Hi guys,

Another cams thread, but it more to confirm my future choice:

The car this summer:

2003 350Z with VQ35DE
Tme attack car only (no regulation on modification, only weight/power ratio)
120K miles
370Z OEM LSD
4.08 diff.
Dyno at 246 whp with full bolt-on:
±2950 lbs with roll bar only (want 2850 lbs)


Soo far on the car (power only)

Z1 tube with Pop-charger
kinetix V+ intake
A/C delete
Racing thermostat
No internal except Rev-up oil pump (new)
Osiris tuner tuned
Strait pipe exhaust
Megan racing header longtube...



GOAL:

285+ whp at the end of the project
(not on this motor, but with a VQ35DE)
7000+ RPM

How to:

MREV2 (in the box)
Motordyne 1/2 spacer
APS strut brace
Cams and valve spring
LSD 1.5
Shave weight
PPE loing tube headers...one day


So, i don't need to end power, (but a really strong under the curve) power. That why i almost eliminated all the 270° cams. The 256° would be nice, but i still need a bit of power to rev past 7K since i have a short diff ratio and always near the cut off.

So the Cosworth ZKI with 268° and 10.4mm of lift (intake). It seem to be the best of both world. I read a lot of 350Z owners that owned the 272° and the complain that they lost a lot of torque.

So, is it a good choice for my goal or i should go with milder cams ? The spring and retainer are a no brainer for my goals. Will take the matching ones.

Any experience with the 268° ZK1 cosworth ?

Thanks

Martin

 

I would go with the JWT C8/C9 cams with JWT Valve spring kit. And I'm bias toward a Quaife differential. I would dump those Megan headers for a set of Stillen's with AAM 2.5" cat-deletes and JIC Magic Spartan Titanium single exhaust.

What have/are you doing for suspension, wheels/tires and brakes?

 

JWT C8 /C9 are more top end cams, i want something more toward the middle range of power. the S1/S2 are better option IMO for my project. I dont want big HP number, but big TQ number.

As for the Quaife, i prefer the Nismo or the Tomei for a race car only or big power car.

For my suspension, i have KW clubSport with all the toe/camber/caster bar possible to help my alignment.

For the exhaust, if i leave the megan racing headers, i only switch to PPE (or SG) real longtube race headers. Stillen+AAM will be similar to megan racing longtube in term of power...or really close. I have an Agency Power single exhaust muffler on the car, loud as hell, but perfect on the track.

Thanks

Martin

 

Why don't you want top end power? I don't understand that? You're going to spend most of your time on track above 5,000 rpm so build the engine to make power from 5,000 to 7,500. The vast majority of people under cam their engine based on some urban myth about "power under the curve." Having more power from 2,000 rpm to 4,000 is useless on a race track. Make the curve fatter in the rpm range where you race.

 

If this is your goal then how poorly geared is your car? You would be much better off putting a 4.xx rear gear in the car and then building for horsepower.

 

I agree 100%!

I totally forgot about changing the gearing.

 

what about some brian crower 264's?

 

I might express myself in a wrong way. I want top end power, but i need a lot of torque from 3000 rpm too. We have a lots of small tracks with tight hairpins and even with my short gear ratio, it really important to have lot of torque.

When i said that i dont want top end power, i'm thinking about the rules of the Time Attack here. It all about power/weight. If i go with huge cams, it usually go with high power number and less tq in lower and middle range (like 280°+ cams and huge lift).

I can related with the QR25 engine. It a torquey engine with not much of top end. We try S1, C2, C3 and different BC cams. The C2 are design for racing only (almost...) and the gave the highest power number, but the racers prefer the mildest cam (S1) simply because the have a lot of torque down low and the are pretty fair up top.

The VQ35 are silimar to the QR25. Torquey engines, but cant have power over 7000 RPM without a lot of internal modifications. So the best range is from 4000 rpm to 7000 RPM in a DE engine. HR engine could benefit of more agressive cams IMO.

So if i want power between 4K and 7K range, what are the best cams ???

Mart

 

have you looked at dyno charts on here?

the C8 is a pretty mild set of cams imo(i have had them for a year or so). even sg's big n/a build made over 260 lb/ft at 4k rpm(c10 intake/c9 exhaust).

 

When a car is classed by dyno tests (HP and weight) then gearing is an ideal way to improve acceleration without getting a weight penalty or a class bump. Cam lift has a positive effect on horsepower and torque. I can't think of a negative unless valve train stability becomes a problem.

There are also lots of ways to make less power during dyno test at the track...

 

I have BC 264. 4.08 Diff. rev to 7.2k

plenty of torque, still not enough high end power on the track. I rarely go under 4.5k rpm. I think I still need bigger cams.

 

In for updates, doing engine next year, getting ready to pull trigger on ppe headers. Cams don't do much unless you have everything else, intake, headers, tune, etc.