So MAF can't handle the airflow, and MAP is really picky about changes to the system. Is there a good "off the shelf" fuel injection system that can adapt to changes and lots of airflow from a turbo?

 

UMM kind of broad question...But Yes there are plenty of choices.. Almost all aftermarket ones are MAP based>>>But with boost you run a 2 or 3 bar map sensor... then have the fuel map add fuel based on the pressure/boost your building..

I have a fast system, 3bar map sensor with wideband O2.. takes most of the guesswork out... Other systems are DFI gen 7, electromotive TEC3, Big Stuff 3 , motec, etc etc.. whichis the best...who really knows.. all of the higher level systems like I posted above would be fine.. However your better off to stay with the newer versions... as in dont go buy a DFI gen 5 and expect it to solve all you tuning woes.. If you have the means get the WB02 option... Unless your a tuning genious youll be glad you spent the $$$$ up front for it..

 

Do any of those systems have a check engine light and report malfunctions when they occur? Any have a limp home mode?

 

Is there a way I can keep my TPI plenum, runners, etc, and just change out the computer? I'm looking for something like wideband O2 that I don't have to program all the tables with a laptop. I'm looking for a efi system that can learn on its own.

 

Yes aftermarket dfi is just a wiring harness and a computer.

 

That is a bad thing. What if a sensor goes bad and the ECM learns and tries to "fix it". O2 goes bad on the rich side.....ECM leans it way out. MAP goes bad, ECM tries to lean out at WOT....BOOM.
EFI is no different than carbs. You need to learn about them to make them work right. There is no complete "self learning" ECM. The stock GM ECM is "self learning", that is what the BLMs and INTs are indicating.

 

Good. So is there something like that but incorporates a wideband O2?

 

I think the acell dfi has it. I dont have a turbo but I am using a dyno jet wide band o2 kit with a stock gm ecm to tune my car.

 

There are so many choices out there, hard to say one is the best because not everyone has the same setup. I think the best one for you would be the one that has all the features you need and fits within your price range. Some of these aftermarket ECM's have alot more features than others. So like most things you're gonna have to do some research and see whats out there and what you need.

 

Have you considered keeping the stock injection system and an FMU? Can't beat the combo for simplicity and it is quite reliable as well. I would recommend the Cartech FMU for ease of tuning. For a mild boost of 6psi or so, I would feel comfortable tuning off of the factory O2 sensor. Shoot for .900-.950v at WOT/full boost. However, WB O2 tuning is far more accurate, and I would consider it a must for over 6psi of boost.

The stock MAF does work with boost. I've blown through mine for quite some time now. It's not a race car, just a nice driver (it drives very near to stock, except for the surge when boost comes in!).

 

I think an fmu is a bad idea. Imo it comes on to late and then it adds to much fuel. Eveyone I have ever talked to said those things are junk.

 

Thats because they didn't buy a real one like a Cartech or Vortech SFMU. They are the only ones I know of that have an onset adjustment so you can richen up the fuel mixture before boost comes (if you want to). Those cheap fixed rate FMU's you buy off eBay will give the problems you stated.

They do work, and can work very well.

 

So the ACCEL Gen 7 with wideband 02 sensor and harness would be a pretty complete setup, right?

 

I was working with a vortech fmu. Why not just get bigger injectors instead of using thw fmu as a crutch.

 

They all work (there’s only 2 different designs out there that I know of, the rest of the differences between FMU’s is cosmetic), its just up to your ability to tune for conditions and equipment.

As far as this thread goes, it’s largely up to your creativity and resources. Look at BBS’s setup, he just used a fuel solenoid and fogger from an N2O setup that opened when he reached a set boost level. It’s sort of a brute force approach, but it did work, and worked well.

 

I messed with a 730 ECM with AUJP code (stock 1992 TPI Camaro) and 42#/hr injectors in my car when I did my first boost app.
What I found was that the 730 ECM with AUJP code (1-bar) MAP, the ECM would run the engine lean when not is PE (power enrich) mode but the engine was under boost.

I would like to hear stories about anyone pulling a long hill with a stock ECM that is non-boost at about 40% throttle and about 6psi of boost.

An FMU is fine, just tune the ECM VE tables for use with the FMU. 89JYTurbo is running MAF from the sounds of it. And it is maxed out in terms of airflow. Basically, the ECM is blind to how much fuel to add, the FMU adds the extra fuel. The FMU is actually better with a stock non-boost ECM than installing injectors. The FMU will increase fuel with boost. Just using big injectors will be held at some max value once the ECM tables are maxxed out.
Anyway, use a boost ECM for boosted apps. if you are trying to squeeze out max HP. Using a non-boost ECM will brobably get you about 90% of max HP. Either you will be rich at low boost or lean at high boost. These are just estimates for the average tuner. Your actual results may vary.

 

So there's no aftermarket MAF system that can handle high CFM's?

Is the Accel Gen VII a MAP system?

How do MAP systems know when the turbo is on? Do they react that fast to the wideband O2 sensor?

 

It is not a question of ECM for you. You need to find if there is a MAF that will read that amount of CFM you have planned.

MAP systems know when "boost is on" by detecting that the intake pressure is greater than 14.7psi (free air). Just the same as a pressure gauge works for filling a tire. The ECM uses the pressure, air temp, and other stuff to figure out CFM.

React that fast? How fast is fast?
The MAP reacts to the turbo boost pressure(more pressure), not the O2 reading. A MAF reacts to turbo boost pressure (more air), not the O2 reading. The ECM reacts to the O2 reading and the MAF (or MAP) reading.

 

What about a FMU with Bigger injectors ? Change the constant in the .bin .....and let the FMU take over when the boost comes on ? I am runnnig the MAF setup aswell and was getting an FMU ( for starters) .

Would this solve the issue of useing the FMU as a crutch ?

 

Im happy with my 749ecm. My car has great drivability, gas mileage, and it was cheap. I drive my car to the drag strip(60miles) run 10's and drive back home. And get 22-25 mpg on the highway. Cant ask for anything else.

 

The 749ECM is a good choice.

 

Impressive results for sure. How difficult was the tuning aspect of things? I don't think I would be as worried about the WOT mapping, but the idle/part throttle/cold start and other fine points I think could be a challenge for me to get perfect. I like using FMU's because they have worked well for me and are easy to use. I have no experience with ECM tuning.

I suggested an FMU because, from reading his posts, it seemed like the original poster was a beginner to turbocharging, and the FMU is a little less complicated to get up and going because it does not effect part throttle drivability.

But you probably won't get into the 10's with one.

 

I am using a 730 ECM with the 749 code in it (essentially a 749 with high impedance-TPI/Mustang type injectors). I went with ford 42#/hr injectors. They are harder to tune at idle than stockish sized injectors. Part throttle tuning isn't that bad. I use the BLMs and a little help from a WB-O2. All WOT is done using the WB-O2.
For a beginner, I would go the FMU route and think about ECM changes later. I don't see why you couldn't get 10's with an FMU and timing retard box. Quarter mile is mainly WOT, so if the FMU is supply enough fuel and timing is reduced than there is really no difference from what an ECM would do (I think).
I would say the biggest thing is tuning WOT with a WB-O2 whether an FMU or ECM is used. Not making the most HP possible (best AFR) is really the only thing that will limit the ET.

 

I think you may have trouble getting into the 10's while using an FMU with stock sized injectors. An FMU is really limited to about 10psi of boost because at that point (depending on your FMU ratio and base fuel pressure), the fuel rail pressure will be in the area of 120psi. I have measured 120psi FP on myturbo Z24 at 10psi boost. You can probably stage your fuel pumps and run even higher, but at what point would the injector solenoids be unable to open against the pressure in the rail? I haven't experienced injector stall on my Z24 with 120psi, nut I would think they are going to be overpowered at some point.

Not saying it couldn't be done, but you need a lot of fuel to go 10's with a 3500# car, and stock injectors will need to work at very high fuel pressures to make it happen.

 

Yeah, I don't see 10's possible with stock injectors. I meant an FMU with 30#/hr or 36#/hr injectors. It would retain stock ECM with just a simple injector constant change. Not a complete ECM/code change. I think the stock 24#/hr with FMU are probably for about 450HP. Approx. very low 12's in a 3500# vehicle.
120psi sounds high. I have heard that some injectors fail to open at too high fuel psi. It is also harder on fuel pumps, but how often is the fuel pump really pushing that hard anyway. I would keep using it if it has been working fine.

 

So , what about 36lb injectors and and FMU with a 165 . Would that work ? Don't want to wash down the cylinder walls ....but don't want it to be lean up top ?

 

It was actually pretty easy. I am no computer wizz, and i did it. I used tunercat. I started with the stock syclone burn and did some very minor changes to tell you the truth. I made changes for the bigger injectors and cam, but i guess a syclone fuel map is pretty close to a turbo tpi setup. I was amazed how good it ran the first time out. Non-WOT driving is great. The only thing is when it isnt warmed up and in open loop. It runs rich. But once it warms up and the ecm reads the o2 sensor (closed loop) it runs fine. Usually right about 14:1 AFR. Then about 11-11.5 AFR at WOT.

 

I'm surprised no one mentioned Megasquirt. www.msefi.com -- it'll handle a turbo setup just fine. There is no completely self-learning ECU. They all need to be tuned manually when bigger changes are made to the engine.

-Dave

 

Yeah, I got an MS-II on the shelf. I didn't get a chance to try it on the Camaro this year. I will give it a try in the spring after I get the 749 code straightened out.
The only problem with the Megasquirt is that it is I/O limited. Once you use up the IAC pins there ain't much left.

J

 

Ok, I see what you meant. I'm under the impression that you run an FMU so you don't have to toy with the ECM at all. As far as the power estimates you gave (450hp/low 12's), that seems to be about correct judging by my results. I dynoed 328RWHP and 467RWTQ, with a best ET of 12.46 at 113 (hot air, drag radilas), best trap of 12.8 at 117mph (cold day, street tires) with 6psi of boost. I ran 24# SVO injectors, which are larger than the stock (IIRC, stock ones in my 890 were 22#). Using stock ECM and PROM, blowing through the MAF.



I've heard that as well. The install info included with Cartech FMU's seems to suggest it is just a myth. I have had no trouble with injecotor lock. My z24 runs the 120psi, my IROC is a more reasonable ~90psi.

 

Depends on the injector design from what I've read.
Multecs (disc type) are the ones that have the problem I believe.
The stock needle style are less susceptible by design.

 

I just buy a Fast XFI last week whit intake, fuel pump, trottle body, injector etc.., should receive all this this week !

Converting to Efi is a 5000$ thing,
Aftermarket is the way to go,
info on Efi:

http://hotrod.com/howto/113_0504_efi/


XFI :
http://www.fuelairspark.com/Products...mation/xfi.asp

Also look ;

Accel, Big Stuff, AEM, Electromotive, EFI Tech, Motec


Stock efi is damn a pain in ***...!!!

 

After a couple of weeks of reading about switching to the $58 bin and rewiring like the cyclone setup, I've decided MegaSquirt-II is the way to go. It's got everything now including ignition control, and can handle up to 20lbs of boost. Also incorporates the wideband O2 no problem. The only thing it doesn't have is a knock sensor. Pretty cool for less than $300.

 

[QUOTE]Originally posted by x007

Converting to Efi is a 5000$ thing,
Aftermarket is the way to go,
info on Efi:

[url]

I guess if you have a spare $5K lying around. My carbed 355ci was converted to EFI twin turbo for $900+$2000 = $2900

Everyone likes different stuff. I am running all OEM parts except for the camshaft. That is, OEM chevy motor with the help of OEM Nissan turbos. Go with what ever works for ya.

Still haven't assembled that MS-II yet. I have to give the 730 with $58 code a fair chance. For me right now, the only advantage I gain with the MS-II is the alternate fire injector that would help at idle with my cheapy injectors. I have approx. 1.5ms PWs and 3.0ms would be a lot better.

I think the MS-II would be a great setup on a carbed vehicle. You get spark control & WB-O2 reading for less than aftermarket stuff.
Being able to record engine data is priceless.

 

[QUOTE]Originally posted by junkcltr

Quote:

Originally posted by x007

Converting to Efi is a 5000$ thing,
Aftermarket is the way to go,
info on Efi:

[url]

I guess if you have a spare $5K lying around. My carbed 355ci was converted to EFI twin turbo for $900+$2000 = $2900

Everyone likes different stuff. I am running all OEM parts except for the camshaft. That is, OEM chevy motor with the help of OEM Nissan turbos. Go with what ever works for ya.

You right , But i always look for the best..
Here is my setup whit the XFI ;

 

???? The best would be polished. Very nice setup though. Does that Vic JR EFI idle better with the injectors than a carb setup?

 

I have no time this winter to polish the intake, its a lot of work...
as for my Idle, I have a smoth idle at 800-850rpm whit my 950cfm Holley Pro (4 corner idle) & a Victor Intake,

So i dont think i will have lot better whit the Efi, btw this is a sequantial Efi (needed for a better idle & huge size of the injector i use), my setup is not finished yet .. still working on my car, i currently rewire the entire car, install the Efi & build a custom Dash (alum.).. So have some work for the rest of the winter.

 

Maybe a little late. www.massfloefi.com 1) no tuning (other than injector size. 2) Plug & Pray 3) Off the shelf parts. According to their web site and some of the car mags. I personaly don't know how well it works; but interested other than price. I'm still thinking bout carbs ,tho!!!