First Goal: 550hp LS1 Getting 30mpg

[bazman]

Update: Well after blaming the cam for my economy loss we've finally discovered the main culprit is the injectors. The ones supplied with the turbo kit are nothing but cheap reconditioned used ones that have had their holes bored out to get the flow up. The spray pattern is not accurate enough to handle a decent lean tune.

Next upgrade is to run with some accurate injectors like the Injector Dynamics 725's or Bosch EV14 52' lb'rs - both are very precise even at low pulse widths so should make a notable difference. I'll combine this with new coil packs and leads to ensure we have good spark.

Right now I can't get better than 15.2-16:1 AFR on around 26-32 degrees timing at 100kph. With better injectors and spark I should be able to hold 17:1 and over 38 degrees timing. Also trailing throttle goes straight to 14's :1 or richer and upgrades should see this go into the early 20's AFR - that'll make a difference over a tank, esp with a bit of mild hyper-milling (coasting). I still want to make 30mpg at 100kph cruising as I do not think it has ever been done on an LS1 auto full sized sedan.

In the meantime, 550hp is still a lot of fun - yee ha

[ksa8907]

kinda jealous, i can barely scratch 30mpg in my 220hp sedan . my, affordable, dream car right now is the 2004 Pontiac GTO 6spd which is of course the same thing you have in coupe version.

[oil pan 4]

I like your work.
You may want to stay away from 16:1 unless you have inconell or better exhaust valves.
I think unless you have problems with it not running smooth try to run leaner.
You are doing what I plan on doing with an LSx at some point. I want to lean burn one, with inconell exhaust valves (not to mention a ton more mods) and stay leaner than about 17:1 for eco cruise.

[bazman]

Originally Posted by oil pan 4

I like your work.
You may want to stay away from 16:1 unless you have inconell or better exhaust valves.
I think unless you have problems with it not running smooth try to run leaner.
You are doing what I plan on doing with an LSx at some point. I want to lean burn one, with inconell exhaust valves (not to mention a ton more mods) and stay leaner than about 17:1 for eco cruise.

No sign of excess heat. The crazy injectors I have now accelerate smoothly and crisply (light load but quick enough to keep up with traffic) at 16:1 and 32-38 timing, but will only hold smooth cruise at around 14.7-15.4 and 26-32 timing - crazy. Trailing throttle is 14.7 when it could be 22+ on some engines.

New injectors will fix this, and over heating valves should equate to higher than normal coolant temps over time, so I will watch for that, but no issues so far. I'm tossing between the new EV14 Bosch 52lbers and a more expensive set of 725cc Injector Dynamics. Both are very accurate right down to very small pulse widths and offer state of art atomization.

[bazman]

There is a tunable 2-3D mappable plasma ignition in the pipeworks - when that is available I will be in like a rat up a drain pipe. That should enable the leanest possible burn an engine can tolerate. I'm also keen to check rumours that plasma will explode water mist as any power there will enable leaner fuel mix and still maintain enough hp for cruising. In the meantime I'll leave that idea as crack pot science ;-)

[F8L]

Good to see STS still around. I had one of their first Chevy truck kits on my GMC Sierra 4x4. it went a best of 12.3@110mph with 13psi and meth injection. Later we switched to a normal twin-turbo and made 719rwhp on 18psi with the 5.3L.

I wish you th best of luck with your setup!

[bazman]

Originally Posted by F8L

Good to see STS still around. I had one of their first Chevy truck kits on my GMC Sierra 4x4. it went a best of 12.3@110mph with 13psi and meth injection. Later we switched to a normal twin-turbo and made 719rwhp on 18psi with the 5.3L.

I wish you th best of luck with your setup!

Thanks for that. Yeah, I found STS good to deal with, but built to a price. They are one of the best horsepower per dollar deals around.

While I did get their upgrade to a larger ball bearing turbo we have had to replace or upgrade a lot of stuff they sent, and the injectors are just the latest thing we have to replace. The average person would not bother as if you drove my car you'd think it was very well tuned and runs great as a daily driver... I just know it can be significantly better on fuel.

I am going to suggest to them they offer a platinum package for people like me who are willing to pay for quality - like scavenge pumps rated at 10,000 hours instead of what is cheap; mapable water/meth injection instead of the very expensive but basic kit that is on or off; better quality fittings etc. Quality costs, but cheap is not cheap when it breaks or has to be replaced and there are people out there like me that understand that and will pay for it.

[Synchronicity]

Have you ever considered a sports bike?

I have a 2001 GSXR600. It'll break the national speed limit in first gear, top speed is about 270km/hr (tested), can be had for 5-6 grand [Australian dollars I mean, well, they're the same now as US dolluz anyway]. 0-100km/hr in about 3 seconds, quarter mile times in the high 10's/low 11's if you're not such a good rider... i.e. it'll blow most cars off the road.

Now to the fuel economy. Driving around like a lunatic, I get 9L/100km or (26mpg is admittedly worse FE than my van). Just going for a cruise with a slower rider I was able to get my lowest consumption so far of 6L/100km or 39.2mpg (not even thinking about FE numbers). Ie. ferrari performance and with a few mods (gearing, detune, driving habits plus some simple aero mods) then 40, 50 or even 60mpg would be easily achievable.

Not fast enough? ... then just get a litre bike and be done with it. Aero mod that and you'd be king of the road.

[oil pan 4]

It looks like hybrid that burns gasoline, alcohol and rubber.

[serialk11r]

Originally Posted by smokey442

Open waste gate at low throttle to reduce exhaust back pressure. I'd try retarding the cam 5deg. keeping exhaust valve closed longer extracting more usefull work from still relativly high cylinder pressure. Later intake closing lowers vacume. Pull an 8"hg depression into crankcase via intake vacume.

Okay so I didn't see anyone talking about these, but I think these are good places to pick up efficiency. Low boost turbos tend to have ****tier backpressure under cruise, if you can get an electronically actuated wastegate for them that would help. I imagine in the real world you only relieve a small amount of pressure but you have a large displacement engine so a small amount of pressure adds up to a lot of loss.

If I'm not mistaken the LS1 has "single cams" (1 for each cylinder bank with exhaust and intake lobes on it)? In that case retarding the cam doesn't work since that would increase the overlap and interfere with combustion stability. You might want to look into a regrind that cuts off a little of the overlap but maintains the same intake closure. If possible having the intake valves close even later is "ideal" in some sense, probably increases your top end power too.