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I am going to start a post on trying to get the car to launch properly, and hold weight in the correct place throughout the track. My setup was working well for a while, but it needs to be changed, because I'm wasting too much energy with the car weight transfer in between shifts. I am using an old school ground control coilover setup with Tockico Illumina 5-way adjustable shocks and Eiback 500lb springs. My front shocks I've set to 5 (stiffest), and my rear shocks I've set to 2 (next to softest). I recently found a video of my car (by the way, thank you for the video, AGracingphoto.com) that has a different, but very interesting view on how the car reacts with the suspension I am running, and I don't like it at all. I have been talking to Ari a bit on this subject, but I also want to know what everyone elses input is on what suspension they are using, and how well they feel it works for them. By the way, you can view the video I found here...... http://www.jigsawrx7.com/videos.html (just click on the 2nd link from the top that says "semi-finals - Me against ESX Subaru").
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Dan Schechter
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As far as shocks and springs go, I'm running the Ground Control Coilovers w/Tokiko Illumina Shocks too.
My car looks like a leap frog trucking down the track. It's ridiculous!
I think our big problem is the 5 speed (Not being able to shift very fast) .
Yeah, if we use a softer spring, and a harder rebounding shock, then I think it will help tremendously. The car won't "boing" as much by using some of the shock rather than all the spring. But 2-way adjustable shocks are expensive!
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Dan Schechter
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I am selling my HKS Hipermax Drag coilovers, brand new, installed, but never driven on if you are interested. The valving is designed purely for drag use. Just an option.
Dan: With the Supra's we had to gradually stiffen the rear as we made more power. We didn't change the setting at all from 800-900rwhp but at 1000rwhp we were in big trouble. We switched to a stiff sidewall slick and set the rear up really stiff. That was fine until 1200rwhp.....at that point we lightened the car up a little and corner weighted it. Then put ballasts back in and slowly started stiffening it up. Our car weighs 1000 lbs more than yours and makes more power but it's all relative.
Have you corner weighted your car? Do you know the front to rear ratio? You could either try and lighten the rear of your car or add some stiffness. If you lighten the rear with a hatch or something you could then ballast it back where you need it and adjust the shocks accordingly.
You might already know all this so sorry if i'm outta line. It's late and i just got in from hanging out.
Did the stock flywheel help any with your shifts and rpm's dropping too fast, or do you think its just the speed of shifting or something else?
I haven't driven it yet but it's going to help. Everytime I would shift, the motor would fall out of boost. The extra rotating weight should atleast keep the rpms up.
I'd like to know what Crispeed is talking about here. I'm not sure if he was being serious or pulling my leg
Quote:
Originally Posted by crispeed
As for shifting fast well I guess with no syncros and 3/4 of the dogs missing on the gears full throttle shifts still using the clutch is possible.
You know you can do the same with the stock tranny.
Have you corner weighted your car? Do you know the front to rear ratio? You could either try and lighten the rear of your car or add some stiffness. If you lighten the rear with a hatch or something you could then ballast it back where you need it and adjust the shocks accordingly.
You might already know all this so sorry if i'm outta line. It's late and i just got in from hanging out.
No, I haven't corner weighted my car, as you know they're very expensive, and people don't like to let you use their set because of this reason . I would like to know what the weights are at some point, but Im not sure if I want to put the weight into the front of the car anyway. I would feel that I need it more in the rear for traction. Don't worry, youre not outta line, thats why I posted this message. I appreciate your post, and It goves me some good information to ponder over. I thought about lightening the rear hatch, and adding weight in other areas, however, first, I don't have the money to be trying all that kinda stuff out due to limited funds, and second, Ari's probably already done that. But if I did, I don't feel that it would solve the problem with the suspension in the first place, just change how the car moves due to different amounts of weight thrown around, and kind of band-aid the problem.
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Dan Schechter
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Dan: With the Supra's we had to gradually stiffen the rear as we made more power. We didn't change the setting at all from 800-900rwhp but at 1000rwhp we were in big trouble. We switched to a stiff sidewall slick and set the rear up really stiff. That was fine until 1200rwhp.....at that point we lightened the car up a little and corner weighted it. Then put ballasts back in and slowly started stiffening it up. Our car weighs 1000 lbs more than yours and makes more power but it's all relative.
Thank you for this information. Reading this makes me feel that I am moving in the right direction by learning what you had to change.
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Dan Schechter
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No, I haven't corner weighted my car, as you know they're very expensive, and people don't like to let you use their set because of this reason . I would like to know what the weights are at some point, but Im not sure if I want to put the weight into the front of the car anyway. I would feel that I need it more in the rear for traction. Don't worry, youre not outta line, thats why I posted this message. I appreciate your post, and It goves me some good information to ponder over. I thought about lightening the rear hatch, and adding weight in other areas, however, first, I don't have the money to be trying all that kinda stuff out due to limited funds, and second, Ari's probably already done that. But if I did, I don't feel that it would solve the problem with the suspension in the first place, just change how the car moves due to different amounts of weight thrown around, and kind of band-aid the problem.
Let me know if you want to use our corner weights when you come to the Vegas race. That's how i found out how terribly light my car is and my exact weight distribution. Right now i'm at about 52/48 but that'll change with the moving around and adding of parts i'm doing.
What tire are you running, if you don't mind answering? We've tried so many different sets of tires with so many different results. Different compounds paired with different sizes equals nightmares.....but we got some decent data. We have the luxury of having one of the best tracks in the country with some of the best drivers and tuners in the country constantly testing on it. The benefit to us? Finding out alot of things people don't see or hear everyday. If i can help you in any way i will with the little bit of knowledge that i've picked up.
Something else i've seen from guys who upped the power on a soft suspension......added tire pressure so it would spin just a tick. It didn't grab as hard and load the suspension. It lost a little et but they played with other areas and got it back. I did this on my Mustang after breaking axles and a ring and pinion with good results. It's not the optimum setup but sometimes mediocre gets the job done in a pinch.
Let me know if you want to use our corner weights when you come to the Vegas race. That's how i found out how terribly light my car is and my exact weight distribution. Right now i'm at about 52/48 but that'll change with the moving around and adding of parts i'm doing.
What tire are you running, if you don't mind answering? We've tried so many different sets of tires with so many different results. Different compounds paired with different sizes equals nightmares.....but we got some decent data. We have the luxury of having one of the best tracks in the country with some of the best drivers and tuners in the country constantly testing on it. The benefit to us? Finding out alot of things people don't see or hear everyday. If i can help you in any way i will with the little bit of knowledge that i've picked up.
Something else i've seen from guys who upped the power on a soft suspension......added tire pressure so it would spin just a tick. It didn't grab as hard and load the suspension. It lost a little et but they played with other areas and got it back. I did this on my Mustang after breaking axles and a ring and pinion with good results. It's not the optimum setup but sometimes mediocre gets the job done in a pinch.
I am running a M/T ET Street 26x11.5x15. I don't have enough torque to run a taller tire, and a smaller one will make the trap speeds suffer, but the launch is good with 1.34-1.40 60fts. I have already gotten to the point where I have raised the tire pressure 1lb or 2, and have been experimenting with different tire pressures (between 12.5-15psi) to find where the best compromise is to spin the tire. Tire pressure is working good for me and parts are holding together, at least as best as they are going to, but the bounce in the suspension is my biggest problem. I am going to stiffen the shocks a bit, and lower spring pressure to try and take some of the load from the springs to the shocks. Have you had any experience with limit straps in the front at all?
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Dan Schechter
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Dan: also a really good alignment helps a ton. We like to run a little positive camber.
I'm just throwing different things around that have helped us out. Sometimes the little things can make the biggest difference.
I have the car set up with all angles on alignment correct except with slightly more positive caster to keep the car stable during higher speed. Whats the reason you run more positive camber? is it for rolling resistance? or suspension travel compensation during squash of the front suspension?
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Dan Schechter
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The stock rear suspension is double wishbone and gains negative camber as it is compressed into bump. If the car is setup with zero rear camber at rest then once the rear squats at launch the rear wheels are no longer at zero camber but at some degree of negative. This means the tires aren't providing the most grip possible right at the instant you need it most.
If the rear has some postive camber at rest then as the rear squats the rear wheels go to zero camber. If it were me I would rig a simple device to meausure rear ride height at launch and then I'd set rear camber to give me zero camber at that ride height. The result would yeild positive camber when the car was at rest. The simplest meausure of ride height is to put zip ties around the shock piston rods. The shock body will push the ziptie up the rod when the car squats and then you can measure that distance to compute the ride height change.
I have the car set up with all angles on alignment correct except with slightly more positive caster to keep the car stable during higher speed. Whats the reason you run more positive camber? is it for rolling resistance? or suspension travel compensation during squash of the front suspension?
The positive camber is like you said (to keep the tires flat during launch)and DamonB explained to even greater lengths.
As far as limiting straps we haven't had to use them except for on the Honda's we've done. On any car setup for drag we've always ran a double adjustable shock and played with spring combo's. Fortunately for us we had some knowledgeable people helping out so it didn't take that many times before hitting a good combo.
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guys im a bit confused about the suspension , we have the second gen, we didnnt go for any aftermarket suspension we swap the turboII springs in the back we took the 1's we have out of an 86 4 lug rx7 that r softer springs,,,thats how we got it to launch the best i mean we havent tried aftermarket ones but this 1's r doing the trick
Even though I got a 1.55 60ft which I am very happy with considering the horsepower I'm running, I feel as if I am having the same problem with the car bouncing around. If anyone has any idea's of how to shave some more time off my 60ft by watching the video it would be greatly appreciated.
I'm launching at 8500rpms at about 12 lbs of boost, have MT street ET's at 12.5lbs, Tein Flex Coil overs with rear set at softest setting, and fronts set about half way.
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Best ET 11.22 @ 123.46 1.55 60ft w/ 472hp corrected
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Question for the guys launching at High RPMs eg 8K, dont you hit the rev limiter straight away and then bounce off the limiter until you hit a decent road speed in 1st? or does the revs drop to an acceptable level and you hook up well?
Currently I launch at 4.5K and my 60fts are 1.6 to 1.7 I run Mickey Ts ET streets on FD stock rims at the rear with Petit launch kit,Mazdaspeed PPF and a diff brace with Tein HA coliovers on the softest setting at the rear
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470rwhp@1.2 Bar HKS T51R KAI Half Bridge Ported FD3s
Reworx.com Motec tuned, Oldone Porting
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Yeah, if we use a softer spring, and a harder rebounding shock, then I think it will help tremendously. The car won't "boing" as much by using some of the shock rather than all the spring. But 2-way adjustable shocks are expensive!
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