High speed leanout

Discussion in 'PSI Superchargers Tech Questions' started by brandon, Aug 9, 2021.

  1. brandon

    brandon New Member

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    Has anyone run a high speed leanout on their car to use it as either at the staging lanes switch for a touch more power or as a "scramble button" like what some turbo people use?
     
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  2. kosky racing

    kosky racing Comp Eliminator

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    Not unless you got nitro hooked to it-----
     
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  3. rb0804

    rb0804 Active Member

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    Good one mike. That made me laugh.

    If you run a grid you can put a few switches on the dash and wire them to the step retard functions. As long as the step retard has 12v, it will pull the preset amount of timing in the respective step retard. Example: you can have 3 switches on the dash, they apply 12v + to step 1,2,3 respectively. Wanna pull 2 degrees, flip one switch up, 4 degrees flip another up and 6 degrees flip the last one up.

    If you run a command module, the later stuff has the ability to shift the timing graph up or down easily. It also has an sd card provision where you can load a few tunes and change them pretty quickly in the lanes. Just don’t get confused as to which file is the hot tune.
     
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  4. brandon

    brandon New Member

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    I definitely thought about doing that with my grid but am using the first two steps for the shifting. It lets the grid know its in the next gear and I can pull timing to try and reduce wheel spin. Doing the rpm drop way doesn't work much. Since the class I run in is just a for fun heads up (not a national event) I was hoping for some way to adjust either on the fly or in the lanes. My tuneup is super fat to stay on the safe side in hopes I don't have to do as much tear down at the track.
     
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  5. brandon

    brandon New Member

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    I could do another step retard and just use it for high gear but I feel it won't be as effective since it would only be active after the first two steps have been activated and I'm in high gear
     
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  6. Mike Canter

    Mike Canter Top Dragster
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    Brandon I am confused on what you are using the step retards for in shifting. The Grid has its own shift function and that if it sees a xxx rpm drop it knows it has shifted and then gets ready for the next shift. You can program different rpm shift points for each gear. The Grid also has a feature that can be programmed to pull out timing on the shift to stop tire spin.
     
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  7. brandon

    brandon New Member

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    I am using them for the shift indicator to grid so I can get the quickest response in retarding the timing when shifting. I looked at the 7730 instructions again and it says you "note: these wires can be used as gear select indicators". Am I the only one who has used it this way? The msd person I spoke to on the phone the other week thought I was crazy and I was thinking the same until I saw this in the instructions. I have only tested it with the handheld tester but it seems to be much better than rpm drop based shift indicator
     
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  8. Mike Canter

    Mike Canter Top Dragster
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    I just don’t see what is gained by doing it your way. The Grid knowing it has shifted has nothing to do with the amount of time it took to shift. I am totally open minded to changes.
     
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  9. brandon

    brandon New Member

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    From looking at the data it looks like the tire is already spinning before the grid knows it shifted and is late with taking out power. I'm open minded as well and new to this, so feel free to be harsh lol. Here is a pic of the data. Red is rpm, green is ds, and yellow is timing.
     

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  10. rb0804

    rb0804 Active Member

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    You can use any of the steps any time. Step 5 can also be used as a anti lag boost building deal for turbo cars on the two step.

    What I have done in the past is use the msd 7760 3 stage timer to send a 12v+ to the step retard(s) of your choice via rpm and time. You can then tailor it to how much before the shift you want it to pull timing to minimize the spin up. In the step retard you can ramp in, delay off and ramp out if you like.
     
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  11. Mike Canter

    Mike Canter Top Dragster
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    Brandon does the car have a auto shifter on it or is it shifted by hand?
     
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  12. brandon

    brandon New Member

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    Auto shifted lenco (cs1). I currently have it setup to where the 12v going to step retards comes from a relay triggered by the activated negative coil side on solenoid. Hope that makes sense
     
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  13. Mike Canter

    Mike Canter Top Dragster
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    So what unit is actually used to shift the Lenco. If the signal is going through a relay before it goes to the Grid then you have a time delay from the relay and the shift retard will always be slightly behind the actual shift. When using an auto shifter separate from the Grid it is best to set the Grid to shift a little before the auto shifter so the actual shift retard was right at the shift. I don’t know how you would do it the way you have it.
     
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  14. brandon

    brandon New Member

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    Msd 75591 is what is sending signal to solenoids to shift lenco. There most definitely is a delay going through relay but I feel better than going by rpm drop. I thought about doing time base retard but dont race enough to have the car that consistent. My entire crew is family and with that it's whoever can make it that particular weekend which would be a max of 3 times a year
     
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  15. WIDEOPEN231

    WIDEOPEN231 Member

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    We ran one way back like 1991 way back. Called it a kill button. Had a 065 to 075 jet and would normally dimple a piston and beat cpl bearings,Hey if it wins who cares. At the time there where no electronics allowed so we did it with air.

    Also had a lean out open in second and shut off in third that actually richened third because temps would climb faster and we needed to cool chamber with more fuel. Something we found by having a pump go gallon lean but ran like hell to half track.

    I loved watching folks trying to figure WTH I was doing. Especially other crew chiefs.
     
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  16. kosky racing

    kosky racing Comp Eliminator

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    did you win with this system -and theory
     
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  17. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Mike in my experience the shift retard function of the grid is too late to be a wheel speed control. Once the rpm drop has happened, it's already spinning if you are using it to try to control spin at the shift.

    One of the reasons I like shifting on time is I can just use the time graph if I need to.

    To answer the original question....I don't think there's much you can do late in a run unless you are real close to them and need a little extra. If you get too greedy with the jet in the 'go get em' button, it might be a good idea to have it wired to the fire bottles too....
     
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  18. WIDEOPEN231

    WIDEOPEN231 Member

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    I would say it worked well. We won cpl national events ,cpl runner ups, few number 1 qualifiers, top 4 car most weekends and 1 round short of world championship. So all in all yes.

    Car was Starr Rider and driver was Rickie Bowie if anyone wants to fact check me .
     
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  19. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    When my dad was racing with Jay Meyer in the early 80's, somehow two pumps flow sheets got mixed up and a smaller pump was put on the car without them knowing. He said they had a car length on most everyone in low gear and by high gear it was death smoke. They couldn't figure it out and were digging pistons out of the trash barrel by the end of the weekend and filing ring lands to get the car back together. Once they figured out the problem, they kind of had an 'aha' moment. They figured the difference in flow in the pumps and made the car think it had the other pump on it in low gear using a whitey valve that closed on the shifts.

    By the time I started tuning the low gear leanout was a standard issue item, pretty much everyone had it. I was working on Jason Cannon's TAD and was putting the steering wheel back on the car. Jason took it apart, I put it back together and we had a miscommunication on what the duct tape labels on the air lines meant. Well when the air lines got swapped, that put the low gear leanout on through second gear.

    Our next race was Houston and it absolutely hauled ass. We went 5.37 at 267 mph, which made us like the 3rd or 4th fastest blown car speed at the time. I was doing bottom end and the bearings were beat up pretty good. The CC's per turn ended up showing us the leanout was on till high gear and the air lines were swapped. Well we "fixed" it and promptly returned to the low 5.40's at 264-265. Next race out, we had two leanouts, one closed in 2nd, the other in high, and calculated the area of the jet we were running and split it into two jets.

    "Happy accidents"
     
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  20. WIDEOPEN231

    WIDEOPEN231 Member

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    Pretty much same deal. Amazing what you learn from screwups. While the speeds are worlds apart,so was the time period. Now 196 in 1/8 means something wrong. In 1991 it meant something was right even if it went wrong afterward, It did. LOL now.
     
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