Char's E92 Build thread

[Rupert]

I've watched the exact same car make two runs within an hour of one another and get results that were 7-8 HP different.

They're good tools, but they shouldn't be worshipped as the supreme and flawless references that some internet bench racers treat them.

Right, on the other hand, a difference of 100 hp is pretty clear (unless there are some huge methodology mistakes).

[GoCougs]

I don't trust dynos unless there is a pretty serious effort at a scientific approach.

They can be trusted, just not trusted to reliably discern 5 or 10 hp, or anything close to that.

[GoCougs]

Or you can use a dynojet that's actually calibrated by dynojet - and reads the same as another one across town.
I'm amused at people who criticize chassis dynos and have never used one themselves.

Does it help if one has designed a chassis dyno?

Simply peruse the chassis dyno results of the SAE-rated Ford Raptor with the 411 hp 6.2L vs. the SAE-rated 2011 Mustang GT with the 412 hp 5.0L. There is typically a wide variation between the two despite the fact that actual engine output is identical (there is also a fairly wide variation of the same car on different chassis dynos).

Chassis dynos suck for absolute accuracy because they don't actually measure torque (or most don't). They measure acceleration of a drum and convert that to power and torque. The issue as demonstrated by the Raptor vs. Mustang is the typical chassis dyno cannot measure drive train inertia and efficiency so when there is a large difference (Raptor will have beefier gears, axle, tranny, wheels and t-case) it throws off accuracy.

Chassis dyons are better for relative measurements but the only real way to use them effectively is do not unbolt the car from the dyno between upgrades/changes as differences in tie down force, tire pressure, diff fluid temp, atmo conditions, etc., will muck with results a fair amount. Even then, you will not reliably discern 5 hp.

Obviously chassis dynos are better than butt dynos but trying to tout a 5 hp gain because of an air filter or KASSY is  . The only dyno that counts is an engine dyno, or a highly engineered chassis dyno which will be built for a single use application (which you will NOT see at Jim Bob's Tuning Shop).

[Rupert]

They can be trusted, just not trusted to reliably discern 5 or 10 hp, or anything close to that.

Right. Like I later explained, never trust someone's posted dyno numbers on the internet (for reasons other than the dyno itself, as well as the dyno itself), but careful relative measurement can be fine.

[hotrodalex]

5-10 hp gains are useless anyway.

So is this autocross challenge gonna happen?

[Char]

Does it help if one has designed a chassis dyno?

Simply peruse the chassis dyno results of the SAE-rated Ford Raptor with the 411 hp 6.2L vs. the SAE-rated 2011 Mustang GT with the 412 hp 5.0L. There is typically a wide variation between the two despite the fact that actual engine output is identical (there is also a fairly wide variation of the same car on different chassis dynos).

Chassis dynos suck for absolute accuracy because they don't actually measure torque (or most don't). They measure acceleration of a drum and convert that to power and torque. The issue as demonstrated by the Raptor vs. Mustang is the typical chassis dyno cannot measure drive train inertia and efficiency so when there is a large difference (Raptor will have beefier gears, axle, tranny, wheels and t-case) it throws off accuracy.

Chassis dyons are better for relative measurements but the only real way to use them effectively is do not unbolt the car from the dyno between upgrades/changes as differences in tie down force, tire pressure, diff fluid temp, atmo conditions, etc., will muck with results a fair amount. Even then, you will not reliably discern 5 hp.

Obviously chassis dynos are better than butt dynos but trying to tout a 5 hp gain because of an air filter or KASSY is  . The only dyno that counts is an engine dyno, or a highly engineered chassis dyno which will be built for a single use application (which you will NOT see at Jim Bob's Tuning Shop).

Again, how many dynos have you been on, have you used personally?

[GoCougs]

Again, how many dynos have you been on, have you used personally?

What does this even mean? If I've designed it I've used it, and it was a manifold more accurate than sucky roller-based chassis dyno.

Chassis dynos can be okay if they're used properly but justifying $200 spent on KASSY ain't one of them.

[12,000 RPM]

Chassis dynos are good for looking at powerband changes. I.e. an intake will usually be good for some HPs up top. A "chip" or dyno tune smoothing out A/F ratios and ignition timing will take the lumps out of a dyno etc. Drivetrain losses are generally pretty linear and won't make for weird lumps or drops in power at ends of the powerband.

I still think we need to discuss how OEM exhausts cannot be improved upon for making power though. Cougs was your degree ABET accredited? How did they give you a degree w/o a class in fluid dynamics?

[GoCougs]

Chassis dynos are awful for "power band changes." Simply peruse the many stock charts for peak power and torque RPM points that are way different than stock.

No, there is no discussion needed about OEM exhaust, just as there is no discussion needed about CAI, grounding kits, or bigger spark plug wires, or w/e. 

[AutobahnSHO]

No, there is no discussion needed about OEM exhaust, just as there is no discussion needed about CAI, grounding kits, or bigger spark plug wires, or w/e. 

-1

[12,000 RPM]

No, there is no discussion needed about OEM exhaust, just as there is no discussion needed about CAI, grounding kits, or bigger spark plug wires, or w/e.

Sure there is. A stamped, crush bent exhaust with various resonators and baffled mufflers will not flow like anything closer to an open parabolic diffuser. There have been extensive flow and engine dyno tests that prove this.

Cold air intakes have been proven to be effective as well.... documented through logs from data channels through OBDII scanners.

I have changed ground wires 3 times- not for more power, but because on my old Accords the starter to ground cable was so gunked with corrosion I would have trouble starting the car. Again though, testing has shown the effectiveness of these kits- a simple before/after of voltage drops at various points shows the effectiveness. "My gauges were brighter"

Similarly various folks with extensive experience drag racing have seen consistent E.T. drops at the drag strip with the install of various bolt ons. So yea, even without a chassis dyno there's proof that various bolt ons actually work.

[FlatBlackCaddy]

Don't forget about "forever" oil, no discussion there either.

[Secret Chimp]

Circa 1975 sure; automakers had to smog up motors but in modern times there's simply too much $$$ spent on powertrain development to botch exhaust (or intake or air filter or w/e ricer add-on du jour).

So if you take a car and exchange the loggy-with-a-honeycomb manifolds out for standard log manifolds, much less something with runners, you'll see zero difference. Oooookay.

[12,000 RPM]

So if you take a car and exchange the loggy-with-a-honeycomb manifolds out for standard log manifolds, much less something with runners, you'll see zero difference. Oooookay.

Stamped choppy flow exhausts are perfect for performance, thats why you see that cheap choked up shit in all levels of motorsport. Catalytic converters choking up the exhaust stream are great too, they love them in F1. Same with single throttle bodies- why minimize pressure drop from atmosphere to the valves when you can create a huge vacuum box and introduce more pumping losses with 1 single throttle body far far away from the valves? After all 1 throttle body per engine costs way more than 1 throttle body per cylinder...

Etc. etc... Cougs is right, questioning OEMs is a fool's errand, no way the exhaust on something like a $20K Civic is compromised in any way for cost, emissions, noise or any other myriad of factors manufacturers consider in the design of a mass production road legal car.

[AutobahnSHO]

Stop being sensible, y'all!!!!

[GoCougs]

This is a lesson you all should have implicitly learned while growing up by running a car on the street with open headers, or more poignantly, dicking around with a 2-stroke motor bike or weed eater without a muffler. Until you've done this you it's hard to understand that it's not about "more flow" or "less restriction" or "no bends" or w/e.

Guys, we've been here before many many times. You're not going to improve upon the performance of a stock motor in a modern car by bolting on this sort of stuff. Forgetting the technical details you all full well know it doesn't cost Ford any more to put a CAI into the Mustang GT than the current air box, or for GM to put in "less restrictive" mufflers on the Camaro SS.

Lastly, you all full well know that choked hp = less mpg, and no auto maker is gonna botch an air filter box or exhaust and cost themselves ever precious mpg.

[Char]

Stock vs useless aftermarket parts like intake, header, testpipe and an ECU tune.

Is that over 60whp, or is my math wrong?

[FlatBlackCaddy]

So they pushed redline to 8k on stock internals?

Will that hold up? I can't believe the motor would make power that high without a different cam or degreeing.

Do you work for z1?

Do I have to buy parts from someone else now?

[GoCougs]

Stock vs useless aftermarket parts like intake, header, testpipe and an ECU tune.

Is that over 60whp, or is my math wrong?

Yes, your math is wrong - HP jumps 70 hp not 60. But your Internetry is broken too. Forget the tech details, I can reeducate you with simple Socratic logic:

First, is a "tune" is not a bolt on?

Second, why doesn't the VQ37 come from the factory with an 8,000 rpm red line?

Third, why does a "tune" void an engine warranty?

Fourth, why don't you question the consistent ~50 lb-ft difference between the two torque curves across all shown RPM?

[GoCougs]

So they pushed redline to 8k on stock internals?

Will that hold up? I can't believe the motor would make power that high without a different cam or degreeing.

Do you work for z1?

Do I have to buy parts from someone else now?

I call shins on that dyno, particularly the constant 50 lb-ft difference between the two torque curves.

Further, in going from the 306 hp 3.5L to the 328 hp 3.7L, Nissan added displacement, VVL, higher compression ratio, shorty headers, higher flowing heads and new cams.

[AutobahnSHO]

higher flowing heads

No such thing, first heads were perfect

[12,000 RPM]

Guys, we've been here before many many times. You're not going to improve upon the performance of a stock motor in a modern car by bolting on this sort of stuff. Forgetting the technical details you all full well know it doesn't cost Ford any more to put a CAI into the Mustang GT than the current air box, or for GM to put in "less restrictive" mufflers on the Camaro SS.

Hey Cougs, pop quiz

What's easier for gas to flow through... a baffled chamber or a straight pipe

Hey Cougs, bonus question

If OEM configurations are the most powerful why do race teams change parts out

Hey Cougs, rhetorical question

What effect do govt regulations have on powertrain design for road legal cars

[Char]

So they pushed redline to 8k on stock internals?
Yes, actually quite common on the VHR/HR motors.
Will that hold up? I can't believe the motor would make power that high without a different cam or degreeing.
I haven't seen any blown motors as a result. No, cams aren't needed (the intake cam have variable lift, and both cams have variable timing, which is adjusted in the tune
Do you work for z1?
No.
Do I have to buy parts from someone else now?
The whole package is about $1400 from Z1 now, but I would do a different set of headers and intakes compared to what they offer.

.

[Char]

Yes, your math is wrong - HP jumps 70 hp not 60. But your Internetry is broken too. Forget the tech details, I can reeducate you with simple Socratic logic:
I knew it was 70, but over 60hp just sounds more meaningful.
First, is a "tune" is not a bolt on?
No, it's not a physical part that is bolted on to the car.

Second, why doesn't the VQ37 come from the factory with an 8,000 rpm red line?
Long term wear and the fact that it doesn't make much power above 7500 in factory tune
Third, why does a "tune" void an engine warranty?
Says who?

Fourth, why don't you question the consistent ~50 lb-ft difference between the two torque curves across all shown RPM?

Why would I question that?

[Eye of the Tiger]

βeta

[280Z Turbo]

No such thing, first heads were perfect

Why would automakers spend millions putting kinks in the intake ports?

[MexicoCityM3]

Cougs once again achieves the seemingly impossible. Char and Sporty are now on the same side of the ongoing argument here!

[280Z Turbo]

Cougs once again achieves the seemingly impossible. Char and Sporty are now on the same side of the ongoing argument here!

He's all about bringing unity.

[AutobahnSHO]

He's all about bringing unity.

Group hug time!! 

[AutobahnSHO]

Why would automakers spend millions putting kinks in the intake ports?

I dunno. I know the SHO engine had funky intake ports because the longer ones were "tuned" to be the right length for the cylinders on the other side of the engine for low RPMs, then over around 3-4k RPMs the short ones opened up via butterfly valve for more air to the cylinder on the nearside.



Also engineering figured out the right length for that crosspiece on the end for optimal airflow, yes it's hollow and has a sensor. (Intake and throttle body are on the rightside of this image, which is the driver's side of the car.)