bmarcinczyk14

I'm going to be supercharging my 02 z06 this spring with the A&A kit. Car is currently stock except for aftermarket mufflers. I will be adding long tubes with catted x-pipe which I was told will put me around 575-600whp. As you may know, the later 2002 and early 2003 z06's have the chance of having the crappy valve springs which snap even stock. There's a good chance my springs are good (early 8/01 build plus car only has 28k miles) but it will always be in the back of my head. Does it make sense getting replacements even though I'm leaving the cam stock or is the issue blown out of proportion and I'd be wasting my money? Should I get dual springs or too much overkill and stress on the valves with the stock cam? Will my stock clutch handle 600whp? From what I've read on the forums the stock c5 z06 clutch isn't the strongest but at the same time I had a performance shop tell me I'd be wasting my money and the stock clutch will have no issues. This is also the same person who said the c5 z06 uses the exact same clutch as c6 z06, which I almost for certain know is false information.

Tusc

I can't speak to the valves as that's something beyond me.

RW numbers vary, but LS6 h/c with boost is a great start.

Some see valve float at upper RPMs, so springs are good to add.

The trunions are a weak point, too, so go with the Straub bushings (NOT comp).

A small cam will amplify your numbers. You'll need to tune for boost anyway, so perfect time for a cam. I have had HUGE cams on NA engines in the past and decided to leave mine stock to avoid the rumble, shaking, noise which makes long drives an actual headache. Of course, now that the build is nearly completed and I've been driving it... I may go back and add the cam. Why not?

Methanol - not necessary, but cheap insurance.

When the clutch goes... everyone loves what they own... and I own a MacLeod RST. Lighter than factory pedal, and will grab an advertised 800tq. RXT is the next step and the RST can always be updated. RST drives like a normal clutch for around town and slipping. RXT I am told is more abruptly on/off.

For all that, absolutely add the Tick clutch master cylinder.

If you go meth and decide you want to trunk mount it instead of using the windshield reservoir, I have an AIS stealth tank and hose for sale.

Sounds like it will be fun.

My combo right now is an older A&A kit with P1sc and 3.85" pulley on internally stock LS1. Without methanol, it made 490 on the current tune.

bmarcinczyk14

Valve float at higher rpm's just from a supercharger and stock cam? With the redline staying the same and no higher lift camshaft wouldn't the need for stiffer valve springs almost be completely negated? And in the event of playing it safe and getting new valve springs, would you say dual springs with a stock cam be overkill and potentially cause increased unneeded wear on the valvetrain? As for upgrading the cam, I really don't think I'll need more than 575-600whp, nor spend anymore money than what the setup is already going to cost lol. Not cheap by a long shot.

LTstewy8

The valve spring pressure is designed to keep all of the pieces of the valvetrain in contact with each other from valve stem -> rocker arm -> pushrod -> lifter -> cam. That factory spring rate is calculated using manifold pressures against the intake valve (1" radius so area=3.14 in^2 stock I believe; ignore the valve stem for my simple example) that a factory engine will see, among other factors. If it's now seeing a hypothetical 10 psi on the back of the valve that's 10psi*3.14in^2 = 31.4 more pounds of force trying to keep that intake valve open. So the spring needs that much more force to keep the valvetrain happy and together.

Anyways that's the very basic logic, here's a handy calculator that I can't vouch for it's accuracy, but wallace racing is a good source. http://www.wallaceracing.com/boost-s...ssure-calc.php

corvet786c

When you start adding a s/c you are going to have to upgrade your entire driveline even clutch, We need more info on your setup, 6 rib 8 rib etc. Get a gates rpm belt and don't look back.

For my setup I have a blower cam with dual valve springs. (Its a must) Stage III 243 heads pushing about 9lbs of boost with a 4.38 pulley. My car is street friendly and a tune is very important. We need more info on what u want to do yo help you.

Tusc

Just as LTstewy said. Due to additional forces exerted, you can see float. This can be visually identified on dyno graphs as rpm climbs towards redline. Stiffer springs keep the valvetrain planted.

I also need to upgrade to the RPM belt. Not to steal the thread, but what is the proper length for A*A with 3.85" pulley?

To add to the OP's topic, I did also add ECS diff brace and pfadt trans mount. The pfadt eliminated wheel hop for me. The diff brace is an inexpensive effort at the hopes of not grenading the transmission if or as it shifts vs the diff. Unrelated, but I also went with the poly six-shooter couplers when I did the clutch. Not sure if they are the best choice for the current setup, but I won't be pulling it apart again until I need a new clutch plate.

bmarcinczyk14

Lots of great information! After some more research I think the PAC 1218x springs would be perfect for my setup since I'll still have the stock cam. I feel duals would be unessecary stress on the valvetrain.

bmarcinczyk14

Dumb question, what would I benefit from going methanol injection? Mainly for reliability measures or performance? Is it something that runs out and you always need to refill? How expensive?

Jurgen1

you can run full meth or windshield washer has 20-30% meth keeps your iat lower so you can add more timing and make more power .

bmarcinczyk14

So a c5 Z06 clutch with only 28k miles and in great condition will not be able to handle 575-600rwhp without slipping? I'm not using the car for track use and don't plan on a bunch of clutch dumps. I figured why not get whatever life is left on the stock before dumping more money on a heavy duty clutch, unless a stock clutch no matter how it's used will start slipping once full power is exerted onto it?

silver408z

the c5z clutch will not hold the power.

bmarcinczyk14

I've just read some people on here claim they were at 600whp with c5z clutch and holding up ok. Biggest thing is traction that will kill a clutch the quickest.

neutron82

if you get lucky and it holds 600 in one gear wait until you have to shift and it won't let you

bmarcinczyk14

You guys all talking from personal experience? So far I've talked to 2 different performance shops and the owner of A&A all who feel the stock clutch should be ok and recommend just replace it whenever it goes out.

vrybad

At around 600/600 on my previous Z06 twin turbo, the stock clutch held fine for a while but one day, on the highway, in 4th gear from a roll, the torque drove right thru the clutch. Was never right after that.

It's only a matter of time but you will need an upgraded clutch at some point.

bmarcinczyk14

Ok, so that's what I thought. I'm finding out the stock clutch CAN hold the power, but obviously it's just a matter of time before it goes. As for an upgraded clutch, does anyone know if the LS7 kit upgrade would be suitable for my power levels? That's the one the shop recommends, but I'm seeing mixed opinions on what that clutch is meant to handle.

vrybad

For the money, I'd recommend a twin disk of some sort.
I know people have had some luck with single disc clutches but there are some reasonably priced twins out there that should allow you to do the job once and forget about it.

I had the RPS Triple Carbon in my Z but I always tend to go heavy when I'm doing drivetrain mods. Clutch replacements in these cars is a bit more labor intensive than most.

bmarcinczyk14

And what's your opinion on lightweight aluminum flywheels?

vrybad

I don't like them.
I am of the opinion that for street use, a clutch that comes in near factory weight will give you the best driveability.

Additionally, there could be structural issues.

One of the first versions of a twin disc I had on a previous car came with an aluminum flywheel. This was a $1,800 clutch assembly.
And I'm no hack when I assemble things like this.

After 20K miles or so, I had to pull the engine for repairs and the aluminum flywheel had cracks around all of the crank mounting bolts.
Don't know how long it would have lasted had I not discovered it.
If I can find an old picture, I'll post it up here.

Let it suffice to say that the clutch manufacturer, who I had done long term business with, changed to a steel flywheel shortly after I showed him what had happened.

I would strongly recommend against aluminum for the flywheel.
Others here may have good results and may prefer a light flywheel but I can't see any good reason to use one on the street.

bmarcinczyk14

Thanks for the recommendation. Considering you have experience with a car similar in power level that mine will be, do you have any good tire recommendations? Car will be only street driven on dry sunny days and I want something that will obviously stick in a straight line but not give up too much with handling.