boosted DD with occasional 1/4 mi set up help.
 

I've asked questions like this before but I figure I post it in the drag forum and maybe get better help.

First off, I'm a suspension noob. I know some but not enough so explain things to me like I know nothing. That way, nothing gets overlooked in your explanation.

mods:
-stock suspension other than urethane rear diff bushing
-boosted on spring pressure at a estimated 470 hp. I want to turn up my boost and hit 500hp/430 tq (it was turned to power level)

*I will get the RJM pedal to help with clutch control sometime soon.

I DD my car and maybe 1 a month, sometimes 2x a month his the 1/4 mi strip. I either bog at launch or spin like crazy while I HOP down the front end of the track till partially in 2nd gear. I want ot turn up the boost but 500ish hp/430 ish tq but what's the point if I cant lay it down and hop around all day. Plus I don't feel comfy hopping down the track because it really breaks the drivetrain down. I don't want to break my car.

What is the best/best bang for buck fix to the wheel hop? I feel that if i can get that under control, I will get way better 60' which means 11's. Please explain why this mod or mods will help.

How much will it cost and what brand to look into. I will most likely DIY it as I like to tinker so put that into consideration.


YzGyz

sticky rubber is typically a good place to start. then flatten out your suspension in the rear for best chance of getting grip. from there it's work on your launch technique and learning what works best with your car's power and the track conditions.

What you mean flatten it out?

YzGyz

get rid of the rear camber.

when you get on the throttle the car squats which increases camber which decreases the amount of rubber you actually have touching pavement.

less tire contact = less traction.

Will doing that kill my tires during DD? I do most of the driving as DD. I don't want to compromise tire life all month for 1 or 2 days at the track.

Trying to do track things with a DD is a so much of a compromise. They really are not interchangable. I'm not trying to do track dedicated times. I'm just trying to get 11's.

Can I adjust this myself? I'm thinking not.

YzGyz

probably will increase tire life but lose a slight bit of handling if you go carve a backroad or something. with even the OEM camber wears out the inside of the rears pretty quickly.

rear camber arms can be adjusted by you but without an alignment machine i'm not sure how you could dial in and out camber and be exact aside from maybe marking lines on the arms where flat and DD normal camber is?

not really a suspension guru for these cars as I live in PA and DD mine so no suspension mods on mine lol someone else may have to shed morel ight on that for you.

Another thing you can do is to change all of the rubber bushings in the rear to spherical bearings. SPL parts. Rubber bushings let the suspension move around.

Next would be shocks adjustable for both compression and rebound. Adjust the front shock full soft on rebound and full stiff on compression. This will let to front of the car come up quicker and hold it there longer. More weight transferred to the rear. Two ways to adjust the rear shocks. Adjusted the rear shocks full stiff on compression and about 50% to 75% on rebound. This will make the rear harder to squat and will not let the rear raise up to quickly. Or adjust the rear shocks full soft on compression and full stiff on rebound. This lets the rear end squat and not let it raise to quickly.

Which bushings are we talking about? That seems more doable and keeps my car more street able than messing with the springs and shocks.

YzGyz

A better diff will help as well something like a quaife if its a daily driver you will feel the benefit on the strip and on the road.

I found my RWD R33 Skyline launched best with the rear shocks set to full soft but this increases the rear camber and reduces the contact patch of the tyre but the weight transfer gets it hooked up quicker

do you drop your rear tyre pressures at all on the strip ?

I would get a cheap set of rear wheels and drag tires... Takes 10min to swap them out on track days. Thats what I did with my RX-7

Be careful with full solid bushings on drag applications. Its not normally the rubber that is causing the issues as far as wheel hop and traction. Maybe the diff bushing, but when you go solid on the others you start to see broken axles and broken diffs, as the rubber helps absorb some of the "shock" on launch.

As for what may help, good shocks and good tires will be the best bet, nail in a good alignment. What are you tuned on? ECUtek has some real nice traction control options that may be of help also.

All comes down to budget, if you can put up between $1200-24000 for shocks we can get you a set built to your needs. Tires will be all over in price depending on what you choose.


The best thing, will be practice. The more you take the car to the track, the better you will get at driving it.

I've found that the rubber bushings in the Z will let the suspension move enough to cause issues. Plus they do not move freely in the intended direction. ;)

Is it any specific bushing you have found that causes the most issue? Im normally a fan of the Urethane or Nismo bushings (If they are around) over a full spherical for a street/Occasional track car.

There is deflection in all of the bushings. You add each bushing together with the rest. It makes for alot of monkey motion. And there is enough stiction in the bushings. If you remove the springs. The knuckles will stay in place. They will not droop down. I've replaced all of my front bushings with SPL bearings. Planning on doing the rear this winter.

I have a set of HR rims that might fit my Z. They are 19/10 +44 offset rims. I was looking into some drag radials. I was looking into NT05 or toyor888 as i can get these at Discount tires. I'm scared that if I hook and hop with the added grip, I will bust my rear axial from the loading and unloading from wheel hop. Each hop is like pounding a on the rear drivetrain with a sledge. I don't want that.

As for what alignment are my rears set at? Probably OEM specs as I have yet to get an alignment done. I think I will on Friday at Break Check since they have a cheap plan for unlimited alignments. I might even go today.

As for the launch, I'm working on that too. IMO it's just about impossible to launch with the SZ 6puck clutch kit. It's pretty much an on/off switch. Everyone stalls taking my car out the first time. Hell, even I stall once in a blue moon if I don't pay attention. These is just no play to let you ride the clutch. I get 1/2'' to 1'' of clutch pedal travel between fully engage and fully disengage. That's why RJM is on my list.

Ad for the budget. I was hoping it would be a simple fix for like $500-$700. Darn!

Please continue to comment on what I can do to help me lay the power down. Yes $$ is limited but, They might not be in the future. However, try to keep it realistic as I have to work like everyone else for there $$.


Thanks again my friends.

YzGyz