Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 30 of 32 FirstFirst ... 202526272829303132 LastLast
Results 436 to 450 of 479

Thread: DIY LTCC or similar system for LT1s

  1. #436
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    50
    Posts
    3,219
    Diesels with throttle bodies? Sounds like you've been inhaling too much of that naptha. They're referred to as anti-shudder valves.
    Ummm... I will not speak for the VW but I will testify that we have two LML Duramax diesels in our fleet which use electronic throttle bodies as throttle bodies.

  2. #437
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    From what I've read the butterfly valve on the newer diesels is modulated by the ecu to control EGT and EGR for emissions. I believe it may be a way of controlling the DPF burn-off. As far as I can discern from what google finds on the subject it's still not a torque management device. That would mean injection quantity and timing are still the direct torque control mechanisms, just like all older "dirty" diesels such as mine.

    However, I wouldn't put it past GM to have developed a hybrid diesel ecu system that forces stoich combustion at cruise speed and controls torque with airflow in the name of cleaner emissions. :-(

    The next few days are toast for me as I have a funeral to attend and then we're leaving for the redneck riviera immediately after. I plan to dedicate at least one day next week to work on the controller as I'd really like to get this ironed out. But if the weather is nice and the wife is in a good mood those plans may get scrapped.

  3. #438
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    Well as much as I was hoping to be able to post that all is fixed, well and good, as usual it's not. Read on...

    While in the sunshine state a few weeks ago I was able to pinpoint with the help of the testbench distributor - spinning it up with my fingers no less - a very repeatable problem. I conceived and implemented a fix, as well as eliminating some of my code in favor of taking advantage of one of the arduino built-in libraries (timer0 / millis()) that has never been de-configured in any version of the firmware anyway.

    Concurrently, I've jumped off the sanity cliff and purchased a set of shaft mount rocker arms that has resolved the valvetrain difficulties I've been battling for the last year or better. But not without bringing with them another set of hurdles (valve cover clearance, band-aids for said clearance, accompanying oil leaks). Nothing is ever easy.

    Finally this afternoon I was able to make a short test drive with the two week old fixes. While I say in the opening sentence that all is not well, this is by leaps and bounds the most driveable rendition of the controller firmware thus far. As I state that, bear in mind that since the last time I made full throttle passes with the controller it has moved from being housed in a breadboard duct-taped to the windshield to a pcb. Also, I've increased displacement with a stroker crank as well as adding the shaft mounted rocker arms. Many of these items have both added considerable SOTP effect as well as other possible pitfalls.

    With all that in consideration, I must say the car in the current incarnation wants to snap me back into the seat like nothing I've ever experienced. That's not quite as boastful a statement as it might seem since my current daily driver is rated by the manufacturer at a whopping 90 hp, and is showing nearly 500k miles on it's odometer. But, as well as my SOTP sensor can recall, the car has never been this eager to accelerate. I've gone from having a pronounced stumble that occurred in distinct RPM bands and closely resembled a rev limiter, to having a single firing event miss while slowly creeping through that same RPM band. I'm optimistic I can resolve this with further refinements of the code.

    So, I guess my report is that the plan for the next several weeks is to avoid falling into the morass of perfecting my tune, and to instead focus on perfecting the controller firmware. Keep in mind that I've gutted the secondary (high voltage) side of my distributor and taken a diagonal cutters to my harness, removing any easy path to going back to using the optispark as originally conceived. It is also salient that you understand that if I get into the throttle with enthusiasm - pin it's ears back so to speak - that the problem is so unnoticeable that I was reluctant to post any of the slew of preceding words. It wants to rev!

  4. #439
    Fuel Injected! vilefly's Avatar
    Join Date
    Sep 2017
    Age
    49
    Posts
    179
    Very cool. I just am not sure what SOTP means. All this without the aid of an oscilloscope? Impressive.

    I always did wonder if tall valve covers could fit in a vette or not. I bet those shaft rockers were pricey as hell. That probably means you have a new set of custom pushrods, too. Never was sure if you had a rev kit in that thing, either. I suspect the only improvement left is titanium valves and pneumatic springs.

  5. #440
    Fuel Injected! sturgillbd's Avatar
    Join Date
    Jun 2012
    Location
    Big Stone Gap, VA
    Age
    45
    Posts
    482
    SOTP = Seat of the pants .... Butt Dyno

  6. #441
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    I uploaded 0.9.16 to github yesterday. Will post back when I have a chance to start chasing down the last ghost.

    Quote Originally Posted by vilefly View Post
    I always did wonder if tall valve covers could fit in a vette or not.
    I'll reserve my answer to that for the moment I'm satisfied with what I have. I went in with 3/8" spacers that are "glued" to the heads with RTV, and the stock covers sit atop the spacers. I fabricated longer studs so the factory covers and all my coil mounting hardware could be re-used. To the untrained eye they look factory with the exception of the coil packs sitting on them.

    Quote Originally Posted by vilefly View Post
    I bet those shaft rockers were pricey as hell.
    In the grand scheme of things, I would have been money ahead to have bought them in the first place. The Scorpions are several hundred less than the "name brands" and if what I've read is true they make the shaft mount kits for many of the big names.

    Where they set up best, I ended up with a stock length PR. No rev kit.

    I did not expect quite as much of an improvement from the shaft rockers. But longer levers mean less energy needed to open the valves.

  7. #442
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    Quote Originally Posted by vilefly
    I bet those shaft rockers were pricey as hell.
    Quote Originally Posted by spfautsch View Post
    ... I would have been money ahead to have bought them in the first place.
    It may not be obvious to newer readers of the thread but last year I bought a set of Crower rockers with offset drilled trunnions to solve the problem of the roller tips landing towards the outer 1/3 of the valve stem. My net spend there was about $500 after transplanting the trunnions into the far superior Comp chromoly steel rocker bodies and selling the resultant hybrid Crower rockers. So if I knew what I know now I would have gladly spent the ~$950 on these (shaft mount) rockers initially because the Comps were $300 or so to start with, not to mention the price of the ARP 7/16 studs and the large collection of guideplates and pushrods I've purchased along the way. The gain in power is one thing, but when you consider all the other geometry problems the shaft rockers fix such as the lifter centerlines being narrower than the valve stem centers, it's kind of a no-brainer.

    After closer inspection of my old rocker arms and studs, I think my valvetrain noise might have been the rocker bodies on one or more cylinders contacting the studs at full lift. This only happened after reaching full operating temp so I would guess I could have fixed it with 0.050" shorter pushrods, or clearancing the rocker bodies slightly to allow for more gross lift. With that said, knowing what I know now if I ever build another Gen2 LT-1 (or any other SBC for that matter) the first item on my shopping list would be Scorpion shaft mount rockers.

  8. #443
    Fuel Injected! vilefly's Avatar
    Join Date
    Sep 2017
    Age
    49
    Posts
    179
    These are on sale at speedway motors. Tall, aluminum powdercoated black centerbolt valve covers by holley.
    https://www.speedwaymotors.com/Holle...ck,377269.html

    Not that you haven't spent enough money, heh.
    BTW, what rocker arm ratio did you settle on?

  9. #444
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    If I can't get the factory covers to seal I may look into those - that's a good price. But I'd still have to do some fab work on the covers for the alternator bearing and likely a whole new stiffener bracket to clear the center peak. Not to mention different arrangements for coil brackets. As much as I hate them being plastic, I really like way the factory covers fit. And no-one I'm going to run into will ever believe I have shaft mount rockers under them. :-)

    I didn't want to push my luck on lift, so stuck with 1.6 but could have made 1.7s work albeit with less optimal geometry. The other discouraging factor is that prices go up with ratio.

  10. #445
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    I think my oil leaks are finally resolved. Drove it for approx 15 minutes tonight with no blue smoke puffing off the headers!

    Oil pump has been swapped out and I'm sleeping better knowing that pressure drops to 40 psi at idle once the oil is hot. Before with the high volume pump it never dropped much below 58 and when revved lightly would easily flirt with 80 psi. I was deathly afraid of pushing it past 4000 rpm for fear of exploding the oil filter or finding the tensile strength of the non-bypass billet oil filter adapter.

    I hope to have time to test more extensively tomorrow. All that's left is to get the wheels aligned and assuming no surprise oil leaks spring up I can drive it enough to actually make some progress!

  11. #446
    Fuel Injected! vilefly's Avatar
    Join Date
    Sep 2017
    Age
    49
    Posts
    179
    Don't forget to tape a $1 bill to the dash.

  12. #447
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    I'm not sure I get the dollar bill joke but then I doubt you're factoring in the corvette tax so it's more like tape a hundy to the dash and hope they leave you a $20 in change.

    Funny story (for anyone who doesn't own a C4 corvette). Turns out we have special 20" wiper blades. Since mine was due for it's bi-annual safety inspection this spring, and the rubber was in bad shape I went to my least favorite store in the world (WM) and bought the cheapest pair of wiper blades they had. I don't drive in in bad weather so wtf do I care right? Installed them when I got home and foolishly chucked the old ones in the trash. A few days after the trash was picked up I notice the hood is a bit harder to close. Turns out the factory wiper blades are special low profile numbers that are only made by a repop company for $20 apiece plus shipping. Joy.

    With the oil leaks staunched, I got to hammer at it pretty good tonight. But it wanted another 5 hours of my labor before it would surrender. I noticed last night that my volt meter was dropping really low at times and then if I'd jab the throttle or brake sometimes it would jump back up. I figured the problem was the alternator wasn't getting a good ground because I hadn't finished fabricating the bracket extension required after raising it up 3/8". So several sweaty hours of shop time later with the bracket extension installed and 100% functional the same thing is happening. Turns out the charging stud was loose in the alternator. A quick alternator disassembly fixed her all up.

    Anyway, I'm finally working on the controller firmware again. I feel like I might have underplayed the significance of the remaining problem, but I doubt anyone with a stock-ish LT-1 would notice. I have yet to break out logging tools but the "hiccup" is happening right at 2000 rpm as indicated on my dash tach. This is right at the sweet spot where I tend to cruise around, so I gotta fix this b/c it's driving me insane.

    On the other side of that coin, I made a few passes in second gear where I applied liberal throttle angle. I noticed no "hiccups" because I flashed through the 2000RPM range so quickly there wasn't time. I wish I had my performance computer project finished because I went from a rolling start in 2nd to ~75mph in what seemed like a very brief time. I didn't bother shifting into 3rd because I can't afford to have my attorney fix a ticket for doing 110 in a 45.

  13. #448
    Fuel Injected! vilefly's Avatar
    Join Date
    Sep 2017
    Age
    49
    Posts
    179
    The dollar bill is for anyone who can touch it ........while you are accelerating. "Go ahead, you touch it, you keep it." VAWMMMP! "Whasamatter? Can't touch it?" VAWMMP! "Stop hitting yourself!"

    I just wish it would stop raining like mad so I can get something done on my days off.

    Well, could be worse. You could be stoned, barreling through the desert in a convertible with the top down, dodging invisible bats and manta rays all swooping and diving around you. "Just one toke, you poor fool? Wait till you see those bats!" "Lets give that guy a lift." "What? No! We can't stop here! This is bat country!" <fear and loathing in Las Vegas>

  14. #449
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    Wanted to drop in with an update. I won't say it's 100% resolved, but after doing a bit of debugging via the serial port I found that it all but disappeared when I disabled all the uart traffic. This is baffling, but I can't argue with results. As slowly as I could accelerate through the "problem" RPM band I'm just barely able to perceive the slightest intermittent weak fire.

    My plan is to remove everything related to logging the controller during normal use from the current code. I hope to have that tested and uploaded to github in a day or two. If nothing else changes I hope to drive it to work one day this week weather permitting.

  15. #450
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    451
    Version 0.9.17 uploaded to github (link)

    This seems to run identically to the version I reported on in the previous post according to my butt dyno. I'm going to do a bit of tuning and test in open loop because I can't tell if what I'm feeling is ignition related or a spot of cam surge. It seems to be happening at slightly lower revs than the stuff that was obviously ignition related, and I've historically had a small bit of surge at this RPM in the past (long before this thread).

    As long as the valve covers stay dry I plan on driving it about 120 miles this Friday. Fingers crossed I won't need a tow truck or my fire extinguisher.

    Edit: Barring any new developments after a long drive I'm thinking this is going to be beta 1 - the obvious subtext here is the need for testers.

Similar Threads

  1. Which TBI system is better?
    By KeyAir in forum GM EFI Systems
    Replies: 41
    Last Post: 05-13-2019, 11:39 AM
  2. Hard start 93 LT1 with LTCC Ignition Mod
    By beestoys in forum GM EFI Systems
    Replies: 0
    Last Post: 05-17-2015, 10:58 PM
  3. ABS system?
    By K1500ss4x4 in forum Gear Heads
    Replies: 3
    Last Post: 02-05-2014, 08:21 PM
  4. Vortec EGR System?
    By EagleMark in forum OBDII Tuning
    Replies: 40
    Last Post: 06-02-2013, 12:07 PM
  5. Quicker way to do Spark Hook test on the street for LT1s and others?
    By sherlock9c1 in forum Fuel Injection Writeups Articles and How to New and Old
    Replies: 15
    Last Post: 03-02-2013, 03:52 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
  •