Drag racer! need your suspension input??
11-04-10, 04:41 AM
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Drag racer! need your suspension input??
Hi guys! I'm a newbie on this forum and need your inputs. I have a 87 Rx7 that I just purchased in September in the intent of building it into a drag car. Just alittle bracket racing for the weekend as a hobbie. I'm not fimiliar with the rx7 suspension. I just installed a turbo II rear in. I've sold the 13b motor and relpaced it with a stock 300+ hp LS-1 with 6 speed tranny from a 98 camaro. The roll bar will be in when it gets here. My big question is and in need of your opinion aswell as your inputs. What do you recomend suspension wise to make the car hook? I'll be running a 10" slicks. Any sugestion will be greatly appreciated. Remember that I'll be running just braket racing so its easy on the drivetrain and less parts to break. Ariel
Last edited by ariel27; 11-04-10 at 05:01 AM. Reason: wrong phrase
11-04-10, 01:39 PM
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What rear-end are you planning on using? If it were my car I would put a Ford 8.8 or 9" behind it. The RX-7 rear-ends are never going to hold that much power for a sustained period of time. The newer 8.8s come with upper mounts that come off like "ears" - I would do a poor mans - 4 link with heim joints. The bottom of the rearend would go in like the stock rear-end again with heims.
Obviously soft springs in the rear to get the car to "squat".
I road-race which is a far cry from drag racing - however I do all my own suspension design - Most of the time it works!!
Are you doing a mini-tub in the rear?
Obviously soft springs in the rear to get the car to "squat".
I road-race which is a far cry from drag racing - however I do all my own suspension design - Most of the time it works!!
Are you doing a mini-tub in the rear?
11-04-10, 10:01 PM
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Thanks for your input. I already sold the 13b and the Ls1 with minor heads,intake and cam change can get you into 500+hp range plus its the LS1 is already in the car. I have a turbo II rear end in the car right now. 8.8 are easy to get and narrowed to fit this car and considered in the future but for now. I'm interested in making the car hook.Soft springs to make the car squat is good sugestion and will take your recomendation. Any other suggestions would be great and I'm very open to it. Also no minitub.I'm also appreciative to you for your response so please keep it coming. Ariel
Last edited by ariel27; 11-04-10 at 10:10 PM.
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11-05-10, 07:14 PM
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Coilover, camber changes, stitch the frame. All great advice that I will do. This is great! I always keep an open mind. There is always something to learn from everyone. Need more advice like this. Thanks guys and please keep it comming. Anything to keep the et down on the track and yes. It will be on slicks. Your friend Ariel
Last edited by ariel27; 11-05-10 at 07:17 PM.
11-05-10, 09:51 PM
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I think you're going to find that the conventional RX7 spring-rates aren't going to cut it.
I'd say get a bit of a beefier setup with a MUCH higher spring (750+ progressive, if you're going that route.) You're going to have to do a couple of tests on what kind of camber you're going to have to run, since the weight is going to play a factor in all of your suspension setups, regardless of the spring-rate.
Stitch-welding the frame would be a great idea, since you're talking a bout a 20+yr old car. The cage will do a superb job at chassis reinforcement, if it's worth it's weight. I've worked on cars that've gone so far as 18g flat-iron to cross-reinforce the chassis and at the proposed numbers you might look into that, at well.
If that isn't the direction you're talking about, please clarify your question, as it seems that the thread kind of went into the direction of your diff, rather than your suspension.
I'd say get a bit of a beefier setup with a MUCH higher spring (750+ progressive, if you're going that route.) You're going to have to do a couple of tests on what kind of camber you're going to have to run, since the weight is going to play a factor in all of your suspension setups, regardless of the spring-rate.
Stitch-welding the frame would be a great idea, since you're talking a bout a 20+yr old car. The cage will do a superb job at chassis reinforcement, if it's worth it's weight. I've worked on cars that've gone so far as 18g flat-iron to cross-reinforce the chassis and at the proposed numbers you might look into that, at well.
If that isn't the direction you're talking about, please clarify your question, as it seems that the thread kind of went into the direction of your diff, rather than your suspension.
11-06-10, 01:52 PM
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Yes your right about the direction of my intended post but its ok by me. I know that I have to run some test. Peoples inputs are good regarless. Right now As we speak.I'm just putting in the 6 point roll bar to stiffin the chassis. I have an option to turn it to cage depending on how fast the car goes and the rule allows so all these suggestion are great. Im new to these cars and I feel that I can never know too much. I've build custom cars for a living before for people in the entertainment buisness. It got to a point where it got too much for me. It went even as far as you have to sign a confidentuality agreement but thats another story. Im just looking for peoples input on these cars to lower my et on the track. Thank again Ariel
before for people in the entertainment buisness. It got to a point where it got too much for me. It went even as far as you have to sign a confidentuality agreement but thats another story. Im just looking for peoples input on these cars to lower my et on the track. Thank again Ariel
11-06-10, 03:03 PM
#13
I have seen a Ls1 FC do a wheel stand on the NA LSD diff... The stock TII diff has seen 8's in the quarter. It will be plenty fine...
Get something fully adjustable, and make changes after each pass to see what happens. Tire pressure, track prep, tranny gearing, ect. ect. ect. will all come to play. What one car has, will most likely not be your best choice.
If you have money to spare, and 9 inch or 8.8 4 link would be your best choice. This way you can have a full adjustable solid rear with coilovers. And almost endless gearing choices. Not to mention the peace of mind that it is not going to break...
Get something fully adjustable, and make changes after each pass to see what happens. Tire pressure, track prep, tranny gearing, ect. ect. ect. will all come to play. What one car has, will most likely not be your best choice.
If you have money to spare, and 9 inch or 8.8 4 link would be your best choice. This way you can have a full adjustable solid rear with coilovers. And almost endless gearing choices. Not to mention the peace of mind that it is not going to break...
11-06-10, 06:35 PM
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Good input. Right now since the turbo II rear end is in the car.Ill just use it till I decide later on for an 8.8 or a 9 inch. I 've heard people running 9's with the stock T II rear but never actually see one in person. I guess I m just going to find out. So far so good. Im truely greatful for the people that responded and I hope that I can do the same. Anymore input is welcome but lets go in the direction of suspension wise like which coilover works good with these cars. Things like that. What kind of modification in the front end of the car for better wirght transfer during luanch. Things in that nature that Im interested in. The battery is in the rear already. etc..... Ariel
11-06-10, 06:41 PM
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Also Im dying to open the links that people have sent me. Unfortunatly Im new on this forum I can't open them till I have 10 or more post. I understand thats this is forum rule and I respect that. I just have to wait just alittle bit more so I can open them. Ariel
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