I want to make sure I didn't miss anything. I always heard that the zone that engine will need the most amount of fuel is at peak torque, like a stock engine in the 3200 rpm zone.
On a stock engine once this area is pass do we see the DC & PW dropping as the rpm goes higher ?????

I'm asking this because with my car I have the VE and PE are pretty well worked out. I managed to be in the 12.5 AFR zone from 3000 rpm to 6700 rpm by having the PE set for 12.5, so this means my VE table is where it's supposed to be. (tested on my WB)

For this my VE climb all the way to the 5200-5600 where it is flat with a VE of 97.3.

My max PW & DC cycle for that run was 80.7 % and 8.32 msec at 5816 rpm, from there it drop to around 76.9 % and 7.23 msec up to 6687 rpm. With a reading of around 12.5 on the WB.

Sorry if this is normal but I had to ask with all the issue I had lately with this engine I'm not sure of anything anymore.

PAT

P.S. Now if I could make Rbob extended VE table work that would be nice.

 

Largest PW will be after the peak torque of the engine. The reason it is after the peak is due to frictional losses.

The highest total volume of fuel required is at peak horsepower. Highest volume of fuel per injection cycle (PW) will be relative to peak torque.

What problem are you having with the extended VE table, and what BCC are you using? Since the table is moved the ECU/TDF will need to be changed accordingly.

RBob.

 

Quote:

Largest PW will be after the peak torque of the engine. The reason it is after the peak is due to frictional losses.

So since my largest PW is at 5816 rpm, my max torque is probably more in the 5000-5200 zone. That would make more sense with the cam I have.

Quote:

The highest total volume of fuel required is at peak horsepower. Highest volume of fuel per injection cycle (PW) will be relative to peak torque.

If I understand this well, even if I see a lower PW as the rpm climb (pass peak torque) I'm giving more fuel (in volume) to the engine for a given time since it's spinning faster than when it was at peak torque????

Quote:

What problem are you having with the extended VE table, and what BCC are you using? Since the table is moved the ECU/TDF will need to be changed accordingly.

I'm using AXCN, the problem I have is that first I never managed to modified my bin (red all the post and everything) and second is that I'm using tunercat and didn't figure out yet how to edit it for the extended VE tables.
Time is commodity I don't have lately (second kid last week bla bla bla) and after 4 hours trying to make it work I told myself that my time could be better spent on something else (test driving the car).

Thanks

PAT

 

I ran my engine data thrue Engine Analyzer Pro v2.1, from that reading my peak torque should be 460 ft/lbs at 5000 rpm and my peak HP 486 at 6500 rpm.

It gives me the injector duty cycle in %, and it's really close to what I got from logged data with datamaster up until 6000 rpm where the engine analyzer tell me I should be asking for 87.7% DC but I'm only at 80.3 %.
By 6500 rpm it tells me that I should be asking for 91.7% when I'm actually at 76.9 % DC.

Does anybody ever seen while logging engine data the duty cycle dropping pass peak torque while keeping the same AFR. Stock engine or moded.

And did anyone ever saw on a WB what kind of reading you would see with valvefloat. Would it show richer or leaner than it actually is??

Now that I can rev higher than 6000 rpm after some issues I still find that the engine is acting weird pass that point. And the reason I find it hard to believe that if I want to keep my AFR at 12.5 pass 6000 rpm I have to drop my BPW & DC.

Hopefully someone knows the answers.

Thanks

PAT

 

I tend to not worry about DC unless I am checking for going static with the injectors. The drop in VE may be from a several things. How much does the MAP drop off at the higher RPMs (> 6,000)? Is the exhaust restrictive?

The main reason the PW is dropping off is because the volumetric efficiency is also dropping off. The peak PW will be at the peak torque which will be the peak VE point of the engine (for the most part, see above for frictional losses and peaks).

As the RPM increases so does the number of injections per second. So there can actually be more total volume of fuel per second even with a shorter PW.

RBob.

 

Quote:

The drop in VE may be from a several things. How much does the MAP drop off at the higher RPMs (> 6,000)? Is the exhaust restrictive?

The MAP looks fine, < 6000 it stays around 98.2-99.3 kpa
>6000 97.4-98.9 kpa.

The exhaust is probably restrictive with my 1 3/4'' slp headers and 3'' SLP catback. (no CAT) I have an exhaust cut out where the cat is supposed to be and I was planning to open it next time at the track and see what happens.

So I may have a hard time at higher rpm getting the exhaust fume out........

Thanks

PAT

 

Quote:

As the RPM increases so does the number of injections per second. So there can actually be more total volume of fuel per second even with a shorter PW.

I agree with that but the way I understand it, is that one BPW/DC is equal to one event per cylinder so the lower it is (to keep the same AFR) the less amount of fuel the cylinder is getting for one burning event.

PAT