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Revhead Kev
Date Registered: 10-2006
Location: Mona Vale, Sydney, AUSTRALIA
TOTAL POSTS: 6355
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Re: NEW QR25DE Engine Specs
So is there any one factor in the new QR25DE in the Sentra Spec-V which we can point to and say "that is responsible for the power increse" over our T31 ?
- increased compression ratio ?
- ecu upgrade ?
- better exhaust ?
- redesigned intake manifold ?
- larger throttle body ?
Last edited by Revhead Kev, 4/Feb/2008, 10:02 pm
--- Kev X450(c) T30 Guru
03 Titanium Ti T30 Series 1 **MODIFIED**
My Blog
My CarPC Worklog
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4/Feb/2008, 10:02 pm
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Eggins
X-TRAIL ENTHUSIAST
Date Registered: 08-2004
Location: Brisbane
TOTAL POSTS: 184
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Re: NEW QR25DE Engine Specs
A big factor would probably be different cam profiles and timing. The higher compression and better exhaust would help here too. The Spec V is a lighter vehicle than the XTrail, so Nissan could easily sacrifice some low down torque for higher RPM horsepower when programming the cam timing.
--- Shawn and Belinda Eggins
2003 STR, K&N, Strut brace, Ground wires, Dunlop LM702's, Tint, Mud flaps, Tow, Nudge, Spots, Mats, Rear scuff plate
http://eggins.synthasite.com/
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7/Feb/2008, 5:21 am
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jalalski
Date Registered: 02-2004
Location: SUTHERLAND, SYDNEY
TOTAL POSTS: 29100
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Re: NEW QR25DE Engine Specs
Guys,
Here are the specs of the T31 QR25DE engine and timing:
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7/Feb/2008, 8:47 am
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Revhead Kev
Date Registered: 10-2006
Location: Mona Vale, Sydney, AUSTRALIA
TOTAL POSTS: 6355
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Re: NEW QR25DE Engine Specs
Kevin,
Our QR25DE is only spec'ed at 9.6 compression ratio. Do I remember correctly that the Spec V has a compression ratio of around 10.5 ?
If different from ours, would there be different pistons, different rods or different head ?
And if different pistons or rods, do you think we could fit them to our engines if they are the same bore ?
--- Kev X450(c) T30 Guru
03 Titanium Ti T30 Series 1 **MODIFIED**
My Blog
My CarPC Worklog
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20/Feb/2008, 4:21 pm
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jalalski
Date Registered: 02-2004
Location: SUTHERLAND, SYDNEY
TOTAL POSTS: 29100
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Re: NEW QR25DE Engine Specs
Kev,
Read the quote on page 1 of this thread about the 2007 Sentra Spec V engine specs and compression ratio and it is explained there where the extra power is coming from:
quote:
revised piston crown shape to support a higher compression ratio (10.5:1); iridium tipped spark plugs for improved combustion characteristics; and a revised cam shaft profile, reinforced connecting rods and 8-counterweight crankshaft to achieve a higher redline limit of 6,800 rpm
I can't see a reason for not being able to swap these over in the T31 engine, but the limitation will be set at the ECU level and I don't think there is a way to overcome this unless a piggy back is fitted (maybe).
Looking at the 2007 Spec V Bore/Stroke and displacement figure, they're almost identical to the T31
Bore X Stroke mm{in) 3.50x3.94
Displacement cu in (cc): 152 (2500)
Last edited by jalalski, 20/Feb/2008, 4:53 pm
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20/Feb/2008, 4:46 pm
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Revhead Kev
Date Registered: 10-2006
Location: Mona Vale, Sydney, AUSTRALIA
TOTAL POSTS: 6355
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Re: NEW QR25DE Engine Specs
Thanks Jalal, but I was more interested in our T30 model and the previous (Kevin's) model of the Spec V.
--- Kev X450(c) T30 Guru
03 Titanium Ti T30 Series 1 **MODIFIED**
My Blog
My CarPC Worklog
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20/Feb/2008, 9:07 pm
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jalalski
Date Registered: 02-2004
Location: SUTHERLAND, SYDNEY
TOTAL POSTS: 29100
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Re: NEW QR25DE Engine Specs
quote: Revhead Kev wrote:
Thanks Jalal, but I was more interested in our T30 model and the previous (Kevin's) model of the Spec V.
The figures you have provided in your post don't apply to the old Sentra SpecV, hence my response.
The old Spec V has the following specs:
Displacement [cc] 2488
Bore & Stroke [mm] 89.0 x 100.0
Compression Ratio 9.5:1
These are exactly the same as the T30
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20/Feb/2008, 9:23 pm
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