Thread: Strange Dyno Graph..Dip + Missing WHP (Updated: ECUTALK logs)

Hello All,

I went to the dyno this weekend and produced a strange dyno graph. It seems I'm missing 30-40WHP over what other people have made w/similar setups. Also, there's a very odd dip between 5-5.5k RPM. Not sure what that's about, but there's 2 problems this car has:

1.) Timing may be messed up. Ever since I've owned the car I've had to advance the timing quite a bit. Even after S4 cam install and multiple cam timing confirmations that it was correct, I still have to have the distributor pretty far advanced to get 15*. (Update: Timing is fine)

2.) There's a boost leak somewhere on the compressor housing and/or backplate adapter.

Another thing I noticed after recently installing a stronger wastegate is that boost will go up to say, 12psi by 4k rpm and slowly move to where I want it, such as 16psi, by 5k rpm. It's very strange.

Anyways, any ideas by looking at the graph?

The 328 run was done at 16.5psi with boost at about 17psi by 7200RPM or so.

Setup:

2871R .64 a/r
S4 Cams
8.5:1 W10 DET
3" turbo back exhaust (no cat)
Z32 MAF 4 bar STI Injectors JWT ECU



Updated..here's ECUTALK logs Fields are..in order:

Time/RPM/Timing/Throttle/Air Flow/Injector/Duty Cycle


06:21:38.18 4138 10 2.44 3.24 10.55 36
06:21:38.26 4300 15 2.5 3.31 11.04 39
06:21:38.34 4250 14 2.54 3.35 11.75 41
06:21:38.40 4325 13 2.64 3.42 12.13 43
06:21:38.48 4312 12 2.72 3.48 12.68 45
06:21:38.54 4388 12 2.86 3.55 13.5 49
06:21:38.62 4375 11 3.02 3.62 14.06 51
06:21:38.70 4450 10 3.2 3.66 14.55 53
06:21:38.76 4475 10 3.42 3.71 15.28 56
06:21:38.84 4562 10 3.6 3.76 15.73 59
06:21:38.91 4650 10 3.86 3.77 15.63 60
06:21:38.99 4738 10 4.22 3.79 15.62 61
06:21:39.05 4688 11 4.24 3.82 15.87 61
06:21:39.13 4788 11 4.24 3.82 15.75 62
06:21:39.21 4875 11 4.22 3.85 15.66 63
06:21:39.27 4838 11 4.24 3.88 15.8 63
06:21:39.35 5000 11 4.22 3.88 15.87 66
06:21:39.41 4975 11 4.24 3.89 15.83 65
06:21:39.49 5112 12 4.24 3.9 15.45 65
06:21:39.55 5100 12 4.24 3.92 15.49 65
06:21:39.63 5212 12 4.24 3.92 15.33 66
06:21:39.71 5212 12 4.24 3.92 15.36 66
06:21:39.77 5275 12 4.24 3.92 15.14 66
06:21:39.85 5338 12 4.22 3.94 15.27 67
06:21:39.93 5325 12 4.24 3.96 15.35 68
06:21:40.01 5438 12 4.24 3.97 15.29 69
06:21:40.07 5512 12 4.24 3.98 15.27 70
06:21:40.15 5512 12 4.24 4 15.27 70
06:21:40.22 5550 13 4.24 4.03 15.36 71
06:21:40.29 5588 13 4.24 4.02 15.45 71
06:21:40.37 5700 13 4.24 4.03 15.45 73
06:21:40.43 5738 13 4.24 4.05 15.59 74
06:21:40.51 5775 13 4.24 4.07 15.61 75
06:21:40.57 5838 13 4.24 4.07 15.65 76
06:21:40.65 5888 13 4.24 4.08 15.85 77
06:21:40.72 5938 13 4.24 4.09 15.81 78
06:21:40.80 5975 13 4.24 4.1 15.87 79
06:21:40.86 6025 13 4.24 4.11 15.85 79
06:21:40.94 6075 14 4.24 4.11 15.89 80
06:21:41.02 6150 14 4.24 4.12 15.81 81
06:21:41.11 6162 15 4.24 4.13 15.79 81
06:21:41.19 6162 15 4.24 4.16 15.87 81
06:21:41.27 6300 16 4.24 4.15 15.87 83
06:21:41.33 6350 16 4.24 4.15 15.83 83
06:21:41.41 6350 16 4.24 4.16 15.87 83
06:21:41.47 6362 17 4.24 4.17 15.81 83
06:21:41.55 6488 17 4.24 4.16 15.83 85
06:21:41.61 6450 18 4.24 4.18 15.75 84
06:21:41.69 6525 18 4.24 4.19 15.77 85
06:21:41.77 6612 18 4.24 4.19 15.67 86
06:21:41.83 6525 19 4.24 4.2 15.67 85
06:21:41.91 6688 19 4.24 4.19 15.61 86
06:21:41.99 6650 21 4.24 4.2 15.59 86
06:21:42.07 6800 21 4.24 4.21 15.53 88
06:21:42.13 6712 21 4.24 4.21 15.51 86
06:21:42.21 6862 21 4.24 4.21 15.43 88
06:21:42.28 6800 21 4.24 4.23 15.39 87
06:21:42.36 6838 21 4.24 4.23 15.35 87
06:21:42.42 7000 21 4.24 4.23 15.33 89
06:21:42.49 6950 21 4.22 4.24 15.27 88
06:21:42.56 7125 21 4.24 4.24 15.29 90
06:21:42.63 7088 21 4.22 4.25 15.31 90
06:21:42.71 7062 21 4.18 4.26 15.29 89
06:21:42.78 7025 21 4.08 4.26 15.23 89
06:21:42.86 7262 21 3.94 4.26 15.23 92

What were your a/f's like. Seems to go flat for a bit right after peak torque which is where detonation is most likely to occur. Could be some detonation but its hard to tell or it went really lean or rich causing it. It shouldnt flatten out like that. more info would be good.

hmm, I didn't get A/F because I had a wideband. We attempted to use a camera to record the RPM + A/F gauge but was not successful. My A/F if anything probably went rich, but I think it's pretty steady. I think I'm going to go watch for this on the road, especially between 5-5.5k RPM.

A/F is right around 11.1-11.5 is what I usually notice, but I'll have to watch for 5-5.5k RPM what I get. Very odd.

-G

Yeah, a/f is fine and safe but if it went really rich at that point or lean thats whats causing that flat spot.

Tune looks way off.

Stratton.

start by fixing the timing issue. Also a a/f ratio would be really helpful to figure out whats going on.

328hp and 300tq, those look like awesome Numbers there ! Don't know much on the dyno graph tho !

I'll try and get a camera shot of the A/F gauge and RPM within those RPM ranges. This is good progress, I always had an idea something was wrong w/the car.

numbers are low for the setup.

I'm going to re-check cam timing for the last(10th) time tonight and rule that out and look at my A/F during some runs. I'm hoping if anything it was going rich and not lean. I don't think I've ever seen a reading over 12.2 on my wideband during WOT, but maybe it blips on there so quick I don't notice. I'll let you all know what I find out.