Nate1647545505

Nah, had some spare time in between classes. Phil - GT3076. By all means, there is still lots I don't know, and many that do. "Tuning", can be as simple as matching an air/fuel ratio and/or watching knock sensor counts/feedback. Its the drive to understand "why" that keeps very knowledgeable professionals and enthusiasts out there. I still learn from friends Marcin Pohle (redhardsupra) and Nick Glantzis (NickG) everday. Just remember, I started out reading posts and asking a fair amount of (stupid) questions when I first joined here. I've come along way since then, but you get the point - We're all beginners at one point or another.

Aeronautical (mainly because of turbo machinery), but I hang around the ICE classes and FSAE team more then I should. The neat thing is, we don't know much more about combustion now compared to the 1950's. The sciences involved are the same anywhere, so ME's and AE's from any university generally study this, but few retain it if they don't see/need the value in it Nate

GT-Power is very hard to come by as its somewhere around 10,000$? Most univeristies have a copy though. Its a very high level engineering program (OEMs use it to model for months, years before an engine is started) and requires a great deal of information about the combustion chamber that can't be easily obtained with your average tools in the garage. Regarding flame speed at x atm, that was a ballpark estimate. I do believe there are charts out there on the net, there is said chart in Heywood's ICE Principles. Nate

Eric- happpppyyyyyyyyyyy face. If I ever get above your or anyone else's head please don't hesitate to bring me back down. I constantly push enthusiasts and professional tuners alike to further their knowledge and scope as calibration has many deep sciences within it. Like mechanics have evolved into technicians, tuners will need to learn and understand engineering math & theory. This is very apparent with the learning curve of the new GM model based controllers (ex: C6 Z06) as well as new technologies like direct injection and valve timing & cam phasing. The nice thing about the universe is the same laws apply to any and all piston engines. While the specific engine design/materials are subject to their unique limits, there still are some general guidelines... Combustion is about heat release, and the respective timing of the release. On the chemical side, a fuel's heating value can be thumbed how much energy the molecules contain. The larger the number, the more energy can be obtained from the fuel. Some examples: 87 Octane is around 42kJ/kg, 93 Octane 43kJ/kg, E85 29kJ/kg. There is slight misinformation on the web that 87 octane has more potential energy compared to your premium 93/94 blends, this is simply not the case. Compared to regular, premium fuels have more groupings of stable molecules that tolerate higher temperatures before breaking down, this is what increases the octane rating (and somewhat slows the burn rate). Best power is usually around lambda of .89 to .92 for an NA engine, where flame speed nears peak. Keep in mind it is possible for combustion to happen anywhere from 8:1-26:1, if the operating variables support it. It has been mentioned already that high intake temperatures, more importantly density, won't allow for NA fueling calibration. Since our homeboy Boyle repersents PV=nRT, you can expect a more violent reaction when both temperature and density skyrocket (boost). Flame speed of 14:1 @ 1 atm is similar to 12:1 @ 2 atm, however the knock limitation of 12:1 @ 2 atm is marginally higher. Most of the padding can be contributed to richer (lambda < .9 ) mixtures having a lower overall burn temperature. A more pronounced affect on timing is present as inlet temperature rises, the timing is reduced as a result of the evaporation rate and burn rate being marginally higher. You may see 11-10-9:1 commanded AFR with OEM calibrations, this mainly to protect the internal components under high load / increased time and to protect the cats from becoming fireballs (they shouldn't operate with incoming temperatures > 1200F). Timing must be added to keep peak burn pressure at the correct crank angle as these overly rich mixtures have a very slow burn speed. Knowing the above, the next large factor in torque output to consider is spark timing. Timing is very unique to the application and conditions. You can model it in programs like GT-Power or Aveos, or find the optimum via dyno. Both fueling and timing affect each other. Its not uncommon for a calibrator to revise fueling, timing, fueling again and timing again. Best power is achieved when the spark is timed properly for the conditions to hit peak pressure at roughly 7 to 15* ATDC. I prefer to find it via loaded dyno (no offense to the non-loaded dyno's out there) and see the power drop off versus using an acoustical knock sensor. The real way would be pressure traces from the cylinder, but even here at Purdue its very hard to get access to such a thing. The actual amount of charge being burned and its relation to crank angle is also something to be pondered, but really not considered. We just would like the charge to be consumed before the exhaust valve opens (google Mass Fraction Burned if you want to know more) Nate

"The devil is in the details". Beading the pipes is a solution, using hairspray on the silicone couplers is a common remedy. I'm not trying to slam your work, just give you some tid bits.

Antwon - Didn't mean to pick you out or anything offensive against you, just a general observation.

I would be cautious with comparing timing #s as one could assume large differences in head design, squish, quench, compression, lamda, etc. Best to make a few pulls and let power/EGT tell you what she likes and verify with a standard knock sensor if the option is available.

The load associated with 4-6 psi @ 3500-400 on a 9.5:1 dohc shouldn't require sub 12.0:1 ratios. Keep in mind flame speed is peak @ 13:1, further you move away from it in either direction, slower the flame gets. The compressor is most likely in a post 65% efficiency range while the turbine isn't a chokepoint and most likely climbing in efficieny as the PR is nearing 2:1 with the log manifold. Usually best power/safety is found with a lambda of 1.0 @ 80kPa (stoich), .92 @ 85kPa (13.5:1), .86 @ 90kPa (12.6:1), .81 lambda @ 120kPa (11.9:1) Tristan - what do your intake temps look like as I ASSume you are running Speed Density? I would work on maintaining 11.9-11.5:1 until redline IF your setup isn't producing a large intake temp spike or your car isn't running a cat(s).

What does the job entail (secuirty/clearance? telcom? etc)

Country - I don't like paying home owners assoc. for what real estate taxes already take care of. I don't think the neighbors would like me in my ghillie camped out on the roof target shooting with the 700R....

I would be afraid of the $ tag on that gun.

I think I found q new desktop background! Very nice collection. Scott, are you a squad designated marksmen? I thought the Army gave all the M14s to the USMC guys....and the Air Force/Navy Academy for parade guns

The C5 kit uses Garrett 2871's or 3071's, possibly with housings machined for larger CHRAs / compressor wheels. The mention of the 20G casts some doubt on that similar turbos are used on the Fbod kit. I have never read anything related to issues with the kits based on design. APS knows their stuff, they are probably one of the better choices for a driveable, T3 based twin kit. *The kit does use a scavange pump, so some are leary about potential oil lubrication failure.

Welcome back to the living Brian

damn right.

Use flash, run, shoot, find cover, repeat. Takes some time, but well placed flashes allow you keep pushing forward into the swarm.

To bad it didn't work

Did it say what octane they used?

Ray, did you change the global injector size? Keep in mind that affects engine load calculation if the displacement variable isn't scaled along with it. Nate

Do you have any information pertaining to Walbro certifying their pumps with alcohol based fuels? The same situation is happening with Bosch's 044 Pumps - they won't warranty/guarantee anything when alcohol based fuels are used - but people still use them. Some with problem, some without. Regarding the electrical/arrestor equipment, that's simply a component of safety. It's a risk, it needs to be managed. God forbid, until there's that 1/1000000 chance things go south, it won't be part of main stream conversion factors. The corrosion rate of eth on most metal is in Mils/year, so penetration wear is somewhat minimal, but introduce dissimilar metals and you may have some funky shit going on within a few years time frame. My responses are considering 5+ years in service. Temperature has a very large impact on the penetration/corison levels, as well as deposits formed from cycling an injector in everyday driving conditions. Nate

The large problem with E85 is unlike gas, it has a moderate level of electrical conductivity. Parts should be 100% electrically shielded (no open contact/harnesses like on most in tank wiring setups). I have heard Walbro buying their failed e85 pumps back, but not sure if they have an E85 specific pump/rebuild kit out. The largest problem when it comes to pumps are the seals. The alcohol (sugar) in E85 tends to make seals expand, in a pump, that means it won't be pumping much as clearances get out of whack. Delphi has had a problem with this in the GM Flex Fuel platforms, but Ford seems to have gotten it correct as there doesn't seem to be many issues with their components. (Ford mechanics please feel free to interject) Here's something that might help with the flame arrestor design: http://www.nrel.gov/docs/fy03osti/34301.pdf If you can find a flex fuel platform in the junkyard, you might be able to adapt their arrestor & other components. Nate

Unless you're PJ or an CCO.............

I think Brandon/Eric & IPS have worked with it. Stand alone would be ideal as it requires operating values outside of the norm chip/piggy back operating range. As you probably know, your fuel efficiency will suffer do to the lower compression design of a traditional gas forced induction engine, but the power and trq output will be substantial (What turbo car doesn't love an alcohol based 100 octane fuel?) If you haven't already, consider the materials and components in the fuel system: Rubber seals/oring need to be switched to viton, any carbon steel/mild steel lines need to be changed to at least 304 stainless, injectors need to be sized larger (around 30%-40%), with the disc design being preferred, a flame arrestor needs to be added to the fill/vent line, and finally, the regulator/fuel filter need to be swapped with e85 compatible equipment. Nate

Scott, I wet my pants at the thought of you and an M107.

Please, do the world a favor and wrap your hands in razor wire before you make a post like this again.