help with idle spark, LE5 turbo

[cobaltssoverbooster]

Wouldn't go over 11.7 if using factory pistons they don't take the heat as well

[noorjSS]

Even with E85? Alright I'll bump PE down to .79 lambda


Forgot to mention, clutch is now slipping. Will return with logs after the KY stage 3 goes in.

Car is very fun though

[cobaltssoverbooster]

well i personally didnt read the e85 part. thats a different monster.
max power rich for E85 is .71 lambda
and max power lean is .86 lambda

id say start at .79-.8 and see if it takes a lot of timing. if it accepts 22-23* then try .81-.82 and reset the ignition back down and see what it accepts. as long as the egt is under 1250 you should be ok. i try to shoot for 1000-1100 range on stock parts because they are sensitive (this will leave some power on the table but for a dd its better i lay safe). the temp if you read it should be pre turbo for best cyl temp reads.

each setup will like a different afr so trying the range will net best results in the end for your specific vehicle.

[noorjSS]

Well generally would more rich mean safer? I'm not necessarily trying to make the most power, I would just like around 300whp but keep it as safe as possible. I also don't have an EGT probe/gauge so I have no idea what they are like. Maybe this is something I'll look into getting soon.

I was under the impression that because I have an LE5, keep the boost as low as possible and timing higher to get to my desired power output. I could certainly get more than 17* timing right now but at 10psi pushing 33lb/min I'm at the power level I want to be at.


Also general tuning question, because the engine sees the highest load and stress at maximum torque, should I keep timing there relatively low (12*) then ramp up to max timing by around 5500-6000? I thought this would keep the tune "safer" but I'm not entirely sure.

[cobaltssoverbooster]

richer is lower temp but at a point your just wasting fuel and helping anything.

le5 has inferior parts, compared to other boost designed ecotecs. rods are cast iirc and pistons are not of quality enough to take abusive heat. low boost with high timing will be good but at what point is your timing going to hit most best torque. that answer can only be found with a dyno. if your at a psi you want then stay there and work out your tune. at 10-12 psi that is about your range on a le5 all factory.

timing is adjusted as follows. hold a specific load x rpm on the dyno and start at say 14* timing. turn the timing up 1* at a time until the torque reaches a max then drops off again. the lowest timing value that made the max torque is value you use.

[noorjSS]

Sorry I worded my question poorly: As I understood it at the engine speed where the engine produces maximum torque, the timing advance is critical because IMEP is highest and (correct me if I'm wrong) overall cylinder pressure is highest. Therefore in this area, would it help to relax the timing advance a little just in an effort to add a little extension of life onto the motor?

Thanks tho, I'm thinking 10psi daily and 12 just for the #'s. Will get back with some tuning results when the clutch is broken in.

[cobaltssoverbooster]

well in every case running it not on the edge is going to extend life so yes if you move ignition to come out of max cyl pressure of course you will extend life some.

[noorjSS]

you try for 1000-1100F manifold? I don't know ecotec egt's (or 4 cylinders at all) at all but coming from smaller gas engine tuning background that seems fairly low. But hopefully between the relatively high advance and E85 the egt's will be on the low side anyway. I'll pull the manifold soon and weld a egt probe bung on it to check them out.

[cobaltssoverbooster]

the max for any engine diesel/gas/exotic is 1300*F at this point your at the edge of melting stuff so i figure i stay away from it and if 1100* shows good promise and the power jumps in huge amounts i will shoot for something higher. i have my own safety net as everyone else has theirs.

[noorjSS]

hey guys, tuning has been coming along well. after a couple hiccups it finally feels very good. I have ran into a couple question areas tho:

on the 60# injectors I could easily squeeze out 17* no problem, now it seems to be knocking on 15*, what could cause this? running E85, tested to 82.5% ethanol, I thought I should easily be able to pull 20*+ Something tells me it is false knock, coming from the metal on metal sound my horribily warn control arm bushing is causing mixed with somewhat rough roads, but I don't want to risk it.

Also I maxed out the 60's so moved to 80's, however the IDC seems very high. Could something be wrong with them? they are the siemens/mototron 80's ZZP sells

here is the tune/log/config for you wizards to check out if you get a chance, thanks!


edit:sorry last problem: on decel it goes real rich, hits the min pulse limit .8ish ms and sits rich until dfco kicks in, any way around this?

80swot2.hpl
eturbo80s.hpt
jasonsconfig.cfg

[noorjSS]

figured it out, changed the spark plugs and all the top end knock went away. NGK LTR6IX-1 #6509 a stage 1 colder plug only lasted about 2k miles. heres another much better log, (lots of wheelspin in 2nd lol)

80swot4.hpl

[DeeJayZee]

figured it out, changed the spark plugs and all the top end knock went away. NGK LTR6IX-1 #6509 a stage 1 colder plug only lasted about 2k miles. heres another much better log, (lots of wheelspin in 2nd lol)

80swot4.hpl

Hey man, I too run boosted LE5, and a good portion of my problems came from those damn iridium LTR6IX plugs. Only plugs that have worked for me have been LFR6A (copper).. Consider giving these a shot!

[cobaltssoverbooster]

E85 has a stoichiometric fuel mixture of roughly 9.78-9.8:1 in E85's purest form (Class 1 85% Ethanol summer blend). As the fuel's Ethanol content goes up the stoich range goes down. For instance, 100% Ethanol's stoich is about 9.0:1.

E85 will maintain max brake torque much richer than stoich than gasoline will. But, because of it's excellent detonation threshold(due to lower combustion temps, lower peak cylinder pressures..etc), it can be run much closer to stoich than gasoline safer. E85 reaches max thermal efficiency at about 13% richer than stoich, whereas gasoline is about 16% richer than stoich(with pump gas being even richer). But again, E85 can maintain Max Brake Torque well into the 30% richer than stoich range, unlike gasoline which is limited to about 18% rich of stoich. DISCLAIMER: Just because E85 itself will still make power at super rich AFRs, doesn't mean it's a good idea or even recommended. A whole host of issues come with running super rich AFRs but im not going to explain them here it would need its own thread.

Therefore Max Rich Torque of E85 is between 7.1:1- 8.5:1
With that being said, here is what i would consider safe and conservative fuel tune on E85. *AFR's listed in bold are for widebands o2s that are calibrated for gasoline, AFR's in ( ) are actual E85 AFR:

Part Throttle lean (max eco) AFR of 16.5:1(11.0:1) 12.4% leaner than STOICH
Part Throttle rich AFR of 14.7:1(9.8:1)
Spool up... AFR of 13.5:1(9.00:1)
WOT... AFR of 12.1:1(8.06:1) 17.7% richer than STOICH


*If you're using a wideband that is calibrated for gasoline(14.7:1) and cannot change the calibration of the wideband, take your gasoline AFR and divide it by 1.5 to get actual e85 AFR or use the wideband in lambda mode. 1 lambda is 9.8:1

Here are some common AFR conversions(Gas AFR on left, e85 on right):

18.0:1=12.000
17.5:1=11.666
17.0:1=11.333
16.5:1=11.000
16.0:1=10.666
15.5:1=10.333
15.0:1=10.000
14.5:1=9.666
14.0:1=9.333
13.5:1=9.000
13.0:1=8.666
12.5:1=8.333
12.0:1=8.000 (max lean on factory internals)
11.5:1=7.666 (max rich on factory internals)
11.0:1=7.333

the normal middle point is 11.7:1 gas which is about 7.808:1 E85. the multiplier will be .796. start there then work your way up on a dyno where you can monitor exhaust temps better. I have seen knock show when going richer like 11.5:1 gas or 7.666:1 E85 so try to keep just above that if you can.
(*helpful hint of the day: don't buy a glowshift egt sensor/gauge combo...get a real egt from innovate. innovate is faster responding, more durable, and 20x more accurate.)

[noorjSS]

DJ- thanks for the suggestion, I actually found the copper NGK LTR5GP to be very good. Got rid of all the weird knock and gapped at .030" don't blow out.


cssob- Thanks for the write up. I've been running a .85 lambda during spool tappering to .80 by 5000 rpms. Once I get my fuel system in and turn up the boost I will be watching EGT's, and potentially go even leaner to help spool.

[cobaltssoverbooster]

Banks power has a read on egt temp limits I think everyone should read. I will link it here and in the help files tonight

[DeeJayZee]

I've been battling EGTs with my 2.4T build, although it may be where the probe is located in my log mani - my cruising EGTs are 1250-1300 without load.. Hitting around 1500 on pulls... Running 13-17* timing in the top end on a 94 octane e10 fuel...

[cobaltssoverbooster]

cruise doesn't need a ton of timing if your having problems lower it some. try putting in some more fuel on the wot to see if it cools it down. most turbo conversions dont exceed 16* timing under boost.

[Ecotec2.4]

I've been battling EGTs with my 2.4T build, although it may be where the probe is located in my log mani - my cruising EGTs are 1250-1300 without load.. Hitting around 1500 on pulls... Running 13-17* timing in the top end on a 94 octane e10 fuel...

DITTO ^^
but here its 90 e10

[noorjSS]

still don't have my egt probe in yet, im slacking guys. but ill report back with what mine are on E85 once I do

[DeeJayZee]

cruise doesn't need a ton of timing if your having problems lower it some. try putting in some more fuel on the wot to see if it cools it down. most turbo conversions dont exceed 16* timing under boost.

More timing = cooler EGTs... I know this because my winter tune has about 7* less timing on a zero ethanol 91 octane fuel (for economy) and my EGTs are around 100* hotter... I can't add any more timing to my cruising timing rpm vs g/cyl because if I do step on it at that rpm, PE engages - and last time I had some advanced timing in the cruising range, I got 3* KR if I stepped on it... It's a fun battle with this setup lol