New 6.70/5.90 drag truck build.
- Thread starter SPEEDSHIFT
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SPEEDSHIFT
New member
I got my wife taking pics... this what I have for 20mins of arguing, thanks Austin. Lol
Sorry I couldn’t get a pic of the lower bar, maybe later. Im pretty sure it is one hole up from the bottom. The lower bar sits level with the ground.
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SPEEDSHIFT
New member
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97rada
New member
That’s a really long instant center man. With radials you are going to want to shorted that up, get it above the get it above the anti squat line a bit. This will drive the tire into the ground and create more traction. Also will want to make sure it doesn’t squat much.
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SPEEDSHIFT
New member
Okay, so I need to move the front of the upper bar down a hole or two?
SmokeShow
New member
Any particular excel sheet/program you use to figure instant center and anti-squat and all that jazz? I have one from Pirate4x4 that I tinkered with years ago. Or do you just crunch out the math with your ME background?
97rada
New member
There are a few methods of going about suspension stuff. Some people use a hole spread method and understand what a bar change should do to the physics of the vehicle and make adjustments and observe.
Others use programs to tell Them where the bars are ect and go from there.
I personally suggest getting Jerry bickels chassis performance book and reading it. Understand what the bars are doing and how the forces are acting on the vehicle ect.
Personally I have tim mccamis program that I have our brackets in. Never once used it. We have throw bar settings in my truck with the intentions of doing a certain thing to the tire and tune the shocks and observe what happens. Having good shock people behind you is a huge help.
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CorneliusRox
Seasoned Rookie
That Pirate4x4 one will get you some decent info though. And a nice trick I learned, put some zip ties on every shock piston as low as they'll go. Do a launch and see how high they are. You can turn your shocks and suspension a lot better knowing exactly how far they squat on takeoff!
97rada
New member
Goal for my truck is little to no squat and actually to get the shock to extend and plant the tire
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CorneliusRox
Seasoned Rookie
I could be wrong on this, but I've always aimed for 30% rebound and 70% compression at ride in height. Then you target using most of your shock travel in compression during a launch to soak up any of the harsh stuttering from the suspension. So if you're getting down to the last 10% of compression in the shock but never bottoming out, you still have damping/control over your chassis with a little bit of margin for unknowns.
I do understand the idea of anti-squat and 'pushing' the tire into the pavement, but it just seems like it'd set you up for a bouncy launch.
97rada
New member
That shock setup is traditional, but it’s intention is to not dead hook a slick and wad it all up sending it into tire shake.
Anti squat is how every radial car gets Down the track. Ryan’s nova didn’t squat when leaving. It drives the tire down and goes. With good shocks and proper setup it doesn’t bounce ect.
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CorneliusRox
Seasoned Rookie
That's interesting. Maybe I need to do some reading. :Cheer:
97rada
New member
I will say very few books will have that info anymore. It’s very new technology. I would look up mark menscer and his articles on the subject
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SPEEDSHIFT
New member
Yessir, I appreciate the help Austin.
I pulled the head Monday and found out it is warped .012”... block is good so I am going to have Longs deck the head and I will go back together with the 625s I was going to put in my dually along with the marine MLS gasket via Maumau Diesel.
I pulled the head Monday and found out it is warped .012”... block is good so I am going to have Longs deck the head and I will go back together with the 625s I was going to put in my dually along with the marine MLS gasket via Maumau Diesel.
SPEEDSHIFT
New member
Figured I would update this thread since I haven’t in a while. I decided to upgrade the nitrous system to help get off the line, upgrade to an 849 ECM with EFI Live, and upgrade (I hope)to a manual master cylinder.
The last few passes I made, I couldn’t get the brakes to hold boost at the line and it seemed my CTS2 was off, even though the ECM saw correct pressure... Even with 30psi at the launch it still wouldn’t hit the tires how I would like, so with a lot of advice from Phillip Franklin I decided to make some changes.
I now have a Nitrous Express Maximizer 5 and three stages of nitrous I can control. With the 849 ECM I can use a staging limiter off a button mounted on the brake pedal. I will roll into the first bulb and start building boost, once I make 10psi the first stage will come on, spraying a smallish .030-.050” jet that will help build boost faster to 25-30psi at the hit, and that should really help get it off the line. I have been just using a WOT switch, so it was fuel only for at least a few feet. Once on boost at the line I go to 100% throttle and the ECM will hold it at the boost level I choose in the tune. Then once I leave, I release the brake (and switch) and the ECM goes to full fuel and I can start ramping in more nitrous if I need it with the other two big solenoids via the MX5 and/or the scramble button.
I am thinking about starting with a .052 spool jet, and ramping in a small .036 jet either at WOT or a little before the 60ft for the second stage, it just depends what the track will hold. Then I will have the third stage for my scramble button, but I don’t see myself using that until I get a built bottom end.
I rewired pretty much everything in the truck, I cleaned up the engine harness and repinned it for the 849, then added the wiring for the nitrous activation and staging limiter. I added a mechanical boost gauge, and trans temp gauge on the shifter.
I also added a 45mm Hypergate to relieve some drive pressure with all the nitrous.
The last few passes I made, I couldn’t get the brakes to hold boost at the line and it seemed my CTS2 was off, even though the ECM saw correct pressure... Even with 30psi at the launch it still wouldn’t hit the tires how I would like, so with a lot of advice from Phillip Franklin I decided to make some changes.
I now have a Nitrous Express Maximizer 5 and three stages of nitrous I can control. With the 849 ECM I can use a staging limiter off a button mounted on the brake pedal. I will roll into the first bulb and start building boost, once I make 10psi the first stage will come on, spraying a smallish .030-.050” jet that will help build boost faster to 25-30psi at the hit, and that should really help get it off the line. I have been just using a WOT switch, so it was fuel only for at least a few feet. Once on boost at the line I go to 100% throttle and the ECM will hold it at the boost level I choose in the tune. Then once I leave, I release the brake (and switch) and the ECM goes to full fuel and I can start ramping in more nitrous if I need it with the other two big solenoids via the MX5 and/or the scramble button.
I am thinking about starting with a .052 spool jet, and ramping in a small .036 jet either at WOT or a little before the 60ft for the second stage, it just depends what the track will hold. Then I will have the third stage for my scramble button, but I don’t see myself using that until I get a built bottom end.
I rewired pretty much everything in the truck, I cleaned up the engine harness and repinned it for the 849, then added the wiring for the nitrous activation and staging limiter. I added a mechanical boost gauge, and trans temp gauge on the shifter.
I also added a 45mm Hypergate to relieve some drive pressure with all the nitrous.
WUnderwood
Moderator
Lookin damn good, amigo
