TimZ

My trigger wheel is already on the front of the damper, so I shouldn't have to change anything.

This would not work. I guarantee that you could not react fast enough to control your boost pressure. Overboost would be practically a certainty.

Ow.

What if God fought Ditka?

Okay... I was having trouble making a consistent explanation of my theory, so I decided to dig a little deeper. As a result, I'm changing my story a little. (at least I admitted it ) In general, changing the spring rate in the front should have no effect on front/rear weight transfer during braking, except from the resulting relative change in the cg height during braking as thurem pointed out. Weight transfer is a function of weight, wheelbase and cg position. So, while increasing the spring rate in the front won't appreciably increase forward weight transfer, it won't decrease it, either. So if you are having problems with the rear end unloading under braking, you should probably look for another solution. Possibly add anti-lift geometry in the rear? This is what BMW does - they let the front end dive a fair amount, but they also have the rear suspension setup to squat a bit under hard braking. The result is a feeling of the entire car 'hunkering down' under hard braking.

Okay, I have to ask... what problem are you trying to solve by limiting brake dive? I think I saw something about not unloading the rear suspension during braking. You do realize that increasing the front spring stiffness will increase forward weight transfer, not decrease it, right?

Be very careful to be sure that the heim joints do not bind at any point in your suspension travel if you do this. Unless your front suspension has radically different geometry than mine (unlikely), a straight tie rod end will not put the middle of the heim joint's travel anywhere near the middle of the suspension's travel. I had to put a bend in the tie rods to allow the proper orientation of the heim joints and keep them from binding.

Well, it's meant to be used on the rear brake, so that would kill the smoky burnout thing. You have to apply the brakes harder than the line lock pressure to get it to release - you can't just flip a switch an have it let go. I guess if you want to install it on the front brakes and just use it to heat the tires it would work for that. Forget using it to launch, though.

Unless they have changed line locks, the one supplied with the AZ Zcar setup is intended to be used in lieu of a parking brake. It is not suitable for drag racing use to my knowlege.

No. I'm guessing it will be in the $400 range - it's very likely that this will be a low volume part for them, so I don't see the price coming down much.

Not necessarily - the VATNs that I have seen are generally intended for moderate power levels (<300hp) on smaller displacement motors (<~2 liters). They have a range of adjustment, but if the displacement is still too large, they can be overpowered. From what I have seen, the L-series in any semi-serious state of tune should be big enough to overpower the VATN. If you recall their use in the Maximum Boost book, two of the larger VATNs were required on the turbo NSX project, and that was just to get it to a little under 400hp at the flywheel. Oops - just noticed that the post was referring to an L-20, which should be suitably small, although it is still possible that you are on the borderline. It would be a good idea to check the function of the vanes and their control mechanism. For a 2.8 I still think it would be too small, though.

I also contacted BHJ to see where they were on this. They are in the process of making me a two groove pulley, based on the part they are doing for JeffP, with the addition of a front mounted 60-2 tooth trigger wheel with an orientation similar to mine. Jeff's part had no provision for the trigger wheel. I don't have solid cost info yet, but it's looking like it will be in the $400 range.

Sorry to nitpick, but most plain stainless braided lines are only rated for constant operating temps of around 300degF. The braided teflon lines are good for 450 degF. Also, the psi ratings vary widely with the quality of hose and the size of the hose itself. 300psi is probably reasonable for this app with a good quality hose, though. 300 degF would still be fine for oil and coolant, btw.

Okay - I'll buy that. Forgot about the 'square law'. oops.

Yes, this has happened to me before - on the same strut (passenger rear) even. I think that several things could cause this - the gland nut can back off a bit, whatever spacer you are using can deform, or the strut cartridge could have been a bit off center in the housing when the gland nut was first tightened, then worked it's way back to the center. How is it that you know the gland nut didn't loosen? The only thing that I can think of is if you had it screwed all the way into the housing. I usually try to adjust my spacers such that the gland nut is a couple of threads from the bottom when it is tightened. This way I know that I have positive retention on the cartridge, and didn't just bottom out on the housing threads. Also, the washers inside the strut housing do take alot of punishment, but they do not support the weight of the car - the strut housing takes that load.

HEY - I addressed it pretty well, too! I've never been so... ummm, never mind.

Dude - chill. As far as I could tell all Dan was doing was pointing out an omission in your post prior to his, and summarizing for those that couldn't make it all the way through your well written but lengthy post (hence the short attention span reference). While it might not have been particularly flowery, I didn't take it as being terribly mean-sprited or rude. As Bob H would say -"Eat your Wheaties".

The rebound in the shock would (and does) control droop whether the spring is there or not. The rebound in the shock will resist movement, but the natural frequency of the suspension will be undefined, as there is no longer any spring rate associated with the suspension (possibly some minimal rate from gas pressure shocks, but this is negligible). As such, the suspension has lost it's ability to track the surface it is moving over. For instance, let's say that the suspension did continue to droop from the inertia of the unspriung weight as the car crested a rise. Until the suspension is back on the spring, it will be able to compress at pretty much the rate at which the undulations in the road can push on it, but it can only re- extend at at the rate at which gravity can overcome the suspension's stiction. This isn't very fast, assuming gravity can overcome the stiction at all. The available traction from the tire in this condition is at best highly unpredictable and very likely to be nil. I don't disagree that it happens all the time - I'm just contending that the additional travel does nothing particularly useful, and is not the same as droop travel when a proper length spring is used. Hence my argument that the additional travel doesn't count.

Wouldn't you be cutting the pressure drop in half with two intercoolers in parallel? Have I missed something here?

When the spring has reached it's maximum extension, any further supension droop is uncontrolled. The suspension might droop farther on it's own, but there is no guarantee that it will. In practice, it won't droop much farther due to stiction (yes that's a real engineering term) in the suspension, and even if it does there is essentially no force on the suspension at that point. So, if your spring only has 5 inches of travel and your suspension has 7 inches, those last two inches of travel don't really "count". Strut sectioning was never mentioned in the oringinal discussion, and I've noticed a couple other posts where people seem to be installing coilovers without sectioning the struts, so I am assuming that ToplessZ was not going to section his struts. I did make that distinction in my post, btw.