V1 Mikes Extended, Full Frame Goblin - 2009 Cobalt LS with 135k donor

[mike_sno]

I should say, how well does a professional tuned E85 80lb/h LSJ idle?

 

[TravMac]

The E85 tunes tend to be a bit cold-blooded. Mine happens to be from ZZP with the smaller pully too. Sometimes on a first startup it'll idle hard and try to die, but the idle air control usually brings it back into shape. Once I get it actually warmed up though it hums along just fine.

 

[mike_sno]

If my car is really cold, the engine starts, but needs one a push on the gas pedal to go over 1500rpm for a second, then it comes down and idles fine. Feels like it needs to come down from rpm to get the regulation right instead of coming from below, if that make sense.

This doesn't happen when the engine is warm.

Cold start behavior is something I have to figure out, but since this only happens on the very first start and is not to concerning to me. I was mentioning the idle before when the engine is warm or at on the way to get warm.

 

[mike_sno]

Once I get it actually warmed up though it hums along just fine.

And what does that mean in rpm fluctuations around idle set point?

 

[Gtstorey]

One piece of tuning advice I would give you is to not chase numbers just because you can see/measure them. This is likely something you would never notice in a stock vehicle isolated from the engine and with full exhaust.

 

[mike_sno]

True. I could just leave it as is and call it a day. But it would be nice to compare it to something. What does a professional tuner think is acceptable ? I doubt that it's possible to get it much better with E85 and the 80lbs injector. Their duty cycle is 0.9-1.0%. But anyway. Would be nice to see what a good tuner get out of them.

This is my advice. After chasing my tail for a long time, this made all the difference.

 

[Rauq]

First two clips are 2 seconds apart in a 10 second window, third clip is a 20s window with the indicator at the same point as in the second clip. So I'm seeing generally +/- 15rpm fluctuations (30rpm total swings) with a target idle RPM of 900rpm. 80# injectors, 93, boost reference fuel pressure regulator set at 42psi, which technically makes the injectors a little bigger because their rated flow is at 42psi at atmospheric manifold pressures. With 42psi at idle, they're more like ~50psi with the engine off.

 

[TravMac]

And what does that mean in rpm fluctuations around idle set point?

I'll have to check the logs that I have using the zzp tune. After seeing Rauq's data, that's a pretty constant idle. It even sounds like yours is doing well on the info you shared. HP Tuners software can also compare data to learn from if you get your hands on one of these "professional" tunes. Might be a good way to catch differences in methods to what you've done in your tinkering.

 

[mike_sno]

Anyone know if the zzp upgraded timing chain kit is worth the money?? Or is it just a marking thing, saying upgraded. I doubt anyone would spend reasonable R&d money to upgrade something...

I just got myself neutral balance shafts and thought I do the timing chain kit as well. Found this one for less than$100

Long term plan is getting stronger valve springs and increasing the rpm. Hope to get save to 8000.

Not planning on changing the cams, just want a little more red line.

https://www.carparts.com/details/Chevrolet/Cobalt/Replacement/2005-2010/KIT-041817-11.html?TID=gglpla&origin=pla&gad_source=4&gclid=CjwKCAiAneK8BhAVEiwAoy2HYZLnOjeQQg1qbjLmE6IptRGrLvxpzNp9F0JJaw_JKkG9hlMRPmc8ORoCbtMQAvD_BwE&gclsrc=aw.ds

 

[Gtstorey]

Most of what I’ve heard about car parts.com stuff is that it’s junk. I don’t see a manufacturer listed so it’s probably bottom dollar Chinese junk.

See if there isn’t a least a semi well known manufacturer on Rock Auto.

 

[mike_sno]

First two clips are 2 seconds apart in a 10 second window, third clip is a 20s window with the indicator at the same point as in the second clip. So I'm seeing generally +/- 15rpm fluctuations (30rpm total swings) with a target idle RPM of 900rpm. 80# injectors, 93, boost reference fuel pressure regulator set at 42psi, which technically makes the injectors a little bigger because their rated flow is at 42psi at atmospheric manifold pressures. With 42psi at idle, they're more like ~50psi with the engine off.View attachment 50747
View attachment 50748
View attachment 50749

Hmm, Your throttle is a bit higher than mine. Are you running the LS throttle body or the standard LSJ? I have the LS so it would make sense that its a bit lower.

Here is a 30 sec picture of another log.

 

[mike_sno]

I'll have to check the logs that I have using the zzp tune. After seeing Rauq's data, that's a pretty constant idle. It even sounds like yours is doing well on the info you shared. HP Tuners software can also compare data to learn from if you get your hands on one of these "professional" tunes. Might be a good way to catch differences in methods to what you've done in your tinkering.

Yeah, it's just hard to find someone with the same mods and willingness to share.

 

[mike_sno]

Most of what I’ve heard about car parts.com stuff is that it’s junk. I don’t see a manufacturer listed so it’s probably bottom dollar Chinese junk.

See if there isn’t a least a semi well known manufacturer on Rock Auto.

Wow, they are really not expensive. https://www.rockauto.com/en/catalog...3737,engine,timing+chain+&+component+kit,5756

Any brands you would suggest?

 

[Keckster]

I put a cloyes kit on mine and I rev to 8000 often at the track and autox

edit: I also deleted my balance shaft all together and ran a short chain for the pump to get the higher rpms

 

[mike_sno]

I put a cloyes kit on mine and I rev to 8000 often at the track and autox

edit: I also deleted my balance shaft all together and ran a short chain for the pump to get the higher rpms

Hmm, since I ordered the neutral balance shafts, would it make sense to run a shorter chain and just let the balance shafts sit without turning??
Did you use the https://zzperformance.com/collectio...etrain/products/zzp-ecotec-timing-chain-guide zzp chain guides?

 

[comegetjoe]

Hmm, since I ordered the neutral balance shafts, would it make sense to run a shorter chain and just let the balance shafts sit without turning??
Did you use the https://zzperformance.com/collectio...etrain/products/zzp-ecotec-timing-chain-guide zzp chain guides?

Mike, I'm pretty sure we just went with the Cloyes set and left the chain the way it was as the sprockets do not change anything with the neutral balance shafts.

 

[mike_sno]

Mike, I'm pretty sure we just went with the Cloyes set and left the chain the way it was as the sprockets do not change anything with the nuetral balance shafts.

I just thought it would be easier on the chain to not go over so many sprocket. I guess the ZZP neutral balance shafts reuse the sprocket from the original balance shafts and just spin free.

 

[Keckster]

Hmm, since I ordered the neutral balance shafts, would it make sense to run a shorter chain and just let the balance shafts sit without turning??
Did you use the https://zzperformance.com/collectio...etrain/products/zzp-ecotec-timing-chain-guide zzp chain guides?

Those zzp chain guides were not a thing when I redid mine. Cloyes kit should come with new chain guides and tensioners. I installed balance shaft delete plugs from ottp and a short chain kit from bradbuilt. Im unsure of if you can leave the balance shafts in without them spinning. Most people deleting them cut the balance shaft off so it is just a sprocket getting spun by the water pump chain.

sorry for the bad photo but here is my timing chain and short chain setup when I did it

 

[Gtstorey]

Wow, they are really not expensive. https://www.rockauto.com/en/catalog...3737,engine,timing+chain+&+component+kit,5756

Any brands you would suggest?
View attachment 50754

Cloyes or Melling. Although it does appears that SA Gear and maybe INA are American made.

 

[mike_sno]

Ok, thanks. Here is my plan at the moment. I will reuse the old sprocket, install them on the neutral balance shafts, get the cloyes timing chain and water pump chain kit. Then I will test it. Valve springs are still not supporting higher RPMs, but at least I am a step closer.

If I like it I may install at a later point the deletion plugs and go with an electric water pump, but first the new valve springs.

Endless modification... lol