Accuracy of Virtual Dyno? Load and Boost Increased but Lost Power?

[Lolmooses]

Hello everyone, just started tuning my MS6 and using Virtual Dyno as a way to track where my changes are going. I've increased my load from around 1.7 to 1.8 which pushed my boost from ~13 to ~14 but Virtual Dyno is showing a loss in power from the higher load to the lower load run? These are both 3rd gear pulls, during the same time of day, very similar ambient conditions and on the same stretch of road. I'll include the CSV's and both tunes below incase anyone is wondering.

Mods are: CS SRI and TIP, CS Cat Back, Ultimate Racing Race Pipe, CS HPFP Internals and a GFB Hybrid BOV.

[mituc]

Virtual Dyno is pretty accurate, I even tested it against real dynos and it's about there.

Regarding those two logs that you posted, the first one doesn't have the timing advance logged.
Also you are logging barometric pressure but not manifold absolute pressure, so we're a bit blind in these logs. We don't know if it was hotter, of you're hitting some limits, or anything.
Please use this monitoring for next time you post logs: https://www.dropbox.com/s/aoqz8qpw3bg9s ... vtpre?dl=0

[Lolmooses]

Hi Mituc, thanks for confirming. I took another log with a 3rd gear pull and a 2nd gear pull after that with the preset you sent. It seems to overshoot the load target by a bit right after I get on it and then it starts following the targets I set a lot better. Working on modifying the BCS DC table.

Edit: Added the tune I used since it differs from the two yesterday.

[mituc]

It seems to overshoot the load target by a bit right after I get on it and then it starts following the targets I set a lot better.

You need to lower the WGDC table values in that area. Load 1.9 is too much for the stock engine at that RPM. Luckily the ignition timing is super lazy at that RPM and load but with that much air and fuel it will still result in a lot of heat.

Also when you update your MAF calibration make sure you update both vectors with the same data.

[Lolmooses]

Ok I'll keep adjusting the BCS bit by bit as I have been then. I remembered to copy the first MAF table into the second one for every version of these tunes except for this one apparently haha. Thanks for pointing that out, might explain why my idle was a little strange.

Does my BCS DC seem reasonable for the mods I have? My tune started from the 91 Oct Base tune and i know it doesn't account for the race pipe and catback, but I've had to lower it quite a bit from the values in that tune. Same goes for when I compare it to the high load with DP OTS tune which I would imagine opens up a much larger restriction compared to the race pipe and catback with stock DP.

[mituc]

Well, with the mods you have you only push about 260-265g/s of air. I would not quit until I'd see at least 280.
Do you still have the factory cats?

[Lolmooses]

Still have the stock downpipe but secondary is gone.

[mituc]

Still have the stock downpipe but secondary is gone.

Ok, 280g/s of air is fine then.
I'd let it tamed down past 6500rpm and even at 6500rpm, just because factory pistons ringlands. But until up there make it suffer.

So you're on 91OCT gas? If it has enough ethanol (like, if it's E10) it can take quite a lot of timing, almost as much as E5 93OCT in the past. Point being it's quite resistant to knock.

[Lolmooses]

Ok great, good to know I'm in the right ballpark there and will do. I typically shift at 6200 or so since I'm getting close to automatic jail time speeds at that point hahaha.

I picked that tune just to be conservative, but I'm on 93 E10. No knock at all during WOT other than some random blips of .35 every once in a while. I've noticed these cars can take a decent amount of timing relative to PI turbo 4 cylinders I've tuned in the past. Once I get the BCS DC nice and smooth I'll work on timing.

How do you feel about modifying DBW tables to hit 45-50% starting at 1.5 and slowly ramping up with load to 80%? I feel that having it where it is now at low 30's between 1.5 and 1.6 and then a sudden jump to 80% above 1.6 load gives the car an underwhelming feeling of acceleration when you go WOT at 3000 RPM or so until it hits that 80% section of the map.