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Old 16th November 2007, 10:28 AM   #12 (permalink)
Wink
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GTR.co.uk seasoned Member
 
Join Date: May 2007
Posts: 38
You guys.....

"KNOW for a fact a stroker kit will come out for it. 3.5L to 4.2L".

The VQ35 engine has a deck height of 215mm from memory, pretty much limiting it to 3.5L. The GTR engine has a deck height the same as the VQ40 (244mm) as the chain drive is carry over from that engine, and this enables the engine to achieve sufficient bay balance for a capacity of up to 3.8L only! The first two phases of the engine were 3.5L, but it was increased to 3.8L to improve off-boost launch, with main focus US market (who aren't so used to boosted cars). The reason why it can go to 4L despite having the same deck height as the VQ40 is the masses of the parts - the piston is much heavier (at over 600g), as is the rod, and the big and main bearing diameters are also much bigger than both the VQ35 and 40 to enable it to run at the high peak cylinder pressures associated with high levels of boosting. The main and big end bearings are 65 and 56mm in diameter respectively, and maximum peak cylinder pressure design limit is 115 bar.


"Yes it is based on that V8 in the 390".

Sorry, but this is just stupid. In the first phase the cylinder heads, chain drive, water pump and valvetrain were carry over VQ35, and everything else was new...although the water pump was speeded up by reducing the number of teeth on the water pump sprocket from 31 to 29. For the 2nd phase it was again all new and improved (even over the 1st concept engines), with new cylinder heads, etc, but NOTHING from the 390 engine!!! The only carry over parts are valve spring collets, and the water pump from the latest VQ35 engine, but speeded up again.


"And when I then said "No... bank angles for all V6s are the same... bore spacing doesn't mean anything but that they've spaced the bores the same as on the VQ --doesn't mean it's now suddenly a VQ engine."

Doh! Bank angles for V6 can be between 15 degrees (e.g. VW VR6), to 90 degrees (Rover KV6, Audi V6's etc). 60 degrees is used as this gives the best compromise between balance, package, etc whilst still enabling even firing. The R35 engine did not need to have the same bore spacing, bank stagger etc as the VQ35 engine, but Nissan wanted to carry over the VQ "DNA" as they say. The R35 engine is actually a bed plate design, which is different from the deep skirted block design of the VQ engines, and is a unique engine other than basic geometry.
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