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Mods to Aussie Zed

2422 Views 22 Replies 10 Participants Last post by  ky350
check out issue 306. Zed with headers,exhaust, intake and unichip upgrade got 15% peak power gain and 20% peak torque gain. Done by Romano autosports in Brisbane at a cost of $4450.00.
Good news is (depending on cost) is they are making a jig for the headers so they may be available to buy.
For discussion.....
I don't know how to set up a link but I had to pay for $6 for the issue.
Maybe someone knows how to do it. Pretty good info in the article...
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If your thinking of linking to it, it will not work for us as we dont have the authentication details you have. So your better off to copy the content and post it here as plain text or convert it into a pdf then post it.
The intake is a waste, so it comes down to whether you think a set of pipes and a unitchip is worth 4.5 grand.

15% peak hp is pretty much what we all got with the cat back exhaust swap. The torque is most likely due to the unichip.

You can get that for 1300 bucks.
Headers will void your engine warranty.

The Unichip will void your engine warranty, and unless you're planning on ripping out and replacing the entire loom if you make a claim, Nissan will still know.

You do realise that the VQ35DE ECU can be reprogrammed directly, right? You just plug a computer into the CONSULT port and you can upload a new map? I'm not sure if its tracable (like some kind of change bit), but it'll still give the same CONSULT outputs so unless Nissan goes and specifically looks at your ROM code, they won't ever know.

My cat-back got me a 10% increase. If you think that another 5% is worth $2500+ and a loss of warranty, then go nuts.
Peter said the normal Nissan guys wouldnt be able to tell if you've flashed your ECU. If they got a special guy in to check out an ECU problem then he would probabally be able to tell.

I dont think headers would affect your warranty unless they are found to be responsible for some problem you are trying to claim, then they would not honor your claim and the rest of your warranty should stay in tact. This could change at some dealerships as some are tighter than others.

On my last car I had headers, hi flow cats, exhaust, airfilter and unichip and Toyota wasnt able to tell I had a Unichip for a couple years, until I asked them to check out something that was near it. Even then they still honored the warranty.
yeah.... murray is correc there.... unless they can be able to prove the faults are caused by those mods, otherwise the warranty is still attached!


here is the write up. Good power gains but waaaaay toooo expensive!
Would rather spend 11K more and get APS TT and get real power gains!!
Zed with Zing

The result of basic mods to a Nissan 350Z.

At a glance...

15 percent peak power gain
20 percent peak torque gain
Exhaust, air intake and UniChip mods only
A cost-effective enhancement for any 350Z

The Nissan 350Z. Since our initial test of the 350Z Track edition we’ve received more emails about this car that any other we’ve covered in AutoSpeed.

It’s a car with an absolutely monumental following.

So it’s a little baffling why so few people modify their 350s. Well, John Gaffney of Queensland wasn’t afraid to give it a go - and here are the results of his mods...

“I bought my 350Z Track spec a couple of months ago because I like the look of it and its performance – but mainly its looks,” says John.

“In standard form it has good response and torque – it’s the sort of car you can be lazy with and drive in a gear that’s too high.”

In factory guise, the 350Z’s VQ35DE engine is rated at 206kW and 363Nm, at 6200 and 4800 rpm respectively. The all-alloy 3.5 litre six boasts DOHC, 4 valve heads with continuously variable inlet cam timing and direct-fire ignition. Its 10.3:1 compression ratio means 95+ RON fuel is recommended.

But, like any mass produced vehicle, its performance is compromised by its conservative exhaust and ECU tune.

John took his still-smelling-new 350Z to Bob Romano Performance after having good experiences there with other cars (John also owns an Audi A4 Quattro that’s been elevated from 110 to 165kW at the wheels).

Chris Romano says the 350Z is an impressive bit of gear in standard form, but basic exhaust, air intake and management upgrades provide good gains.

John’s car has a replacement exhaust from the heads back. A custom pair of headers feed into a parallel front pipes with an X pipe joining each side. The twin pipes then merge into a single, large diameter pipe before again separating into dual pipes toward the rear. A single high-flow cat and twin canon-style mufflers are fitted to John’s car. Note that the tips are cut at an angle to suit the style of the car – a nice touch.

Chris says a lot of development was put into the headers.

“We tried six different designs and we settled on a design that gives the best overall spread of torque – a happy compromise between top-end and everyday torque,” he says.

“We hope to be constructing the headers with a jig very soon.”

According to Chris, the factory headers have particularly small primary diameter. Replacing the stock manifolds with a good pair of aftermarket jobs is said to double the power gain normally seen when a cat-back system is fitted.

In other words, it’s worthwhile going all the way with the exhaust.

The only other hardware mod to John’s car is the fitment of an aftermarket panel filter. The lower half of the airbox is also modified to flow a larger volume of cool induction air.

“The UniChip brings the exhaust and intake mods together,” says Chris.

He explains that the factory mixtures fluctuate through the top two-thirds of the rev range and, once the UniChip is wired in, this can be ironed out. Top-end mixtures are also leaned out to enhance power. Ignition timing is also revised over the entire range, with special attention to improving response at light load.

Note that Chris recommends filling the tank with 98 RON fuel once the vehicle is modified. At minimum, a bottle of octane booster should be added to the tank whenever you’re forced to use normal unleaded.

On the Romano Dyno Dynamics chassis dyno, these mods saw peak power increase from 151kW to 174kW at the wheels. That’s a gain of 15 percent, so – assuming the factory quoted power is correct – you’re looking at around 237kW at the flywheel.

In addition to the 15 percent power gain, this graph shows a strong increase in torque all through the rev range – up to 20 percent. This graph shows the standard power and torque curves in red, while the modified curves are in blue. Note that these runs were conducted in fourth gear and in Shootout Mode.

On the road, John says the 350Z is now much more throttle responsive and ‘fatter’ through the mid range. Top-end performance is also noticeably improved – so much so that John is hoping to run a low 13 second quarter mile.

The exhaust is resonance-free and – although much louder than stock – it’s not obtrusive

“I don’t hear it at all while at cruise,” says John.

So what’s the cost, you ask?

Well, Bob Romano Performance charges AUD$4250 for the new headers/exhaust and UniChip fitment and tuning. The replacement air filter and airbox mod adds an extra AUD$200, bringing the total up to AUD$4450. This isn’t a bad price considering how much more difficult it is to extract more power from a NA engine compared to a turbo. John is very happy with the result and has no further plans for mechanical modifications.

The only other mod John has made is a new set of wheels’n’tyres.

“I don’t really like the look of the standard 18s. They let the car down,” says John.

The guards are now filled by polished G.MAX rims measuring 19 x 8.5 at the front and 19 x 9.5 at the rear. Note that John says it was a challenge to find wheels that would clear the Track spec Brembo calipers. Tyres are 245/35 and 275/30 Falken Azenis.

“The Falkens are a great tyre,” says John.

“I still haven’t found their limits.”

Interestingly, the step up to 19s and extra low profile rubber hasn’t caused much extra bump harshness.

“I’m really happy with the car now,” says John.

“I’ll probably hold onto it and see if there’s anything better that appears on the market in a couple of years.”
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Thanks for that.
20 percent peak torque gain

Sorry to be a sceptic, but that statement above makes the rest of it nothing more but random scribbles. I have no problem believing in power-gains of any percentage ... heck, I'm sure that one could get 300kW out of the 350Z while staying N/A.

Though, torque is not something that can be 'engineered' into an engine. In an N/A car, torque is a product of displacement and efficiecy. Both have limits set by the laws of physics. What I'm saying is that torque is not somethng that can be increased in such magnitude on a car like 350Z. You might be able to do so on an engine that is pushing far from the optimum numbers, but not the 350Z. 350Z produces 363Nm out of 3.5L engine, which makes it's 'efficienty' for producing torque 103.7Nm/L. That is very efficient and will put in into top 1% of engines in world ... anything over 100Nm/L is very impressive. The torque/liter figure is dictated by physics and efficieny ... and effience has limits. The most 'efficient' production torque/L engine in the world is in the M3 with 112Nm/L. Other cars in that range are some of the new exotics like Ferraries. Even S2000 manages a 'measly' 104Nm/L.

So to say that there's a 350Z engine producing 20% more torque than the standard 363Nm would mean that the engine would have to make 435Nm of torque, and in turn 124.5Nm/L!!! Not even F1 engines can get close to that.

Realisticaly one could possibly see 110Nm/L from the 350Z engine, but I don't think it's going to be as simple as intake/exhaust/cpu. Still, even if 110Nm/L were possible then that would see the 350Z engine producting 385Nm, which is less than 6% improvement in peak torque figures ... not 20%.

Top-end performance is also noticeably improved – so much so that John is hoping to run a low 13 second quarter mile.

And here's another quote which casts a shadow over the reputation of this article. Low 13sec quater? We've had a fair few people on the 400m strip with the 350Z ... some were stock, some with exhaust, and some even with exhaust, filter and Unichip. So far we have not had a manual 350Z brake into the 13s, even though I'm sure that in theory with the quicker ones can probably make a 13.7sec given perfect conditions (maybe even 13.6s). I seriously doubt that even in theory that there is an exhaust/filter/unichip car that can run another 1/2sec quicker. Not on road tyres.

RWD cars running low 13s unsualy have better than 6kW/kg weight-to-power ratio. Realisticaly a 350Z with exhaust/filter/chip will push 230kW at best, which would give it 6.3kW/kg.

“The Falkens are a great tyre,” says John. “I still haven’t found their limits.”

Even with my R-spec tyres I can find their limit pretty easy ... it sounds like he does not know much about cars, let alone about driving them hard (even in the straighline). Afterall, its pretty simple to brake traction just with a quick gear-change.
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Just putting this up...Like I said I think it is way too costly to contemplate...
Attached is a link to the dyno.... .
Attached is a link to the dyno....

You can make dyno say anything. We have a range of reading from 140 to 180kW (atw) for the 350Z. Most of the variaty in the readings is between the dynos, not the cars. No only that, but we don't know when the pre/post runs were done ... it's pretty easy to get different pre/post figures without changing a thing on the car, just by fiddling with the dyno.

My problem is with the '20% increase in torque' claim ... I'd almost say that it's physicaly imposible (on anything close to resembling regular fuel).

ps. Here's another 'bogus' article from autoSpeed. This one claimed 27% increase in power for the S2000, and has the dyno plots to back it up. Though so far 10% is the best anyone managed out of the S2000 ... and even for that it took a lot more than this article mentions.

From what I remmeber, the S2000 guys found that that they fudged the 'original' power figures/plots, and the resulting power/plot is really what a stock car has. So in other words, there were no gains at all. Which is what (I think) someone proved by putting the same mods on the car.

Oddly enough, it seems to mention "Romano" in the article as well.

Those are nice mid-range tyres (ie. Azenis ST115)... I put them on my sisters little Mazda 323. They might be on par with the OME RE040, but are generaly classed as a lower spec tyre.

ps. I've found their limits on an 80kW Mazda without any problems ;-)
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Yep, I am sceptical as well, no doubt that 'romano' might have written the thing himself.
I thought it was interesting though, and posted it because we don't have as much write ups in Oz on the Zed when compared to the USA.
Nice to have some homegrown stuff...
The dyno tyre pressure is wrong and they didn't run the car in 1:1 ratio. Which is 5th gear.

Expect to see 165kw with the correct settings.

As stated're not going to get major Torque gain without FI.

I disagree with his choice in wheels.

In the looks department and the potential weight increase.
never seen chrome wheels that look anything but "tizzy".


Get some RAYS



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Gotta agree Murray. Don't like those wheels.
I agree with all of you.

If this car was making 435Nm, it would be a missile between 2-5000rpm. But the owner claims only a little better throttle response at mid range.

WTF is it with all these dyno testers running the Z in 4th gear. If you don't run it at a close 1:1 ratio, then you may as well run it in 1st gear and claim to be a dyno queen. Infact, I believe that Romano ran it in 4th just to display a large power number.

And those wheels. Well if you ain't got nothing nice to say, then don't say nothing at all, if you know what I mean!

After all this critisism, I'm sure the owner is satisfied with his Z - but we must sort the wheat from the chaff.
Its ok if you like the wheels KY, your entitled to your opinion as well. ;)

Post edited.
I cannot comment on those wheels, but Frosty's rays look about 1000% nicer!
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