Reactor

I agree that the method i've described is "crude". But then again, it comes from days back when hot wire sensors first came out and tweaking with ECM was at its beginnings. To achieve proper compensation (correct a/f ratio under all conditions while maintaining emissions and longetivity of the engine) on a modified motor using stock ECM is a very difficult thing to do. And success of such modifications is measured over a longer period of time. You seem to have enough knowledge to go forward so i look forward to see where it takes you. Good luck!

son-of-frimbus

To Simplyscion:

Where was I a year ago? I was driving a 1994 Dodge Dakota pickup and looking at the DodgeDakotas webpages. It's life was cut short in December of '05 by someone without a driver;'s license, no comprehension of English, and figured that hanging an illegal (no pun intended) left turn on red is something we do here in the U.S. Next I bought the Xb as a replacement and here I am. I am sorry about the demise of your car, I liked reading about what you had done with it and your the reason I looked for a Garrett turbo, though not nearly as good a one as the one you got with your TSI kit, but really was it still a TSI kit with all you had changed on it?

To Reactor:

It's not really that crude of a change, there a aftermarket manufacturers that do the same thing still with small block Fords MAF sensors. The more tech savvy aftermarket guys use a larger pipe for scaling purposes, but as a added benefit they get more flow due to less pressure drop. It's not crude, it's just harder to get right, but it can get decent results.

To rollhard:

I looked at the Megasquirt site today and I'll do that (that's is I can remember how to solder) if my calibrated MAF experiment goes belly up. I was going to purchase a A/F wideband for tuning my Fiero within the next few weeks, what do you think of Innovate motorsport's LM1 with auxbox, is that what you are using?
I got a Walbro in the Fiero and sort of did what you are going to do - I calculated that I needed 36 lb/hr injectors for what I was doing (I was going to go to 19 psi boost) on the 2.8 and I was too cheap to purchase the injectors so I found a set of 30 lb/hr on a ford supercoupe for $30 and I modified the fuel pressure regulator to go from 43.5psi to 60psi. The car ran real good out of the box after I scaled down the fuel map in the idle and mid-range RPM's by the ratio of the 2 injector flow rates.
If you're at 7.5 psi boost right now and using the 310's I calculate that you should have something in the range of 359 given the 139whp you're making now ( I am using .6 BSFC, pressure ratio of p/p1=1.62, a 15%drivetrain loss, 1 psi intake loss and a 80% max injector duty cycle). This means that you need about 16% more fuel while under boost to go from 310 to 359. If you raise the pressure with Mr. Perrin and Mr. Walbro you should shoot for 58 psi to get the flow you need. The way I calculated that was the ratio of what you need (359) divided by what you have (310) which gives 1.16. Flow is related to pressure by a squared function, so if you square 1.16 that gives you 1.34 and if you multiply the stock pressure (I assume 3 bar, or 43.5 psi for our cars) by that 1.34 you get 58 psi - the starting point for the experiment. (BTW I got the Fiero up to 19.5 psi before the head gasket blew out, but I wanted to upgrade to a 3.4 anyways and I wanted to see if this guy's prediction that it would let go at 18 psi was right - he was. Here's his website: http://www.turboz24.com/ )

O.K. now for some food for thought:

How come nobody has placed the intercooler into the area that is just behind the "upper fake" grille, you know - the one that is body colored and is solid so that no airflow can get thru it? Why hasn't somebody tried to put one of those "mesh" grilles with an intercooler behind it? Sure it would be a tight fit, but the airflow there has got to be better that placing 1/2 of the intercooler behind the crashbar. If you wanted to really get the wind to sail thru the intercooler in this placement put this hood on:

http://cgi.ebay.com/ebaymotors/02-03...23362278QQrdZ1

Your Xb would start to look like an EVO but even better yet, it would cool like one!

Still nobody interested in how to totally eliminate turbo lag? Come on just ask, I guarantee that you'll break a half shaft in about a week or 2, but man it will be a really fun 2 weeks. Remember, you're not having fun if you're not breaking parts!

Simplyscion

lets hear it...how do you get rid of turbo lag...also you got any tricks for centrifugal blowers??

rollhard

Wow, your math is giving me a headache. I was never good at math. Since Im asian, I had many people copy my math tests when I was in highschool, only to find out they got a D or C. LOL. Wrong guy to copy from buddy!

Anyhow, in my experience, calculating % from going larger size gives you a rough idea but I have seen AFRs way off. Right now, I am using the AEM UEGO in the car but I also have a Dynojet 224x with wideband that I use to tune. The AEM is a good tool to just monitor AFR while driving. I have tuned with the Innovative unit before and it works well also. It read a little more rich than my dynojet unit but pretty damn close. I guess Dynojets system reads it on a little more conservative side. As for putting the intercooler behind the fake grill, the hard part is getting the pipes in from the center there. I did however, dremel the slits open (wow, that didnt sound so good) to allow air to flow in. Ill let you guys know how it goes with the new fuel pump.

BoogieQ

Apparently all you guys have to do is slap in large injectors and run a good maf pipe = 180whp.

There HAS to be more to it than that! I like the discussion here, some of it is past me as I'm all to used to completely rewritting the PCM (Pontiac Grand Prix's) to have it do what I want.

Keep the good info rollin!

rollhard

Here is another thing that is interesting. Again, Im learning more and more about this ECU because the turbo Elise we are working on has the SAME issues with the ECU. If you disconnect the 02 sensors, the ECU goes to a permanent open loop mode putting 50/50 air and fuel. What you can try is tune from that as it has no way of telling whether its rich or lean. It will put fuel in according to the air flow signal, tps, etc.

son-of-frimbus

To rollhard:

You're probably alot better at math than you lead us to believe and there are several websites that explain this better stuff better than I. If you don't like math, but just want answers Ray Hall's turbocharger website has Java applets that do all the calculation for you to select a turbo. They also have compressor maps! They're here:
http://www.turbofast.com.au/javacalc.html
If your into the math, Garrett's website (turbo tech101 thru 103)gives great explanations of how a turbo works and they're at:
http://www.turbobygarrett.com/turbob...ch_center.html
And if you want to calculate injector sizing and other fuel injection stuff RC engineering's website is excellent, but better have a calculator and as usual they explain this stuff much better than I. They're at:
http://www.rceng.com/technical.htm

I hope you find these websites as interesting and informative as I have!

Lastly, yes you are correct you CAN NOT use these calculations to tune your car, but they will do 3 things for you: 1) give you a starting point from which to go once you have some combination of parts to start tuning at, (gets you in the ballpark) and 2)select parts that match for what goal you have set and 3) tell you what doesn't fit when all the tuning in the world doe not make the car run right. These calcs are a tool that provides a pretty good "rough guesstimate (is that even a word?) where you should be and tuning is the "fine tune adjustment" on your "tube T.V." Yes, I can remember when T.V.s had tubes in the back and you had fine tuning adjustments when you would change channels.

To Simplyscion:

I will try to do my best to explain how to eliminate turbo lag, so here we go.

Turbochargers are air pumps that basically operate like 2 fans connected to a common shaft. One fan (the turbine) extracts energy from the exhaust stream coming out of the engine and turns the shaft which then turns the other fan (the compressor) to push air into the motor. Seeing as we live (currently) in a world in which virtually everything has mass, the rotating assembly of this turbo unit (the compressor wheel, shaft and turbine wheel) has what is called in engineering "rotational inertia. The translation of that into English means: a mass at a distance that can rotate. Now stuff that is heavier (for the same force applied and at the same distance away from the center of rotation) will take longer to "spin up to speed" than stuff that is lighter. this is the reason that a big "detroit iron" V-8 comes up on the rpms slower than a Honda B18b. The connecting rods pistons and crankshaft are all heavier in the V-8 than the 4 cyl. This is also the reason why Garrett came out with a ceramic turbine wheel - because it is lighter than the steel one that it replaces and the reduction in mass allows lower turbo lag, faster reaction. (sidebar: just remember that the wheels on your car also have rotational inertia (read: big flywheels) and reducing their mass and diameter will make you car go faster, but there is a limit to that effect)

Turbos generally don't start making serious pressure until about 80,000 RPM due to the fact that they are centrifugal pumps and not positive displacement pumps like a "roots type" blower (Eaton M-series). (sidebar: if you can pour a cup of water thru the blower or turbo it's centrifugal and if the water just "sits" there - then it's a positive displacement roots type). Turbos compress air 100% of the time while the engine is running, but to varying degrees during different comditions.

At idle, the exhaust stream is still powering the shaft that turns the compressor AND the compressor is compressing a "stagnant" or not moving volume of air. Why doesn't this volume of air that is contained between the compressor and the throttle valve move? - because the throttle plate is closed (It's idling!) What does compressing this "fixed volume" have on the compressor? It puts a load on the compressor wheel and sort of like a brake, keeps it from spinning at a really high speed. How fast? If that load wasn't there, the turbo would spin at about 120,000 RPM. This is why the tubo starts out at 20,000 RPM and when you "stomp on it" it takes time for it to spin up to 80,000 RPM to make pressure (turbo lag)

So, now that you understand the concept of "rotational inertia" and how it has an effect on "turbo lag" I will now explain how to eliminate the "turbo lag" effect.

You can see that if the compressor isn't required to compress the "stagant volume" it will spin at a high rate of speed, but how does one do that and still make pressure when one wants to? Easy, add a bypass valve. This bypass valve is a normally open valve that when vacuum is applied to it's actuator - closes. This valve is installed in the section of piping that is contained between the compressor on the throttle valve and when its under manifold vacuum stays open and lets the compressed air "leak" back to the airbox. At idle, all otto-cycle (gasoline burners) engines have fairly decent vacuum readings at idle (about 18"-21" depending on several factors) and this"signal) is what is applied to the bypass valve to open it. The only time that you don't have a strong vacuum reading in the manifold is at the "open thottle" position (non-turbo cars read 0 PSI turbo cars - whatever pressure the head gasket will take)

So how does this operate? Well at idle, the turbo is spinning at 120,000 RPM instead of 20,000 RPM and is generating NO PRESSURE in the intake mainfold because it is happily sending all EXCESS PRESSURE to the air box. Remember that I had said that it takes 80,000 RPM to to make pressure? Guess what happens when you floor it? You approach 80,000 RPM from 120,000 RPM and NOT the measly 20,000 RPM.
This is like two guys raing at a stoplight, one stopped at the crosswalk and one driving 60 mph while crossing the crosswalk as the light turns green. The guy who is standing still had better have the Spaceshuttle's engine. What does this look like on the turbo gauge? Well you start off at 18" vacuum and as fast as you can snap your fingers you go to MAX BOOST.

I did this on my first Fiero that I turbocharged (over 10 years ago now) and on that little 2.8 liter engine the gauge when form 18" vacuum to 14 PSI from idle (when I floored it) and bled back down to 12 PSI at the 4800-5300 RPM range and from 5300-5600 RPM range it dropped to 8 PSI, but that was because the Garrett T-2 that I was using was too small. I got that turbo for $35 in the junkyard, so beggars can't be choosers.

What is the downside? Due to the shock loading of the compressor wheel you possibly could blow out the thrust bearing in the turbo quicker. What of the drivetrain? The engine shouldn't have any appreciable wear due to this, but the transmission and the halfshafts will probably take a beating. Broken parts from too much power - YEAH!!!!!

What's the upside?Elimination of turbo lag - confused competitors - the ability to size the turbo slightly larger (more higher RPM usage without sacraficing low end performance), real kick-*** performance off the line.

Will this work with my supercharger - no. The supercharger is belt driven and governed by engine speed. Is there anything that can work like this for supercharging? No, not that I have found - and I have been looking for over 11 years for my supercharged Firebird Formula.

Well, there it is. Rollhard, you look like a good candidate to try this on your car, so the part that I used was a heater control valve to a mid-'70's Chrysler product. You will have to bore a hole into the pipining (3/4") weld a 3/4" tube to it and use 3/4" heater hose to get back to the airbox. Yes, you can let it go to the atmosphere, but is makes a terrible whisling noise and I like the "stealth" approach in life, so I use the airbox as a muffler.

I know this works - I have used it already. That's enough for now, my fingers hurt from typing. Good luck and have fun.

son-of-frimbus

To Boogie Q:

Well there is some more to it than, slap in large injectors and run a good maf pipe = 180whp." Slapping in a correctly sized MAF pipe should give "get you in the ballpark" close enough to make the tuning chores much easier. It is like using a coarse adjustment with the MAF and then tuning is the "fine adjustment". I believe that ZPI got their car to run with just the calibrated MAF tube alone - albiet with a couple of lights on in the dash, but the got it to run and according to my calculations it's very possible to do this. Rollhard has said that we don't have a wideband O2 (but I have not confirmed this (mainly because I am old, lazy and it is raining outside right now), so real time correction via the O2 is not possible. If he's right (which I have no reason to doubt) then we would also need some other "stuff" to make this run right.

If I need some other stuff, I will probably go MegaSquirt - looks like the shizzle. I'd probably go MSD 6 BTM so I can get so ignition retarding insurance - I used it before (the MSD) and it works really well.

I just remembered another bit of info you guys can use. When I first installed the ATI ProCharger kit on my Firebird I kept getting a nasty break-up and miss at over 5000 RPM and that turned out to be the sparks shutting off at the higher pressure. At atmospheric pressure, a spark can jump 1 inch for 40,000 volts and under boost less than .035", talk about loss. Some guys use a tighter gap on the plugs so the stock coils can still light the flame, but it really is much better to enhance the system so it can really throw a lightening bolt in there. Costs a little more but worth it in the long run because it eliminate one more variable in the chain.

As far as writing code, I wrote the BIN definition file ($24A - 1226869 ECM) for the 1985 2.8 liter Fiero Engine. This is the interface file that goes between TunerPro Rt and the 1985 Fiero ECM and allows you to write to the correct spots in the ECM. When you are,"used to completely rewritting the PCM (Pontiac Grand Prix's) to have it do what I want." you are using code the was developed by someone like me.

I thought tuning was hard - until I tried using a hex editor for a month, so I could even get to the tuning part.

lastlookcustoms

[quote="son-of-frimbus"


To lastlookcustoms: I couldn't find anything on the web that does MAF to speed density for our cars, but I have been told that I can find stuff even with a flashlight and a guide and GPS, so it's probably me.

"[/quote]


www.map-ecu.com


Its not "for our cars", its a universal piggyback that gets rid of the MAF and converts to speed density and offers FULL fuel mapping. I sell them on my site as well...

rollhard

The price of the Map ECU is that of the megasquirt. FOr me, I would rather convert to MS. Anyhow, I have concluded that its not the fuel tuning or the MAF that is the problem. The problem is with the stock 02 sensors. They are what is throwing the ECU NUTSO. You make the airflow corrections, the ECU does as you want but then the 02 reads that its either rich or lean and tries to make its own corrections regardless of what the piggyback wants it to do. Its a combination of both but I think the 02 is a bigger problem at this time. What I am thinking about is going with MS and using their mapsensor.

itsme

man i luv this thread im actually learning so much just from da first few post....i think ima read on a learn more from you guys and hope i can achieve anything out of this and do some research on somethings that i dont undersand through reading or better yet ask someone here...........gotta give you props for the first thread that is actually on topic about something (well as far as i read so far haha) and dishing out the knowledge that you all have from experience.....PROPS....now i gotta get me some eye drops cuzz my eyes are dry

rollhard

Im glad you are learning from this. My headache = your gain? lol. Ok, the latest. CEL is on, AFR is good. Basically the Emanage is winning the battle of the ECU. With -45% fuel trim, the ECU cant do much more and then Emanage is taking over. Idle is at 14.5-15.5 which is good, partial throttle under boost is around 12.5-13 which is good, WOT is at 12.7 which is perfect. The only problem I am having now is that occassionally since I am tuning from a 0-5v hotwire meter, sometimes the air flow is the same as what it would be under boost even when I am not in boost and it would run rich? Make sense? Monitored my tank of gas as I usually do and I am getting a sucky 21mpg. The car is running good though. Me and the CEL are learning to get along now.

ERIC-TC

I'm running into similar issues with my ultra smart tC ECU... The dam ECU is so quick that I've been logging it fight against my emanage MAF correction map. So in the meanwhile I'm like wearing out the negative terminal on my battery... This lowers my AF to my liking for about 2 days of commutes.

I'm trying to figure out which wires I need to put a set of relay contacts on the ECU to reset the learnt long-term fuel trims. I want the ECU to reset every time I turn the ignition off -This is my opinion will give me a working solution for my daily driver turbo car.

I gree with you guys that getting control of the 02 circuit will be the best way of getting rid of further ECU compensation and get fuel control as a result. Don't forget that the ECU also checkes the value of the narrow band 02 past the catalytic converter. This second part will be very difficult to do and will probably result in CEL for low catalitic efficiency.

rollhard

Try adding more fuel and dont bother resetting the ECU. After about 45% the ECU can no longer trim fuel so tune with the CEL on. Youll be ok. I did that and the ECU hasnt been able to trim any more fuel down. Its a med-long term thing the ECU does and the people making the turbo kits are most likely not doing any long term tests. Thats why their maps work in initial testing on the dyno, etc. Eric, do you know what your AFR is?

ERIC-TC

I'm going to post this bad boy here -I know what my A/F I'm logging it with emanage, tell me what you think.

Okay, here is some data. This is a Stage 0 running in a closed track environment...

I'm currently injecting 10% methanol distilled water solution down-stream of the turbo. Water/Meth Injection is running off a stand-alone MAP sensor.

I disconnected the battery last night -hooked it back up and let the car idle. Then I drove to the closed circuit track and logged this data... This data is with a fresh ECU that has all learnt fuel trim data erased.

Small plots are from emanage-blue that is being fed A/F by a PLX M300. The large plot is from my ODB2 scanner/logger Autotap. I get updates every 1.1 seconds with the data that I'm recording. The less data the quicker I can refresh the data. No corrections are being made by emanage it's basically only datalogging for this experiment.

I can get my servo actuated throttle to go from 0 to 5V with the engine off (IGN on). Once the ECU takes over it clamps it at 80.1% open and with foot off the throttle and engine running I get about 16-17% TPS.

So when emanage says 80% throttle then this is basically wide open throttle for my car. I need to adjust my thorrtle throw on emanage setup screen so that it matches the odb2 readout.






This basically shows the car switching over from closed-loop to open loop and adjusting long-term fuel trims down by 5%. It also shows the AFR at 13.5 WOT at the peak torque RPM range this from what I can tell is the most important spot in the power curb and the area of most possible engine damage.

When the ECU is allowed to learn the turbo (takes about 3 days) it will lean the car out more and more until are boosting with A/F of 14.7:1 or leaner and will hold it longer and longer into the RPM curb until the car transitions into open loop.

I will post some plots of this latter this week.

Hope this helps to answer some questions on how our ECU handles a Stage 0 with no management.

rollhard

-5% long term fuel trim is why you are running lean. I didnt reset my CEL and let the ecu continure to trim -45% and it hasnt been able to lean it out more than that. I tuned with Emanage and its much better now. I had similar problems like you when I would reset the ECU every couple of days.

ERIC-TC

Actualy according to the manual it can only go down to -35% long term fuel trim. So basically I get the emanage injector harness and I add fuel in the open loop until I exceed the ecu's ability to lean it out. Does this make sense? There was talk that you only needed one of the harnesses on emanage for a 4-cylinder engine to do fuel correction and timing correction. I already forgot -I only have the standard emanage harness. Do I need to buy the injector harness or the ignition harness? or both?

rollhard

I guess the TC ecu is a little different than the XB one cause its showing that im getting -45% long term fuel trim. I added more fuel with Emanage and I havent had a problem since. Are you running larger injectors?

ERIC-TC

No I'm still running the stock tC injectors these are 370cc I think.



Here are the specs from the service manual for the tC. Stock injectors flow max 92cc in 15 seconds so that basically is a 370cc injector upper end to 304cc lower end of the spectrum.

According to RC Injectors website this injector (370cc) is good for 160HP which matches the rated stock output of the tC. For a turbo charged 4-cylinder engine capable of 225HP you will need at least a 440cc injector. Which also makes sense as this is the injector size included with the supercharger kit on the tC.

Okay -I'm seeing the writing on the wall I need new injectors 440cc and the injector harness for emanage if I'm going to have any plans of keeping my engine latter this year... You got to pay to play!!!

metal112524

GOD im so afraid to boost right now, i dont know which way is up after trying to read this stuff.