I've been considering doing some cams on my Z with 70K miles on it, no maintenence troubles. I do time attacks and HPDEs, so the car runs 20 minute track sessions in the southwest USA. I have an oil cooler and the oil pump is the OEM unit. If I were to do cams, I would probably do the whole valvetrain upgrade. I also have a UTEC to modify the rev limit/fuel/ignition.

Any experience regarding how high you can push the rev limiter without causing damage to the rods, bearings, etc?

 

The stock rev limit really shouldn't be pushed. Buy cams to make power all the way to your redline. Also why do you need cams?

 

That's good to know. I am trying to figure out the best way to achieve a 1:10 hp/weight ratio for competition. Almost any form of forced induction will take me past there. Weight loss beyond my car's current state is very expensive, NA mods are very expensive. I am thinking that some weight loss combined with some NA tuning items might get me close for around $5000. Or I could go with mild FI and maybe add some ballast. Additional weight is something best avoided, so I'm trying to sort out my NA options. I need another 50-70 whp but will settle for less. My racing weight is currently around 3300 lbs and dynos at 250 whp. The car has to be street driveable. The only silver bullet cure I can think of is nitrous, but that only helps in the straights and isn't always legal.

 

I have run 7200rpm on my stock bottom end for a good amount of mileage....with no issue. My car makes within 10-12% of peak power all the way to 7100-7200.

 

Ask Sasha at SG Motorsports, they are running a stock DE bottom-end in their race car. If I remember correctly they run a signifcantly higher redline than the stock 6600 with a set of Nismo cams. To make big NA power these engines need revs. And in order to rev they (DE's) need cams, otherwise you'll be spinning the motor with no power being made. I think the motor needs to be balanced better from the factory but other than that they should spin pretty well with a modest increase like what 03threefifty is suggesting.

 

I will have to weigh the cost vs. the gain. All the cam accessories (springs, retainers, etc.) to raise the redline are costly. I just realized that the Stillen stage 2 twin scroll supercharger is rated at 313 whp with plenty of low end torque for around $6500 with the hood and all. I could sell my UTEC and tuner for some cash back. Hmm. It makes an annoying whine though. Meoooow, meoooow.

Thanks for the info about SG Motorsports.

 

Stillen is garbage. Those things heat soak in about .00000000000000000000234324234 seconds. If you plan to do hpde's etc.....I'd look at the HKS kit. It's cheaper and sfarrah is now using it on his NASA W2W car with good results. Neither the stillen or HKS is a huge power maker, but the hks will make more. You also don't have to run a hood with a retarded bump in it to clear the roots blower.

 

Yeah... I've heard the same. Also the HKS S/C whine is minimal.

 

can u go forced induction and use a restrictor to drop hp to your target?
if thats the case id go the HKS
that way u will have your target HP and more torque (the restrictor will give u a wide flat area in the top end power)

 

I've run the stock VQ at 7200 for about 15hrs without a failure, but Rod Bolts have been reported to let go anywhere above 6800rpm, so don't say you haven't been warned!

For the final race last season I was also running to 7400rpm in qualifying and practice. It was scary but sounded so good and I needed the RPM entering two specific corners where I was otherwise on the rpm limiter.

 

SG, thoses are some sexy long tube headers you are working on. If those gains are what they appear to be, the $ per HP is pretty reasonable, too. I was following your intake design thread a while back.

I was concerned about Stillens heat soak, too. The HKS kit looks nice. More info is good- it makes the decision that much harder. It will be a good year before I take the plunge, so hopefully some of those parts will be on sale to the general public by then.

 

Hey Sasha,

What is being thought of as the Rev-ups bottom end limit?

 

i have cams with my de bottom end.. just did a vortech supercharger. but i was na for a couple years.. i revved all the way to 7200 strong. but now since im supercharged im going to take it easy and bring limiter back to 6600. the cams feel great btw.. it never runs out of breath

 

I had a stock Revup in my car for a season and consistantly ran to 7500 rpm and the only problem was the unsupported intake cam lobe on #5 and #6 would break off.

 

Thanks for the info GT-2.

 

The non-revups weak link are the factory rod bolts

GT2 - never heard of the rear cam lobes breaking off, could you tell me a bit more about that? Factory springs and cams?

 

The cams and springs were stock and when you looked at the break it was a very coarse grain structure and I figured it must have been a defective casting.But when the other side broke later, I thought I might have to drill into the end of the cam and put in a pin to strengthen it. I have not had any problems with race cams, just the stock cams.