Ronny

iTrader: (1)

I just increased both tables significantly to allow for reduced DC%(<85%). I am at 23 lbs fuel pressure with 75 lbs injectors. Thank you Dominic S.

I see two tables for TBI injector correction offset and injector correction multiplier. I added considerable to both tables. Approx 60% more in usec(offset) as compared to stock EBL.bin and 45% more in multiplier % of change.

Why are their two tables? Seems like they are the same voltage being based. One being asn adder and the other a multiplier.

RBob

iTrader: (1)

It has to do with the injector dynamics. In that not only is there a longer time to start to open as the voltage drops off, but that the injector also gets sluggish.

The multiplier taking care of the sluggish part of the injector dynamics. I've seen this with the Delco style TBI injectors. They will start to spray fuel in a reasonable amount of time. But are a sluggish injector, taking more time to fully open then a RPD TBI injector.

RBob.

Dominic Sorresso

Ronny,

I appreciate your acknowledgement but the credit really goes to RBob. He's the one that pointed it out to me when I was tuning my Xfire. I was running 20psi at WOT with a <85% DC for the injectors. Helps eliminate the "bathtub" in the VE tables you typically see when using higher pressures and larger injectors. On the LT-5, I have 16 injectors so
so running out of injector isn't an issue.
BTW, some of ZR-1 buds ran in Indiana this weekend. They ran 10.9s @134mph w no power adders other than using a 427 LT-5. Should've seen the look on the faces of those
C6 Z06 guys!!! ROFL!

Ronny

iTrader: (1)

OK this got ugly. I changed both tables adding approx 60% more to each table. So 14.4V in Inj correct multiplier went from 0.0 to 2.3 a double of value. Same table 7.0 went to 10.0 or 50% higher. Offset wet up 60% at 12.8V and same at 14.4.

Datalog has these values from 5600 rpms to 6250 at 100% TPS. Then hit rev limiter.

MAP started at 86 and went to 87. A restriction.
sPW went 5.6 and fell to 4.8.
Here is the biggy DC% went from 100% to 108%(5850rpm) and fell to 98%.
WB showed 12.5-12.8(nice)

Now should I continue adding another 25% to inj bias values OR up FP from 23 lbs to 26lbs or BOTH?

Again a GM TPI pump.

Above is w/o N20.

Ronny

iTrader: (1)

I did 20% add to bias. This AM same road same pull. I saw 5.2 sPW max and DC% 100-105. 5800-6200 rpms. 2nd gear pull of 4. car pulled hard to 5800 when engine sounded a bit funny which I am thinking is static. Air temps around 40dF.

so it appears my only choice is to up FP ay this time. offset #'s at 12.8 v are now 747. correction mult is 12.5

Dominic Sorresso

Ronny,

Do you know that your peak power is at 5800+?

Ronny

iTrader: (1)

prior cam on dyno was a 210/214 @.05 114 LSA 223 HP @ 5100 rpms(was max HP)

current cam is 224/230 @ .05 114 LSA not on dyno but comp cams says 5800 rpms(max HP)

Dominic Sorresso

Roller? My cam was a full roller setup, at 218 single pattern and 108 LSA.
Lift was .528" and hp peak was ~5K.

Ronny

iTrader: (1)

No flat tappet

Dominic Sorresso

I guess the rule of thumb is that you can add 10d to the spec because of roller with greater area under the curve. The tighter LSA would also suggest a greater overlap and so higher rpm power peak. That's why I am questioning the 5800rpm peak.

Ronny

iTrader: (1)

I believe I have RBobs .xls for bpc (vafpr) 23 bs at 75 lbs equates to 377 HP. And that is insufficient for DC%. I will move it to 26lbs tomorrow..

kataklysm01

so what came out of this? I have a similar thing possibly going on where I'm very close to 100% VE and hitting it at some places. So you're increasing the INJ offset and Multiplier values for the whole table? I increased the first table *1.2 and I'm not experiencing any positive effects yet, or maybe it's going downhill.

so adding to the time value lengthens the pulse width on the range of voltages it applies for? I'm trying to determine if I should increase FP or not based on my understanding of this.

Ronny

iTrader: (1)

My issue was not VE. My VE tops out at about 85.

That issue was for DC%. I moved FP as stated but ran out of time as vehicle had to be stored. Wisconsin.

Is your BPC correct?

I upped the values as stated and found no benefit as far as DC% so fuel pressure was my remaining option. I will know more in Spring.