Page 2 of 7 FirstFirst 1234567 LastLast
Results 16 to 30 of 99

Thread: 87 Corvette single turbo tuning

  1. #16
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by 63LT1Vette View Post
    Dave, the dynamic efi looks to be what I wanting to do, But even it reads like I need to change to an 7727 ecm?

    BTY I really appreciate you guys for the help.
    The 1227727 and 1227730 have identical electronics. The 1227727 is an underhood version of the 1227730. Both 1227727 and 1227730 can be upgraded by Dynamic EFI. I've copied pasted a special note about the 1227727 from the Dynamic website, " Important note for '7727 & '8260 ECM users (under hood version). When ordering let us know that you are using the under hood version of the ECM. A different comm connector cable will be supplied. This is due to the unavailability of the ECM harness terminals. Along with the actual connector shells not having the terminal locations molded for them."

    The connectors for the 1227727 can be challenging to find. It might be easier / less expensive to use a 1227730.

    There are "Pro's / Con's" to either system Dynamic EFI vs. $12P. The decision on which system to use is ultimately yours.

    dave w

  2. #17
    Super Moderator Six_Shooter's Avatar
    Join Date
    Feb 2011
    Posts
    2,968
    The '7730 is can easily be used with boost. Just use $58, or $59 and you're good to go. $8F can also be used, but it's less supported and in my experience less capable than $58 or $59.

    Since you have the '165 it wouldn't make much sense to the '7727, it would make more sense to use a '7730 (or other replacement service numbers), since both the '165 and '773 are under dash versions. The '7727 is physically larger than the '7730 even though the circuit design is the same due to the weatherproofing of the case and cane be difficult to install in an under dash application.

    My order of preference for this would be:

    -Keep the '165 and use $12P
    -Swap to the '7730 and use $58 or $59
    -Look at other alternatives, such as the EBL, or even a non-GM based system.

    My order is based mostly on cost and portability. Using unmodified GM hardware means that if there's an issue with the hardware (which in my experience is rare), you can replace it easily anywhere, since it'll all plug in and work. You can also keep the costs down for the actual tuning. Going "all out" and adding an emulator to tune the GM ECMs in real time is still cheaper than any alternative I have found. Yes, it takes a bit more research and knowledge to know exactly how to set up a strictly GM based EFI system in an application it wasn't intended for, but for me, that's part of the fun.

    I like the idea of the EBL, and it's flexibility out of the box, but the price of entry is high and you can only use the EBL on one vehicle, where as the method I choose I can use the same hardware on multiple vehicles, I just need to make sure I have a PROM (and MEMCAL adapter) for the vehicles I'm not tuning at that moment. To me the EBL and some other systems are geared more towards people that want to tune their own vehicles, but don't really want to understand the tuning process in depth or get into it as much as some of us, and there's nothing wrong with that. There are other aspects in my life where I'd be the same way, chose a product that makes it easier and less time consuming for me to get something done than the "hardcore guys". ;)
    The man who says something is impossible, is usually interrupted by the man doing it.

  3. #18
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    I'm thinking I want to try the 165 and $12P as it is here and running now, I also have two back ups in case I let the smoke out of it. Sooooo ok, Lets get started. LOL

  4. #19
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    what is the reason that no one likes to use the MAF for the turbo engines? I think that the 89 Turbo trans am's were a MAF system correct? if it is a flow problem couldn't a person change to the lager LT1 MAF?

  5. #20
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    Well over the weekend I continued to tweak the turbo install and got everything finished, the car starts and runs very well in the shop, it rained all weekend so I wasn't able to do a road test. I still haven't ran down why the fan is running with the engine, and no one has a reason to change to SD vs MAF. Tuning to begin using TunerPro today. Going to stay with the 165 to start with but keeping an open mind for the future. Going to try and make the MAF work first.

  6. #21
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by 63LT1Vette View Post
    no one has a reason to change to SD vs MAF. Tuning to begin using TunerPro today. Going to stay with the 165 to start with but keeping an open mind for the future. Going to try and make the MAF work first.
    I wonder, will the Turbo produce more than 256 grams / seconds?

    dave w

  7. #22
    Super Moderator Six_Shooter's Avatar
    Join Date
    Feb 2011
    Posts
    2,968
    There are more drawbacks to a MAF based turbo system than positives, from the vehicles I've been involved with.

    Some people find that placing the MAF between the turbo and the intake makes for better idle and driveability, but will usually max out the MAF quickly. This requires a larger MAF that can make idle tuning a bit difficult, and so you get on a cycle of finding the right MAF.

    A MAP based system has no actual flow limits, and while it may be a little less forgiving of mild modifications, it seems to produce the best results in teh end.
    The man who says something is impossible, is usually interrupted by the man doing it.

  8. #23
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,847
    what is the reason that no one likes to use the MAF for the turbo engines?
    I've done MAF with supercharger and stock sensor in the 165. It can work because there is a linear relationship between rpm and boost that can be correlated to a specific throttle angle. PE mode can be set to engage at a specific rpm and throttle opening with ever richer AFR and decreasing spark advance. The values are corrected by repeated review of datalogs and WBO2 readings. But a turbo is load based. As airflow exceeds the ecm/sensor's limits the MAF system with small sensor makes it nearly impossible to match AFR and spark with only the PE settings. 2500 rpm downhill at 40% throttle will not have the same load as 2500 rpm uphill and 40% throttle. So if the MAF is already reading maximum airflow, how does one adjust the timing and fuel delivery?

    I think that the 89 Turbo trans am's were a MAF system correct?
    They were. They use roughly the same powertrain as as Buick GN (minus the 8.5" rear diff). http://www.superchevy.com/features/0...turbo-feature/
    When using a stock MAF the GN crowd attempts to tune the system so it performs correctly even as power production exceeds system design. The GN's 148 ecm measures a max of 255 grams of air per second just like the Vette 165. There are plenty of tricks to get around this. Put the sensor in a larger tube so it doesn't read all the air. Use increasing fuel pressure to match fuel delivery to manifold pressure. They'll increase the spread between max and min integrator and BLM values to try and get better street manners. Use WOT PE Mode variables to reduce timing as rpm increases. Ultimately they're still playing the same game. They're primarily trying to use ecm variables designed for WOT and open loop fueling to cover the system's inability to accurately measure airflow. It was a big deal when guys figured out how to use the Syclone ecm with 3 BAR MAP on the 3.8 Buick turbo engine.

    if it is a flow problem couldn't a person change to the lager LT1 MAF?
    Yes. The Delco MAF sensor used on the GN and on your car produces a varying voltage output based on airflow. The LT1 / LS1 MAF sensors produce a varying frequency signal based on airflow. There is a device called a "maf translator" to convert the frequency signal from the LT/LS sensor to a voltage signal for the 148 / 165 ecm.

    Much is different in code between the NA 165 and the turbo equipped cars. GM worked to include driveability and emissions controls into the turbo applications that are not in the NA code. You may get the car running well enough to claim victory but if you decide to make changes, SD would be the way to go. Unfortunately $58 from the Syclone has a few code issues related to V8 applications but they can be overcome. I *believe* $59 does not have those limits.

    I've never tried a $12 Aussie code swap. Last time I was in a position to do it there was only a rough definition file available, no scantool support here, and few in the US even knew it existed. With the support today I'd probably give it a go.

  9. #24
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    I have already had to work on the Idle from modifications before the turbo, Right now with the tune that I had before the turbo it Idles very well. the biggest thing now is when I let off of the throttle it will die. meaning that if I just hit the throttle it revs up nice but when the throttle is closed it comes down and dies. My current configuration is that the MAF is directly in front of the turbo inlet. I have been told that I need to have the BOV exhaust back into the intake track behind the MAF, so that the engine doesn't blow off air that the MAF has already measured. I haven't been able to street test yet because of the weather this is just from sitting in the shop. Hope to road test today.

  10. #25
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    Thanks 1project2many (LOL that sounds like me) Previously I was having a friend burn chips for me for this car but with everything I'm doing to it now I have ordered everything to do it myself, I think I had wore out our relationship previously anyway LOL. So with that said I had already started to look at all of the $12 stuff, just get familiar with it. I'm not afraid to go to SD I just wanted to make sure it is what I wanted to do. I am performance based not easy based so I want to go the right way from the start.

  11. #26
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    Quote Originally Posted by dave w View Post
    I wonder, will the Turbo produce more than 256 grams / seconds?

    dave w
    some quick calculations of my setup are:
    engine is 355ci, Max rpm of 6500.
    10psi of boost is 56.8 lbs/min =.946 lbs/sec = 429.09 gr/sec
    15psi of boost is 63.7 lbs/min = 1.06 lbs/sec = 480.81 gr/sec
    18psi of boost is 67.7 lbs/min = 1.12 lbs/sec = 508.02 gr/sec

    So if my numbers are correct the I am wasting my time with the MAF and should concentrate on going speed density.

  12. #27
    Super Moderator Six_Shooter's Avatar
    Join Date
    Feb 2011
    Posts
    2,968
    Yes, or find a MAF sensor that will work that supports the flow you have as a target.

    I'd go SD personally.
    The man who says something is impossible, is usually interrupted by the man doing it.

  13. #28
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by 63LT1Vette View Post
    some quick calculations of my setup are:
    engine is 355ci, Max rpm of 6500.
    10psi of boost is 56.8 lbs/min =.946 lbs/sec = 429.09 gr/sec
    15psi of boost is 63.7 lbs/min = 1.06 lbs/sec = 480.81 gr/sec
    18psi of boost is 67.7 lbs/min = 1.12 lbs/sec = 508.02 gr/sec

    So if my numbers are correct the I am wasting my time with the MAF and should concentrate on going speed density.
    The math and logic look sound to me. Out west ... some say you can't put 10 gallons in the 5 gallon hat.

    dave w

  14. #29
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,847
    I have found that it's fairly easy to exceed flow of the stock MAF with even an NA engine. I think you're realizing there's a faster path to a good combination.

  15. #30
    Fuel Injected!
    Join Date
    Dec 2013
    Location
    DeRidder La.
    Posts
    61
    Thanks Dave for that flow map, It helps to know what I up against.

Similar Threads

  1. My $59 problems/tuning a turbo camaro
    By fasteddi in forum GM EFI Systems
    Replies: 589
    Last Post: 09-23-2015, 11:01 PM
  2. Help with tuning an unusual turbo tbi project.
    By scottyd in forum GM EFI Systems
    Replies: 18
    Last Post: 12-13-2014, 12:53 AM
  3. 98 Corvette M6 JET DST TUNING FILE
    By johnny in forum TunerCat OBDII
    Replies: 10
    Last Post: 03-22-2014, 05:27 AM
  4. turbo lt1 tuning advice needed
    By supr67 in forum OBDII Tuning
    Replies: 4
    Last Post: 02-14-2014, 01:46 AM
  5. 2014 Corvette E92 Controller tuning started!
    By EagleMark in forum OBDII Tuning
    Replies: 4
    Last Post: 11-10-2013, 10:46 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •