Sounded nice when you took off today from the shop

 

^ I think the exhaust is pretty broken/insulated with carbon now; I noticed it sounds a little less harsh. Nice FB post haha.

 

Headers shipped, but got caught up in customs. I'm hoping they'll be here by the end of the week.

 

Nice.. Suspension wise, I suggest sticking to quality coilovers. You can run them near stock height (like mine). I have HKS sport III coils. If you want a ride let me know. I think we live near each other. (Old bridge)

 

Nice. My first choice was the Bilstein Pss10s, but I actually picked up a suspension off a 07-08 Nismo, so I have a modest drop (I believe .6") and a more aggressive springs rates in the front and rear. The rears are also progressive.

I have probably seen your car around. I live by the EB/OB border. Near Old Bridge Tpk.

 

^ its a date gentlemen.

i honestly love my bils, no issues smooth ride and they get crazy aggressive the harder i start driving.

having driven other z's with diff suspensions they just do not compare in my opinion. but we'll see how the mo's do on yours.

 

^Yeah. Will be nice to see something a little more aggressive. I'll pm you,Plump.

Dr, I have that GTSpec front lower tie brace that I need to install with the Nismo stuff and then get everything aligned. Should stiffen the front up some more, but the front and rear will not compare to the seam-welding and everything done to the Nismo Z. I'd prob need the 4-point underbody brace to compare.

Either way, should be a nice upgrade over standard OEM. Wish I had the adjustable ability, though. Oh well. It will remain an upgrade to anticipate.

 

 

Oh ****!

 

As far as the vacuum leak. I suggest letting the PCV valve vent to a catch can and blocking off the vacuum port on the plenum just to see if it improves things and also maybe drill out the PCV valve. I have a vacuum leak from the PCV system now and don't know why.

https://my350z.com/forum/engine-and-...cuum-leak.html

 

Off the shelf coilovers are usually poo. Extreme spring rates (too high, or too low) and mystery dampers, whose crappiness is generally hidden under the term "adjustable"

Select a spring rate, and get the dampers to match.

 

We picked up 30+ whp at redline w/ the addition of headers, a short 3" exhaust, and a gutted Maxima intake manifold w/ minimal power loss in the low RPM ranges (I probably could have tuned it out, but the car stays wound out). I put the redline at 7300 before the day was over. (VQ35 in a Sentra)

Most headers are going to be "designed" (and i use the term lightly) for a motor that is close(r) to stock.

Can't say for sure what mod the power came from because we did all 3 before we hit the dyno. We addressed flow on both sides of the motor and it paid off.

 

Nice work, huge difference up top.

 

Hey Kacz, did you ever run a diagnostic log of the engine to find out if there was a problem on the top end (coils, cam phasing, etc.), or are you suspecting the headers?

 

FWD, nice gains w/ those mods. I spoke to JWT a while back about optimizing my setup. This was before the SG headers went into production. I believe I spoke to Bill/Ben? and Clark and reviewed each mod that I had. They actually told me that SG was making headers for their cams, specifically, the C8Rs found in my motor. I realize that a "tuned" header is an arbitrary term, but the SGM research presented here and the recommendation of the JWT engineers helped to make the decision to pull the trigger on them pretty easy.

Some of the manifold discussion in SG's "346whp w/ no boost" thread points to the revup manifold as a harbinger of high RPM power. I'm going to point to your modifications to the Maxima manifold as YOUR redline power generator on STOCK cams, moreso than the headers. No doubt they helped you, but opening up the intake to allow them to to generate power and keep the tq up at high rpm.

If you threw some more aggressive JWT/BC/Tomei cams on your setup, you might see powerband begin to mimic the stock powerband (with the tapering of power towards redline) again as you start reaching a point where the headers or gutted manifold reach their flow capacity. That peak at 6250rpm will become more prominent. In my amateur opinion, I think the headers would be the chokepoint first, but there is so much grey area that is filled in with the cam timing.

 

I am bringing the SG headers over to RT for install and tune. They also have to take a look at a leaky GTM oil cooler and inspect the valve covers to try and remedy some slight oil loss.

Again, in my amateur opinion, I think the headers and a little cam timing adjustment will allow the engine to hold power in the high RPMs, rather than tumble downhill. I think that keeping the MD Mrev2 on will give me a little more low end grunt than the revup, but it will cost me a little peak power up top. Still, it will flatten the power from 6250-8000RPMs, just might not hold or peak quite as long or deep into the revs.

Additionally, the ported exhaust runners, on the Import Parts Pro built longblock, running into smaller primaries from the Megan long tubes are likely affecting the mid/top, but I am unsure how (could be keeping velocity up w/ smaller opening or slowing it down by way of restriction(larger exhaust runner I.D. running into MR primary tube I.D.). I don't know how much they were ported, but I can find out when RT swaps them out.

Again, a discussion in SG's "346whp" thread between Sasha and GT20IR talked about primary openings and midrange and top power:

https://my350z.com/forum/8823002-post83.html

^That's where the discussion begins.

I don't have time to complete this post, but I will get to it later.

 

JWT uses a specific method to come up with cam configurations. If you look at their exhaust durations vs. everyone else they tend to be more aggressive on the exhaust side.... for a reason.

There is no doubt a lot of the gains were related to the intake and the changes in resonance that happened in removing the divider but also, and probably more so, due to increased plenum volume available to each cylinder, like with a plenum spacer. But, addressing the exhaust side helped tremendously. Even as I pushed the redline out further there was no drop off in HP, it was literally a flat line all the way out. not much peak gain, but amazing up top, and this is with OEM cams and no head work.

As your cam durations go up and overlap goes up the motor is going to become even more sensitive to exhaust flow variables, more so in regards to JWT cam sets because of the way they are designed. The duration, and cylinder head flow numbers on a bench may look great, but what goes in has to come out, or the ratio of in to out gets jacked up.

Stepped headers work well for a reason, once the low pressure area behind the exhaust pulse is used for cylinder filing it really becomes all about mass flow at that point (so if you figure out overlap window, exhaust speed, and cam profile you can calculate primary length), which is the reason for the step up and the largness of everything past the primary pipe. SG talks about what changed with a primary pipe diameter change. SG also said they lost power with a ported head. I would like to see the C10 exhaust cam with the C9 intake cam, as opposed to the test they did with the c10 intake cam and c9 exhaust.

Ok time to go, been on the computer too long.

 

Kacz07, your z is still slow.

 

^Hahaha, your setup is probably pretty legit. You need some dyno numbers. I'm curious.

 

https://my350z.com/forum/8823309-post84.html

The ported heads may not have been what caused the restriction so much as it was the primary diameter, being 1 3/4 of an inch. That step may have been what was causing the biggest restriction. Throwing 1 7/8" production primaries on a ported head might change that. It is still untested. Agreed?

Dang. I misunderstood that post. It still goes from 1 3/4" to 1 7/8", but does not include the 2" step. I'd need the 1 7/8th primary. So, the headers will not release all that power until I have larger primaries. I'll have to see how ported the exhaust runners are.