silicone boy Posted February 12, 2006 Share Posted February 12, 2006 OK, my TTV8 car is running, and there are things I haven't considered during the build. I originally put on 225 lb/in coilovers at all 4 corners. The car squats so hard right now that I need significantly stiffer springs during acceleration. What setup do most of you in this situation. Car is to be used for autocross/road course/occasional street use to dust the pesky ricer and middle aged Porsche/Vette/Viper owner. Do you run a rear sway bar? I wasn't going to. My shocks are Illuminas and while not optimal, they are new and I don't want to toss them. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 12, 2006 Share Posted February 12, 2006 You're going to run out of damping at about 250 to 275 in/lbs. I'm running 200/250 on mine, and it's fine for me, but I've still got an NA L6, so not quite the same deal hp wise. By a LONG SHOT. Anyway, if it were mine I think I'd try some Koni shocks and some springs in the 350 in/lb range. If you're stuck on those shocks, I'd push my luck and throw a 275 in the back and see if that worked a little better. I think you're going to end up needing more spring rate than that though. Obviously I'm just taking a SWAG at this since you proably have 2x the hp and 3x the torque of my engine... Quote Link to comment Share on other sites More sharing options...
silicone boy Posted February 13, 2006 Author Share Posted February 13, 2006 Thanks for the advice, cause it gives me a ballpark to shoot for. I'll probably end up biting the bullet and getting new dampers for exactly the reason you mentioned. Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted February 13, 2006 Share Posted February 13, 2006 So, how does it run? Still have rear tires left? Glad to see you got it done. Hanns Quote Link to comment Share on other sites More sharing options...
260DET Posted February 13, 2006 Share Posted February 13, 2006 Increasing the bump setting on the rear shocks should help, depending on where that is now. 225 should not be too bad but 275 should be better, a little bit of squat helps power down. You don't need me to tell you how important that is when its shovelling lots of power Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 13, 2006 Share Posted February 13, 2006 Silicone Boy The published Illumina specs will not allow you to go to 300lbs on the rear without damage to the inserts. the typical set up for spring rates do call for at least 25lbs more in the rear than the front for "all around" handling. This appears to be your target. You cound bump up to 250 to 275 in the rear, click up on your Illuminas and you will most deffinately see an improvement. Sway bar in the rear only dampens cross loading and will not prevent/ affect squat. a stock sway bar is about all that one really needs in the rear to retain your desired handling versatility. if you dont have LSD more sway just hurts you. If all else fails...break out the check book!! Good luck sir, keep us posted. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted February 13, 2006 Share Posted February 13, 2006 Ben, I'd pretty much do the strut swap to Konis (Check the Sticky at the top of this category concerning racing strut inserts) in the rear and go with the 300 spring. Doing the 275 won't hurt, and they are cheap enough that having them on hand isn't a bad thing. But based on the info in that thread, 250 is the ceiling for the Ilumina insert. So you're at that right now. Read that other thread tech info (Reason we made it a sticky was all the good solid tech data) and go from there. I think if you're getting that kind of squat, you're gonna need to step it up and maybe even consider a custom valving on the insert you go with... We're not talking about a huge increase in cost here either... And I bet you could see those rear inserts quickly. Mike Quote Link to comment Share on other sites More sharing options...
johnc Posted February 13, 2006 Share Posted February 13, 2006 Unless you're building a drag specific car, stop worrying about squat. Spring rates are chosen primarily to achieve neutral, steady state cornering balance. For the shocks you have, I would keep the 225s in front and go to 250s in the rear. Also add a rear anti-roll bar about 19mm in diameter and put a 25 or 27mm anti-roll bar in front. Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 13, 2006 Share Posted February 13, 2006 Ditto Double ditto! Well put Johnc... His earlier post claimed to be searching for balance, and the set up you discribed IS balanced. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 13, 2006 Share Posted February 13, 2006 I saw a Eclipse GSX bust a rear CV joint at an autox once. He sat on the line revving it to 6K, dropped the clutch, the rear suspension bottomed and BOOM, there went the CV. After he got stiffer springs, he still launched that way but I never saw him break a CV again... Quote Link to comment Share on other sites More sharing options...
mark Posted February 13, 2006 Share Posted February 13, 2006 On my lt-1 powered 240 Z I ran 225's front and 250's rear. It was a great compromise for street and track days. This was with double adjustable Koni's. For the last few years, I've used 350's rear and 325's front. It is not any fun on bumpy roads now. Even with extensive monkeying with the adjustable struts, it's still to hard a ride for my 45 yr old butt. I'll be going back to the other springs nest time the car is apart. Mark Quote Link to comment Share on other sites More sharing options...
silicone boy Posted February 13, 2006 Author Share Posted February 13, 2006 Thanks for the input. Looks like I'll be swapping out the rear shocks and springs a little stiffer. Quote Link to comment Share on other sites More sharing options...
Clifton Posted February 14, 2006 Share Posted February 14, 2006 I'm running 250 F / 280 R with Koni da's. Good ride on the street, even better on the highway and it works good autocrossing. Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted February 14, 2006 Share Posted February 14, 2006 Wish those struts would work on my 240Z. I would buy them from you since your swapping them out. Mike Quote Link to comment Share on other sites More sharing options...
buZy Posted February 14, 2006 Share Posted February 14, 2006 Not to highjack the thread but I was just reading the posts... I have adjustable Illuminas with 300 rear and 275 front springs. So is it true then these springs are to hard for these struts to function right? This is street car. If these are too hard what would be a good spring rates for the street? 250 front 225 rear be ok? Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 14, 2006 Share Posted February 14, 2006 buZy At 300lbs the rebound strength exceeds thoes inserts ability to dampen without extream wear and damage. They may hold for a while, or they may go right away. I have heard tell of adjustable Illuminas giving up on test drive #1 with 375s on the rear. I'm using Illuminas so I have decided to stay at the high side of the charts but under the recommended max. John hit it on the head above by the way. Thought he was looking under my rig!! One can always shell out more dough for tougher inserts if one needs rock crusher springs. The dough is significant by the way. Do a search hear on inserts or hit the web. you will see what I mean. Balance. I chose balance. On a straight liner, totally different set up. Quote Link to comment Share on other sites More sharing options...
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