jmd1487

Looking for some advise on what to do next, this past summer I picked up a 03 c5 z06 only 22k miles on it. It already has a p1sc with I think a 4.0 pulley 7.5-8.5lb boost, 1 3/4 obx headers borla catback, coilovers. Last dyno it has it put down 570hp 490trq. Im looking into the next step, don't have a ton of funds but labor is free so take that into consideration. My options I believe are blower cam, meth, better headers maybe 1 7/8, pulley down 3.8, 3.90 gears..??? Just some things that come to mind. Let me know what you guys would do...

r0nd3L

I'm running same procharger with Speed Inc SC2 cam, LG 1 7/8 headers, but a bigger 4.1" pulley which makes about 7PSI on my setup. Car put down 594/476 SAE corrected. I'm going to pulley down to 3.8", install A1000 pump, larger injectors, and run E85. I believe all that together will put me well in the mid 600s.

I know this doesn't really help you at all, but wanted to share.

jmd1487

Any input is helpful, thanks. I guess what I'm wondering is if upping the boost or swapping the cam would be safer for the motor? Also if meth injection helps or hurts the motor?

r0nd3L

I would say cam would be safer as it would allow engine to breathe easier versus stuffing more boost into the motor. Meth definitely keeps the motor happier as it decreases IATs, increase octane, has higher knock resistance, etc. Personally, I wouldn't use meth to increase power, but rather use it as a safety measure. You could also look into E85 if that's readily available in your area.

jmd1487

Sounds good, e85 is readily available however I have heard there is some doubt in the quality level of it, so that does steer me away from that route. But yes I believe a good blower cam and a meth kit would be a good next step. There's a lot of blower cams out there...any preferences? Stock cubic inches....

Chicago1

lol that's a few g's right there...Just found it funny you said that then list all these parts. labr or no labor..You are on the right track should be easy 650+. Do you have tires? pretty useless to have all that power and can't use it..Trust me I know...668rwhp on some crappy bald tires

jmd1487

Lol those were just options not necessarily everything I wanted to do. I have a brand new set of toyo r888's.

r0nd3L

Going to go strongly off topic, but how do you like R888? I'm set on getting them on all four corners once spring arrives.

jmd1487

The best tire I have ever run, great in the corners and great in straight line launches.

2bridges

In your shoes - I would do the following

pulley down -3.70
injectors swap to 60lb with BAP
clutch upgrade (mcloed rxt)
DTE or similar rear brace
phadt trans mount (if you can find one)
diff output shaft upgrade
NOT a gear change - deeper than 3.42 on 600+ whp street car, you'll hate it
swap trans from MN12 (Z06) to the better high HP gearing in MN6 (non z06) trans
single nozzle meth - alky control (or ECS)

You will put down 640RWHP with a safe tune and remain pretty durable
my setup as described run dozens of standing mile runs, several open road race events and tons of street abuse over the last 4 years.

Is proving to be a nice sweet spot in performance & durability

jmd1487

So a cam swap is unnecessary in your setup?

2bridges

running stock LS6 cam - did go with a dual valvesprings, otherwise stock longblock

Also running ARH LT headers, no cats and corsa pace car catback

r0nd3L

I've been thinking of switching over to E85, but that's almost a $2k project. Might just go with alky control meth kit as you seem to be having good luck with your setup. I assume you're running 93 octane?

umrjmac

Keep an eye on your injector duty cycle and (just as important) fuel pressure. if you're still on the stock fuel system you may need to upgrade (someone mentioned 60's and a BAP). a BAP and the stock fuel pump alone may not be enough, especially if you go E85.

If you do need to upgrade the pump, check to see if you have the early c5 fuel system or the c6 fuel system (the switch occurred in the middle of the 2003 model year, your VIN can be used to check) as that will determine some of your options.

I hit the point where I knew I would need to go beyond just a BAP, so I went much bigger than I needed so that I would only have to do the job once...and managed to ding the fuel level sender so I have to take the tank out again

I have a ID1000 injectors, C6Z fuel pump, Aeromotive A1000 on a 4PSI switch, -8AN feed, -6AN return, Aeromotive compact EFI boost referenced fuel pressure regulator, and a few other odds and ends. I started with the ECS kit and used some of that along with some other parts.

If you run new fuel hose, be sure that you do a little digging. The normal stuff is somewhat permeable so your car has the potential to smell like a gas station if it sits for a while. I went with the PTFE stuff which is not and haven't had an issue. How much this is a problem I do not know since I went down the "not a problem" path rather than risking it. That type of hose requires different -AN hose ends, so just be sure to do your research and talk to some vendors before you spend a ton of money on it.

Oh, word to the wise...if you do an ECS trans/dif brace and some fuel upgrades that require dropping the tank AND if you have the c6 style fuel system, be sure to do your fuel work before you install the brace. Getting the crossover hose disconnected or installed with the brace in place is a royal pain in the butt. For me its a bit exacerbated because I'm using Pfadt motor and diff mounts, so the trans doesnt move much when loosening things up to get some clearance.

2bridges

I am tuned for 91 as that is what is available here.
Also tuned conservatively as this car sees standing mile land speed type use. Definitely left some power on the table.

2bridges

This is an excellent point

On my setup I am just about maxed on fuel system with stock pump, BAP and 60lb injectors @ 10PSI boost and 640rwhp

E85 you would definitely require fuel system at this power level - no way around it.

jmd1487

So what size pulley will get me to 10lbs?

Chasewhatmatters

I have a 3.85 6rib pulley that should get you there. Not sure if you have a 6 or 8 rib setup. $50 and I'll have it delivered to your door. PM me if your interested.

Taking your OP into consideration, I would contact Julio @Alky and have him set you up with a dual nozzle kit.

Chase

2bridges

with 3.70 Pulley I make 10PSi @ 6500 with the mods above (ARH headers, no cats X pipe, full exhaust, stock LS6 w valve springs

bikeriderga

^ This ^