Extended MAF readings?

[ijames]

Originally posted by JDEstill
You are probably right Todd, good thinking. Drive train losses are probably more a function of rpm and mechanical design than hp going through it. Well, I guess I'm satisfied now.

Just because you say you're satisfied, I have to post . The frictional drive train losses are under 5%, probably under 2% if I recall correctly. Otherwise the transmission and rear end would melt - think of dumping 100 hp as heat into a transmission! The big losses that people talk about with automatics are the rotating weight acting like a large flywheel that has to be spun up as the engine accelerates. The flexplate is small compared to a flywheel, but that converter and planetary gearsets are pretty heavy. In theory you get that back at the gear changes, but converters and clutches all slip some so some of it does go as heat (or maybe wheelspin or suspension motion as the car jerks and rises on the shifts or ...). Anyway, [runon sentence coming] the more hp the engine makes the faster it will accelerate and thus the faster you want to spin up that flywheel and so the more hp you have to use to get it from the start to the finish rpm in a shorter amount of time, so the "loss as a percentage" actually works pretty well for automatics [whew].

I've been offline for a few days while I moved into my first house [yay, me ].

 

[JDEstill]

Congratulations on the house Carl! Having a garage is primo!

I wasn't very clear on what I'm satsified with, I'm afraid. I guess I'm satisfied that the mph equations do give rear wheel hp, and I'm satisfied that going with air and fuel flow and BSFC that you do end up with flywheel hp, and I'm satsified that there will be some losses through the drive train, and (since I got an email back from Joe L.) I'm satsified that Joe's spreadsheet is a bit optimistic since the mph's he shows came from the rear wheel equation while the injector size and fuel flows are based on that same hp instead of on the flywheel hp needed to make that rear wheel hp necessary to run those numbers. And I'm satisfied that Kenne-Bell did the same thing when they made up a chart of mph-->hp-->fuel flow.

John

 

[TRDirks]

"Any chance we can get inj duty cycle readings from Tim's test passes?"

Sure

On one of the previous tests at 16 psi boost, top of 3rd, 5450 rpm, MAF 203 g/s (17 degree chip) The inj. duty cycle was 100.6%

Run last night, 17 psi boost, top of 3rd, 5450 rpm, MAF 184, (21 degree chip) The inj. duty cycle was 93.5%

The only other thing I can add is that it does seem to pull considerably harder now aswell. Sometimes the little changes make the biggest difference. On the two runs above according to the Accelleration calculation in DS I was at 4.2 mph/s and last night it was 6.82 mph/s. How accurate the calculation would be is questionable but I thought I'de add anyway

 

[JDEstill]

Tim - I looked back through the thread and never saw... what size are your injectors?

Based on your latest info, I find a VE of 87%, which is high for these engines to the best of my knowledge (which is admittedly incomplete and inperfect), but is certainly in the realm of possibility. So maybe you do have it dialed in pretty good now.

To get an a/f ratio of 11.5-12:1 with that air flow and that injector duty cycle, it looks like your injectors should be in the 43-45 lb/hr range. What are they really, and what fuel pressure do you run?

John

 

[TRDirks]

The injectors are 50's and the static fuel pressure is currently set to 50 lbs. I have had the fuel pressure set lower before but had to crank up the WOT setting on T+ which caused the inj. PW to go static even at low boost (16-17psi). Based on knowledge gained from Carl and Bob I have zeroed out the WOT setting and turned up the fuel pressure to help let the ECM take back control of the fueling. The way its looking now if I turn the boost up much further I will have to go to a lean setting on the WOT and turn the fuel pressure up further to keep the ECM in control of the fuel. Bob had posted previously that the chip in question is dumping lots of fuel and I should be having to pull out fuel and I think now that this must be what he was talking about.

I never could have imagined that this post (which I almost didnt do cause I thought I wouldnt get a response) would shoot off in all the directions that it has. This board (and all its members) is incredible.

Knowledge is good.......Feed me

 

[TurboJim]

Originally posted by TRDirks

Also I hooked up my TL boost sensing cable to a 3 bar map. So now I have boost sensing for Directscan. Has anyone else done this? I'de like to swap some info in relation to the boost/temp readings at certain levels.

Thanks

You know, DS will display raw data. If you gave it the IAT address, it would be easy for a guy like TurboBob or someone to convert that to actual boost to display. I wonder why Kent hasnt done that yet. It it more difficult than it looks?

 

[TurboTR]

I recall him posting once that he didn't want to step on KM's toes, at least that's what I gathered and he had plans for an external add-on data acq box, or something like that.

TurboTR

 

[JDEstill]

Okay Tim, lets do some more cipherin'!

Running at 50 psi fuel pressure turns your 50# injectors into ~ sqrt(50/43.3) x 50 = 53.7 lb/hr injectors.

Assuming that the % duty cycle is linear with the flow (which could be a bad assumption) then the fuel flow per injector is .935 x 53.7 = 50.2 lb/hr, x 6 = 301 lb/hr.

Your air flow was 184 x 2 = 368 gm/sec = 2921 lb/hr

So your theoretical air fuel ratio was 2921/301 = 9.7:1

Sounds like too much fuel still maybe? With those 50# injectors, if the air flow measurement is correct you'd expect to see something around 79% duty cycle range (at 50 psi fuel pressure) just to get back to 11.5:1.

All theoretical calculation to be sure, but it does say that those 50's shouldn't be running out of room at that boost level, and odds are you are still rich and need to tune out a little fuel. It would be nice to get some independent confirmation of that. Maybe Carl will build you that DIY wide band Anyway, if you plan on turning up the wick, with the air flow you seem to be getting it looks like you will need some more injector!

John

 

[1badTTA]

Here's some food for thought, the HP losses for the driveline are more like a fixed number plus a percentage. For example, on a normal 500HP flywheel engine say you lose 25% which is 125HP, but on a 1000HP engine you only lose 175HP which would be 17.5%. So it could be that you will lose a certain amount of power to just turn the drivetrain and an additional amount that increases with HP. Basically a 75HP loss plus a 10% loss, make sense?

Just my %.02

 

[Turbo__Tim]

("Just a Tim, Huh? )

Hey Tim this was such a good post, I thought I'd bring it back!

Our combinations are somewhat similar, less the cam (I'm stock), and a couple other things. With the translator+ zeroed out, I get 260 gps at 10 PSI, and 340 at 17 PSI. I havn't started tuning yet, but I have a feeling that I will be turning the alchy injection on around 12 psi.

It is amazing how much power is added with good flowing heads!

Btw, what times are you running now?

Also, is anyone else using alchy with their alum. heads? I know Genos' friend is, and man would I like to pick his brains! He was into the 10's (10.97) last I heard....

 

[TRDirks]

Tim,
No new times yet. My new converter (YANK) was on my doorstep when I got home last night and I want to wait until I get it in before I go back to the track again. My current converter (AC L/U) is too loose for my tastes. I had to shift into OD on the 11.67 run. The next problem will be track limitations since I dont have a cage and would rather not have to cut the car up. I may do some half track runs and compare my 1/8 times/readings. If all looks good I will end the evening with a full pass which I will get booted for I am sure. I will post results when this happens.

 

[J. Lubrant]

Hey!! you guy's are killing me

My original chart was put together many years ago when even us older guy's really didn't know what it would take to get these dam TR's moving. I made the chart to give everyone something to go by. Some people back then didn't have a clue that you needed some other size injector to accomplish your goals.
Remember when everything was a secret????

Street cars on pump may have to run .6 or .65 bsfc.
Great or Very Good Race turbo cars easily run .5bsfc.

I have personnaly seen dyno sheets of race type TR engines in the .48 to .5 range. Of course you will need OCTANE and good timing to accomplish this feat.

Also the chart did have a disclaimer relating to the old plus or minus 2 tenths & 2 mph error.
Turbo cars in my opinion (the truly fast ones) normally run slower e.t.'s than the mph. Hence most turbo cars will not 1/8mi as quick as what is calculated by what it turned in the quarter.

I have real world experience tuning an 8.60 car that ran 165-166 mph. Based on the duty cycle of the injectors reflected in the FAST(Speed-Pro) system we were burning 1190-1200hp worth of fuel, and by calculation/or by chart it reflects 1140hp to accomplish this at the weight of the vehicle.
I was using .5 bsfc, I did not use any reference to a/f to do this calculation. Based on the rpm that the car went thru the traps, we were exhibiting approx. 4 to 4.5 percent slippage/or drag.
This of course was based on tire size gear ratio etc. So if I factored in the slippage, the mph would have been higher, and the actual fuel burn & hp would have matched.

I have always used my chart as A REFERENCE to accomplish my goals, and it has always worked out for me!!

Most people know what I have accomplished with my car during the different build ups I have run. I have always obtained the goals within reason of what was originally charted.
When I ran 10.30's with 55#'s in a 3650# car, I said to my self thats about all there is Joe.
I remember telling RED A. when he was running 55# with a 7th, that he didn't need the 7th because he wasn't using the full capabilities of the 55#'s yet.
I quess we all know what RED A. has been able to accomplish with Jane's car with the 55#'s??? I wonder what bsfc or a/f ratio he was running??, or how many Grams per minute???

I am not disputing all the calculations or senerios that are being dicussed in this thread.
I am saying that my chart was not just something I threw together. It was just a reference to get people in the GAME, or a least in the BALLPARK. The chart was using commonly used formula's,
Most people appreciated any kind of information to help them set up their cars.

Bottom line is the more effecient an engine or combination the less fuel it will take to make 1 hp.
If you can make 660hp with 55#'s than you are using .5bsfc and have a pretty efficient engine/combo, but your on the edge.
If you need 65# or 72# at 100% d.c. to accomplish 660hp then its time to go back to the drawing board!!

I don't want someone to have to run the injectors at 100% to accomplish their goals. Pick an Injector between 70-90% d.c. for hp needed and you should be pretty safe.

 

[JDEstill]

Hey Joe -

I am really sorry if you took offense to *anything* I posted! I certainly didn't mean to imply that there is any significant problem with your spreadsheet or the advice you give out. We are all appreciative of your efforts, and putting that spreadsheet out to where people can use it and learn from it helps us all. I refer to your spreadsheet all the time. I think it is 95% perfect. After going through all the stuff in this thread, I think it would be 100% perfect if there was a spot for a fudge factor to account for driveline losses. But that is just my opinion, and I recognize the fact that what I think I now have straight in my mind could be in error.

As a design engineer I really get into the number crunching aspect of this sport; figuring out how and why these things are doing what they are doing fascinates me. I spend my days doing this same thing for refineries and chemical plants, figuring out what the equipment is doing and why, and what needs to be upgraded and what doesn't, and how all the pieces should work together as a system. It isn't a big jump to do this for an automotive engine. I think I do this sort of thing well. I think that if we really understand why something works then we can take the greatest advantage of it.

But in the end what happens in the real world is what truely matters, and I know that when it comes to practical experience I fall far short of you and many others on this board in that regard. I recognize that, and when real life says that something isn't working the way I think it should then I hope you'll continue to fill us in so we can fill in the gaps of our understanding and continue to move onward and upward.

John Estill

 

[J. Lubrant]

John,

I was not at all offended by anything you, or anyone else posted.
Heck, there was plenty of very informative data, that has me re-thinking different senerios.

When you use HP numbers to come up with a predicted performance, not only do we question is it Brake HP, Net HP etc.,or is Peak HP or Average HP? Enough to keep anybody busy!

When I first played with the calc's for the Chart, I found it interesting that (if I remember correctly?) at 245hp the typical GN would run somewhere in the low to mid 14's. Which most did.
The GN from the factory was rated at 245hp at 4400rpm. I believe they used an(SAE) Net HP figure?
Assuming that? I think net HP, means the HP is measured at the flywheel, on an engine that sports all its belt driven accessories.
I am not sure that it would take in driveline losses thru the trans etc.?
In the old muscle car days of 427's, 454's etc etc. they advertised hp ratings were BHP(at flywheel). I believe it was just the engine with no additional accessories bolted on it?

Getting back to GPM's as measured by the stock MAF or manipulated numbers with extenders etc., I have to ask how accurate or linear are these to make precise calculations on actual hp being produced?

No matter what anyone comes up with, even if correct for peak hp. The actual performance of the car is going to vary significally based on combination of the components.
A car/engine/trans/gear etc has a major impact. Even if both engines peaked at 600hp in the same weight type car. The car that was set up to maintain the higher average hp thru the gears/rpm range would always come out on top.

Using the FAST system, I would figure an average HP by using the capabilities of the Data logging function. Just after the car shifts into 3rd gear, you can lock on to the lowest rpm say 5500 at the bottom of 3rd to say 6200 at the top of third/thru the traps.
The unit log function allows you to average the Injector D.C. for that rpm range(i.e.5500 to 6200rpm).
Lets just say for example that the average d.c. for 83# injectors was 70% than as a Ballpark (.5bsfc) the average hp was 697hp.
The d.c. of the injector may have been 65% at 5500 (647hp) & 75% at 6200 (747hp)
I guess i'm saying what hp number do you use for performance level?? Peak? or average??
I would tend to lean more to the average hp number for actual performance of the car.

I know it gets confusing for us trying to pin down actual power just by saying i'm flowing 360grms per min air, or #'s per hr of fuel etc. It almost never calc's to a finite, to many other variables.

In closing my personal opinion of the engineering fudge factor is the so called VE of the engine.
The rule of thumb is the engine is normally most efficient at its torque peak. I will agree with that!, but the engine sure does burn alot more fuel at its hp peak!! even though the VE is lower.
Bottom line again the more fuel you can burn the more power you can make, just add the right amount of air or visa-versa!
Food for thought, we have TR's out there that run 10.5 to 1 A/F, 11 to 1 A/F, 12 to 1 A/F and run the same e.t's & mph. Whats up with that?? I would bet that the BSFC varys quite a bit between these cars.

Thanks for reading my ramblings, getting late, got to hit the hay,3:30am wake-up to go to work

Joe

 

[JDEstill]

Hey Joe -

I certainly agree with you, there are a ton of variables here! Just looking at the shape of the torque and hp curves, I can see how two cars with the same peak hp, but one with a flat torque curve and the other with a peaky torque curve, could run two very different times.

My own opinion is that when it comes to sizing turbos, injectors, and fuel systems that starting with a desired hp and working backward is not the best way. I think that it is better to start with air flow and go from there.

If one starts with a certain displacement engine, sets a rpm limit, decides how much boost to run, makes an educated guess as to the engines VE, then you can make a pretty good estimate of the max air flow the engine will see. This lets you size the turbo, injectors, and fuel system with some level of confidence, and it gets rid of the uncertainty you have in BSFC and drivetrain losses and so on.

Once an air and fuel flow estimate is reached, THEN you can move on to making a guess at BSFC and so on, and then the approximate hp that will be made and the possible et/mph.

At that point, if you aren't happy with the answer, then you can start asking questions like "What do I need to do to get a better BSFC to make the hp I want out of this air and fuel flow rate" or "Looks like I'll need an unrealistic BSFC to get the hp I want out of this air and fuel flow rate. How much more boost or revs do I need to get the air flow to make the power I want at a more realistic BSFC?".

That's just they way I think it is most logical to look at the problem. It kinda saves the big assumptions for the very last thing. That way you can say that "A gm/sec of air is flowing, so it needs B lb/hr of fuel, and will make between Y and Z hp" rather than "we want F hp, so we need to move between G and H gm/sec of air, which will require between I and J lb/hr of fuel". If I'm picking parts out, I would rather have the uncertainty be in the final hp made rather than the amount of air and fuel needed. In the first case you can pick parts with confidence; in the latter case you have to pick parts with an eye to the range of variablility in the answers.

Hope that made some sense...

John

 

[J. Lubrant]

John,

Your last post positively makes sense.

In my old combination that use to run 10.1x's et's at 134-135mph at approx. 3650# with a PT 70 3-bolt at 22 psi, no matter what I did it wouldn't run any faster.
I tried running the boost up higher 24 to 26psi and it just ran the same.
I did some calculations on what the engine demand would be in the rpm range I was running. I don't have the old figures handy but that 274 cube engine needed more than that turbo could effectively supply at 63-6400 rpm. I beleive the turbo was done at 5800 to 6000 at 22psi. So raising the boost did absolutely nothing to increase the performance.
Not looking at my chart I think I was producing somewhere about 710-720hp?
I forget what the exact air flow capabilities of the 70mm is but it is somewhere in the 80#/hr range. Of course that probably assumes a great turbine side to match, without a lot of back pressure. I think a excellent 4-bolt version could produce 750-790hp, but the smaller 3-bolt turbine housings would be significantly less, so I was in the ballpark.

My next step of course since I had a great engine, heads, fuel inj. etc, it was time to add more air flow capabilities.
I could have just gone to a 76mm which should have added another 10 or 11# (100-110hp approx.), but I went on to the 88mm & cam change to allow 73-7500rpm capabilities, and the rest is history. The 88mm was about a 300+hp increase over the 70mm 3-bolt. I'm sure its at least a 150-200hp over a 76mm depending on engine combination.

I think alot of people are tired of the saying "combination-combination", but it is the key! Set you goals and pick-and choose your components very carefully.

Many of us thru the years took baby steps obtaining the best performance with as little as possible, and running the cars to the edge & sometimes beyond (ouch!).
The true performance capabilities of most components/engine combinations are known. Just need to select the best for application, and don't oversize or undersize. Many have great components but no heads. Sorry I'm from the old school Heads is were the power is. You don't have to run as much boost to fill the cylinders (VE) when you have great flowing heads. This of course is true whether Normally aspirated or turbo.

I guess I am rambling again but I'm sure most will get my point, as I am sure they will yours. You have always provided excellent points and topic discussions. I know that you always keep me thinking.

My old brain is tired and its time to turn in, as I said before those 3:30am wake-ups come pretty quick.

Later,
Joe

 

[REDS HOT AIR]

so if the hp charts are rear wheel hp then your saying i made over 500 rwhp with a ta-49 turbo...wow

3700# at 121.54 mph trap speed

how much would i benifit from going trans+ and LT1 maf ?

yea i peg the stock set-up real quick.

 

[JDEstill]

Reds, I think a Translator/Extender would be a great thing for you! Or a FAST I would bet you are moving well over 400 gm/sec of air, maybe in the 450 range? That's what I would guess anyway, to run that kind of mph. How much boost do you have to run to do that? Got direct scan? Any idea of your injector pw? How hard are those 50's being pushed?

Speaking with the voice of inexperience here, the beauty of those systems is that with the stock setup, once you get to 255 gm/s then the fueling is purely a guess (albeit a well educated guess ) by the chip programmer. Makes me wonder how the chip gurus do it as well as they do! If it is hotter or colder outside or you run more or less boost than what the chip is set up for, then the fueling is off, you can't get and hold that a/f ratio you want. Maybe you'll be a bit lean, maybe a bit rich, maybe both during different parts of the run. With Trans/Ext or the FAST, the computer is still measuring the amount of air flow you've got, and it can add the right amount of fuel on it's own. Turn up the boost and it sees the air flow increase and it automatically adds more fuel. Turn the boost down, it cuts down on the fuel. No sweat! It's got to make dialing it in at the track a lot easier. The Extender chip is high on my list once I get to the point where I'm happier with how my car is running.

John

 

[REDS HOT AIR]

man im in the dark with tuning it i read the plugs and watch the crappy a/f gauge

the gauge isnt acuate but if it starts falling toward lean i know something is wrong.

i dont know if im running out of injector yet i havent got any tunning time in

i'll be going in a few weeks now and try to get it tunned in a lil but with it being mazed out the whole time all i can do is adjust fuel to max boost and let it be rich in the process of getting there.

its uneal but the race trim pass was only at 22.5 #
now that the 51 turbo is on the car i hope it picks up a couple mph ..i know it should but wont know till i get a time slip

i have a LT1 maf and plan to get a trans. + to go with it so i'll have a little more stuff to tune with and at that point i plan to put the maf in my uppipe(reason for not needing 3.5" maf

im sury gonna need the better setup when the 4.1 motor is ready.