mannykiller

iTrader: (93)

Hey Dave!!! Long time!!! And Yea, no games here!! Not trying to reinvent the wheel either! just trying to get the most efficient set up possible for my purpose. And that comes to being reliable, and having the engine set up "Breath Easy." With the Room..and EMAP we've measured...I can even afford to drop back down to the slightly more responsive 8374. I wish I had more time to do cool little projects. I wanted to map out the 8374 with the A/R 1.45 turbine housing to see how much damage it did to response. I still prefer the 8374 because it came on like a freight train. The 9174 feels lazier.. still strong...but def lazier.

Also, not to change the subject but I had a chance to do quite a bit of tuning on one of your engines. Built nice and sturdy! Good work man.

I get where your going with that. But look at it like this.... Pressure is pressure. So no matter what.. the wastegate is going to Open when (in my case 17lbs of spring) has been reached. The Spring doesn't know how much fuel is un-burnt. It just knows that 17lbs of pressure is pushing it's valve open. I'm no engineer but if I'm correct...that would be considered a mechanical variable that is fixed. What the spring doesn't know...is how much fuel is un-burnt and how much of it is still expanding. You vent that un-burnt fuel early...and you don't get to fully take advantage of it's energy. Vent it too late..and you lose energy due to heat loss.

With my last set up...venting the exhaust gas right when it came out of the housing...The car would hold solid 6" blueish Orange flames in the higher revs when the gates opened. Now with the gates on the housing....I see the flames the minute they open.. Slightly less blue but all the way to redline. It could be all in my head. But The set-up feels very responsive.. EGT's are low and EMAP is good So I'm happy with the set up

I wish I could find the Pull to 9600. I could have sworn I logged it.

But thanks for the kind words man!!! Much Appreciated!

RGHTBrainDesign

Aaron, what EGTs would you consider a good point? I'd assume around 1650F would be a nice WOT figure to aim for.

lastphaseofthis

iTrader: (8)

with water injection can you even tune using EGTs? the water doesnt throw it off?
i know when widebands were not available it was the way to tune for years...

mannykiller

iTrader: (93)

1100-1250 Max for Any Track car..... My car hit 1100ish from what I remember. But I'd say anything over 1400 and you're asking for issues and breaking things. 1700...Inferno.

Sure...But it's not a very safe method. A Safer way would be to tune without the Water Injection...then Tune with it... And make sure that "IF" the water injection fails... the car is still going to be safe to drive

MaD^94Rx7

iTrader: (1)

Is that Fahrenheit or C ?

lastphaseofthis

iTrader: (8)

i understand doing that doing it that way is generally the safest way to do it..
however im looking into like 200cc of water at 15psi boost, tuned without it , but there for saftey. then a trigger from the ecu turning the 500cc nozzle on(progressively), and turning up the boost to 25, if pressure is lost at the nozzle boost reverts back to 15 with water there or not.. depend on what part of the water system failed... the 200cc nozzle is turned on from turning the pump on, and runs as along as the pump runs, but the 800cc is behind a solenoid... make any sense?
i plan push the envelope not worried about destroying my motor, it doesnt start hot any more anyways. wanna see what happens at 13.5 afr, and EXACTLY the btus of water needed for cooling.. basicly maximizing the oxygen content by removing all unneeded fuel/ water. yes if the water fails so does the engine. but if designed properly the boost will just drop back to safe levels. i havent run the math so the 200cc and 500cc figures are pulled out of a hat. i think 1000cc to 1500 is ball park for 450hp. its like swallowing a sword. i think with skill i can pull it off without cutting my insides up, and people, they're gonna be like wtf.

anyways sorry for the thread derailment with ideas i've been brain storming.

really like your wastegates btw... what did you use to cut the turbine housing?

RGHTBrainDesign

I think he means Fahrenheit, which seems incredibly low for a turbocharged engine. My setup I was planning on running a safety buffer of added fueling at 900C (1652 F). I'm also measuring dual band pre-turbo EGT. Not sure if he means POST turbo, which I don't find that information very helpful in tuning at all.

WANKfactor

iTrader: (1)

Its F. Alarm bells should be ringing at 800c. No reason not to be able to stay around 650-700.

MaD^94Rx7

iTrader: (1)

That's what I was thinking...
Heck I'm at 400c approx at idle.

j9fd3s

iTrader: (3)

i've put an EGT probe on a couple stock ECu cars and those are tuned more to keep cat temps reasonable (between 450c where it lights off, and 650c where it starts melting)

the FD ecu cruises down the freeway @800c, pre turbo. going WOT has it dip, and then it comes back up to about 820c so far.

the S5 NA was the one that never went over 700c, but then there is no turbo to pull heat out of the exhaust.

RGHTBrainDesign

Just to clarify since not all of you read the original reply, Aaron meant in Fahrenheit at 1250F (676 C).

WANKfactor

iTrader: (1)

Yes, i edited and fixed my brain fart

ninesixtwo

iTrader: (9)

Catalyst preservation is likely the reason that full load EGT is so low on the stock car. McLaren P1 uses fuel enrichment to limit turbine inlet temps below 980C for the same reason.

WANKfactor

iTrader: (1)

Im seeing around 650c both rotors cruising at 13.7 ish afr, peaking maybe 750c at 10.7 or so. Egt taken about 1 or 2" from exhaust ports. 98ron with a dash of water.

WANKfactor

iTrader: (1)

Thats interesting, mine runs cooler than stock then.
Im seeing around 650c both rotors cruising at 13.7 ish afr, peaking maybe 750c at 10.7 or so at full boost. 500 about as low as it goes idling (high 12 afr's) Egt taken about 1 or 2" from exhaust ports. 98ron with a dash of water. 8374 1.05 ewg.

Shainiac

iTrader: (7)

I had 2 K thermocouples mounted approx 2" from the exhaust port in the Turblown cast manifold. Heavy walled that retain a lot of heat, and ceramic coated inside and out. With a EFR 9180.

I would see 1550F (850C) cruising at 3400rpm and 14.5:1 on the interstate.
WOT would peak around 1650F (800C) and 25psi.
If I was crusing and smacked the throttle, EGTs would drop to 1200 or so and climb back up.

Idle EGTs were typically 1000-1200F depending on how heat soaked the car was. 13:1 AFR and 1000rpm

RGHTBrainDesign

See, that sounds perfect to me.

mannykiller

iTrader: (93)

There are going to be different determining factors that will make everyone's set up's run at different temps.

Fuel type and the Tune will be the largest. E85 is going to bring EGT's down because it's Ethanol. And Ethanol burns cooler than Gasoline. And yes heat is energy...and may produce more over-all power. But EGT's in the 920-1000 C range won't cut it for any track car that needs to be driven hard for more than a pass.

For me, it's more important to be able to hop in my car after a 20 Min Track Session in the dead of summer.., Start up..and head back out on track when people need to "Cool Down" their cars. So if I have to leave 20-30...hell even 50 WHP off the curve in order to keep everything healthy, safe and reliable... then that is what we do.

Keeping EGT's down as low as possible, plays a big part in that.

j9fd3s

iTrader: (3)

i agree with all of that. just driving around with the stock ECU and EGT, you immediately see that EGT's are managed. doing it for a track car seems obvious, although you don't have to worry about melting a cat, just the turbo, and passengers shoes

i can't find the paper i'm looking for, but as a piston material, iron retains heat, and aluminum um disperses? flows? err doesn't retain heat. so when you get the rotor too hot, it stays hot, and engine goes boom, even though it was fine yesterday, and ok on the dyno.

mannykiller

iTrader: (93)

Yea man. But the majority of people don't use EGT as a parameter at all. And although it's not necessary... and there are ways to tune the car to maintain safe levels of EGT's without a physical sensor.. you'd be surprised how many people are driving around with inadequate tunes. Will they work? sure... for how long? who knows.. in what conditions? far less than a solid tune with safe EGT's could handle.

I actually laughed at the "passengers shoes" comment #truthbetold

RGHTBrainDesign

If you look at how the engines are designed, it thermally makes sense to keep the manifolds decreasing thermal conductivity as you move away from the combustion area.

On a Turbo II, it goes from Iron intake passages (doesn't want to change temperature, k (thermal conductivity) = ~ 80 Watts/Meter*Kelvin) to an aluminum combustion chamber (k = ~ 205 W/m*K) that dissipates VERY quickly in comparison, to a steel exhaust manifold (k = ~50 W/m*K) and a steel turbine housing, which you want to keep temperature in for thermal expansion (and therefore a shrinking turbine hole = tighter tolerances on a turbine lead to more efficient usage of that exhaust mass).

When you think about it, going to an inconel manifold is only going to cause issues, and here's why. k Values go from 205 > 12 > 50 (or 80 if your turbine housing is Iron) which can cause to exhaust leaks or the thermal expansion being such a problem (since the Inconel WON'T expand at the same rates as the Aluminum or Steel/Iron) that things crack under stress.

Bottom line is, you want heat in your turbine housing. You also want as much MASS as possible to turn your turbine, so you get the most reaction out of the event. You'll want to add as much fueling as possible while keeping EGTs at peak values. Fuel's mass is MUCH higher than Air's mass, and MASS is what turns that turbine wheel. At the same time, too much fuel runs cold, and you want the turbine wheel to damn near scrape the turbine housing due to thermal expansion.

I would rather take out timing and run the sucker hot and get more efficient use of my turbo system as a whole, not a single analysis of ONE piece of the puzzle.

Rub20B

This is somewhat very incorrect. at lamda 1 an engine running gasoline uses 14.7 times more air mass than fuel mass. even at afr 10, the fuel mass will be less than 10% of the exh massflow

What turns a turbine wheel is volume flow.

look what happens at iso boost iso engine speed and iso AFR ( means iso fuel air and thus exhaust massflow) when you retard timing.

Right, boost will go up. why? exhaust gas gets hotter, volume flow, enthalpy, increases.

There are 2 ways to increase volume flow, more massflow at equal egt, or more egt at equal massflow.

the good way to tune lamdda/afr at mid to high rpm is to advance ignition as far as possible till knock threshold is reached, then adjust afr to reach your target egt., this can require a few iteration to get spot on, as a richer mixture (afr<13.5) is less knock sensitive due to its slower flame propagation speed.

Optimal fuel efficiency is near lambda 1, maximum power at 13.5-13.7. any extra fuel you go to end up with an egt colder than you target egt is a waste and costs power. lets say lambda 1 is 100% power, going richer will maximum gain 2%-2.5% power, but can cost already 7% fuel at afr 13.5.

with water injection a part of the fuel used for cooling can be replaced by water, as done in M4 GTS for example.

Skeese

iTrader: (11)

Hey Aaron

I want to go back to "Non-Balanced but weight Matched". You mentioned that your usable powerband was XXXX-9600 rpms. I'm no expert but I was under the impression that dynamic balancing was one of the factors that contribute to a motor reliably spinning above the factor 8000 rpms for extended periods? Ive seen a stamp balanced motor come off balance and the rotor face knock a chunk out of the front iron at 450 rwhp with no detonation involved. Just curious as to the logic. Given the amount I've seen go into this semi motor I for whatever reason assumed it was dynamically balanced.

Skeese

RGHTBrainDesign

No, it's MASS per unit volume (DENSITY), that turns a turbine. Here's a bit of Fluid Mechanics in its simplest form:

Air Density @ 900C (Wide Open Throttle Exhaust Gas Temperature) = 0.301223 kg/m3
Gasoline (combusted) is roughly 719.229 kg/m3.
Our ratio of 11.0:1 Air to Fuel Ratio: [(0.301223 x 11) + 719.229] / 12 = 60.212 kg/m3 Estimated Average Density of the Mass

Air Density @ 700C (Mid-Throttle Application Exhaust Gas Temperature) = 0.364713 kg/m3.
12.5:1 Air to Fuel Ratio for Mid-Throttle Application, leave Fuel (Gasoline) at same. [(0.364713 x 12.5) + 719.229] / 13.5 = 53.614 kg/m3 for the Mid-Throttle Application Average Mass Density

Air Density for Tip-In (Light Throttle Application) is @ 400C =0.527253 kg/m3
Air to Fuel Ratio is 14.7:1 for this light throttle application.
Same Fuel Mass Density of 719.229 [(0.527253 x 14.7) + 719.229] / 15.7 = 46.304 kg/m3 Estimated Average Density of the Mass for Cruise/Light Load Application.

Why does boost go up when you retard timing? Well, you had it partially correct. The fact is that you now need to sustain a higher TPS value to continue running the engine at the same given RPM point, which decreases engine vacuum (increased boost). You do this dramatically and you get what's known as an "anti-lag" system at idle in which you're always dumping excess fuel (which has a MUCH greater mass/volume (density) into the turbocharger to spool it.

BLUE TII

iTrader: (9)

Rub20B

Quote:
Originally Posted by SirLaughsALot View Post
You'll want to add as much fueling as possible while keeping EGTs at peak values. Fuel's mass is MUCH higher than Air's mass, and MASS is what turns that turbine wheel..
----
This is somewhat very incorrect. at lamda 1 an engine running gasoline uses 14.7 times more air mass than fuel mass. even at afr 10, the fuel mass will be less than 10% of the exh massflow

What turns a turbine wheel is volume flow.

look what happens at iso boost iso engine speed and iso AFR ( means iso fuel air and thus exhaust massflow) when you retard timing.

Right, boost will go up. why? exhaust gas gets hotter, volume flow, enthalpy, increases.

I would say you are both right.

More fuel into the engine for the same amount of air into the engine will result in lower AFRs in the exhaust manifold because the unused fuel in the exhaust reacts with the unused air in the exhaust and expands. We know this.

So, that is more volume flow into the turbo and not just by the volume of fuel, but by the volume of however much of that extra fuel you were able to expand with combustion.

Practical application-

I ran into this when I maxed out my turbo. I was stuck at 16psi boost and couldn't get it to hold more. It would make more boost as it spooled no problem and then the engine would suck it down to 16psi.

Trying to make more peak power we added timing, took timing out and leaned it out and no positive changes to peak hp from our base,

I have a pumped ignition so we tried just dumping fuel.
With AFRs pegged below what the wideband can read (richer than 10:1) we were able to speed up the turbo shaft speed and get 18psi boost and made a whopping 5 more hp.

Not a lot of power (because turbo speed lines converge at max flow at some point), but more than we could get with proper "tuning" on this maxed out turbo.

When you think about it, going to an inconel manifold is only going to cause issues,

Inconel is used in motorsports for exhaust manifolds because it maintains its structural strength well at very elevated temperatures. This means you can build the manifold light and thin without it blowing out from manifold pressure.

In motorsports they deal with thermal expansion with inconel bellows and slip joints.

If they want to insulate the manifold thermally they could use thermal barrier coating (again, light weight).

http://i.ebayimg.com/00/s/MTIwMFgxNj...UOEpV/$_57.JPG
IRL Honda EFR 9180 with bellows and thermal barrier coating. Aluminum center housing (again light)