....

Sunset01

Thanks for the comparison and encouragement... If I saw more like 20-25, I'd probably not have batted an eyelash. But the 35hp and the short shifting issue has me wondering. I also have spoken to a guy with a bolt-on car & same 3200/2.0 that loses 20-22hp.

Sunset01

Oh, and even though the other Midwest 3200 guy loses only about 20hp, he picks up 2 tenths & 4-5mph by locking up very top of 2nd and all of 3rd... Which again to me shouts inefficient. Just wish people could make up their mind about the Vig multdidiscs. (including PI, as they seem to not like to recommend for ls1's.)

Sunset01

SOrry for the triple post, but one more piece of weird info--- I actually lean out 0.5 AF when going to unlocked vs. locked. Never seen anyone have that before... just to add to my confusion.

chief455

iTrader: (21)

Does seem strange. But you might be reading into the dyno too much for your information. I would think tuning the car to the best numbers, a/f ratio and then daily driving ability you should stop. Track test it and enjoy it awhile.
You may find the car perfect on the street and pulling decent track times, so why beat yourself up over glitches on a dyno chart?
The dyno is probably less perfect or consistent as your tune might be
For both our sitations a converer swap may be in order though..

foff667

iTrader: (2)

looks a little lean...13.6:1 & leaner on the dyno?

Sunset01

It's not really that lean. 13.6/leaner is from a tailpipe sniffer after cats... and this is while my innovate wideband reads solidly in the 11s... I was basically getting a 2 point AF difference between them. The truth is somewhere in between. I was getting no knock retard with up to 29deg timing on 93 octane gas . (other than ~1pt or less at tip-in)

99-LS1-SS

I had a very similar problem with the tail probe on my car when I had it dynoed. My car dynoed very lean but showed no signs of knocking and it lost power when we richened it up. Can you explain the "kit" that is dead nuts accurate? I want to look into getting something for my car.

Sunset01

And you were showing lean with no cats... I kept making power richening up until the tailpipe probe read about 13.5, which after cats, way down the exhaust system, I wouldn't be surprised to read about 1 AF point lean... which still makes me believe my wideband is reading about a point rich... that being said, I used that sensor to get the AF curve nice a smooth, if not at exactly the right level without consulting the dyno output. The kit is the newer kit out there and is sold only direct, I don't know if that means I can put the url here. http://www.tuneyourengine.com

DEEZ98Z

iTrader: (5)

Great numbers... I have about the same result form mine Sorry to hear about your tranny though

Sunset01

I've the 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.

Dean

destroyerSS

iTrader: (2)

Dean, nice #'s my original guess was pretty close Hope you get your converter problems fix soon and all goes well. It's getting close to some track time seay in touch, Shawn

Sunset01

Yup, definitely ready for one of the Friday nights out at Island in a few weeks. Need to turn around the converter and redyno...
Just happy I figured it out and that I probably have the answer to the short shift. Too bad I didn't realize it before I spent the dyno time.

How's the progress on yours? Heads in yet ?


Dean

destroyerSS

iTrader: (2)

Just sent Jay @ Absolute my LSX so he could port match it and i should have my heads at the end of this week or monday Also i should get my chrome moly torque arm and LCA relocation brackets from Sphoon tommorrow. Friday night's at island will be a great time. What stall do you want to go to? Later Shawn

Sunset01

I'm sticking with a 3200- that is they will be making (hopefully) the 3200/2.0 that I originally ordered work that way with the power that I have. I still want to have some decent street feel.

Hey, if you've got a sec, take a look at my debate in this thread- I am nuts ?
In the end, as long as my midwest is made more efficient, I don't really care. But I'm curious about how this stuff really works.


https://ls1tech.com/forums/showthrea...94#post1284994


Later

destroyerSS

iTrader: (2)

It sounds like you got a basic stock style internal converter with a raised stall. So lets see what happens when they redo your converter and if your still not happy i can hook you up with a real nice converter. But hopfully midwest steps up there effort and vastly improves this lacking converter that was sent to you! Hopfully all goes well :Later Shawn

Sunset01

Update regarding my wideband reading rich- I'm starting to believe it now- I was hitting 29-29.5 deg of timing due to being at lower load on the dyno than for the street. This is likely too much, but you can get toward max power by compensating with an overich mixture. Check this link and snip from Klauss at Innovate:

http://www.innovatemotorsports.com/f...=1389#post1389

Most engines develop max torque (equal to max power for a given rpm) when the peak pressure point (ppp) in the cylinder is about 14-19 deg ATDC. The important thing to know is that this value is INDEPENDENT of engine load and rpm, but dependent on engine geometry like bore/stroke relationship, rod length and so on. The point of ignition advance is to time the onset of burn such that the ppp is at the sweet spot. If your ignition is too advanced (even without ping), you are earlier than the sweet spot (with normal mixture). By richening up the mix, you slow the burn so you hit the sweet spot again (rich mixture burns slower). But of course you produce less power, but the max that can be achieved with the ignition setting. I would try to retard a bit and see if you can't make more power with a leaner AFR.

Sunset01

Thanks Shawn. Yup, we'll see how the Midwest does & if it isn't upto snuff, I will likely take you up on your offer. So you think it's a little bit of bull that the impeller/converter needs to build to suit various power levels?

Dean

destroyerSS

iTrader: (2)

Don't get me wrong, Weight,gear ratio's,power and traction all play a big part in setting up a converter but this info is used more to achieve the right stall!! If this converter was in fact what it was supposed to have been the biggest differance you should have seen would be a higher stall due to the fact of your car making more power than you told them it would make. Definitly the added power should not make your converter less efficent just higher stall. Like i said it sounds like you got yourself a basic raised stall stock style converter BTW what did they charge you for this?