Afr's, egts, timing and boost.

[TurboDario]

Hi guys, been lurking on here awhile, learning lots and finally have my project to the point that I have some questions that I can't get a straight answer for. Here is the details of the project.
97 Chev 1/2 ton shortbox
6.0l ls truck engine Coil on plug with a msd 6010 box
Dual 425 mixers, dual model E's, 1 vff30
80mm turbo, big intercooler
turbo 400 transmission

The mixers are worn out, (next thing on the to buy list) afr's are in the 10's at idle, but ok everywhere else. Had it on the chassis dyno, made 541whp at 15lbs of boost, 12deg total timing, .87 lamda 13.5afr.
Build thread http://ls1tech.com/forums/forced-induct ... sults.html
Dyno Video http://youtu.be/Q0HZJK-LIjc

Ok, questions are:
Are my afr's ok? Am I on the ragged edge? Should I richen it up?
I plan to put a pyro gauge on it, what should I shoot for EGT wise? I think my total timing is pretty low, what will adding timing do to my egt's?
Once I get a handle on the tune, I'd like to turn it up more and take it to the track. Any help would be appreciated,thanks

[franz]

Very, VERY NICE!

Dont assume that richening a fuel mixture will lower EGT, we dont have liquid fuel cooling the combustion charge. The first thing I would like to see are turbo out EGT's. Under WOT, I think 1000°F would be a max but it depends on how the rest of the engine is running.

12° total timing feels to me a bit short. How are you controlling timing? Less total timing will result in higher EGT's but lower bhp. Detonation is your indicator of the narrow balance of max timing and boost at that AFR. At that level of boost and rpm, you may never hear the detonation before it affects the pistons. A knock sensor-retard kit from MSD might help here.

How is your chassis dyno operator measuring AFR? At the exhaust or by calculation? I had to invalidate a total engine design program because the initial engineer calculated the test data AFR based on gasoline instead of LPG. When it was corrected, the engine wouldnt pass emission tests until the fuel management map was re-written.

Anyway, nice build and outstanding dyno results.

Franz

[TurboDario]

Cool, just the person I wanted to here from. So you think I should mount the EGT probe after the turbo? I was thinking of mounting it just before the turbo like the diesel guys do since some of the egt would be reduced after the turbo? The timing is computer controlled with my laptop. I can adjust timing vs rpm in 1deg increments. I can also add a Map sensor so that I can use another table to add timing during cruise. (which I plan to add once I change my mixers) At 15psi if you herd detonation it would be too late. With more dyno time we can creep up on the tune by adding timing 1deg at a time and seeing if the power picks up, stays the same or goes down. We use a wideband O2 sensor on the dyno that is tapped in 12" from the outlet of the turbo. It reads Gas afr but we can go in and see the lamda readings after a run, the leanest it got was .87 lamda which we converted to 13.5 afr propane. Thanks for your input.

[franz]

Turbo inlet temps would be ok too, and probably a better choice. If you want to get scientific, do both and see how much heat the turbo radiates, its surprising!

Franz

[ttxpc]

I run pyro pre turbine, a/f in the high 14's (gasoline scale), 28 deg, egt's 1350-1400 @ full boost (10psi) on an extended run, ie truck fully loaded up some longish hills we have around here

[TurboDario]

Just took it out today for acouple quick blasts with the EGT hooked up pre turbine, @10psi EGT's were in the 1250-1350* range at WOT on the highway. I didn't have time to play with timing much, I just wanted to see what it read on the EGT gauge. I'll hit the dyno again when I get my new mixers installed.

[TurboDario]

Update: Finally took it to the track ran, 11.8@120mph with a 2.0 60' time. Boost is 20lbs, egt's were in the 1600* range pre turbo, and afr's are in the 13's on a lpg scale, I also added water/meth (washer fluid) injection that comes on at 8lbs with a 625cc nozzle. So far it's been awesome, drives like a stock truck, I worry about the egt's sometimes but I think alot of it has to do with my low timing (12deg) in boost. We plan on doing some more dyno testing before the snow flies to see what we can get away with on this engine before it breaks.

[Johnmaster]

I cooked my 5.3 at 1650 egt on a hot lap at the track, most likely butted a ring from all that heat but I still need to do an autopsy, truck has been sitting in the weeds. I think if I would have let it cool down between passes it might still be running. Would love to see how the meth nozzle works out. My assumption was that the single eb2 I am running wouldnt vaporize enough fuel and much of it was coming through as liquid droplets that were richening the mix and creating lots of extra heat. I love seeing another guy playing with a propane turbo LS motor. Your intake arrangement is how I would love to have mine if I had the time to do it over.

Great track time and with your mph and 60 foot time it looks like low 11s or even 10's could be in your future:)

[TurboDario]

Update! Took it to the track last night, drove 160 miles one way, no cool down, it went 10.91@126 @ 4600lbs and 17lbs of boost. 1.67 60' on 10 year old drag radials. Spun hard on the second pass hit the rev limiter and blew one of the carb hats off lol, called it a night. Here is a video my buddy finished last night of when it was on the dyno. Haven't touched the propane in over a year, made just north of 700rwhp, still on 2 425's and 2 model e's https://www.youtube.com/watch?v=EDXoLRQROrQ

[storm]

Your link is broken or incorrectly formed, all I get is a youtube page saying this video does not exist.

[TurboDario]

Fixed