AVCS - Intake and Exhaust Timing

[shr133]

I have to run it some more but defiantly revs better.....

[shr133]

I have to run it some more but defiantly revs better.....

[Kodename47]

My AVCS spreadsheet has a tab that creates the base table the same as the safe/normal should you guys so desire
@KoolBRZ I hope you weren't trying ztan's AVCS, turbos require different mapping to aid spooling. Also, my cam maps will be of little relevance either as I am running more boost.

[KoolBRZ]

Originally Posted by Kodename47

My AVCS spreadsheet has a tab that creates the base table the same as the safe/normal should you guys so desire
@KoolBRZ I hope you weren't trying ztan's AVCS, turbos require different mapping to aid spooling. Also, my cam maps will be of little relevance either as I am running more boost.

I combined the best of both ztan and shr133's tables to make these. The Base tables are exactly the same from .15 - 1.3 Load, (with ztan's scaling) and from 800 - 6800 rpms as the Intake and Exhaust maps. I'll let you know how they work. My first attempts were only a tiny bit off. I think these will be good.

[thambu19]

Originally Posted by KoolBRZ

These maps feel a bit tame under 3000 rpms. I like what @shr133 did at the low rpms, so I'm going to do some blending and I'll post what I find works for me.

Are you saying this by just looking at it? The SC maps will be different from Turbo maps and they both should be different from NA maps

[thambu19]

Unless you have a dyno this approach could spiral you away from a good cal. You could use accel numbers which I think you are already using.
Best way would be to start at a good starting point and add or subtract 5 deg of Intake or Exh not both and see how it feels. So on and so forth. Always compare back to where you started.

[KoolBRZ]

Originally Posted by thambu19

Unless you have a dyno this approach could spiral you away from a good cal. You could use accel numbers which I think you are already using.
Best way would be to start at a good starting point and add or subtract 5 deg of Intake or Exh not both and see how it feels. So on and so forth. Always compare back to where you started.

Most dyno owners seem to think time is money. So they don't waste time with acceleration or low-end torque. If I owned my own dyno, yeah that would be a different story. I have a Phantom ESC. Which takes a combination of NA and FI tuning to get the most power from it. What do you think about @shr133's idea of using a max of 25 in the exhaust tables?

[freerunner]

Originally Posted by KoolBRZ

I combined the best of both ztan and shr133's tables to make these. The Base tables are exactly the same from .15 - 1.3 Load, (with ztan's scaling) and from 800 - 6800 rpms as the Intake and Exhaust maps. I'll let you know how they work. My first attempts were only a tiny bit off. I think these will be good.

I'm not a pro, but I think closing the exhaust valves this late at low loads is only good for spooling up a turbo. You'll lose power and FE on a NA engine.

[KoolBRZ]

It's actually to reduce pumping losses at low loads.

[shr133]

Originally Posted by KoolBRZ

Most dyno owners seem to think time is money. So they don't waste time with acceleration or low-end torque. If I owned my own dyno, yeah that would be a different story. I have a Phantom ESC. Which takes a combination of NA and FI tuning to get the most power from it. What do you think about @shr133's idea of using a max of 25 in the exhaust tables?

Dynos are not an end all just the base and you tune from there... and most shops don't tune for mid range power and drive ability... Plus we still have our base maps...
The only thing that matters is your goal, which normally the best acceleration...
So 0-60, 30-60 1/4 mile times are the best measure if you are accomplishing your goal.... Does it just feel faster or is it faster... I think I have to come up with a 3000 rpm roll on test... 3rd gear roll on's work good...

The max exhaust timing seams to be around the 25-30 range then you start to loose power and it won't pull....
Intake seams to be around 30-35....

N/A seams to like less exhaust timing, it revs much better in the high mid range... But still trying to test, it's raining, so now it just spins like crazy with this tune...

Seams like I may have to add a little more exhaust timing below 5000...

[shr133]

Originally Posted by KoolBRZ

I combined the best of both ztan and shr133's tables to make these. The Base tables are exactly the same from .15 - 1.3 Load, (with ztan's scaling) and from 800 - 6800 rpms as the Intake and Exhaust maps. I'll let you know how they work. My first attempts were only a tiny bit off. I think these will be good.

I like those maps....

Not a fan of the 40 degree exhaust timing at low load, other than that they look really good....

With a supercharger I think intake maps are the same as N/A, but you need more exhaust cam and a wider lobe centers... So your exhaust maps may be different than a N/A or turbo...

On N/A V8s we ran 106-108 lobe centers...

"For best performance with a blower, you should look for a cam that has higher lift and longer duration on the exhaust side. Street performance with a blown engine is usually best with a cam that is ground with a 112- to 114-degree lobe separation. With the use of an aftermarket camshaft, follow the camshaft manufacturer’s recommendations for valve springs. Blower cams can typically be run “straight up.” Note that a blower has tendency to lessen the rough idle of radical cams."

[shr133]

Also looks like as the cams are more efficient boost will drop on a supercharged car... in a good way..
and too tight of lobe centers will loose boost in a bad way...
So you will need to data log your boost also.......

[KoolBRZ]

Those tunes under-performed, so I went back to shiv's ESC tune, added radiator fan limits, quiet start, and PFI% changes, then added as much of @shr133's low end tuning as I could. Remembering his comment about trying a max of 25 in the exhaust table I made some identical tunes with the only difference being the max on the exhaust tables. I started with 26, then 27, 28, 30, and 32. Just got back from the store, and 26 max has more low-end torque, while 32 has more top-end. Now to blend the best of both together...

[KoolBRZ]

Originally Posted by shr133

Also looks like as the cams are more efficient boost will drop on a supercharged car... in a good way..
and too tight of lobe centers will loose boost in a bad way...
So you will need to data log your boost also.......

No matter what I tried to change the base tables to, it always sucked compared to OTS tunes. I don't know the theory behind the changes Shiv made to the base tables, all I know is it works. I finally gave up trying to change the base tables, and concentrated on the intake and exhaust tables. It seems these tables are just about right, except for a slight hesitation off idle. I'd like you to try these tables on your car and see if you can improve on them. They wouldn't work anywhere near as good without using Shiv's base tables, so I've included those as well. The Intake and Exhaust tables are easy to make, just highlight the biggest square and type the number, highlight a square within that one and type a number, and on until you get to the inner-most square. This tune does just about what I'm looking for in a tune. It makes the car seem eager to go faster. My wife compared it to an excitable little dog like a terrier, that just wants to be let off the leash to run as fast as it can.