I disabled the cat warm up on my LNF. Now on cold start ups or a startup after sitting for a while, it has a rough idle and I watch the vacuum teeter back and forth like the wastegate is opening and closing.
How can I tune this out?
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I disabled the cat warm up on my LNF. Now on cold start ups or a startup after sitting for a while, it has a rough idle and I watch the vacuum teeter back and forth like the wastegate is opening and closing.
How can I tune this out?
Cam tables help a lot, GMTech has posted some moderate ones that work well cold and warm.
Sweet. Thanks a bunch.
I'll look those up.
I'm slammed at work right now. (My browser with all the forum tabs is up when I go to flash a car at work so sometimes I can't help but look at what's up online!)
Maybe tonight I'll post up some good info on fixing the cold start issues that come up after doing the cat warmup delete. It can be fixed, we've got two Sky's with perfect cold starts and warmups thanks to Chris and Bill.
Hey Chris or Bill, any updates for us? The "Load Damping" still doesn't seem to do much. Didn't you say you had some ign timing tables or load tables in the works for us?
That would be phenomenal, thank you. I found a set of cam tables that you posted but I'm not 100% positive they are the right ones (I think they're warm tables) and I'm doing this on my phone so I can't get the link to the post just yet.Quote:
Originally Posted by gmtech16450yz
Wait on the cam tables I have much better ones. I'll post tonight.Quote:
Originally Posted by Gremlin85
:worship:Quote:
Originally Posted by gmtech16450yz
Here you go, try these. (You too Tom, you might like these better.)
The cam tables I posted in my learn and share thread are pretty aggressive as far as leaning towards power and away from mpg, as Tom mentioned. They also work better on my particular setup because I'm far from stock. These tables I'm posting here work extremely well for power and mileage, just make sure you're particular freeway cruise rpm is the same as where I have the exhaust timing retard in the tables. Watch your rpm and load at 65-70mph and retard exhaust around there, then smooth out around it. You're gonna get a big spike in the table image, that's ok and actually less than stock if you do it right. (not as steep)
Make ALL cam tables for intake match each other, and same with exhaust tables. That means knock, warmup, etc. Make sure ALL idle tables for the particular cams match each other also.
I'll also include a screen shot of some injector and idle tables. I believe these inj timing numbers work better with the cam timing. If you notice on the stock inj timing tables, there's a pretty big retard around the same spots that cam timing is retarded. (Imagine that!) My theory is they obviously want inj timing to match cam timing, and moving inj timing back up along with cam timing works much better. On idle speeds, raise desired numbers in these tables, but also realize you'll need to massage DAL's in those areas to make sure you're not getting any ign timing dump. (For those that don't know, if you request more DAL than is needed at low rpms or idle it will retard ign timing to try to control idle speeds. This is standard practice on many ECM's. The balance between airflow and ign timing is what controls idle speeds, mess one up and you'll mess the other up also.
You may also want to work on the ECT/Ign timing table, if you're still getting fluctuations in the idle, try raising the timing in the specific cell that the warmup is at as far as load, rpm and coolant temp.
Oh, btw, what you felt might have been the wastgate going back and forth is most likely the throttle plate and ign timing hunting up and down because it can't maintain desired idle speeds without overshooting. Try these things first. I guarantee these LNF's can be made to have a nice, normal cold start with a mild fast idle (which is what you want) and enough ign timing to run smooth and quietly. Thanks again Chris and Bill for giving us that tiny little button to turn Cat Warmup off!
http://i841.photobucket.com/albums/z...owerandmpg.jpg
http://i841.photobucket.com/albums/z...dinjtiming.jpg
I'm running a bit more negative intake cam in the midrange for economy, but nowhere near stock. I max around -25*
Wow, thanks. That's way different than what I had.
I, too, had closer to -25* midrange. I'm not worried about gas mileage, I want maximum power.
I'll test these out and see how they suit my needs and wants. I'm thinking they'll be pretty damn decent as they are.
Thanks again! I've always been pretty scared to go too far with these tables.
Maybe Im mixing something up here, but doesnt more timing get better economy not less? So -10* would get more than -25*.
Not on cam timing. What they're doing when they retard cam timing is lowering dynamic compression, which lowers pumping losses. Think about how hard a high compression motor is to turn over vs. a low compression motor. Multiply that by 3k rpm and you'll see why lowering dynamic compression to only what's needed has an effect on parasitic losses. Remember, if you only need 75hp to maintain 70mph, a 100hp motor will do it more efficiently than a 500hp motor will.Quote:
Originally Posted by acesneights
Tom, exhaust cam timing has more of an effect on mpg's than intake. Try lowering your intake retard a little closer to mine and making sure exhaust is closer to stock if you want mpg's. Are your inj timing numbers close to mine? They seemed to really help the cam timing changes as far as mpg's and torque goes.
I just updated the inj window tables yesterday evening. I'll see how the mileage goes. Looks like around 24 mpg on 60% ethanol right now. Hoping for dry roads to flog it a little. Very rainy spring here. If I get out of work tonight I'll post the cam tables up. They will look familiar to you except the highest load column. I have the best luck with the stock tables so far greater than 200% load.
Here's my cam & boost tables with DAL's at 255 in the highest load columns & a bit more above 5k in small steps. Pretty flat 24-25 psi boost in 3rd & 4th with the 50* IAT2 range, .898 PE Lambda. Should give a few guys a fair starting point.
Remember I'm pretty well bolted up so it flows 32 lb/min VE in the upper midrange with stock MAF tables. Never got over 125 to see how 5th pulls. lol.
http://www.hptuners.com/forum/attach...1&d=1303344216
Here's the PE, DAL's and timing. All 4 timing tables the same.
Use GMTech's Inj Window tables and have fun. I've noticed that the Commanded PE lambda runs .007 richer in the table when logging than commanded in the tune so .898 is truly .891. YMMV.
http://www.hptuners.com/forum/attach...1&d=1303345172
are you keeping your malt table at 100% all across? did you limit the torque in 4th and 5th to tame the boost spike or save the clutch?
MALT is 100% from 2500 rpm up. Torque limit in 4th & 5th is to clamp boost under load at ~24 psi or it would see 26 psi in those gears. I has no clutch slippage. SPEC Stage2+. :D
Holy timing!
God i wish I could run E85 :(
Meth is coming in soon, though. I think that'll help a little.
My pathetic timing...
http://www.hptuners.com/forum/attach...1&d=1303356287
That's 3-4* more than I could run on 93.
This is good info for others too, not just Iam Broke...
Hey Tom I think we can get you to 28mpg with a little more massaging. You're our mpg mule so it's all up to you to test out mileage theories! It sounds like you have a nice freeway commute to get solid results with. My son is getting around 24 and I'm getting 21 or so with about a dozen speed runs per tank. We're both running E47.
Here's some ideas...
Try either advancing your intake numbers or retarding the exhaust more right around that freeway cruise area. Your overlap numbers are closer than stock and I don't think you're getting as much EGR effect as you can. Remember, copy the exhaust table to the intake by "special- add" to see what the overlap looks like. (Obviously you don't want to leave the tune file like that, just don't save when you're done looking at overlap.) Basically you want to keep the intake and exhaust numbers similar, or even have the exhaust more retarded than intake for more cylinder charge exhaust dilution. (we're just talking about freeway cruise areas for mpg here.)
Another thing that will help a lot is ign timing. We can't do a direct comparison of our timing tables because I'm using a different approach than you for the E tune. I have pretty aggressively advanced main tables, but I also advance based on IAT quite a bit. The IAT add and multiplier tables give you more control over when you're adding timing with the E or in my case, Meth. It also gives you more safety when IAT's get too high, you can make sure you're timing isn't too crazy unless intake temps are safe. Look at your timing drop below 2500-3500, it's pretty steep. It can take a bunch more timing down low, and that's where you're at freeway cruise too. Advance the crap out of it down there, or at least smooth everything out more by increasing. Another thing I do with the 4 tables is don't just pick one table to use and make the others the same, I do a series of copy/pastes between the 4 tables to make sure you're using all of the HIGHEST numbers of all 4 tables in every cell. The tables all have cells that are higher AND lower than the others, so just using one will mean there are spots that you're loosing advance. (Sorry if any of this is old news to you in particular Tom, I know you've figured out a bunch of stuff on all of this. I'm using your tables as an example for others and also so I can pass along some of the things I've learned. In other words, we have very different approaches on some of this stuff and that means we've learned lots and can learn more from each other!)
Here's another thing I noticed... Your "torque/gear" tables can be tweaked more I think, I also use those tables with great success to control boost. I learned long ago that it's VERY useful to be able to control boost per gear. If you lower boost by DAL's or MALT's or now with the actual boost tables to eliminate the boost spike, you're sacrificing boost in lower gears to keep the spike away in higher gears. What I've done is reduced torque/gear severely in the upper gears also, but ONLY around the 3700rpm boost spike area. Once you're past that area, like 4k or so, you can go back to full 100% in every gear. That is unless you want to control traction of course. Same with down low, I'm at 100% up until 2500rpm or so.
Again, not trying to pick on your tables Tom, you know a lot and yours are better than most. Advance the crap out of midrange load and low rpm ign timing, dial in more cam overlap and oh, I just thought of one more thing... Decel DAL's. I've never seen anyone mess with the rest of the DAL table, 99% of tuners just change the 2 far right columns. Why? It's a big table with lots of throttle mapping control. I don't think there's a single cell in my DAL's that's stock! So here's my thought as far as optimizing mpg's, try lowering coastdown DAL's a lot, like maybe 50% even. What this does is makes sure you're getting into DFCO more often, and also even if it's not in DFCO, you're burning less fuel with a smaller throttle opening. You can drop the numbers quite a bit until 1250rpm or so. Work on the 10-19.9% columns. This will also help on exhaust burbling or backfiring. Here's another one, MAF correction table on decel- those same areas have a HUGE effect on coastdown. Again, I never see anyone changing those areas to improve driveability or eliminate backfiring, etc.
Damn, sorry to ramble guys! Hope there's a few tidbits of info for somebody in there!