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Showing content with the highest reputation on 07/29/2021 in all areas

  1. Yay! Another LT4! Tons of suggestions routes you could take. The main one I'd suggest; find someone that will trade you for their '90-'91 manual car + cash. You'll have a better starting point and you can throw the money towards the build. Mainly, you can't lose points and without doing an engine swap, you're going to be at 550points. More info below: Points: If you're serious about getting it under the 500points, you need to find an L98 from an '88-'91 Vette and do the complete swap (ECU/Harness/ETC); it will be the tuned port motor w/ Al heads. Declare it as a '91 and you'll be at 450 points. You can sell the LT4 in there for decent money; keep the harness intact and with the computer, it's worth about $1500-$2500 together depending on the market down there. The LT4 starts at 550 so you're hosed walking through the door. The motors are drag and drop in from a mechanical standpoint, just keep the block mount brackets to attach to the later model C4 K-Member. Cage: Find your tallest driver and build the cage around them. These cars suck getting in and out of with the stock roof line; getting the cage under the roof leaves very little room for "oh poop, I'm upside down and on fire". Transmission: You have what's called a "blue tag". It has a dual mass FW. FW is good for the street, garbage for the track. Try and find a used aftermarket steel FW. Any clutch kit you get, the FW must be for the L98 which I believe has a different balance than the '96 and the throwout bearing for the '96. The blue tags have a smaller diameter input shaft sleeve than the black tags; the TO bearings aren't interchangeable. Carolina Clutch is a good source for reasonably priced clutch kits for these cars. Get the stage 3. Don't do unsprung; harder on the driveline and not worth it. Engine: Again, the LT4 forces you to be a '96 and you walk in the door w/ 550points before you upgrade anything. You can switch to the L98 to enter as a '91 and start at 450points. My suggestion is you spend ALL these points on cooling/oiling, even if you're going further into the hole for the LT4. I know the rules are about to change next year WRT radiators; will have to check how it will impact, but Champion makes a very inexpensive 2 core AL radiator (<$200). Regardless of engine you chose, you're going to want to crack it open, check out the bearings, and do a basic refresh on the motor. At minimum you're going to want to ARP the rods, new bearings, and have the bores cleaned up. Get some ARP head bolts for if you inevitably have to change the heads. The L98s intake/exhaust is horribly limiting; they fall flat around 4500-5000 rpm. They make good torque, but no HP up top. This is actually a GOOD thing for survivability; early shifting. High RPM kills these motors, notably the rods. So it's imperative to keeping it well oiled and well cooled. With that in mind, do a aftermarket radiator and a accusump. One of the reasons the LT4 sucks is it uses the optispark. I have changed this damn things more times than I care to admit. The L98 uses a traditional distributor. Suspension: Obviously rebuild it with new bushings. All manual transmission C4 vettes came with a Dana 44 which is bulletproof for stock HP. More than likely a 3.45 rear ratio. Don't waste your time on cheap wheel bearings, they will only last a single race if that. Moog bearings are pricey but they have 3 year warranties. (Timken only have 1). On the front, you'll need to have someone cut/shave down the spherical washers the upper a-arms mount to get any sort of negative camber, especially once you start cutting weight out of the car. For springs, you'll have to look up the codes but get the absolute stiffest one up front and softest in the rear. Not so much a problem on the '96 but earlier years were horribly oversprung in the ass. Did this once at the track. Every braking zone was a game of chase your tail. Brakes: Upgrade to the C5 kit at minimum up front regardless of the year C4 you land on; stock C4 brakes can't take extended track abuse. I run carbotech X12's in the front with good luck. Stock brakes in back are sufficient and I run XP10's in the rear to prevent lockup. Other: Sell the gauge cluster. It's a one year only unit; the tach goes to 8k vs normal 7k due to the LT4 revving higher. Corvette owners fap over this. Worth about $400. Sell everything else you can in the car interior as well. It all has to come out anyway. Again, the '96 is a good car but honestly, I really think you'd be better off trading/selling it and getting a '90-'91. You can see with all the stuff you'll have to do, it's going to get really expensive really quickly.
    5 points
  2. Yes. You may find that the engine likes slightly over 13:1 AFR.
    3 points
  3. Tune fuel pressure @ wot under load to achieve target afr and let the rest fall wherever it does?
    3 points
  4. Do you need the bellows? Looks like you have room for thermal expansion at the Y, if you make slip joints there. If you have welded the pipe at that point, hopefully you can remove the weld. At the slip joint use tabs and bolts with mechanical interference nuts to keep the slip joint from separating. Design the joint so the slip joint is only 3/4 or so engaged when at rest (room to grow) with bolts set to have minimal slop at this point. FWIW most of the race cars I have seen use slip joints over bellows. On my own cars I have never been able to make the bellows last when mounted near the engine\hot side of the exhaust.
    2 points
  5. Fuel injection connection has a good video displaying what happens to the stock injectors passed 60psi;
    2 points
  6. Great practice race. Jay, Mark, Clinton and I all had our time at the front. I have a newfound respect for the difficulty of staying in P1. Led 23 laps and was really in the mix for about 2/3 the race until I made a mistake in turn 3 that ended with a close encounter with the barrier. 9 cars entered, and somewhere over an hour in there was 1 second between P1 and P3! Crowded at the front.
    2 points
  7. What he said! Points be damned, keep it "his" car If this happens, I can supply a spare set of matching rims from my late brothers vette.
    2 points
  8. That was some solid advice! But... I am going to suggest, contrary to the excellent advice above, if you are want to use this fallen officer's car as a racing memorial, consider eating the points. Let it be the "officer's car". I think the emotional value for people might be greater if it was really "his car" not just a shell with a platform swap. Kinda made me think of the song Riding with Private Malone that was on the radio a lot a few years back. Either way, I think this is a great project and look forward to seeing what you do with it! Ff you haven't already reach out to the 100 Club they might have some good contacts or people interested. Might even be able to get some media coverage, even if you don't have front runner. For example: NASCAR Truck Team Remembers Fallen State Trooper Tyler Edenhofer (sports360az.com) Also that is a great example of using the agency's livery as well. Do you know his badge number? Might be cool to put it on the car. Might be able to get some PR support from the agency itself if you reach out to their PIO.
    2 points
  9. The fuel injection doesn't know what changes you made to the engine, all it does is read the various sensors and command a pulse width based on the programmed fuel map. If a change you made improves the air flow through the engine (eg, better exhaust scavenging), the MAF should read that improvement and adjust the AFR accordingly. The compression ratio change will affect thermal efficiency and improve the engine's output and fuel usage but won't change the commanded AFR.
    2 points
  10. The National Championship standings to include regional standings and the Mazda class championships are located here. https://champcar.org/web/championship.php
    1 point
  11. I am getting close to retirement. I wanted to do something for our Police Brethren who put there lives on the line for us everyday. I, for one, am disturbed by the growing contempt towards these gentlemen for political gains and retribution towards those deemed as the “enemy “. This corvette was owned by police officer killed in the line of duty that lived in my development. He left behind a wife and 3 children. I did not know this man personally, except for the wave and cold drink offered as he patrolled our area. My wife is the HOA President and worked with the Officers wife through the association. She is now faced with raising 3 teenaged children by herself. A handful of us have helped however we can. Obviously selling the Vette was not an easy decision. The cost of upkeep and maintenance of this car just is not possible for her with limited income. I would like to build a tribute car for fallen Officers. I have interest in my area. A local shop has offered to work on the car for free as long as I pay for the parts. I have a cage already donated. Working on other safety items. A local tire shop has offered tires at just above cost. I have an appointment with a local Chevrolet dealership for some sponsorship. There is some issues with the Fallen Officers Fund that needs to be worked out. Hope to hear from them soon on how to move forward. I have no Guarantee on if all will come together. It does seem to be gaining strength. I will need some help with this build. I am not very knowledgeable on the C4 Vette. So…..a few questions for the Forum Jockeys. ANY help will be appreciated. The car is 1996 LT4 ZF 6 speed with the Z51 package. The motor leaks oil from everywhere except the Optispark. The wheel bearings need replaced. All the Bushings need replaced. The electrical system is……..well not as horrid as European models but it’s bad. At idle the Speedometer will go from 0 mph to 4, 5, 3, 6 mph at a stand still. The interior lighting is possessed by demons. Nothing that cannot be overcome. At 540 points it will not be competitive. If someone has a game plan to get this C4 under 500 points let me know how to accomplish this. It will need a road race oil pan at 25 points to live for an entire race. Do I claim the car as an 88? Does anyone make a wiring harness for the C4? I cannot find a stand alone harness for the motor. The serpentine belt system is not very conducive to removing AC or modifications for no points. Suggestions?
    1 point
  12. I agree this part of the rules is outdated, and more than a little confusing. I take it that this part of the rules is to charge points if someone wanted to run a MSD distributor and or ignition box Distributor, non-OE, or aftermarket ignition system: 20 pt But in 2021 why would you ever run a distributor in the first place? The rule regarding coils reads. Ignition coil(s), aftermarket: 10 pt It doesn’t say anything about using coils from a different Chevy engine. The aftermarket ignition system rule is made kind of redundant by the free ECU rule, since even the cheapest modern ECU can run both fuel and ignition. I believe this area of the rules is outdated because nobody has really investigated it for a while, the vast majority of people running in ChampCar today don’t have to worry about distributors or MSD boxes. Seems like an area ripe for a petition.
    1 point
  13. To answer your questions - Harness: Just cut the crap out you don't need from the harness. It's really not that difficult. You'll have to get the ECU tuned to have the stuff like the secondary O2's and the passkey stuff removed. I think the company I used for this was LT1PCMTuning or something of that sort; guys name was Simon. Fairly inexpensive (~$150). The '96 cars use OBII and it takes a special SW to tune it (HPTuners will NOT work). I think it's call Dynamic Spectrum Tuner. The PCM is finicky when getting programmed as in sometimes when you're tuning it will randomly brick itself. You can use the ECU out of a '97 Camaro as a backup. In '96 (and '97 camaro LT1/LT4) the cars came with a crank position sensor. This sensor does not control anything about timing/etc and is only used for diagnostic; it allows the PCM to determine exactly which cylinder has/had a misfire. Brakes: I've had nothing but good luck with the C5. IIRC The C6 Z51 calipers are simply slightly more rigid than the c5 setup so they don't taper the pad as much. Dealers choice. Pinto Dave: Don't listen to a word that man says. He sold me to a bunch of australian pigmies for a nickel one year and it took my 4 months to save up for airfare to get back. Dave is good people; he loaned me an opti one time after my third one crapped out on the track. . . Once you get a good opti, keep it forever. AC Compressor: The bearing is actually separated from the internals; it's a sealed bearing that rests on an outside lip. You'll remove the armature anyway (as well as the internals) so it's not a problem.
    1 point
  14. . . . I have a team mate who can't stop referencing that thing . . That stated, I *think* the terminator X may work off the crank position sensor on the cars. The trigger wheel is only 4x so it's kinda low resolution. That stated, the *ideal* way of solving the opti is the torquehead 24x system which is only a couple hundred bucks; it uses LS coils. . . but again, it is yet more points.
    1 point
  15. As far as a wiring harness, I'd look at the Holley Terminator setup since it's going to be a race car. Not positive, but it SHOULD work. Contacting Holley should get the info needed. Just looked; https://eficonversions.com/blogs/holley-efi/holley-terminator-x-for-1992-1997-lt1-engines Should be simpler than trying to work with the factory harness, let alone finding a replacement. eta-Get well soon.
    1 point
  16. A 1991 C4 had 245hp. As there is not an LS with equal or lesser power it would never be a 50 point swap. The swap would be based off the '91 HP, not the 96. Last I looked is a distributor change is still points. While ECU's and such are free. Ridiculous.
    1 point
  17. I can add one extra point, I have worked with bellows engineers on multistage turbo applications. The one thing that will always cause bellows failure very quickly is any twisting motion. In your case since you also replaced the 3 bolt flanges with v-bands it could be possible that once the connections were up to temperature the v-band flanges slipped and caused a twisting load to the bellows. Its also possible that in the instillation process the flange had some twisting motion as the v-band was tightened down. I would always prefer a v-band flange over a bolted flange, but in your case you may benefit from installing a small anti rotation pin on the v-band flange. We use them all the time on turbos.
    1 point
  18. Our M20 exhaust setup. One vibrant flex where the stock bellows is and another after the merge.
    1 point
  19. So these, at the slip where the runners enter the merge?
    1 point
  20. That's what I use and have over 6 years on it.
    1 point
  21. It was fun. All of us tried out best to not be in the led with mostly little mistakes here and there. I just lasted longer and never had a big off. That was my first real effort in the dark and I loved it. I can't really count racing with CC at Daytona at 10 pm as night racing. It's so well lit it might as well be day by VIR standards. You really had to focus and once the sun came up, driving was easy.
    1 point
  22. except I had the wrong standings up. lol. that should be correct now
    1 point
  23. Yes it scrolls nicely on my iPhone
    1 point
  24. 1 point
  25. The breakers are only a few bucks each. Also, the aim pdm32 comes with a dash, datalogger and gps for around 2K. You can spend almost that on a dash alone. https://www.amazon.com/dp/B08ZSJDVK6/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B08ZSJDVK6&pd_rd_w=ScLWS&pf_rd_p=91afecf5-8b2e-41e2-9f11-dc6992c6eaa1&pd_rd_wg=GE73K&pf_rd_r=BJ5RSD5X017C33NP0T0F&pd_rd_r=b4f81c39-1aaf-4f4b-a3eb-a61fd4d57548&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExSU9GSjFGQzcySjdOJmVuY3J5cHRlZElkPUEwODM4MTM4UjBYTlIwWFVLTlgyJmVuY3J5cHRlZEFkSWQ9QTAxNDMyNDYzUUoxTjFLN1E3SlhWJndpZGdldE5hbWU9c3BfZGV0YWlsJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
    1 point
  26. Thanks for the help
    1 point
  27. Engine and Transmission went in last night.
    1 point
  28. Might be worth reading, Terry does a great job of documenting builds https://www.vorshlag.com/forums/forum/vorshlag-motorsports-discussions/vorshlag-project-cars/7168-vorshlag-c4-corvette-tt-build-project-danger-zone
    1 point
  29. I think I'm confused by this. Why would that make your afr change so much that the stock system can't keep up? Doesn't higher compression ratios essentially just make for more efficiency without actually ingesting any more air (hence same fuel requirements).
    1 point
  30. Ehh, it's my own damn fault. I'd run a stock regulator if I could. The real reason my AFR went up is I opted for a thinner head gasket and it boosted my compression a bit.
    1 point
  31. That is what we have found. 245 is just too much stress on suspension. 225 on a stretched wheel works ok, when measured over time.
    1 point
  32. Should be in my opinion. 245 will be more consistent with temp and time from my experience. 1 or even 3 lap pace will probably not be effected.
    1 point
  33. yep.....actually we went 2s faster on 225's at Road America...That was average times btw, I do not focus on ftd....Gingerman will be an even better test for us to really analyze data. I can only assume that at some point the amount of HP provided by the vehicle to drive the increase in friction comes into play in similar way to drag vs. hp. 225's on 9's just seem to work well for our hp number. Also, wear is identical if not better with the 225s, more uniformity.
    1 point
  34. He was last in the car Saturday and did the fastest lap of the day on the last lap. I feel that the digital tech forms should be able to be viewed by others. Being in tech at the Autobahn there were many times when a item was not moved from the paper tech form to the digital format seemed like an honest mistake and there are probably more of that out there. If tech forms were viewed before hand I think that would better prepare teams before heading to impound in regard to a protest.
    1 point
  35. Damn fella, you know how to come out of the gate spittin fire. 1. Champcar doesn't check vin's. You can buy a 2002 focus and race it as a 2003 focus. If there are differences in the years, you need to account for them. You can't take the Best 2002 parts and put them on your 2003 and call it a 2003. It needs to be raced in a factory configuration. You cant take a 2003 focus and race it as a 2008 focus, since that is a 2nd gen chassis. This is for cost control. The focus came with a 2.3 so its not an engine swap to race it with a 2.3, as long as it has the correct 2.3 for the year being claimed, and all the associated parts. All 1st gen foci are 200 points (except the svt) so this is really a minimal issue on this platform. 2. Champcar can and has checked displacement at impound, upon request. 3. You can swap suspension points. Specifically hubs are 2.5 points each.
    1 point
  36. As a local, I would like to update this with the comment that more information has recently come out and it didn’t sound good, additional research is required... Word has it land surrounding the track has wetlands restrictions, not sure where that additional area is going to come from if it isn’t the facility itself. Hopefully I heard wrong
    0 points
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