Found this while surfing and thought I'd post it here:
http://www.dsmtalk.com/forums/showthread.php?t=193755
Q45 Halfshaft Mod with Pics!
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: Q45 Halfshaft Mod with Pics!
For 8 years I've tried to encourage members to measure "before they cut" anything!
What is the area of TB with and without a throttle plate period + how much restriction does the throttle plate add period.....a good thing to know!
OR just measure the differential pressure [vacuum] across the in to output with a manometer under different rpms [assuming all you care about is WOT].
27.7 " H2O is = to 1.0 psi which is = 6.8% density loss.
HINT worst case TB on Q45 is 7" or 0.25 psi = 1.7% for entire assembly front to rear..................about 5.3 HP loss assuming a tuned/peaked ecu mod.
LOTS of work and future risk for what might amount to 0.5>0.75 HP gain on a perfect day.
The Q45 oem TB is already too large for smooth progressive throttle response especially at low rpms [low rpm torque until 2,500 rpms suffers] but a size decent trade off for WOT.
What is the area of TB with and without a throttle plate period + how much restriction does the throttle plate add period.....a good thing to know!
OR just measure the differential pressure [vacuum] across the in to output with a manometer under different rpms [assuming all you care about is WOT].
27.7 " H2O is = to 1.0 psi which is = 6.8% density loss.
HINT worst case TB on Q45 is 7" or 0.25 psi = 1.7% for entire assembly front to rear..................about 5.3 HP loss assuming a tuned/peaked ecu mod.
LOTS of work and future risk for what might amount to 0.5>0.75 HP gain on a perfect day.
The Q45 oem TB is already too large for smooth progressive throttle response especially at low rpms [low rpm torque until 2,500 rpms suffers] but a size decent trade off for WOT.
-
Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: Q45 Halfshaft Mod with Pics!
"Nissan/Infinity Q45 4.5-litre V8 (VH45DE)
A-ha! Here's the monster of the group! Rated at more than 200kW, the VH45DE is Nissan's top-line 'VIP' engine that's a mechanical tour-de-force. You can quite literally fit your entire hand inside this throttle body - its 75mm bore is by f-a-r the biggest we've sampled. Ignoring the throttle blade, this unit gives a sensational cross-sectional area of 44.2cm2. We were unable to accurately measure its bolt pattern, but it is an offset square arrangement with less than 80mm from bolt centre to centre. You'll need a big feed pipe to connect to this bugger - its inlet pipe is a humungous 90mm in diameter! This is a brilliant throttle body if you can find one - Adelaide Japanese Dismantlers suggests you'll pay around AUD$150 for this rare beast.
Bore Diameter 75mm
Bore Cross-Section (Ignoring Throttle Blade): 44.2cm2 (Rank 1st)
Overall Length: 109mm
Bolt Pattern: Four bolts - offset square pattern
Inlet Pipe (OD): 90mm round"
copied from :
http://autospeed.co.nz/cms/title_Thrott ... ticle.html
A-ha! Here's the monster of the group! Rated at more than 200kW, the VH45DE is Nissan's top-line 'VIP' engine that's a mechanical tour-de-force. You can quite literally fit your entire hand inside this throttle body - its 75mm bore is by f-a-r the biggest we've sampled. Ignoring the throttle blade, this unit gives a sensational cross-sectional area of 44.2cm2. We were unable to accurately measure its bolt pattern, but it is an offset square arrangement with less than 80mm from bolt centre to centre. You'll need a big feed pipe to connect to this bugger - its inlet pipe is a humungous 90mm in diameter! This is a brilliant throttle body if you can find one - Adelaide Japanese Dismantlers suggests you'll pay around AUD$150 for this rare beast.
Bore Diameter 75mm
Bore Cross-Section (Ignoring Throttle Blade): 44.2cm2 (Rank 1st)
Overall Length: 109mm
Bolt Pattern: Four bolts - offset square pattern
Inlet Pipe (OD): 90mm round"
copied from :
http://autospeed.co.nz/cms/title_Thrott ... ticle.html