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N/A Options Almost Exhausted; Time for Cams and/or Supercharger?
With my N/A modification options almost exhausted, I completed my second dyno-tune (UpRev) yesterday and thought I'd share a bit about my brief and expensive journey.
I never did a baseline run, but the shop told me to expect a 16% driveline loss on its dyno. With the 287 hp VQ35DE, stock whp was estimated at 242, which according to the operator, was in line with stock non-Revup DE Z33s.
The tune revealed that the above mods, without any tuning, added approximately 13 whp. UpRev dyno-tuning freed up another 9 whp, bringing the total to 264 whp.
The second UpRev dyno-tune allowed these parts to add another 13 whp, bringing the total to 277.
I was very pleased with the effects of the tunes, particularly the linearity of the gains across the entire powerband. Each tuning session resulted in noticeable power, torque, and throttle response improvements that boosted the overall driving experience. Never mind the WCF numbers themselves. What's important is that the same dyno was used each time, resulting in a reasonably accurate 15% power gain from stock - now basically matching that of a stock 370Z, but with more torque.
I suppose an argument can be made for mild "street" camshaft upgrades, but I'd say that outside of a Vortech or HKS supercharger kit, I'm almost at the limit of usable + reliable modifications. The limited data surrounding larger TBs and/or TB spacers don't show full powerband gains (and even disappointing power decreases in some areas) and metallic intake pipes seem to to fall victim to heat soak.
Thoughts?
1. Header choice is leaving power on the table and so is the intake choice.
2. Although controversial the ability of the Kinetix velocity to make more power up top would be better suited than OEM+anything if the goal is to stay NA (again power on the table)
You can't have it all unfortunately, these engines are limited without boost, cams will help you get a bit more but will that be enough?
If the answer is no or IDK, then boost is clearly the only option.
As far as heat soak goes, it's effect on performance while moving is negligible, while the stock box isn't restricted the pipe is and needs to be bigger if more power is the goal.
I've gone through way TOO many setups and my current is my favorite but it's also my only tuned one.
I have Injen intake, NWP TB, Kinetix velocity manifold, Okada coils, Tomei headers, Berk HFC, and HKS twin. I can tell you my current manifold feels way better than a modified OEM plenum with a spacer. The little losses of power here or there are irrelevant if the final outcome is a faster car. All that being said, I have a HKS supercharger chilling in my basement, NA power isn't enough for me.
I hear you on the headers. As NISMO discontinued its headers, I had been eyeing the Tomei ones for a while, but then a fantastic Craigslist deal on brand new DC Sports headers came up (1/3 the price of Tomei) on which I just couldn't pass up. Intake mods are, as you noted, controversial, so I stuck with simple, dyno-proven products that require little to no modification if a supercharger ever became a reality.
Certainly switching brands here and there will pick up horsepower that's been left on the table, but, you know, money.
I've been looking at the Tomei PonCam camshafts (256° duration; 10.2 mm lift) as a mild (and wallet-friendly) upgrade. Since I'm not sufficiently mechanically inclined to install them on my own, the cost of paying a mechanic (at least one day of labor?!) to do it is holding me back, as well as a lack of information about how much power these will add.
The only apples to apples comparison was the one done be Sasha if you want to see what cams could get you. If you are mechanically apt enough to do a supercharger I'd just get that, 2k for cams to give you maybe 15hp vs the supercharger that will give you much more.
As far as Tomei vs Z1....I've said it MULTIPLE times here, size is negligible, what isn't is the fact that Tomei are MUCH better built, is a more complete kit, and have way more R&D, than Z1. I'm sorry but it's not even a competition, I've had both.
The best advice I could give as someone who's had like 10 different combos including 3 different exhaust layouts and 6+intake setups... everything has its ups and downs, right now I'm OK with how the car feels but I'm not going to cam it only to want even more power later.
This is the reason I bought the supercharger, I will cam a built block cause why not lol, but it will be an add-on to the boost.
Get a used supercharger or ditch everything you have and get LTH, RZG or Admin intake and a Kinetix velocity manifold along with some 272 cams. Unfortunately NA is not the way on these cars.
Thanks for posting the graphs along with the changes, Tou. I'm working out the progression from stock to maxed out right now so I can have a plan of attack and manage my budget along with the priorities. Your posts here are super-helpful.
One often-overlooked upgrade is to lighten the rotating mass of the engine and drivetrain...
Flywheel
Crank pulley that drives the belts
Carbon fiber driveshaft
Brake rotors
wheels
These will give you WHP, but not CHP (crank HP). However, WHP is what matters, so these items a must at some point. The great thing about them is that they don't change the engine, so don't affect reliability--unless, of course, you start driving more aggressively because the car is so much more fun. You'll notice more torque at all speeds, but most notably at lower end and especially in lower gears. For this reason, they're a great compliment to any setup.
Lightening the car overall, is a valid choice, too, but difficult in a daily driver where you want to keep its comfort and usefulness. The stock seats are seriously heavy, for example.
Another incremental power source is high-voltage ignition coils with a larger spark plug gap. These will speed up the flame progression of the combustion process and allow the spark timing to be later in the cycle, where the crank arm is closer to 90deg and can provide more torque. A later ignition also shifts some of the BTDC pressure to ATDC, converting this source of parasitic power loss into output power. While you're at tit, upgrade your spark plug wires to the loqweest-resistance set you can find. This will deliver more voltage to the ignition coil and give you the hottest spark possible with a given coil.
As an out-of-the-box thought, I now wonder if it's possible to boost the 12VDC delivered to the coils to 14V or something higher without sparking through insulation. A DC boost regulator is the weapon of choice, but they put out a pulse, so a capacitor would be needed to smooth out the chop. This boost regulator is rated for up to 20V of input voltage, which will produce an output voltage of 200VDC. The few components required are less than a dollar each. This would make a good test project but could be expensive if something went haywire and blew. I think I'd test it on a junker car, lawnmower, or go-kart first...
A note on the numbers: Dynamometers aren't at all likely to give you any sort of absolute, calibrated value. Calibrating one accurately is difficult and any tuner is going to want to give you a reason to stick with his unit, anyway, so you have numbers to compare as you work your way through the upgrades. You might want to use 0-60 time or 1/4 mile results to baseline your performance against "stock". Of course, the driver's shifting skill is a factor here, but that might be a reason to invest in thatparticular upgrade. Also, you'll have to make several runs to get an average...a fun problem to have !!!
At any rate, other than missing the baseline pull, you're doing this the right way. (You could, of course, remove all of the mods and do a dyno run with the stock parts... ) I appreciate your sharing your progress with us in specific detail. As you'll figure out pretty quickly, I'm taking advantage of the opportunity to perform some research and document it in a sensible place.
Originally Posted by DarkZ03
cam a built block ... but it will be an add-on to the boost.
This is prudent because a high-lift cam will really show its value with any sort of intake compressor.
Speaking of value, the classic $/HP measure applies here and it turns out that you might get good value from a valve cam change. A 10.2mm or 10.8mm high-lift cam from Z1 Motorsports runs $800. if it gives you 15Hp, then that's $53/HP. This is quite good, actually, given that most mods cost between $70 and $100 per HP.
BTW, the camshaft is Tomei from Z1 Motorsports, so Dark350Z ought to approve. For $1,100 you can get a 10.8mm or 11.6mm crankshaft from Brian Crower. Compare this to the factory cam at 9.5mm. With higher lift, you'd expect more HP over the 10.8mm cam, so let's say you get 18HP. That's $61/HP.
Lift height is only one of several factors to balance; lift duration can be more important that lift height since a longer duration leaves less residual burned gas to dilute the next charge-bang cycle. The Tomei from Z1 has a much longer 258deg duration than the Brian Crower's 222 and 234deg.
A $6,000 intake compressor that adds 80HP will cost $75/hp. If you've put on the right otherparts like high-flow injectors and a high-volume/high-pressure fuel pump, you can expect more HP for the intake boost, but then you really should include at least some of the cost of those additional parts in the dollar-per-horse ratio.
Brian Crower has some comparison graphs that show the relative effect of 10.8mm lift versus 11.6mm. (P.S. The baselines are odd since they don't match. I assume that the baseline on the left is without intake boost. Maybe a call to Brian Crowder Motorsports would explain that.) If one can directly interpret the graphs with confidence--hardly a given in self-reported situations, especially when sales promotion is in full swing-- the increase from 10.8 to 11.6mm yielded 40 HP. While this isn't impossible given that it produces just under 8% increase in valve flow area, I wouldn't assume this is valid until after that call to Crower. I say "not impossible" simply because 525 to 570 HP is an increase of 8.6% and the increases balance out: the high lift applies to the intake and exhaust, so there's a double benefit that indicates each high-lift cam producing an extra 4.3% of power for the 8% increase in lift. With high-flow exhaust and intake compression, this seems plausible.
Since we're at it, we might speculate that a cam lift (as opposed to a face lift or butt tuck ) might produce a 3% overall increase on an engine with high-flow intake and exhaust. If we apply that to your current 277 WHP, that gives 12 HP before adding a compressor. These are wild guesses (with 40 years of engineering experience behind them) so not absolute at all. Just food for thought and constructive discussion. I think my numbers are conservative--at least I hope so. Finding hard, comparable numbers is difficult so, again, thanks for posting your results!!
The issue is OP doesn't have the knowledge to do the cams, which means labor will double the costs. Everything you mentioned is typical text book, but in the VQs case with a more advanced setup... coils aren't "needed" and we have no wires.
I wouldn't used a lighter crank pulley even if I got paid to, and I have lighter brakes, also the Z has a carbon shaft from factory.
So yeah not a whole lot is left on the table to unlock.
I really need to hit the dyno this summer to see where the car stands, I like the feel if driven hard but my ultimate goal is to have the same feeling at 50% which it where boost comes in. I won't necessarily be using all of that power but it'll be nice to have it when I do.
I assume you mean high-voltage wires from the coils to the spark plug electrode. The voltage loss in wires to the primary coil is still a factor (even greater than secondary due to higher current in primary than secondary wiring). No one makes a high-quality ignition harness? What about NISMO or 3rd-party racing suppliers?
Originally Posted by DarkZ03
...which means labor will double the costs.
Absolutely valid point. I've not dug into the VQ yet but the job looks like medium-advanced difficulty. Certainly not for everyone. The install does indeed appear to be $1,100 or so, at least in Southern California; rural Alabama might have cheaper mechanic labor rates; no idea about Vancouver. P.S. this site and its members are a FANTASTIC source of information.
Turbo install labor doesn't come anywhere near doubling the cost of the parts, so the $/HP calculation favors the turbo when professional paid labor is involved. Definitely something to figure in.
This article at ZchickZ.com has some dynamometer data for a camshaft upgrade. The author didn't say what lift was used but 15HP may be optimistic for a valve cam change. It is possible that the 17 HP advertised was for a milder cam profile than the one installed...
Originally Posted by DarkZ03
...I wouldn't used a lighter crank pulley even if I got paid to...
Why is that? Clutch chatter? More work to heel-toe in downshifting?
Originally Posted by DarkZ03
...the Z has a carbon shaft from factory.
So it does. Thanks for pointing that out. Go Nissan! I haven't been under my Z yet but will be upgrading the clutch this weekend, hopefully. I'll check it out while I'm down below.
Here's another possible option: a JWT POP Charger. Jim Wolfe advertises6.5 WHP gain, mostly at top end, by far, starting at 4700rpm. Someone did an independent test and reports 11 to 16 HP gain, though then goes on to say that gains versus a fresh factory filter would probably have been 6HP. Evidently they used a dirty filter in their baseline...? Wow. It's hard to take their test seriously with that sort of oversight. Putting the factory intake back on would have only meant an extra 30 minutes plus another dyno run.
The key question is how it compares to your drop-in NISMO air filter. Could easily be no different. Might only be good for one or two HP...
I've avoided aftermarket flywheels, clutches, and crank pulleys because I feel they are too aggressive to complement daily driver duties. The potential issues with balancing and bearing wear from the aftermarket pulleys have also steered me away. Admittedly, the only cars I've driven with more aggressive flywheel and clutch setups are in Gran Turismo.
No aftermarket brakes for me, as my car already has Brembos, but reducing unsprung weight was certainly important when I was searching for new wheels. Because I wanted 19"s for aesthetics, however, the combined weight of the 370Z NISMO's Rays wheels and OEM tires I chose ended up weighing more (sure, by only 2 lbs, but still) than my OEM 18" setup. Aftermarket 18"s are the way to go with lighter wheel + tire setups for our cars; there just aren't any 19"s available that are light enough to make a worthwhile difference.
It seems that if I'm not ready to spend $10,000 CAD (parts and labour - ugh) on an HKS/Vortech supercharger for a 30% power boost, then $3,000 CAD (parts and labour - ugh) on a mild Tomei cam upgrade for a 5% power boost is the next step. Wow, the camshafts aren't looking so logical.
To those that have installed "mild" aftermarket camshafts - what difference did you experience in sound, particularly when idling? I'm not a fan of that deep idle tone from aggressive cams on our cars (and have zero valvespring upgrade aspirations), hence my focus on the less aggressive variety, but I haven't been able to find any feedback on what sound changes, if any, result.
Unless you are knife edging a crank on a inline engine and balancing it with the pulley, lightweight pulleys don't have a good reputation. I will be using a Nismo twin plate clutch which will chatter anyway.
Not a fan of the pop charger myself.
I would try to go for a used Vortech and install yourself, typically not that hard.
Ever consider nitrous? It is the cheapest bang for buck mod, you just have to be sensible with it.
The total unsprung weight savings by going Advan GT = 10 lbs, but it's debatable whether or not this is a substantial difference. Rays really did a good job on keeping the 370Z NISMO's wheel weight low, and the GT's price of $1,000 USD per wheel is...well...I can't...I just can't
Sounds like you're well on your way. My '06 Rev-Up was making 281 whp with every bolt on. I had a set of JWT S7 cams, but traded the car in and sold the cams.
I wanted to get the GTs myself but then I fell in love with my current wheels. Heavier and slightly cheaper, but not by much. I got a quote on both and the difference was less than $500, what ultimately drove me to get the Work wheels was the ability to order the offset and style I want as opposed to over the shelf choices.
04-08-2021, 12:17 PM
N/A Options Almost Exhausted; Time for Cams and/or Supercharger?
) I appreciate your sharing your progress with us in specific detail. As you'll figure out pretty quickly, I'm taking advantage of the opportunity to perform some research and document it in a sensible place.
