Explanation for Byron Disappointment

[XfireZ51]

I mentioned in the Byron thread that I hadn't noticed any real improvement in trap speed from my first time out with stock motor/B+B exhaust and this last trip to Byron after having installed Watson headers.
I decided to check injectors and those ohmed out fine. Nice day today s I threw on the scan tool and went for a ride just to see if headers had "leaned" things out. BLMs were in fine range of 131L/128R, typical split BLM. I made a couple of WOT bursts curious to look at NBO2 just for grins.
(I know you can't really tell. I have ZT-2 to install maybe tomorrow).
But what I did see on scan was Total SA was 23d at full tilt. Looking at the bin file, I should be getting 29d at 6000rpm/95-100kPa. There was about 4d KR but I'm also seeing a 1.8d SA relative to ref at 850rpm! SA table shows I should have 20d. Maybe I have some of the terminology wrong but even accounting for an additional 5.9d as Initial SA, the numbers don't add up. Any help is appreciated.

[petefias]

I mentioned in the Byron thread that I hadn't noticed any real improvement in trap speed from my first time out with stock motor/B+B exhaust and this last trip to Byron after having installed Watson headers.
I decided to check injectors and those ohmed out fine. Nice day today s I threw on the scan tool and went for a ride just to see if headers had "leaned" things out. BLMs were in fine range of 131L/128R, typical split BLM. I made a couple of WOT bursts curious to look at NBO2 just for grins.
(I know you can't really tell. I have ZT-2 to install maybe tomorrow).
But what I did see on scan was Total SA was 23d at full tilt. Looking at the bin file, I should be getting 29d at 6000rpm/95-100kPa. There was about 4d KR but I'm also seeing a 1.8d SA relative to ref at 850rpm! SA table shows I should have 20d. Maybe I have some of the terminology wrong but even accounting for an additional 5.9d as Initial SA, the numbers don't add up. Any help is appreciated.

Just turn the distributor a little to get an additional 6 degrees advance. :)

Sounds like the knock sensor is picking up some noise because of the headers.

[XfireZ51]

Just turn the distributor a little to get an additional 6 degrees advance. :)

Sounds like the knock sensor is picking up some noise because of the headers.

KC stays the same even tho I am seeing KR. But thanks anyway. :wink:

[LGAFF]

Haibeck notes on his site that the ignition timing sensor is offset by 6 degrees on the LT5, so you need to add 6 degrees of timing to your #s if you have Diacom, Tech1 automatically adds it in

http://www.zr1specialist.com/HAT%20Web/articles/knock2a.jpg

LGAFF

[GrayZ]

You live in chicago?? one word....Haibeck

[XfireZ51]

Lee,

I'm using EASE scantool. Not sure if it includes 5.9d of Initial SA or not.
I'm getting KR even though the Knock Counts don't change. I may change the bin to reduce or eliminate KR depending on what I see from the Wide Band O2. We should do yours and see if we get similar results from the scan.

[XfireZ51]

Looking at the scan further, it seems that EASE doesn't include the Initial SA, so the timing looks to be correct. Looks to me like the cal is very sensitive. My experience has been with an 84 Xfire so not sure if the
LT5 required that level of protection. Given that the car ran very similar trap speeds with and without headers, I might conclude that the headers are what's causing the KR. With the 84, I actually ran with the KR at 0 in the cal. The point being that the tune should be such as to not bring in knock. Here the KS may be reporting a false knock. Looking at the scan, the prevalent area for KR seems to be coming from the 4000rpm range. Typically its pulling 3-4d and in one case 10d.

[Pete]

Dom,did you compare the MPH from 2 different tracks or both from Byron.

The other reason i can think is that TriFlo resonator has to go.

The man you bought it from gained 7rwhp with a stock resonator and Mangaflows over the B&B in your car.

You put the headers on, corked it back up with the exhuast so your back to square one.
7200RPM likes to breath.

LGaff has headers with no resonator.

Pete

[XfireZ51]

Dom,did you compare the MPH from 2 different tracks or both from Byron.

The other reason i can think is that TriFlo resonator has to go.

The man you bought it from gained 7rwhp with a stock resonator and Mangaflows over the B&B in your car.

You put the headers on, corked it back up with the exhuast so your back to square one.
7200RPM likes to breath.

LGaff has headers with no resonator.

Pete

Pete,

The MPH was from our September Byron trip compared to last weekend.
Looking at the my current cal and compared to stock bin, there is an additional 2-7d in from 2500 through 5000rpm/ and from 70-95kPa.
Looks aggressive and most of it is coming back out due to the KR.
This is a fairly old Marc Randolph calibration.
I could drop some timing and see where it stops tickling the KS.
I'll eventually do something about the resonator. But it was the same resonator for both sets of runs. Could use the one from the exhaust I took off or put on an Xpipe. That would give Al a chance to burn my fingers again.:sign10: