First dyno: PRC 5.3's & Patrick G cam
 

OK, here's 3 pulls from today at Norris Motorsports. We didn't feel it fall over at all on the dyno like I had felt on the interstate above 6000RPM :confused: Setup is by no means completely tuned, just a baseline and some quick adjustments.

Pull 1: Baseline. Low timing but logging wrong PID to determine where to adjust. AFR was set ~12.5 below torque peak and about 13 above. VE isn't quite polished yet to yield what I command. 3-4* of constant KR at WOT.

Pull 2: Set commanded AFR to 13 across the board and this time we could see what was going on with the spark. 19-25* from 2400->4400. 3-4* of constant KR at WOT.

Pull 3: Put in some mid-to-upper 20's advance values to get in the ballpark. Temporarily altered max KR table.

Thoughts.... I like the curves, but I'm hoping some dedicated WOT tuning will shift those curves up more. I like that my 'peaky' 110+2 cam is dropping very little from 6000 through 6700. Fueling is still off up to 3% across the board according to the HPT logs. I'll run a tank of 104 to confirm the KR is false.

Not interested in an EWP, but I am interested in a ported Fast90/90 or maybe just wait to see how that new Starr Performance intake performs next spring when it arrives on the market. My Grot headers have gotten pretty dinged up in the last 7 years. Hopefully better exhaust before spring.

you're going lean in the upper rpms vs lower rpms. maybe try and command more fuel at 4400 rpms and above. graphs got smoother as you played around.

Great results. That's some serious power under the curve. Funny, some of my colleague mocked this design for autocrossing and road racing, but if you look at the curves, they're strong at every rpm you'd use in a competitive track racing. You may need to check to see if you're getting false knock. It's very common and can really hurt your power. You should be able to run 26-28 degrees of timing at peak torque and 28-30 at peak power.

I continue to get P0327 and P0332 codes. Went through the Helms manual and we did everything short of replacing the PCM; the diagnostic procedure generated no faults. I guess I'll have to haul it to the dealer and see if they can isolate the reason for the codes. If their diagnostic tests clean, could it be something mechanical not covered in the Helms manual?

knock sensor(s) and/or cable is bad... that is why you were getting full allowed KR whenever the car was in PE, it's a built in "safety net".

You can check all the eng sens fuses and what not, but it's almost surely a sensor, followed by the cable.

I understand that. What I don't understand is that two different people reading the respective diagnostic procedures on two separate occasions using two different DMM's come up with both the sensors and the harness being good.

Both the old and new harnesses gave us readings of 99.8-100KOhm between the end of the harness and the ground while connected to the sensors, and the acceptable range was 93-107. I bought a new knock sensor and put it in the front hole. Tapped on the inside of the hole and saw minor voltage changes which reverted to zero when we stopped tapping. Did the same thing with the original two knock sensors in both holes and they behaved in the same manner. The diagnostic only dictates they should move, not by how much.

The second time we went over the procedure, we also tested for continuity, grounds and shorts between the block and both pins of the rear wiring harness connector, and then between both pins of the rear wiring harness connector and pins 68 & 69 on the PCM (KS front & rear). No problems found. I think the last step was to replace the PCM, and we didn't have a spare '98 PCM.

Ironically, after we put everything back together the second time, I incurred a grounding problem on the rear of my driver side head. One eyelet was broken and the other loose, and the bolt was also loose. Dealer fixed that but the KS code didn't show up while the car was in their possession, but it did later that same day. Even though the diagnostic mentioned nothing about the head grounds, I was hoping something would be magically fixed as a result.

Just a follow-up that replacing the PCM has fixed the knock sensor issues.

Good to hear!!!

How 'bout re-upping the graphs too?

What are the cam specs?

can you post the graphs...either the links are down or blocked from my computer. I am at work for an extended period and will not be going home for a while.

Graphs are back up... I removed them when cleaning up the folder. Cam is a 227/235 .645/.650 110+2 on LSK lobes, per the cam doctor sheet. Still hasn't been formally tuned on the dyno. Mike Norris' dyno has a reputation for being stingy, and he advised he prints the STD numbers because they end up being very close to SAE numbers at other local shops.

The STD version of the last graph is here.

pretty good numbers..are the heads milled or anything?

I ordered them with 59cc chambers. As it came from TSP, the bolt boss indicated it had been cut .020 (3cc, as requested) but when the chambers were cc'ed they were 62cc. So I had them cut again to get 59cc.

Your curves are almost identical to my setup! You'll love the powerband!

o ok i am thinking about picking up a set milled to 59cc's..thanks