PDA

View Full Version : SR Torque and Power



SRFiveTen
08-23-2001, 09:54 AM
Curious about torque.
Someone please enlighten me.

SR20DE PS/Torque SR20DET PS/Torque
S13 140ps/18.2kgm : 205ps/28.0kgm
S14 160ps/19.0kgm : 220ps/28.0kgm
S15 165ps/19.6kgm : 250ps/28.0kgm
S15A 200ps/21.8kgm

I was under the impession that there is a direct relation between torque and power.
As the max power is increased, torque increases, as observed in DE motors, and as expected when we modify our rides.

Why are the factory torque rating for DETs same regardless to significant power increase through evolution of SRs?

[This message has been edited by SRFiveTen (edited 08-23-2001).]

Mav1178
08-23-2001, 09:59 AM
Numbers mean JACK if you can't see the graph.

From raw memory, the S13 vs. S14 vs. S15 power curves have the same peak HP value, but different overall torque curves. Not drastically different, but enough so that midrange power is increased (as well as top-end).

It's the same as the S13 KA24DE vs. S14 KA. Both engines are rated at 155HP and 160ft-lb of torque, but the S14 power curve is better because the overall area of the torque curve is larger than the S13's by about 5-7%.

-alex

SRFiveTen
08-23-2001, 10:11 AM
<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by Mav1178:
the S13 vs. S14 vs. S15 power curves have the same peak HP value, but different overall torque curves.

-alex<HR></BLOCKQUOTE>

um, ps value increased, where as the torque ratings remained the same with det,,, and i asked why?

Mav1178
08-23-2001, 10:17 AM
<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by SRFiveTen:
um, ps value increased, where as the torque ratings remained the same with det,,, and i asked why?<HR></BLOCKQUOTE>

Oops, brain fart. I meant to say "peak torque value".

-alex

SRFiveTen
08-23-2001, 12:31 PM
so,,, nissan didn't/couldn't raise the maximum torque in their sr turbos??

they did raise the torque in non-turbo,,,,

'97 S14 SE Turbo
08-23-2001, 12:54 PM
By simply listing the power and torque value is deceptive. You need to also list the rpm for the peak hp and the Peak torque. That tells more of the story.

I could very well say my car puts out 278hp and 280ft-lb of torque. To me that doesn't mean much. But when I say 278rwhp @ 6,000rpm, and 280ft-lb torque @4,300 rpm it tells a story that the power band of my motor is pretty broad with the peak of the torque mountain right smack in the middle of the rpm range, and that near redline, the torque doesn't fall off that much.

<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by SRFiveTen:
Curious about torque.
Someone please enlighten me.

SR20DE PS/Torque SR20DET PS/Torque
S13 140ps/18.2kgm : 205ps/28.0kgm
S14 160ps/19.0kgm : 220ps/28.0kgm
S15 165ps/19.6kgm : 250ps/28.0kgm
S15A 200ps/21.8kgm

I was under the impession that there is a direct relation between torque and power.
As the max power is increased, torque increases, as observed in DE motors, and as expected when we modify our rides.

Why are the factory torque rating for DETs same regardless to significant power increase through evolution of SRs?

[This message has been edited by SRFiveTen (edited 08-23-2001).]<HR></BLOCKQUOTE>

SRFiveTen
08-23-2001, 03:39 PM
<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by SRFiveTen:


SR20DE PS/Torque
S13 140ps@6400rpm/18.2kgm@4800rpm
S14 160ps@6400rpm/19.0kgm@4800rpm
S15 165ps@6400rpm/19.6kgm@4800rpm
S15A 200ps@7200rpm/21.8kgm@4800rpm

SR20DET PS/Torque
S13 205ps@6000rpm/28.0kgm@4000rpm
S14 220ps@6000rpm/28.0kgm@4800rpm
S15 250ps@6400rpm/28.0kgm@4800rpm
<HR></BLOCKQUOTE>


Less deceptive?

**DONOTDELETE**
08-23-2001, 05:47 PM
SRFiveTen,

As you probably know, power is the direct product of RPM (well, rotational rate anyway) and torque. What's happening in the SR20DETs is that the torque peak is being moved higher in the RPM range (from S13 to S14) so that the "falloff" of torque is less, and the product of RPM and torque is higher at 6000 RPM, leading to a higher power number. Between S14 and S15, it looks like either redline or high RPM breathing was increased allowing the torque to keep from falling off as drastically at 6400 RPM.

As you also probably know, there are a lot of "remedies" that could be applied to increase the torque production.

NOSTALGIC_HERO
08-23-2001, 09:15 PM
can anybody say "JUN cylinder liners" ?? he he!!

SRFiveTen
08-24-2001, 12:19 PM
qzp, I think your guess on the red line and breathing seem to be pretty well backed by the following features on S14 & S15s.

Stock surge tank on S14 & S15, sorta reminds me of the aftermarket power yielding tanks offered for S13, such as those sold by Greddy.
NVCS, allowed the usable power band to be shifted to higher rpm range.


Could it be that 28.0kg-m is the maximum torque SR can produce with factory boost? (assuming that all SRs have the same boost limit from the factory)

[This message has been edited by SRFiveTen (edited 08-24-2001).]

**DONOTDELETE**
08-25-2001, 04:04 AM
<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by SRFiveTen:
Could it be that 28.0kg-m is the maximum torque SR can produce with factory boost?<HR></BLOCKQUOTE>

I would think that you could design the cams to achieve a higher torque peak, but it would come at the expense of other performance parameters such as peak power or drivability.

Put another way, that is probably not the peak torque limit for the engines, but they were configured to have that peak torque value even in successive generations in order to improve on other aspects of the engine operation.