FFDP

iTrader: (2)

It has to be losing power with such low timing. And that VE seems rather incorrect in the higher RPM's.

You really shouldn't ever see over 100-105 kpa on a NA motor and you have it all the way up to 116. If it was me I'd be retuning the VE more,

mikevanky

Yeah I was planning on working on the timing tables at the track, and seeing where I can add. Also yes the VE tables need some work still.... Do you think that there is a lot power being left on the table with the richer AFRs ?

Confused about your comments on kpa readings? I do not see any readings in the log much over 100 and I do not understand the correlation between higher kpa readings and VE tables. Could you elaborate a bit more there?

mikevanky

SO.... Things are not looking good to get to the track this weekend.

Ball joints are in and the knuckle is back on but due to my truck being a change over year sourcing axle components is a nightmare.

The list now is:

1. Source and install wheel bearing hub and spindle
2. fix oil pan leak
3. Replace water pump that has magical started to leak
4. replace the new break booster/ master that has decided to stop working
5. install oil gauge
6. add revers lights and get the truck inspected
7. still need to figure out if I have the TCC break switch hooked up correctly


anyone know how to use a scan tool or something to confirm the status of the TTC input?

FFDP

iTrader: (2)

That was kind of my point, you aren't seeing numbers over 100-ish kpa but you have your VE setup so that is does. You are saying that there is far more air in the engine than there really is with how high the VE numbers are currently.

mikevanky

Im not saying my tune is accurate, but technical its possible to have higher VE values than 100%. The Manifold pressure sensor measures the pressure in the intake and will only ever see atmospheric pressure ( I think around 101 kpa) at best on a NA engine. At least in the placement of the sensor on the stock intake. But you could actually be achieving cylinder fills over 100% due to inertia of the air mass moving in the intake.

That being said I think the values are a bit high because I don't think that cam is aggressive enough to produce that high of a VE and as you said earlier it gets fairly fat up higher in the RPM range.

Vortec350ss

iTrader: (20)

Your VE table, while technically should be the engines volumetric efficiency, is no where near accurate from that stand point. There are way too many variables that come into play. Your fuel system, your MAF tune... list goes on. Hell even Gm's VE table is 'wrong' by most tuners standards. Meaning if you kill your MAF, the tune will seem Way off. However, with the MAF in use it gets the job done. My point being that while we each have our own views and some seem better than others there is more than one way to skin a cat. It's hard to look at a tune without the vehicle running next to you and say flat out "your VE is wrong".

And mike is right. You can have more than 100% volumetric efficiency. That's the phenomenon that overlap in a cam creates at certain RPM. Hence why specific valve events are so important. You know that though.

FFDP

iTrader: (2)

Right, I understand that is more than possible to see that and I did mention that in one of my previous posts where I said around 100-105kpa is about as high as you'd see.

I wasn't just trying to say flat out that the tune is all wrong or that it's not totally accurate but just that certain parts like the VE table don't seem to be correct for the engine setup.

mikevanky

Welp.. Made it no the drag strip for the first time last weekend! Met up with Rob and one other member at the track also.
While it was a ton of fun it only confirmed that my tune is way off still.

The best run of the day was 9.56 @ 74 in the 1/8 (Apparently too windy for the 1/4)

So not great. But this was the most timing I could throw at the motor without knocking. pass before had 2 more degrees in it up top and KR took me into negative timing. The best pass had about 10* in it up top and only fell off towards the limiter because I had not tuned the cells due to upping the limiter at the track. Ill post up the log

So in desperation tmrw night I will be tuning out the knock sensors and throwing 20* at it and using the old listen and pray method to see if this is false knock or not. Ill also be chopping the motor after the pull and looking at the fresh plug to see if the timing strap says anything about the pull. Not an expert by any means at that tho so....

Anyone have any advice before I pull this borderline risky maneuver?

Also any input on that log from my best pass at the track?

last pass.hpl

mikevanky

so its been a while since the last update.

So I ended up adding 20 units to the knock sensor tables and changing the timing to 20* up top.

Result is the motor loved it! truck actually moved like it should and it was a blast. Ran impressively well. only thing now I am afraid to add timing now that I have taken so much authority away form the knock sensors...

mikevanky

I wasn't planning going turbo any time soon but I recently realized that there is no time like now!

I ordered a china made turbo from an Ohio based dealer. They have a pretty impressive selection of turbo kits. I got their "70 mm" turbo.

I didnt run any sizing math so hopefully it works well.

On a low budget for now so I am planning on low boost and skipping the intercooler for now.

I also have a set of turbo headers kicking around that I put on my 4.8 for mock up. I also purchased a set of 50 lb injectors and truck rail from a bud at work . They fit nicely on my ls1 intake.

Still not sure if Ill run it but it looks so much better than the ugly truck intake.

also a big issue with these obnoxious headers is that the #1 lead is hard up on the manifold. Anyone ever run into an issue like this?