porting and polishing
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truesports03
- Posts: 14
- Joined: Tue Dec 19, 2006 10:23 am
- Car: 2003 nissian maxima
porting and polishing
well, i was interasted in porting and polishing my throttle body and possibly the plenium. did anybody here do this to there vq35, and what kind of hp did you get.thx
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C-Kwik
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- Car: 2013 Chevy Volt, 1991 Honda CRX DX
You don't port and polish throttle bodies. If anything, you have them machined with a larger bore. In either case, a matching larger throttle plate would need to be fabricated. It'l probably be a lot of trouble for very little benefit there. Not sure about any results for the plenum though. I haven't heard any complaints about the runners, and spacers seem to be the ticket here.
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Q45tech
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- 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: (C-Kwik)
Before you exert much effort take time to measure the air flow resistance across the throttle body/plate.
The few dozen [various Infiniti] I've measured on a flow bench indicate that they have 7" water column at most under flow conditions at redline.
7/27.7"= 0.25 psi or 1.72% maximum inpediment to air flow.
Unfortunately making them larger might only decrease that 1.72% by 10-20% say 1.376%........................4/10 % of 300 HP is less than 1.5 HP.
Easy to measure with manometers at WOT, what the differential pressure is across the plate ----- hose before and after.
Careful the lower pressure [vacuum] when the throttle is closed or almost closed can suck the guts out of sensitive instruments............you must rigg a valve/solenoid that can be closed at high vacuum and only opened at WOT and closed before you let off.
Nissan engineers have internal design guide lines for common items like Air box, air filter, MAF, TB, Plenum etc to limit how much loss each can have because they subscribe to SAE guidlines that limits the entire induction path to no more not to exceed 28" water column to limit losses to 6.8% [1.psi or 27.7" water column].
The pressure loss from the Earth supercharger [14.7 psi] all the way thru everything including the valves must be less than 28" W.C..That means that the average filling pressure into the cylinder is 13.7 psi [if barometer is correct 29.92" Hg].
They usually set air filters at 1-2", MAF at 7", TB at 7" this leaves them 12" for air box and duct work, plenum runner, and intake valves.
The few dozen [various Infiniti] I've measured on a flow bench indicate that they have 7" water column at most under flow conditions at redline.
7/27.7"= 0.25 psi or 1.72% maximum inpediment to air flow.
Unfortunately making them larger might only decrease that 1.72% by 10-20% say 1.376%........................4/10 % of 300 HP is less than 1.5 HP.
Easy to measure with manometers at WOT, what the differential pressure is across the plate ----- hose before and after.
Careful the lower pressure [vacuum] when the throttle is closed or almost closed can suck the guts out of sensitive instruments............you must rigg a valve/solenoid that can be closed at high vacuum and only opened at WOT and closed before you let off.
Nissan engineers have internal design guide lines for common items like Air box, air filter, MAF, TB, Plenum etc to limit how much loss each can have because they subscribe to SAE guidlines that limits the entire induction path to no more not to exceed 28" water column to limit losses to 6.8% [1.psi or 27.7" water column].
The pressure loss from the Earth supercharger [14.7 psi] all the way thru everything including the valves must be less than 28" W.C..That means that the average filling pressure into the cylinder is 13.7 psi [if barometer is correct 29.92" Hg].
They usually set air filters at 1-2", MAF at 7", TB at 7" this leaves them 12" for air box and duct work, plenum runner, and intake valves.
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ghost_infantry11b20
- Posts: 71
- Joined: Sat Aug 12, 2006 11:20 pm
Re: porting and polishing (truesports03)
go to my350z.com and use the search there is a guy the did the port and polish and show the step on it
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