Nice numbers but im sure the z has more to give. Keeps us posted!!!

 

During the tuning you could see airflow after 5000 rpm is hurting the topend performance. I really don't know what is the bottle neck. I can't tell if I just don't have the cam advance just right or the intake manifold or the throttle body is limiting the airflow. Below 5000 rpm the limiting factor is the cam advance. If I could have advanced to 55 degrees I really believe I would have gained a significant amount of torque compared to a stock Z below 5000 rpm.

 

what kind of dyno was used?

 

It was a dynojet from UpRev. I am going to change out my exhaust to and redyno where I had my car dyno'ed last to see if the differences.

 

cool keep us updated. I thought your numbers would be higher on a dynojet. weird!!!

 

I figured they would be higher...I mean we we advanced the cams and got to 279 rwhp I figured when we adjusting the timing I would pick up a at least 5 to 10 more rwhp. It was weird that I didn't gain but maybe 1 or 2 hp from ignition timing and all my gains were from AF ratio and cam advance.

 

the exhaust, throttle body, etc are not your problem - I doubt you'll see any significant changes. Your headers (I think you run the NISMO?) are one factor for sure (not going to play all that well with those cams)

the timing (not even talking VTC which can shift the power curve around a bit for sure) makes a HUGE difference NA - what it comes down to is what their timing maps look like. You'll pick up lower end power by advancing the VTC on the intake side, but it won't really make any significant differences on the top end.

 

I think 279 rwhp is pretty impressive for an NA VQ. Is you engine a revup?

Did you ever think about putting the stock MAF back on and trying that? I've heard that the larger MAF tubes can hurt unless you have a lot of headwork done.

 

Well its a nice start and good working platform. And I think you are going to use it for Track events Roadcourses. I would really like to see a dyno.(I know your waiting for it) What are you reving out at?

Chris

 

I am running the Nismo headers...I would love to do some good long tubes.

The VTC helped bring back power on the bottom end and midrange. After 5000 rpm UpRev stepped down the advance from 27 degrees to about 6 degrees at 6600 and it did shift the peak power from about 6200 rpm to about 6500 rpm and added about 15 rwhp on the peak side. The software was limited to cam advance only to 6600 so we couldn't see what would happen with continue to slowly bring the advance down after 6600. Once UpRev sends me the dyno data I will post some of the progression of the cam advance and their results.

As for the timing that is why I was surprised I really couldn't make significant gains....I wonder if the sweet spot is very small so you have to be right on it to make a difference.

 

That's a fairly good start. I too, would expect a little bit more from a DJ number. That is the type of number I would expect from our DD instead.

I agree with your tuner, that even when running race fuel, there is minimal power to be had by running more timing up top.

 

It is a non rev up...actually I made more power with the maf housing after we tuned for it. Should work good with the Cosworth heads.

I am reving to 7350...really didn't need to go past 7000 but I wanted a little bit more room so I could shift right at around 6800 rpm and not bounce off the limiter.

 

So is that normal? Well I guess I am going to need the Cosworth manifold now!

I really think finding the perfect cam angle is going to really increase the power. I noticed if we moved the angle just a couple of degress we would lose a chunk of power. For example...Uprev set the angle from 6 degrees to 8 degrees at 6000 and I lost 6 hp consistently until we put it back up to 6. Just didn't have enough time to keep looking for the perfect angle.

 

I was also thinking that your camshafts would have created more improvement up top in the powerband. I can't remember if they were Tomei 272's or even higher??

 

I have one question. Why did you choose to keep the compression nearly identical to stock on an N/A build? Wouldn't moving closer to 12.1 be a much better idea for an N/A build? You managed to ad .6 to your compression ratio, that sounds pretty lackluster to me. Anyone have any input on this?

 

I think the duration specs are hurting things. Too much exhaust duration and not enough intake duration to take advantage of it. He's got a ton of overlap I'm sure due to late exhaust valve closing, but the intake valve closing isn't late enough to make power up high enough to reap the benefits of all that overlap. Then there's the whole "excessive cylinder blow-down" at lower RPM thing from an exhaust valve opening that might be too early considering the significantly improved exhaust port flow (cosworth heads).


We'll never know exactly what's going on without valve timing data, though. It really sucks that JWT is the only cam manufacturer (that I know of) that offers it. Lift and duration specs are NOT enough!

 

The cams are 272's and I agree....thought the higher duration would have improved the top end. Once UpRev can get the VTC adjustment past 6600 I might be able to get more topend...I can't carry any cam advancement past that point and its at that point my power falls. I want to try to carry a couple of degrees of advancement past 6600 rpm to see what happens.

I didn't want to have problems running on pump gas and I knew it would be awhile to before I could get the car tuned. I agree a higher compression ratio probably would have really worked great with the cams.

Good point...didn't think about that.

 

compression has very little overall affect when on pump gas, and it only has a big affect on race gas when you start running big compression figures

I am only at 11.3:1 - jumping to 13 might have netted me another 10 hp...maybe

The cam specs are fine...again, mine are way milder from both a duration and lift and my car is making nearly 30 whp more, on a dyno dynamics. In fact the Tomei's have a really steep ramp rate, and as such, make broad power. The headers are definitely limiting things (not the right one for those cams), but even still the #'s should be higher I think.

Again, I don't think the VTC is your issue whatsoever, and in fact, I didn't even adjust it on my car (I have no way to do it as I didn't use the NISMO VTC pullies nor can UTEC adjust for them)

Your timing is insanely weak to be honest with you. You are running WAY less advance than you should be (I am running considerably more than you and mine is really, really conservative still)

Other companies give you the cam specs with the cams...it's on the cam card they provide (I got one with my Tomei, and I'd assume the set he is using got them too), so setup should be quite easy. I didn't even need to buy new lifters with mine (retained my stock valves though I went to NISMO springs)

Definitely a good start, and nothing to sneeze at, but I wouldn't start ditching parts just yet till you get it narrowed down

Start with the fuel/ignition maps first...worry about VTC angles last

You also should be revving it higher too (speak to Sharif about where he feels it can go to comfortably). I hit 300 whp at around 6700 ish rpm. At 7350 for example, I'm a bit over 300 whp and rev'd to 8200 as I recall on the dyno (and now have upped it a bit more)

What was torque curve/peak like?

As for the MAF it will absolutely help if you've got the heads to support it (which you do, even if they are unmodded). The throttle body, I honestly don't think will change things all that much, yet.

Also - this jsut dawned on me too. What spec 272 are you running (they offer a dew different ones). Got the part #?

 

Maybe I missed it, but how much timing are you running near redline?

Also, post up a dyno chart...we are somewhat blind without one.

I'd like a crack at tuning this thing, if you can bring it down to us. Would make for a fun roadtrip!!!

 

According to Z350lover's findings, going from stock compression to 11.5:1 netted 19 WHP. That's pretty significant in the n/a arena especially considering these gains from raised CR can be found everywhere in the powerband.

Do you know this for a fact? Duration and lift specifications are only 1 part of the equation when it comes to cams. Too much exhaust cam duration can do more harm than good depending on where that duration is placed, exhaust port flow, and the intake cam specification.

I guess I should've said they make the valve timing specs available to you BEFORE purchase so you can make a truly informed decision. What good is knowing specs AFTER the fact? You're stuck with 'em either way.

He stated that the HP peak was at 6500.

A larger MAF housing can add power and improve throttle response even with stock unmodified heads.