Basic VVT Tuning info

[wrickm]

For all the N/A'd LE5 owners
Alright, my summer course ended and I've had a week to fool around with all the various hypotheses I've had and worked out some pretty sweet timings for the exhaust and intake timings.

I've attached a log of my recent testing efforts as well as the most recent tune.
Mainly what i've been trying to do is maximize between MAF airflow and VE airflow. The results from the scanning logs is pretty good. It definitely pulls harder all the way out to 7k rpm.
Im still washing out the KR though but im trying to sort out real knock from phantom knock since my car can get kinda moody with that (it'll still show some kr even with tdc spark timing). Results may vary on that front
PE is leveled out for consistency with a small increase in richness at the topend as a tiny safeguard to reduce kr, though that'll get set to lean out later on once im happy with the cam timings

wrickm, i think you've gone the same direction I've gone. Your log looks pretty similar to what i've got going on though yours has got this weird jump/hump just before the top of the revs that bumps up the maf and ve. My maf values are a bit lower since Im still using stock parts but the ve airflow seems to be about the same
Pulling the timing on the intake back to 0* is where im at now for revs past 6800. What im still testing is how far I can go with exhaust advance to increase some overlap before it starts decreasing performance

VRK, I was going to mention that the difference might be just the intake and exhuast mods I have. Let alone any differences in platform. I only get two days a week that are feasable for making runs due to a hectic work schedule. I have a tune ready with the intake timing at 0. The Exhaust table you have is pretty similar to the stock Solstice table. I have a couple different combos I am going to try (al top end figures: 0 vs 8, 0 vs 10)
Have you noticed gains from increasing you advance in the low end. I really havent touched mine, not sure whati could hope to gain.

Glad to have another tuner working on it. my high MAF thus far is 19.152lbs/min

[viceroykarl]

I have tried using 6 and 8 deg on the exhaust side but the stock 10 deg seems to be the best so far. I'm going to try testing times more advanced than 10 though to see how they stack up.
I haven't really modified anything in the lower end of the scale much though since its spending most of the time above 3k rpm when putting the hammer down. though im finding that the stock timings for between 2k and 4k rpm for cylinder air masses above 0.54g/cyl work best.

I'll post up 2 logs i have where i ran it out with all 0s on the intake/exhaust and all 25s.
the differences were noticeable, especially with running all 0s. It was slow enough to take over 10 seconds to get to 60 lol.

Edit:
can only find the one scan right now where the 2 tables were zeroed out.

I'll hopefully have some more time to do some testing today since Im trying to find that exhaust sweet spot, though from other logs i know anything past 12 deg decreases performance. It may turn out that the stock exhaust table is already right on the money

Im only able to test the success of these tunes from the logs, 0 to 60 and quarter mile time though since there isnt any dyno shops nearby, only a half mile deserted service road that goes along the turnpike

[wrickm]

I have tried using 6 and 8 deg on the exhaust side but the stock 10 deg seems to be the best so far. I'm going to try testing times more advanced than 10 though to see how they stack up.
I haven't really modified anything in the lower end of the scale much though since its spending most of the time above 3k rpm when putting the hammer down. though im finding that the stock timings for between 2k and 4k rpm for cylinder air masses above 0.54g/cyl work best.

I'll post up 2 logs i have where i ran it out with all 0s on the intake/exhaust and all 25s.
the differences were noticeable, especially with running all 0s. It was slow enough to take over 10 seconds to get to 60 lol.

Edit:
can only find the one scan right now where the 2 tables were zeroed out.

I'll hopefully have some more time to do some testing today since Im trying to find that exhaust sweet spot, though from other logs i know anything past 14 deg gets a huge fall off in performance

interesting. careful with that knock BTW. Also just goes to show how different the cam settings are for difference apps. Everything on my low end is stock and it varies wildly from your stock settings.

[viceroykarl]

Just another addition, i tested 6 deg on the exhaust time again in high rpm and its still in the good range. The maf flow is a bit lower but the ve gets along higher. Seems a bit more powerful but there isnt anything conclusive in the 0 to 60 times due to the amount of possible error in recording that.

im going to try testing 4 and 0 again for the high rpm range only. The problem i think that was happening when running 0 and 0 across the board was the air was never moving fast enough from the beginning to get any compression though inertia

[wrickm]

this is why i want to use a dyno progam. It doesn't have to be accurate, just conistant. I can't feel power changes ar 5500-6900rpm with enough accuracy to make informed decissions. I would usually use MAF over anything for "power" VE is kinda newer to me. so it's going to be interesting to see where that goes. Brad Barnhill said the Solstice would be n the next gen of his software. so that, at least, will be another tool.

Keep me posted so i can shamelessly steal you findings!!

[viceroykarl]

Heh, I like sharing these finding to others in hopes that i'll get more people working on it too and share back their results so everyone wins

Hopefully with virtualdyno automatic gear ratios are accounted for since I use 2nd gear from about 4k to 7k so i can keep it between 40 and 80mph

The air is pretty hot right now today so im really not getting any consistent results, stuff that worked fantastic last night are crap today with airflow rates up to 0.60 lb/min lower. Giving me a good idea though of how the hotter air is affecting my kr.

I still need to get my exhaust fixed. The good ol flex pipe broke and is doing some rattling around 3k rpm and 5.5 to 6k rpm which I think is making my kr go mad and pulls timing out. Some of the knock today though was real but that "high quality" gm flex pipe is messing with my results when it gets rattling.

What i did find out though from earlier today is that 6 deg on the exhaust only really works well when the intake air is not over 85 F and had more poor results than just using 9 deg which works just about as good with cold air but a bit better with hot air.

I think though that 0 deg intake upwards of 6k rpm and between 8 and 10 deg on exhaust works the best

[wrickm]

I have to try this application i found called virtual dyno yet to see how that can feed me results back.

The air is pretty hot right now today so im really not getting any consistent results, stuff that worked fantastic last night are crap today with airflow rates up to 0.60 lb/min lower. Giving me a good idea though of how the hotter air is affecting my kr.


I think though that 0 deg intake upwards of 6k rpm and between 8 and 10 deg on exhaust works the best

Virtual Dyno is what i am talking about. the desinger is adding in my solstice info for his next release.

Yay for more vairiables. . .

I got a line one some dyno time for definitive answers, but it's pricey and i am not yet sure how long i would have. I'll be taking donations for doing research lol

[viceroykarl]

im getting clean 2nd only pulls now from hp tuners on my testing road and feeding it into virtual dyno, while its not giving me the real hp numbers its letting me see comparisons between tunes in a different way.
Its raining now anyway so i cant safely test the tunes. hopefully i have enough logs to see some differences

i think im at the point though where i've wrung out all the power its got to give with stock parts

EDIT:
feeding my runs into virtual dyno were not really useful at all the results were all over the place, even for identical runs. though it still seems that anything past 6k and you cant go wrong using between 6 and 10 on the exhaust, i have mine at 9 for something in between

[wrickm]

ok last run for the day: new highs 20.714 VE Airflow 19.425 MAF

0 advance on intake, and 8 advance on the exhaust.

only 64 thousand more test runs to go.

[viceroykarl]

I have a few more ideas to test out but sadly my normal semester is about to start and i'll be running my economy tune on the car.

only 64 thousand more test runs to go.

lol i know what you mean, every day im messing with the settings in the tuner and flashing the car. Always trying to make it better. It never ends

[cobaltssoverbooster]

this is why i want to use a dyno progam. It doesn't have to be accurate, just conistant. I can't feel power changes ar 5500-6900rpm with enough accuracy to make informed decissions. I would usually use MAF over anything for "power" VE is kinda newer to me. so it's going to be interesting to see where that goes. Brad Barnhill said the Solstice would be n the next gen of his software. so that, at least, will be another tool.

Keep me posted so i can shamelessly steal you findings!!

lnf motors in a virual dyno are inaccurate due to the high torque levels genreated by the di system i have the sim software and i tried to get an accurate stock tuned power curve but it was always 60-70 lbtrq off even with changing the cams in the programs vvt section. basically we need a deisel software for 4 cyl wich isnt out yet

[Leafy]

lnf motors in a virual dyno are inaccurate due to the high torque levels genreated by the di system i have the sim software and i tried to get an accurate stock tuned power curve but it was always 60-70 lbtrq off even with changing the cams in the programs vvt section. basically we need a deisel software for 4 cyl wich isnt out yet

Wrong kind of virtual dyno. Brad Barnhill's takes logs and compares speed, rpm, and time to generate horsepower and torque.

[wrickm]

to update, i did a few more test runs this morning. I think the intake set at 0 is best. i tried exhaust at 6 and 8 and 12 and 8 was the best for me. I aslo tried leveling the cam charts out and smoothing them for everything over .52g/cyl, and found that i got lower values for both VE and MMAF throughout the rpm band. That one kind of surprised me. I didn't expect to see much if any more at the very top but i thought i would see gains lower, but it was clearly the opposite.

Kinda with VRK now, i think i have gone as far as i can as is. Now i need a dyno.

[cobaltssoverbooster]

Wrong kind of virtual dyno. Brad Barnhill's takes logs and compares speed, rpm, and time to generate horsepower and torque.

awesome

[emaxxer]

I'm curious as to whether or not my engine has an adjustable exhaust and intake cam. It's a 2008 3.7 i5 chevy Colorado. I know I have the tables to adjust them but I'm really imagining big potential with this motor if I have this adjustability. This motor has surprised everybody that I've lined up next to.

[Leafy]

I know the 3.5 has an adjustable exhaust cam.

[emaxxer]

I know the 3.5 has an adjustable exhaust cam.

I hope mine is different because then the 3.7 would be a monster of a motor for only 5 cylinders! I love this engine!

[viceroykarl]

http://archives.media.gm.com/archive..._26822_pr.html

They say it has VVT but they don't mention if its for both exhaust and intake or just exhaust

EDIT:
http://www.gminsidenews.com/index.php?page=Engine_Guide
They mention that its got a variable exhaust cam only

[emaxxer]

http://archives.media.gm.com/archive..._26822_pr.html

They say it has VVT but they don't mention if its for both exhaust and intake or just exhaust

EDIT:
http://www.gminsidenews.com/index.php?page=Engine_Guide
They mention that its got a variable exhaust cam only

well at least you can advance the exhaust cam to spool a big turbo pretty easily! at least that makes me happy!

[Saab2.8TAero]

Hello everyone,
As my username suggests, and I know this forum in particular is for the Ecotech, I have the boosted 2.8T alloytech motor in my saab. The motor has VVT on the intake only, and I was wondering if the rules for reducing overlap are the same for this engine since I wouldn't be able to alter the exhaust timing?

I've attached a pic of the cam profiles so you guys can see what I'm talking about.

My car has been tuned by another member on this forum, but I was just wondering what more could be done with the stock setup (turbo exhaust etc) through cam tuning.