Well, I finally got around to doing some logged runs on the car last night with Datamaster. The car is a stock 97 LT4 Firehawk with a tune from Madwolf. For those unfamiliar with them, the LT4 Firehawks got a balanced and blueprint factory LT4 (no hotcam, just standard LT4 cam), but used the stock LT1 ECM and fuel injectors.

Here's the run in a csv file:
http://www.lt1.net/images/run1.csv

From the Injetor duty cycle numbers, it looks like I'm pretty much pushing the limit of the current injectors (peaking around 97% at 6000rpm). Granted, I'm running past where a stock LT1 would, but is this normal for this power level? Which injectors should I step up to?

Any other suggestions?

Oh yeah, guess I should post my last dyno with A/F too:
http://www.lt1.net/images/Firehawk/ecmdyno1.jpg
I haven't had it to the dyno and logged it with Datamaster at the same time yet, so I'm not sure how the O2s relate from a highway to dyno run.

 

the afr is still too rich at higher rpm..

Have the tune leaned out and you might step away from that 97%.

Honestly I wouldnt' worry about it, I personally made over 340rwhp on those injectors with plenty of room to grow.

I wouldn't spend too much time thinking about that DC that datamaster says either.. I've seen it go up to 175%... now think.. does that make any sence at all?

 

I'm running a 94 LT1 w/ 375 RWHP on stock injectors. I kicked my FP up and rescaled my injector constant a bit to squeek by. Your only slightly rich so I wouldn't get too uptight about things. Looks pretty good to me actually.

I'm getting my heads tweeked again so I'll probably go up to
30#'ers to give me some more cushion.

Steve

 

So what do you guys think I should shoot for on the AFR? 13:1? I still want to leave a little room for error, but I've seen a 96 TA with an LT4 conversion and tuning run 13.5:1 on the same dyno.

As to the top end, I think there may be a loss there from not having the LT4 knock module installed at that time. The first run I did that day actually had a good 5+HP more from about 5200-5700. The next time I get dynoed I'll take the Datamaster and verify if there's any knock and see how the factory O2s look compared to my highway run. The only thing that's kept me from leaning it out a little more already is that I'm not sure if the Ram Air intake will actually lean it out a little at high speeds.

 

I think I already posted on another board that the TTS DM DC%'s seem a little too high on many logs I have seen. You might want to add the base pulse width (BPW) data to the .csv file. That way I could just fiddle around with the BPW and the RPM to see if the Duty Cycle numbers make any sense. TTS says they use BPW for the DC calcualtion, but the actual pulse width.... I THOUGHT.... included the BPW plus certain adjustments for operating conditions. Might be the source of the problem.

The A/F plot on the dyno pull cetainly looks like you aren't maxing out the injectors, and the O2 mV's, if we can use them for a ROUGH indication, also look right on, with no sign of lean out.

One thing to remember, and I don't think it is the case on your setup.... the dyno pull only lasts a few seconds. The injectors might operate at 100%DC for that brief period of time, but try to run them that way for an extended period of time and it might start to cause flow to deteriorate and cause them to wear out prematurely.

 

Ok, I've updated the file, let me know what you think.