ECU Capacity For Larger Injectors

07/25/2008

Help! Ok so I have a set 42lb injectors on my car. Does anyone know if the stock ECU will be able to handle bigger injectors, or injectors that big? Carter? Eric? What size injectors are you using? I'm really trying to avoid a piggy back. Kenny?, You've mentioned this before.
Jose Cuellar
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No way a stock ECU would be able to adjust from 19 lb/hr to 42 lb/hr injectors. You MUST get a new tune.
Daniel Holtman
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Well, hmm. Ok so with a tune the stock ECU will handle the 42lb injectors
Jose Cuellar
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With a tune, the stock ECU isn't the stock ECU any more.
Ryan Dudek
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Yes. The injector size is coded into the PCM, and is used to determine pulse width of the injectors. If you go to larger injectors and don' t change the injector size in the PCM, the car will run incredibly rich. The PCM can only adjust 25% richer or leaner from the calculations based on HO2S feedback.

Daniel Holtman
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Ok, I'm going to go put on my dunce hat now. That makes sense, thanks!
Jose Cuellar

Why the hell are these turbo guys telling me about a piggy back system? It must be so they can sell me sh*t I don't need. No thanks, I've already poured enough money into the economy with this car!
Jose
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A piggy-back system could refer to a piggy-back chip: it plugs into the port on the back side of the PCM. Nowadays hand-held tuners have all but replaced chips - they tune just as well, can read codes, don't have to physically connect to the PCM all the time (there can be connection issues in the SHO as there's not much room for the chip behind the PCM), and your programmer can update your tune via email so you don't have to send the chip to him and wait for it by return mail.
Daniel Holtman
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They're talking about a piggy-back fuel controller. See here: http://www.innovatemotorsports.com/resources/piggy-back.php

I'm not serious enough into built cars anymore to know for sure, but I've had the impression that these setups weren't as popular anymore with the increase in popularity the hand-held tuners that can upload a full tune in no time, changing what needs to be adjusted and leaving the other settings alone.

Ryan
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My car will start on the stock program with the 38# injectors but it look like a diesel on a cold morning; very rich black smoke. With Doug's programming on my ECU using the SCT X-Cal2 I have no issues that relate to the larger then stock injectors.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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What was that problem you had with cyl # 5?
Jose
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Been out late the last couple weeks trying to get my new garage/house dried in. I'm sore, it's hot and my underwear is soggy.

Yes, you should be able to program for the larger injectors. If you don't I'm thinking you will probably wash the rings out. If the software for the sho is similar to what I like to use on the sti, there will be a table like, "injector scaling". You need to know the flow rate of the injectors, (yes they can vary widely from what they are supposed to be), then it's as simple as plugging in the new size. Injector latency, time it takes for the injectors to open/close, will also need to be adjusted, they should of sent the latency information with the injectors. To be sure your settings are close, data log at least a/f's along with long term and short term fuel trims. Data logging is good, it shows problems way before you ever feel anything amiss.

You will probably need a larger maf w/boost. Again, if the software is similar, there will be tables to modify the maf readings. Usually tuning in a maf is a real pita. Very few have a clean flow rate at all volumes. Small bends/turbulence near the maf can make it a nightmare to tune.

They're probably telling you about some kind of system to manage spark/fuel/boost/knock sensor while under boost. I'm about 99.99% sure the stock sho ecu will not have the needed tables to adjust for boost. You will need something that works in conjunction with the stock ecu, or replaces it. This might be a complete stand alone system or something as simple, (really not simple), as a boost controller that is able to take over/override/modify the signal to/from the stock ecu while under boost only to hand back over to the ecu during normal driving. I'm thinking some of the more advanced boost controllers can handle these parameters but I'm not that up on boost controllers and such as the ecu's in the evo/sti are very good at what they do and an upgrade/stand alone is not needed until very, very high levels of modifications are reached. (or you have lots of money). Really, me thinks the turbo honda guys will have the information you need on controlling engine parameters, just have to know which ones to listen to as a lot of them like to talk out their azz.

k mier
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The jury is still out on that. I suspect it was an issue related to the individual triac or transistor in the ECU that was firing that injector wouldn't hold the duration long enough during WOT situations. I changed the ECU and complete harness the last go around before last years convention. So far so good.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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Jose, we talked about this. The factory PCM will do everything you need it to do, Boost or no-Boost. It'll handle 72lb/hr injectors if you want to put them in there. I tuned a turbocharged '04 Cobra with 72lb/hr injectors to 700hp. Still had a dead smooth idle and would get somewhere close to 20mpg on the highway. If you're looking at piggyback or external controllers, remember that you've still got an automatic transmission to consider. Don't mess with load or it'll kill the tranny.

Doug Lewis
Ford Performance Specialists Inc.
Atlanta Georgia (770) 949-7191
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Doug, I've already swapped out tranny to an MTX-75 and with what SHO folk have explained to me, all I need is a good tune on the stock ECU and I already know I will need a MAF.
Jose
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Go hang out on SVT performance and NLOC.net (Lightnings) Always folks
selling their old stock stuff for dirt. That is where I got my MAF for
SHO R T S.

Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
97 Ebony 182k Resurrected, Welded, Experiment in progress
96 Medium Willow Green Metallic 103k Resurrected, Welded, Eaton M90 inside
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, 2007 Best Gen 3, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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Air intercooler. I got 30 MPG on the way to Kalamazoo and on the way back from Indy.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
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Exactly the Stock Engine Control Unit, and even it's stock program will work just fine. Tuners do not change the program, just some variables or paramters called a calibration file.

I know it's semantics to most but changing a real-time engine control program successfully is something not to be attempted even by most computer engineers. You can do enough damage just with the calibration files modified incorrectly.

In some ways it would have been easier in the early days of the gen III to get an aftermarket racing ECU and put it on the Yamaha (a true non stock ECU). But with the high quality programmers out there to set almost any calibration you want, and a few folks who have put the blood, sweat and tears into figuring out what works and does not with the stock ECU and program, I cannot think of a modification I would not just get someone to tweak a calibration to support.

Hmmmm...on reflection... if you wanted something wild like launch control or added stability control (which I assume the stock ECU has no way to interface to on the sensors, nor the program and cals to adjust powertrain output to match).

Jose, we talked about this. The factory PCM will do everything you need it to do, Boost or no-Boost. It'll handle 72lb/hr injectors if you want to put them in there. I tuned a turbocharged '04 Cobra with 72lb/hr injectors to 700hp. Still had a dead smooth idle and would get somewhere close to 20mpg on the highway. If you're looking at piggyback or external controllers, remember that you've still got an automatic transmission to consider. Don't mess with load or it'll kill the tranny.

Doug Lewis
Ford Performance Specialists Inc.
Atlanta Georgia (770) 949-7191
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Why the hell are these turbo guys telling me about a piggy back system?
It must be so they can sell me sh*t I don't need. No thanks, I've
already poured enough money into the economy with this car!
Jose
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Exactly the Stock Engine Control Unit, and even it's stock program will work just fine. Tuners do not change the program, just some variables or parameters called a calibration file.

I know it's semantics to most but changing a real-time engine control program successfully is something not to be attempted even by most computer engineers. You can do enough damage just with the calibration files modified incorrectly.

In some ways it would have been easier in the early days of the gen III to get an aftermarket racing ECU and put it on the Yamaha (a true non stock ECU). But with the high quality programmers out there to set almost any calibration you want, and a few folks who have put the blood, sweat and tears into figuring out what works and does not with the stock ECU and program, I cannot think of a modification I would not just get someone to tweak a calibration to support.

Hmmmm...on reflection... if you wanted something wild like launch control or added stability control (which I assume the stock ECU has no way to interface to on the sensors, nor the program and cals to adjust powertrain output to match).
Jim
'71 Torino GT "M" code 359 CI shaker convertible
'96 & '98 SHO's 3.4l
'08 HHR 2.4l
'08 G6 3.9l hardtop convertible
'08 STS-V (Cobalt SS ordered)
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I take it that you used a lightning MAF. Is there a better MAF ( aftermarket wise ) than a lightning MAF?
Jose

From my Advantage 3 software for the SCT Xcaliber....

Paul

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Have to ask, how can the sho ecu handle boost/cross over alone? I could see sneaking by on a few pounds, but I do not see the 15 or so Jose is looking for.

k mier
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I believe Jose has the driveline mostly in place and wants to validate the motor and tranny as it is a whole new driveline, and the motor has custom internals as well, heck with an MTX the sub frame isn't even stock anymore....

I think the first thing that needs to be determined is if he will be using the stock ECU with boost.

If yes, then he will need a tune anyway, so strike a deal with the tuner of your choice and tell them the plan up front. First step with the stock ECU would be:

Turn off the ATX and change the injector sizing.

That would allow NA driving of the car around the block or for whatever duration for validation of the driveline.

Send it to the turbo shop to have that work done, retune after they are done.

OR

If a a different ECU would be used post turbo (brings in lots of fun questions like speedo input and the like). A hack way to feel out the driveline NA for a brief term before going turbo would be to leave the stock program in the PCM, and since you'll likely need an adjustable FPR for the turbo car anyway, a short term hack would be to run the injectors at a lower pressure (about 18 PSI). This is a total hack approach, and I would only employ it if an SCT tune wasn't going to be needed on the completed car.

Scott
aka Beaker
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Wow! That's something I did not realize (about the subframe not being stock). I have an SCT xcal 2. I should be able to have that flashed just for a quickie way for NA driving while I make sure the drive line holds up. I will run a modded tune to the factory ECU via the SCT for the finished turbo set up. I don't think I'll need a stand alone for 15 psi. Scotty I'm still working on those pics. The ones I took came out crummy as the flash was too bright! New phone, better camera, just haven't figured it out quite yet. BTW thanks for the help, always a pleasure talkin with you, hopefully one day we can sit and have a beer.
Jose
*Ed note - maybe two brews?*
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I can dis-engage the supercharger and drive with no ill effects other then the milaeage drops to about 22 on the highway and 15 in town. Doesn't seem to cause any real issues.

Carter Fuji
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Do you still get 30 mpg on the highway with the SC engaged?

Doug
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Carter, if I can figure out how to post the tables to an e-mail attachment I'll show you just how many tables are involved in adjusting for boost and keeping the car alive. I just can not fathom the sho ecu alone having enough tables to deal with all the possible situations. Just a few pounds of boost, ok, fifteen +, no way.

How do I post the program tables using windows xp home?

k mier
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Depends on if you can export the tables to some other format (like Excel or possibly print them to PDF). If you can print the tables on a regular printer, then install one of the free pdf printer software's to accomplish this. (PDF creator is the one I use).

If you cannot print or export to another format, then a series of screenshots may be the only way. To screenshot, hit the print screen button, then in word or whatever hit edit, paste, repeat until you have everything in the document as you want it.

Scott
aka Beaker
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I understand that Doug said if I had gone with the Hitachi made SCT 90mm MAF that there were substantially more data points to work with and he actually preferred I go that route but it would cost more then twice the Lightning 90mm MAF.
Carter Fuji
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Mine is limited to 10 psi though which is why it isn't such an issue with mine I guess.
Carter Fuji
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Highway and city mileage both drop when I disengage the supercharger using the current tune.
Carter Fuji
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Lucien has a few posted that include mine at Kalamazoo on Knoll Park's quarter mile. You should see how much black smoke was coming from the tail pipes before it got past the 100' mark. The second pass would have been a real impressive one if he had caught it since the intake tubing between the intercooler and throttle body had separated just after the 1-2 shift as I watched the boost gauge climbing past 6, 7, 8 then drop to ZERO with a loud pop followed by silence which had my wife and dad in the stands start thinking how we were getting home. I coasted through the lights with a 32 second ET jumping from the car at the turnaround ramp pushing from the end of the track. A quick twist of a screwdriver at the scale and it started right back up.
Carter Fuji
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Hitachi made SCT 90mm has more data points then the Lightning.
Carter Fuji
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Yes, but are you getting in the area of 30 mpg on the highway, with the current tune and the supercharger on?

That is interesting, and I would just like to know if you are getting somewhere in that area.

I get about 23 with mine, no mods and regular gas tune from Doug. Tranny is not in the best shape, but it does get the car around.
Doug

Almost all the MAFs can have more data points added.

The stock 80mm one can be increased over 20%
Paul N
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I was under the impression that the resolution was much finer on the Hitachi version though.
Carter Fuji
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With Mr. Lewis's initial tune on my car with the 36# injectors, 10# of boost, liquid to air intercooler, 90mm Lightning MAF, Welbro 255 Hi-Flo/Hi-press fuel pump and ND Irridium plugs two heat ranges cooler on the way back from Indy and again on the way to Kalamazoo I did 30 mpg, assuming my stock fuel tank can hold no more then 21 gallons filled to the rim. These are the only two recent times I have done that (filled over 21 gallons) on an otherwise no-stop highway trip at 70 - 80 mph speed. My tranny is from questionable source but it does have a Phantom-Grip "LSD" (not a true unit like a Quaiffe) installed but it has lasted 4 years after having the torque converter welded.

That said I do know I have also taken a half of tank out at about 9 mpg up at the track and in town get around 18 now.
Carter Fuji
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Just took a nice long road trip.

One tank with the windows down a bit and the sunroof open = 20 mpg -
AVG speed 75 - 80 mph
One tank with the AC on = 22 MPG - AVG speed 75 - 80 mph
Myth busters VINDICATED !

Eaton M90 supercharger - Max 10 PSI boost. RARELY saw any boost -
mainly straight and level cruise both tanks. Boost gauge usually read
between 10 - 20 inches of vacuum.

Trans is modified, running 3.98 : 1 gear ratio, hopped up TQ Conv,
extra clutch packs - blah, blah, blah...
42# Lightning squirters.
90 mm `04 Cobra MAF
Tune by FPS

and 1 temperature reactive coil on the rear bank that is really
pissing me off. :-(
Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
97 Ebony 182k Resurrected, Welded, Experiment in progress
96 Medium Willow Green Metallic 103k Resurrected, Welded, Eaton M90 inside
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, 2007 Best Gen 3, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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Mine on my Harley F-150 reads @ 17 inches of vacuum @ cruising speed. Is that good?
Jose
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YES.

When the Vacuum reading gets closer to "0" is when your gas mileage tanks.

It is hard to get much more than 20 out of any well running V8 with
stock cams. If you have aggressive cam profiles, it is not uncommon to
see only 10 - 13 inches of vacuum even at idle. That is why one see's
highly modified engines unable to pull enough vacuum to power the
brake booster safely.
Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
97 Ebony 182k Resurrected, Welded, Experiment in progress
96 Medium Willow Green Metallic 103k Resurrected, Welded, Eaton M90 inside
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, 2007 Best Gen 3, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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I forgot to mention that is one of the reasons I upgraded the brakes. If I was hotrodding it a lot I would only get a marginal boost assistance when I jumped on the brakes. It also takes a little re-routing to keep from "pushing" oil out of the tubing from the breather lines off the head valley "dog-house". Really confused me to see it pouring out of the air cleaner until I thought about where that pressure was coming from.
Carter Fuji
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Hence the reason the Mustangs tend to use hydraulic pump (diesel style) brake boosters. I considered that but really didn't want to go through all that plumbing.
Carter Fuji
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Any V8 at all or any SHO V8?

I can get 24.5 out of my 469 HP North star in the V and break 30 in a Corvette on the highway. I was routinely breaking 25-28 in my V8 Super on the highway.

Now to support your point, I average 18 all around in the V, and if I jump on it and drive mostly in town I can average as low as 11 if I try hard. My Cleveland is averaging maybe 10 MPG but it spends a disproportionate amount of time with one or more tires exhibiting dynamic friction rather than static.. :-).

A higher number of cylinders can be a disadvantage due to pumping losses and the cylinder surface area vs displacement, but even so IMO V8's are not inherently low MPG
Jim
'71 Torino GT "M" code 359 CI shaker convertible
'96 & '98 SHO's 3.4l
'08 HHR 2.4l
'08 G6 3.9l hardtop convertible
'08 STS-V (Cobalt SS ordered - 30 MPG and 0-60 in 5.5s)
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Are you talking about MPG? Eric was talking inches of vacuum...

I think you may have been a bit confused there. :)

Regards,
Jon Heese
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No, I was talking about vacuum. Because I have a boost/vacuum gauge in my truck. I've always wondered what the vac was for.
Jose
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Just the way the gauges are made. They show negative and positive because they are attached to the intake manifold.
Carter Fuji

Bust some ring lands and you will see the vac change.

k mier
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Yeah, you and Eric were on the same page. I was correcting Jim (hitechrv).

Regards,
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No, he was talking about the ridges on piston between the rings that tend to shatter from leaning out. Mine crack then melt.

Carter Fuji

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Tried what you guys said and I had no success. I'm sure it can be done, just not by me. I give up.

If you want to take a look at all the variables involved in programming a boosted car you can download the ecu programming/logging freeware here : http://www.romraider.com/ If you want an ecu map to play with there are some on the forum there also. Don't expect me to load my ecu with your map though! :0 Seth, Ron, if you want to look at your suby ecu programming, would like to know exactly how well the motor is running, or even a code reader...it's free and straight forward to use.

k mier
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Don't see any Ford PCMs there.....

Paul N

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