Anyway, back on subject. Judging by the dyno charts you can see how drastic the effect of the velocity is, your max hp/tq RPMs are way more desirable for a track car. I'd pick yours over his any day, his higher mid range torque would be better on the street tho.
If you can have one made that's bigger and better you would probably raise the peak hp even higher in the powerband.

 

@RobPhoboS

I just compared your dyno sheet against my own dyno sheet and they look very similiar the only difference i can see is that your torque is dropping off at around 5200 RPM yet mine is still rising at 6000 RPM.
My guess would be if you improve the intake that the torque won't be dropping off this fast.

btw i looked around in mine shop and found a 3.5 inch intake (around oem length, made of steel) i can send you this if you pay for shipping to see if this improve your curve, but you still need a new sillicone curved hose to remove that bottleneck.

 

Ah cool, I will have a look at their software, granted I won't know much about it but curious to look.
I shall definitely send you a PM !


Yep, at least that's something I can easily resolve here. Not sure why it's particularly bad on my setup.


Might be worth trying to get a couple of intakes made, one at 3.5 and one at 4, with the large velocity stack/filter, short and blocked off from heat as much as possible.
Would be easy enough to switch over to see if it made any difference.

I'll have a look at why my coupling is messed up over the weekend, I'm guessing it's probably too long or the pipe itself is pushed up too far into it.
I remember your cams are more aggressive than my ones so we'll always have that difference but yep, perhaps the larger intake may help the torque curve a little more for me too
I shall send you a PM regarding the tube you have, that's also much appreciated !

Thanks for all of the replies !

Just reading through onevq35de's post here (for ex, although his quote looks like its from a Camaro board):
https://www.infinitiscene.com/thread...5#post-1245013

 

I'm aware of his setup and was actually going to suggest something similar, if you are concerned with squeezing out every last HP up top then just get that 3.5" cold air and that should be it. Now if you want to experiment and possibly end up with a better feeling car, short ram is your friend. My initial idea was to use the stock box, but altered enough for stack and a 3.5" pipe. You could make your own heat shield but I would recommend having a duct in the bumper to maximize cold air induction.
It would be interesting to see a 4-3.5" gradual taper intake but that would be a bit harder to make, I would try to not have a silicone elbow tho, full metal is possible but you might need to use pie cuts.

 

Rob, how about taking it to see Mark at Abbey literally just for a dyno run on their Dynapack hub dyno? Shouldn't cost that much and only about 1½ hours from Jez?

I'm pretty sure Jez's dyno reads at least a little low, and it's a chassis dyno meaning lots more variables.

 

Also keep in mind the throttle response will be much better with a short ram vs a cold air, that curve at the front kills velocity needed for said throttle response.
I'll admit if I cared to switch intakes anymore I would go short ram without a doubt, the injen pulls directly from the grille which is cool but I do notice the low response vs something like the Stillen intake. If you can fabricate a copy of the Gruppe M? intake that's the best designed but also most expensive.

 

Hey msitpro!
Actually Mark is only about 20 mins from me, heh. I basically ended up heading to Jez for consistency as it was the first place I had it mapped.
It would be interesting anyway just to see what it's like on a hub dyno.
I think first, mess around with an intake.



I'll see what we can get done, and appreciate your input too!
I think either a 3.5 or 4" should work better in my case just due to the cams/head work (well, I hope that's the case hah). I've no idea about a tapered one, definitely possible!

My hot compression test went OK I think, 170-178, which sounds okay for the C8 cams. Makes sense the static compression will be down a little compared to stock.
The one step colder spark plugs look alright too, they have about 350 miles on them now. And the pistons have a bit of carbon on them already but I think it's clearing up a little compared to how they looked pre-remap.

​​

 

Rob - what do the C8 cams effect with a compression test?

 

I meant 'dynamic' pressure, my mistake
Also a couple of years ago one of the engineers at JWT replied to me about my compression test (when I was trying to determine what was going on in my engine):
'On the cranking compression test, the cams might lower the value by 15 psi but not by 20% in each cylinder.'

A quick google:
'...back to those two identical engines with different cams; if you did a compression test on either of these two 9:1 static compression engines, the engine with no overlap (or even negative overlap) would probably have about 140 -150psi or so in the cylinders.
The engine with more overlap may only have 110 - 120 psi or so, depending on how much overlap the cam has, how narrow the lobe separation angle is, and most importantly... what the intake valve timing is.'

 

Interesting Rob - I'm a little bit smarter today!

 

Minor update, just need to take some measurements to ensure the spare pipe ItsLeon has will fit (should be fine) & I also picked up a ViPec ECU.
The ECU AFAIK, runs on the Link G4+ software, I'll know once a laptop arrives and I can temporarily plug it in to confirm everything works.
A good mate over here had it spare from his build, was an irresistible price so I thought why not, it should be ideal for my Z.
I don't need anything fancy and it opens up far more options for tuning and some good safety features for the engine.

I most likely won't be using it at the moment for a couple of reasons.
Firstly I need to work out what to do in regards to widebands (no idea what I can use), I'm not fussed about having a gauge inside the cabin, I just want it to work with the ecu.
Secondly, well I just want to use the car for a few track days before getting into tuning again.

Had a rudimentary alignment done too as I replaced some aging DW fuca's (gone with GKtech v2s):
Front:
-3°30 camber
-00°02 toe
+9 caster

Rear:
-2°30
+00°07

 

Well, thought I'd revisit this thread and it's continuation of oddness...
So fast forward pretty much 1 year - what little has changed:

I slung an ISR single exit on (y-pipe back), just as I'd had the other exhaust on the car since around 2013.
I made a 3.5" short intake, with a 'custom' air box around the filter (made with DEI 'form-a-barrier'), not pretty but works.
Note, wouldn't work with the stock air box, cut one open and not possible due to space and my filter/velocity stack
Installed the Vipec ECU (Link G4+), widebands & IAT sensor (no more MAF).

Here's the weird bit - it made EXACTLY the same HP as last time ! (1hp dif)
Same dyno, different tuner & venue.

I'm utterly perplexed as I would have expected either more or less, not the same
So for now I just want to drive it, get the roll cage sorted, tidy it up and some more track days sorted!

I don't really want to rip into the engine again to chase a few more HP at this stage as the original goal was to have a reliable engine... but obviously I'd like to know why it's not quite reaching what I'd expect.
Of course I probably won't find out unless I go further with it (ITB's, dif cams, higher CR, more displacement).

 

Howdy again

What dyno was it run and tuned on this time?

I'd be interested in seeing the graph, VE, ignition and VVT tables from the Link too.

Even the past run; on Jeremy's dyno, 327bhp is likely minimum 285whp (42hp transmission loss) and possibly as high as 290whp.

290whp would put you right in the ballpark where Sasha tested his C8 cams at I think?

 

To be honest there's no reason it should make more from the change of ECU, on the assumption that it was tuned both times with timing at MBT and fuelling somewhere between 12.3 and 13.5:1 at WOT in high rpm.

 

Hello sir !

Same dyno (Dyno Dynamics & same config just in a different place).
Well the reason I wondered if the power would be different is due to the (thread title) intake tube being a restriction/issue, which it doesn't seem to be better nor worse.
Which is why I thought there would have been a difference at the very least going from 3" to 3.5" + shorter.
Yeah I didn't think there should be a difference just from the ECU change itself, although it's fantastic just being able to hook up the laptop now and adjust anything I need to.

Happy to ping you a few screens from the Link.

Dyno


New (bit more torque)



Old

 

One thing i noticed from the dyno sheet is there is no correction for weather? These have a big impact on how much your car is making. If the old dyno run was done in the winter vs the new one in the summer the difference can be high.

 

Could be worth looking at.

Usually dynos use a SAE STD correction. Think it's based on like 19°C ambient or something and a specific air pressure and humidity.

Dyno Dynamics do always seem to read lower than a Dynojet even with SAE STD correction. Because they are always in bhp I wonder if their calcs for determining transmission loss are different.

I have a turbo mx-5 that when it was dynoed on a MAHA dyno shows losses at bang on 40hp at 7000rpm, which is always the estimate that Mark at Abbey Motorsport used. As power increases to say 400bhp it may creep to 45hp loss.

Rob, if you use atgtraining.com VE calc using your air pressure and intake temps then you can work out your VE at specific points. You can then use that calc to work out power at different IAT temps.

Don't know if Link takes lambda into consideration for VE numbers, but a full bolt on DE (mine) or a stock HR peak about 110-111% VE from memory at peak torque output.

Yours should reach higher than this with your larger cams.

 

Based on 290lbft/253bhp at 4600rpm it looks like in your latest dyno, and assuming 101kpa and 30°C IAT, you hit as high as 123% VE

Edit- just opened this on desktop - I see IAT was 26 - VE of 121% - still very impressive.


One thing your data may be showing at long last, is how the Kinetix intake that you (and I) have doesn't seem to flow that well... slightly better than a DE plenum, but still nowhere near an HR plenum. (dual TB benefit ofc)

Note that peak power stops increasing at 6800rpm... with a 272 agree cam and 12mm lift!! That's more duration and around the same peak as a VQ35HR and they peak around 6800-7100rpm with their 248 degree duration cams.

Myself also coming from mk1/2 MX-5 world - Mazda B6/BPs 'notoriously' have poorly flowing heads, but if you put a 270+ degree cam in there you'd be hitting peak power over 7800rpm. Even 264 degree cams would be over 7500rpm at peak.

Supposedly VQs have ports that flow pretty well. So this points to the plenum being the bottleneck. And we have seen this proved by Sasha of course. I wonder if you slapped ITBs on there if your peak power point would rise to 7800+

 

Really appreciate you taking the time to have a proper look at that !
I've not used a VE calculator before, spotted but not used (will check out some YT vids!).

My car is on the stock (not flow tested) injectors, we're using Traditional mode for fuelling (instead of Modelled).
So from what I vaguely understand, there's no VE table in that mode unfortunately.

I still have my original plenum, and had been considering doing a similar thing to Sasha (widen/smooth the neck), and an extra large spacer to see if that makes a difference over the Velocity.
I had considered trying to get the HR plenum and dual TB's to work as well (not sure it's possible with my Link G4+ and the Link E-throttle G4 device), although they have squared runners iirc.
And yep, lastly, it would be ITB's

Each one going up in price

I guess I should rename the thread.
Ruddy, bloody VQ plenums or something like that

 

What a masochist

Tuning by pulse widths in milliseconds then I think? Mad