well ecu's all linked up bar map sensor just sorting that now.grams/sec is reading off due to LS1 maf on a smaller v6 maf calibration untill my smaller maf turns up.needs more vacums just doesnt pull enough air yet which i knew would happen with only one vac
hope everone has a safe and prosperes labor day, and don't forget do a lot of good cooking, cooking seamse to get my mind off of a lot that goes on every day.
Holy crap! I was a mechanic for a total of 16 years, owned various cars, trucks, motorcycles, and thought I new a thing or two bout them. I've recently found myself in a position where I have more cool stuff than ever before, and 2 projects going that are kind of affecting each other. Due to this it has caused me to do more planning and critical thinking on exactly what I want out of the end result of each project, which has lead me to doing a ton of research. I have probably been reading forums and articles for about 3-4 hours a day for the last week or so. There is so much to take in, and so much that I didn't know. I suddenly feel like I am light years behind in the high performance world and really never knew a dang thing. The bad thing is I don't think I'm any closer to a decision on either project today than I was a week ago, except for knowing what I want my end horsepower to be on each project, which I knew that before I started. LOL. Just a rant really, sometimes it's good to vent this stuff.
... so what kind if EFI system are you thinking of for your projects?Originally Posted by 77bird
dave w
Well, I already have a Holley Projection 4 twin tbi set up on my 327 in my bird that I have had a lot of problems with. That was what initially atrracted me to gearhead efi. I was originally thinking that I just needed a better contol system on it but I have come to realize that I may actually be having so many problems with it because my 327 is theoretically already running near the maximum horsepower that the sytem can support. The motor is currently estimated to be coming in somewhere between 500 and 600 horsepower, and since the system I have maxes out at 550 hp, (which I'm sure is slightly overated by Holley) I think that may be a large part of the issue, set aside the fact that the old analog controller is just flat out old out dated technology. So I'm considering putting that system onto a more mild small block for my wifes 62 skylark but will definitely still be wanting to set it up on a gm pcm but I really still don't have any clue where to begin with that project. As for my car I'm seriously considering a fresh small block in the 350 to 400 cid range with a projected boosted (twin turbo) hp range upwards of 750 hp. Any recomendations on an injection system for that type of set up? Would a tpi set up be at all pheasable?
I think a stock TPI system would be OK for about 300 HP, and a modified TPI would be OK for about 400 HP. The TPI system is designed for low to mid range RPM performance.
I don't have a specific recommendation for an EFI system that would support more than 2 HP per cubic inch. I would take a close look at maybe using the LS computer, 24x system with coil per cylinder? Hardware wise, I would take a close look at a single plane intake that provides port fuel injection system with the ability to flow 1000 CFM.
The option of a LS engine is worth considering also. The $$$ per HP with a LS engine is worth looking at?
dave w
That is all definitely very good information. I had no idea that a tpi was so limited. LS is definitely a direction I have been considering. What about a gm ecm to control the old holley twin tbi set up? I'm thinking I'd be building an engine for it to go on that was more in the 400 to 450 hp range. Is there an ecm you'd recommend? Would it need IAC? Would you recommend wideband or narrowband o2? It is on a pro dominator tunnel ram if that makes any difference. I appreciate your interest and advice.
The GM 16197427 (aka '7427) TBI PCM is really the only good choice for the Holley system you currently have. The '7427 PCM uses narrow band O2. With some minor modifications the '7427 can be tuned for Open Loop using a WBO2. I was thinking the Holley system you have uses a GM type IAC?
dave w
No currently it has no IAC, I would have to add it. The throttle bodies do have the castings for where it would have gone however the TPS is in the way of it on the front throttle body. I don't think it would be to hard to add to the rear throttle body but would it work to only run one in the rear or will I need 2 of them since I have 2 throttle bodies? Also does the ecm have to be modified to be able to run the 4 injectors as opposed to the 2 injectors that the 7747 is set up for?
Maybe you can post a picture of your throttle bodies? Only one IAC would be needed. The injectors impedance (ohms) will need to be measured to see if the '7427 can handle the current draw of 4 injectors.
dave w
Maybe this is a dumb question but what good would it do to run a wide band o2 in open loop? Isnt the whole point behind going wideband to give more precise and faster reacting control of the system to the ecm? Just seems to me like if one was going to run it in open loop then a guy might as well just delete the o2 from the ecm all together and maybe install a gauge with wideband o2 to manually monitor it. Please understand I'm very new to all of this and really only have experience with factory systems.
IMG_0135.jpgHere is a pic I have stored on my computer. Let me know if you can't see enough of what your looking for and I'll try to get some better pics tomorrow. I will ohm the injectors tomorrow as well. From what I have talked to Holley it sound like these are pretty standard throttle bodies they used with 80 pph injectors.
For a '7427 TBI engine making at or less than 1 HP per cubic inch the narrow band works well for closed loop. When a '7427 TBI engine is exceeding 1 HP per cubic, the narrow band closed loop is not as effective. The tuning process for the '7427 is the same for both narrow band or WBO2, data is recorded and the fuel table rich / lean conditions are corrected. When the '7427 TBI engine is properly WBO2 tuned, the fuel table will provide the correct AFR's for both normal driving and performance driving.
I don't mean to cause confusion. The '7427 is a very popular PCM. Many people have donated hours and hours of their time ( hacking / reverse engineering) to provide features into the '7427 PCM, that only expensive aftermarket EFI computers have. One of the features that can be added to the '7427 is getting the WBO2 AFR's into the data log in real time. The WBO2 does not control or adjust the fuel to the injectors, the '7427 fuel table settings control the fuel to the injectors. The real time WBO2 AFR's are used correct the fuel tables so open loop will provide the correct amount of fuel to the engine.
dave w
Ok I think that is starting to make sense to me. I'm still a liitle confused though, so when the switch is made to WBO2 is a person then only using the O2 data for data logging and then making program adjustments to fuel tables based on that and that is the end of it? Or will a person data log it, make program adjustments, and then will the ecm will make real time adjustments based on WBO2 data it is receiving? Not trying to beat this dead just want to make sure I am understanding it completely. I really appreciate all the time your taking to answer my questions. As I'm sure you've already noticed I have a very very long way to go with a lot to learn.
Did you happen to see the picture? Any initial thoughts from looking at it? Anything that you see as being a problem right off?
There is not a switch to WBO2. The WBO2 is an optional feature that someone figured out for the '7427. The WBO2 information does not control the fuel in the '7427.
The "Tuner" (a person) will make changes to the '7427 fuel tables. The information from the WBO2 can be configured to be in the '7427 data log (recorded engine information when the vehicle was test driven). The data log contains information like, RPM, MAP, TPS, IAC, BLM, INT, and dozens of other parameters.
I saw the picture. I think a good plan would be replace the rear throttle body with a throttle body that has an IAC, (maybe a used Holley Throttle Body) I also think it would be a good plan to upgrade to the new style Holley TBI injectors.
dave w
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