Knock on the VQ37VHR - gear heads step inside

WShade · 01-20-2009, 08:54 AM

Z1 states 50 miles on their car when this pull was made. Could be something as simple as bad gas from the dealer just like JoeyD said earlier.

TomatoEvo · 01-20-2009, 12:26 PM

So the dip is supposed to be knock then? Come on guys that could be any number of things (tach signal loose, gummy injectors, etc.). You want to measure knock get the proper equipment on a load bearing dyno at varying engine speeds.

In a knock event where timing is pulled you will see some indication on the A/F curve(abruptness) and it looks pretty smooth on the Z1 graph.

I'm not saying that its not possible I'm just saying that these types of statements can get taken too far on very little evidence.

Side Note: Much respect to Berk for there excellent testpipes on the S2000.

BerkTech · 01-20-2009, 03:03 PM

GTM graph with knock response. (red lines)

BerkTech · 01-20-2009, 03:23 PM

It's hard to tell without seeing these cars in person. But the AF will not always change when the ECU pulls timing. These motors might just be very sensitive to knock levels. Remember that the ECU is using a narrowband microphone to measure the characteristic sound signature knock gives off, but isn't a direct measurement of knock.

Hi Tomatoevo! Greetings. I guess you guys already know us from the S2000 world. Your S2000's as well is very prone to pinging & knocking even with the stock ECU. I have had nearly stock cars ping away on the dyno with nothing more than intake/header/test pipe/exhaust.

Time will tell if the 370's are as knock sensitive as I think they are.

RCZ · 01-20-2009, 06:52 PM

Hmm, you are going out on a bit of a limb to call that knock so early in the game and without any real data other than a blip in a dyno curve...

BerkTech · 01-20-2009, 07:29 PM

Quote:

Originally Posted by RCZ

Hmm, you are going out on a bit of a limb to call that knock so early in the game and without any real data other than a blip in a dyno curve...

Exactly. That's why I'm posing the question here. What does that blip look like to you?

Double Down Motorsports will be back to back dyno testing our 370Z HFC's later this week. We'll get some real answers from DDM pretty soon.

ZforMe · 01-20-2009, 08:14 PM

Quote:

Originally Posted by BerkTech

Double Down Motorsports will be back to back dyno testing our 370Z HFC's later this week. We'll get some real answers from DDM pretty soon.

SWEEEET!!!!!!

Before i was set on the 370Z i was going to get a G37 sedan, and the Berk HFC's would have been my first mod.

Assuming everything goes well at the Dyno, when do you expect the 370Z HFC's will be ready to order?

RCZ · 01-20-2009, 08:58 PM

Quote:

Originally Posted by BerkTech

Exactly. That's why I'm posing the question here. What does that blip look like to you?

Double Down Motorsports will be back to back dyno testing our 370Z HFC's later this week. We'll get some real answers from DDM pretty soon.

I'm going to say that it might be knock or an oversensitive knock sensor....but who knows...could be many things including very slight loss of traction on the dyno or the "driver" adjusting his right foot. I do have to say it looks an awful lot like timing is being pulled...

TomatoEvo · 01-20-2009, 10:40 PM

Quote:

Originally Posted by BerkTech

Hi Tomatoevo! Greetings. I guess you guys already know us from the S2000 world. Your S2000's as well is very prone to pinging & knocking even with the stock ECU. I have had nearly stock cars ping away on the dyno with nothing more than intake/header/test pipe/exhaust.

Time will tell if the 370's are as knock sensitive as I think they are.

Can't argue with that, S2K's tend to lean out with basic modifications on stock tune.

TerribleONE · 01-26-2009, 01:44 AM

breaks loose in third? huh...?

RCZ · 01-26-2009, 12:16 PM

Quote:

Originally Posted by danops

Regarding the 'knock'....

Has anyone looked into the C-VTC & VVEL variables on these motors? This could be the primary cause of the 'knock' symptom.

Does the 'knock' experience vary at a different throttle position/load?

Out of curiousity... I'd like to see more details like datalogging, dyno results that include throttle input & calculated engine load, air fuel, etc...

If these issues are apparent from just a stock motor & stock motor w/ test pipes, I would be very concerned about reliability with additional modifications including intake systems, headers, exhausts, and other parts without precise tuning.

+1

Need more info.

Crash · 01-26-2009, 08:33 PM

What does VSA stand for?

TomatoEvo · 01-26-2009, 11:15 PM

^ Its Nissan's term for their traction/stability program.

Vehicle Stability Assist maybe?

Crash · 01-26-2009, 11:27 PM

And disabling it let the motor work harder?! Interesting.

BerkTech · 02-03-2009, 01:47 AM

Quote:

Originally Posted by Crash

And disabling it let the motor work harder?! Interesting.

Not really. If it detects wheel slippage it will cut the throttle. It's just Nissan's nomenclature for "electrical traction control". Goes by the name of DSC, TRC, E-Diff, etc. But it's all the same thing.

Your foot (gas pedal) isn't actually connected to the throttle plate. It's all done by electronics. Hence the term DBW, "drive by wire".

01-20-2009, 08:54 AM	#16 (permalink)
WShade Track Member Join Date: Jan 2009 Location: San Antonio, TX Posts: 765 Drives: 09 370Z T/S/N Rep Power: 187	Z1 states 50 miles on their car when this pull was made. Could be something as simple as bad gas from the dealer just like JoeyD said earlier. __________________ Q50S Q60 RS400

01-26-2009, 08:33 PM	#27 (permalink)
Crash A True Z Fanatic Join Date: Dec 2008 Location: Los Angeles Posts: 1,853 Drives: 02 Corvette Z06 Rep Power: 589	What does VSA stand for? __________________ 2002 Corvette Z06 - Totaled 2003 Corvette Z06 50th Anniversary

01-26-2009, 11:27 PM	#29 (permalink)
Crash A True Z Fanatic Join Date: Dec 2008 Location: Los Angeles Posts: 1,853 Drives: 02 Corvette Z06 Rep Power: 589	And disabling it let the motor work harder?! Interesting. __________________ 2002 Corvette Z06 - Totaled 2003 Corvette Z06 50th Anniversary

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01-20-2009, 12:26 PM	#17 (permalink)
TomatoEvo Base Member Join Date: Dec 2008 Location: Qatar Posts: 36 Drives: Stripped S2000 Rep Power: 16	So the dip is supposed to be knock then? Come on guys that could be any number of things (tach signal loose, gummy injectors, etc.). You want to measure knock get the proper equipment on a load bearing dyno at varying engine speeds. In a knock event where timing is pulled you will see some indication on the A/F curve(abruptness) and it looks pretty smooth on the Z1 graph. I'm not saying that its not possible I'm just saying that these types of statements can get taken too far on very little evidence. Side Note: Much respect to Berk for there excellent testpipes on the S2000.

01-20-2009, 03:03 PM	#18 (permalink)
BerkTech The370Z.com Sponsor Join Date: Jan 2009 Location: Irvine CA Posts: 279 Drives: Lots.... Rep Power: 272	GTM graph with knock response. (red lines)

01-20-2009, 03:23 PM	#19 (permalink)
BerkTech The370Z.com Sponsor Join Date: Jan 2009 Location: Irvine CA Posts: 279 Drives: Lots.... Rep Power: 272	It's hard to tell without seeing these cars in person. But the AF will not always change when the ECU pulls timing. These motors might just be very sensitive to knock levels. Remember that the ECU is using a narrowband microphone to measure the characteristic sound signature knock gives off, but isn't a direct measurement of knock. Hi Tomatoevo! Greetings. I guess you guys already know us from the S2000 world. Your S2000's as well is very prone to pinging & knocking even with the stock ECU. I have had nearly stock cars ping away on the dyno with nothing more than intake/header/test pipe/exhaust. Time will tell if the 370's are as knock sensitive as I think they are.

01-20-2009, 06:52 PM	#20 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1118	Hmm, you are going out on a bit of a limb to call that knock so early in the game and without any real data other than a blip in a dyno curve...

01-26-2009, 01:44 AM	#25 (permalink)
TerribleONE A True Z Fanatic Join Date: Jan 2009 Location: Socal Posts: 10,203 Drives: WOT Rep Power: 5850	breaks loose in third? huh...?

01-26-2009, 11:15 PM	#28 (permalink)
TomatoEvo Base Member Join Date: Dec 2008 Location: Qatar Posts: 36 Drives: Stripped S2000 Rep Power: 16	^ Its Nissan's term for their traction/stability program. Vehicle Stability Assist maybe?