Our car club went to a dyno day today and I have a sheet I would like you guys to look at. They couldn't lock the converter, so these are unlocked numbers from a new yank SS3600 with probably just over 200 miles on it. I really had no idea what to expect since they couldn't lock it, but I ended up with a best run of 313/320.

A couple other guys in the club that went before I left worth mentioning were an M6 LS1 SS with bolt ons and a custom LG cam that made 401/382 (said he made 421 I believe the day he got it tuned... nothing has changed), a manual vortec supercharged Mustang GT that made 384/368, an M6 LS1 SS with the stock SLP dual-dual catback, a new MAF, and a lid that made 314/327, and a 100% stock M6 LS2 GTO that made 329/339.

The graph looks kinda weird to me, but you guys can tell me what you think. The guy there tried convincing me that the little "bump" at the end of the graph could have been the converter locking up, but I told him it isn't supposed to lock... That's right, right? Here's the graph:

 

Any ideas of why this graph looks so weird compared to other ones I've seen? Slowly going up and then spiking, coming down a little again, and then making kind of a round shaped up and down again above that?

And what's up with run three? One and two look pretty similar, with two just being a bit higher, but three looks completely different. The torque never comes up, and those two weird drop off/disappearances.

At least the AF looks good.... haha

 

so you made 313hp and 320 tq with the mods in your sig?
i think thats good.

ive seen a few lsx cars have that dip

 

btw are you up to date on all your maintance? plugs, wires, fuel filter?

 

Yeah I should be. I put new plugs NGKs in when I changed the headers (like 5k miles ago) and the car itself only has 26k miles on it now.

I just thought it was strange how much more jumpy this one looked than others I've seen, or even others on the same dyno that day. Take the GTO's graph for comparison. I know the LS2's have more torque down low, but compared to mine it was almost rediculous. His hit over probably 320ft-lbs immediately when they hit it and stayed there until after at least probably 5800rpm. Almost completely flat across and smooth too. Mine is nowhere near that flat. I would have thought I would see a little higher low end torque because of the converter, but I could be completely wrong about that. Another thing that is weird, most of the cars runs were almost right on top of each other, and look at mine. Specifically the torque curve. One run was more than a full 25 ft-lbs higher (probably at least 30) at 4k rpm, and all around there. Run one I hit 300 ft-lbs at around 4500rpm, run two I hit it at around 4200, and run three never even made it there. Run one hit it's peak right about where run two did, around 4800, but run 3 peaked at about 5700...

Speaking of that, whats up with that last run? The only thing I can think is maybe traction control. He turned the car off and then turned it back on before the last run for some reason, and I was thinking that if it needs traction control off that he may have forgotten to do it again after turning it back on.

What would a wet filter do too btw? We drove 2 hours to get there in light rainy stuff the whole time, and as you can see in my sig, I have my hood debaffled/sealed to the airbox (if you haven't seen a WS6 like that you can look straight in the nostril holes and see the filter . lol), so I'm sure it got water all over it. The GTO didn't take his filter out to dyno either, but the SS with the Lid and MAF did, so that maybe have helped his numbers a bit too.

 

Anybody else have any thoughts?

 

Guess not... lol

 

Bump...

 

Thoughts on the dip? Whats the run log look like? Any knock retard? Is the COT turned off? The A/F dips right at the same spot, not bad, but a little.
If it was the converter locking it would look different. Usually have a loopty loop, or a strange looking squiggle, because not only does the hp drop, but the rpms drop which causes the graph to loop backwards and then forwards again. Kinda hard to explain, I'll see if I have a graph of one to post.

 

Also, if you get it tuned right, it should make very repeatable hp and torque. Not be all over the place like that.
As for the traction control, if it was on, they wouldnt have even been able to do that. It'll start kickin the pedal back as soon as you go about 10 mph.
Why werent they able to lock the converter? It actually looks like its locked. The lack of a torque hump down low, and the fact that the pull starts a little over 3000. Did they have it locked in third gear?

 

Yeah, it does drop a bit there, I noticed that too. I didn't think much about it though because it was really the best of all the cars that I saw go (about 10 of them). Everyone else's was jumping around a lot more than that.

I know what you mean about the converter locking. I've seen that before, and I could imagine what it would look like anyway. I didn't really think about that before, that's a good point. I tried convincing him that that wasn't the converter locking, but he didn't believe me... lol. I told him it wouldn't lock up at WOT like that...

I did get it tuned by Chad at Green Light Motorsports, who is supposed to be very good at it, so I would have figured that it would have had a good tune. Would there be something that might be messing it up? The only thing I could possibly think is that I had a little tranny fluid on my arm when I was working on the converter and I touched the end of the 02 sensor on the passenger side that i had hanging up higher. I hoped it would just burn off almost immediately when i put it back in, and it has been running perfectly fine, so I didn't even think twice about it.

As for it being locked, no it wasn't, I'm sure. It was a mustang place and they didn't have the software to lock it, and all they had plugged in were the little rpm sensor and the A/F thing in the back. The thing with the torque curve starting so low and slowly coming up was one of the things that I also thought was weird. I know the LS1's have lower torque down low than the LS2's, but the stock one that I saw was ridiculously different. His hit just about his max at just over 3k and stayed within like 10-15ft-lbs the entire way up to about 6k. My curve looks pathetic compared to his, and even a lot of other LS1's I've seen (including the two others there dynoing with me) had better looking torque curves. I mean, run three had about 180ft-lbs at just about 3500 rpm o_O. That makes no sense...

Thanks for taking the time to look at this and help me out.

 

Yes, it def has issues. But, without a run log its all speculation. Maybe take it to a shop that has a different dyno, and the ability to diagnose it.

 

Hmmm... There is no way those could be saved or anything and I could call them up and get it somehow is there? I know nothing about dynos really...

 

The run logs would have been recorded with a laptop and scan software. If they were a Mustang shop with no ability to lock your converter, then I'm sure they werent logging either.

 

Well... I guess I'm not going to know until I go to get it tuned again. Or go to the track and my times are worse with the converter or something... It was running just fine before, and alway ran consistently (not consistently slow either, as you can see from my 12.8 with just bolt on and stock stall/tires). It doesn't really feel like it's running any worse now though either, just that dyno looks weird. Is it possible that I screwed up that 02 sensor though? Or would it not get messed up that easily?

 

Ok, new development. I just watched a video that a guy made there that day and looked over my runs many times and this is what I noticed.

I don't know if he drove it different on there than the other cars like mine because it was an auto or what, but he did. I watch the rpms along with the A/F, and just plain old listening and the 1st and 3rd runs he didn't hit it until right about 4500rpm, and the 2nd run at about 4100rpm. The car would get louder and the A/F would drop like a rock and then stay planted there the rest of the run so it was obvious where he would step on it. I wish he would have gone from lower so I could see what that torque converter was really doing for me... I also wish he would have because I find it funny that the run where he stepped on it 400rpm earlier I got my best numbers... I wonder what would have happened if it would have been like 3500 or less when he hit it?

Actually, that makes me think. Since he only did that with my car, and it was the only auto (that I watched there in the video, the 1st 4 cars), could it be because below about 4000rpm or so it would down shift to third? I suppose that could be why he wasn't hitting it hard until so late.

Either way, looking at that graph I'm not so worried anymore because watching and listening to that video perfectly explains it. I knew it didn't feel down on power on the low end (or the top end for that matter) . The thing feels sooo good .

 

With an auto, you want your car to be dynoed in third. According to your comment, he dynoed in fourth. That is wrong (and he probably did do it in third). In an A4 car, third gear is your 1:1 ratio with fourth being an overdrive gear. In an M6 car, fourth gear is the 1:1 gear and fifth and sixth are overdrives.

Make sure he dynoed in third.

 

Yeah, he did, sorry. I watched the video earlier today and noticed I got that wrong. I'm not sure why I assumed it was fourth.