nismology

iTrader: (8)

....but this time it's on pump gas!!

http://www.my350z.com/forum/showthread.php?t=284761

Relevant parts list:
Weisco Pistons (.020 over stock)
Eagle rods
ARP rod bolts
Fully balanced and blueprinted - not only balanced as individual components, but also balanced as a rotating assembly
OE Nissan bearings
Full Ported and polished heads
5 angle valve job (stock Nissan valves)
Tomei 268 cams (268 duration, 10.5mm lift)
NISMO valvesprings
NISMO headgaskets
Lots of time spent porting stock, non rev up lower plenum -we logged over 100 hours between the heads and plenum, going off recommendations from MCR Japan, as well as things we found on our own.
Motordyne 1/4 inch spacer
Unorthodox underdriven crank pulley
rev up oil pump
Final Compression checked in at 11.3:1
3 inch MAF housing




Note the relatively mild cams and CR. There's more power yet to be squeezed out of this platform, for sure.

gtr_rider

iTrader: (50)

you sir are making us think you actually got some work done

SR20DEN

iTrader: (7)

Very nice. I wonder what it puts down on an internet dyno.

03BlkSETE

iTrader: (3)

Good stuff. The only frustating thing, is that just about all that work requires big money. I wish their was a cheap way to bump compression up.

DandyMax

iTrader: (7)

Hah! Funny how all of these 300whp N/A Z's are never on a DynoJet..

Nevertheless nice build.

nismology

iTrader: (8)

Dynojets typically read higher than DD. On an internet dyno (as SR20DEN said) the numbers would likely be in the 315+ WHP range. I support his decision to have it tuned on a load-based dyno, either way.

nismology

iTrader: (8)

Higher compression is only a small part of a good build. But yes, custom C/R pistons on their own are in the $800 range.

DandyMax

iTrader: (7)

Sorry I sometimes forget that things often don't "read" on the internet the way you intend them or would say them in person with body language etc. My remark was just me being in a facetious/tongue in cheek mood.

I understand exactly why those kinds of dynos are being used (did you really think I didn't? ) and I take no issue with it.

03BlkSETE

iTrader: (3)

Yeah, plus the cost of tearing down and putting the engine back together. Unfortunately milling the heads or using thinner head gaskets are not an option for us.

nismology

iTrader: (8)

Noooo. I know you know what the advantages of tuning on a load-based dyno are. I was just saying that I'd do the same if I were in his shoes and would choose that dyno over bigger numbers to post on the internet.

speed racer

iTrader: (10)

That is nice. Like to know what he actually did to the heads to make them flow more. The balancing of the Crank is key to having it rev that high up. I imagine there is very little vibrations since he shaved and balanced the crank to as close to the center of gravity as possible.

msp35

Where's the torque?

nismology

iTrader: (8)

If you're asking a serious question the relatively low torque could be attributed to the modest compression ratio, lack of an aggressive cam lift, or the tune. Might be a combination of all three. I'm assuming you actually clicked the link and saw the graph.


If you're being facetious (read: trolling), tread lightly. That's as nicely as I can put it.

Jeff92se

iTrader: (82)

Where is your logic? The torque curve is pretty damned flat if you ask me. And that's what you want. Torque is more based on displacement on a NA build.

Looks like they used rpm and alot of breathing mods to make that hp number. Odd thing is I see a stock upper manifold w/ no spacer. Maybe the lower is hogged the hell out. Which makes that decent torque curve all that more impressive.

nismology

iTrader: (8)

They used a 1/4" spacer Jeff. But I'll admit, the torque number is kind of low compared to other 290+ WHP n/a dyno's I've seen. As a rule, cams with more valve lift will produce more area under the curve, especially in the mid-to-top end. I'm sure that's playing some part. Low end torque can be better as well. But yea, they ported the lower plemun along with the heads. Don't know about hogging it out though. Sounds like they were pretty deliberate and careful with the porting job.


But we have to take into consideration that this was on a dyno dynamics machine. Had this been on an internet dyno (dynojet) the torque number would be well into the 250's.

DAVE Sz

iTrader: (2)

am I supposed to be impressed?

XJinCT

iTrader: (3)

hmmmm very nice

nismology

iTrader: (8)

How's your build coming along?

Jeff92se

iTrader: (82)

Depending on the cam, they usually hurt torque to get high rpm hp. I believe duration is the biggie that hurts torque if it's too long. More lift might also do this if it also affects the duration. You can't ramp it open/closed too fast as it hurts valvetrain life. But it looks like his torque is pretty good down low but tapers off up high. Torque also might be hurt from the porting. As larger ports and more intake manifold area typically hurts gas velocity. But again, looks like they avoided a peaky, high rpm motor. Props.

DAVE Sz

iTrader: (2)

I don't think I'd waste my time with that. Is it really that hard to get 300whp out of a 350z?

Jeff92se

iTrader: (82)

I suppose if it's a non-rev up 03 motor. What was the 03 z putting down? 240 whp? That's over 60 additional WHP na.

I know it sounds easy to you Dave.

nismology

iTrader: (8)

You're correct in that duration dictates where the power is made for the most part. But if you compare two cams with identical duration where one is 10.5mm lift and one is 11mm lift, as a general rule of thumb the cam with more lift will have make more mid-range torque, especially on the intake side. At least with VQ's. That's the general consensus on my350z and I've seen some dyno's over the years that support that. The trick with cams with high lift is to get it to peak lift as quickly as you can without introducing excessive friction between the lobe and tappet so that the ramp down can be more gentle. This is what tomei does with their pro-cams (11.3mm lift).


And good headwork doesn't always involve hogged out ports and reduced velocity. One of Crawford Z's cars use 292/265 cams with around 11mm or more lift and headwork along with the crawford plenum (among other bolt-ons) and made significantly more power and torque EVERYWHERE compared to the stock baseline. From like 2500RPM on up. The mid-range was much fatter, surprisingly enough.

nismology

iTrader: (8)

Well it's not as simple as a pushrod V8 where you get a head/cam package that essentially does what this build did without ever touching the bottom end: significantly improve cylinder head flow, more aggressive cam(s), and increase compression. To increase compression with our motors, you need aftermarket pistons. If you do that, you might as well throw rods in. That's ~$1300 right there, at the very least. Since there are four camshafts, it's usually gonna cost > $1000 for GOOD aggressive cams. Proper headwork? Easily looking at $2000 or more. Then there's the cost of machining the block and balancing the bottom end, among other details including gaskets and fasteners. It's not that it's hard so much as it's expensive. The built all-motor path IS NOT for people looking for HP/dollar. There's more to it than that for the people that decide to go through with it.

It also goes beyond peak HP numbers. You absolutely CANNOT beat the response of a dialed-in all motor setup. Also the amount of HP that it carries to it's 8000 RPM redline and the higher average HP throughout the rev-range makes for a quicker car than the the peak HP number would suggest.

KRRZ350

iTrader: (29)

I love how nismology considers tomei 268's mild cams...... and yes, I already know your response to that one. to the comment about making us think you actually got something done

DandyMax

iTrader: (7)

They ARE mild cams... hehe

DAVE Sz

iTrader: (2)

I know. I take a **** in the morning and my max gains 11whp.........