Titan's V8 compression ratio?

[Quad T]

Does anybody know?

I checked the Nissan website and did not find it listed in the specifications. The reason I ask is I'm interested in the performance mods Infiniti has made to the 5.6 Endurance engine.

The QX 56 (Armada having survived Infiniti finishing school) is rated at 315 hp., an additional 10, with 390 lb.-ft. an additional 11. The Infiniti website lists the compression ratio at 9.8:1, and it requires premium fuel.

I suspect the performance increase is nothing more than revised mapping of the electronic control unit and maybe a refined exhaust and intake. However, if the compression ratio has been increased Infiniti has done some additional work tot he engine.

Thoughts?

[keane]

Originally Posted by Quad T

Does anybody know?

I checked the Nissan website and did not find it listed in the specifications. The reason I ask is I'm interested in the performance mods Infiniti has made to the 5.6 Endurance engine.

The QX 56 (Armada having survived Infiniti finishing school) is rated at 315 hp., an additional 10, with 390 lb.-ft. an additional 11. The Infiniti website lists the compression ratio at 9.8:1, and it requires premium fuel.

I suspect the performance increase is nothing more than revised mapping of the electronic control unit and maybe a refined exhaust and intake. However, if the compression ratio has been increased Infiniti has done some additional work tot he engine.

Thoughts?

The Titan's engine compression is also 9.8:1. I think the difference was mentioned on another thread as being titanium lifters and some other mods.

That is about all I know, others have more indepth info if you need it.

[Quad T]

Thanks for the reply!
I'll see what happens when I do a search if nobody else chimes in...

[Ti-tan]

the titanium valvetrain and high compression is on the 4.5L engine...not the 5.6L in the titan or QX56. I would suspect the HP diff is a matter of intake or exhaust being more efficient or possibly ECU "tuning."

[bestatchess]

Originally Posted by Ti-tan

the titanium valvetrain and high compression is on the 4.5L engine...not the 5.6L in the titan or QX56. I would suspect the HP diff is a matter of intake or exhaust being more efficient or possibly ECU "tuning."

Or maybe the HP diff is a function of the person operating the word processor.

[Kyle]

Originally Posted by bestatchess

Or maybe the HP diff is a function of the person operating the word processor.

My thoughts exactly...

[Austin]

General Endurance 5.6L Info

Cylinder arrangement: V-8
Displacement: cm3 (cu in) 5,552 (338.80)
Bore and stroke: mm (in) 98 x 92 (3.86 x 3.62)
Valve arrangement: DOHC
Firing order: 1-8-7-3-6-5-4-2
Number of piston rings: Compression-2 Oil-1
Number of main bearings: 5
Compression ratio: 9.8
Compression pressure kPa (kg/cm2 , psi)/ rpm
-Standard 1,520 (15.5, 220) 200
-Minimum 1,324 (13.5, 192) 200
Differential limit between cylinders 98 (1.0, 14) 300

Exhaust valve open duration: 232 degrees
Intake valve open duration: 230 degrees
Intake valve open/Exhaust valve open overlap: 5 degrees

NGK Spark plugs Double Platinum tipped –
Standard Heat range: PLFR5A-11
Hot type: PLFR4A-11
Cold type: PLFR6A-11
Gap (nominal) 1.1 mm (0.043 in)

[SarkaZm]

I read somewhere that Nissan originally had it at 10:1, but then reduced it to 9.8:1 to allow for the use of regular 87 octane. Hope this helps.

[bighawaii]

i doubt they had to drop compression .2 just to run on reg gas. there are many engines with 10:1 or even higher that are designed to use reg.

[SarkaZm]

Originally Posted by bighawaii

i doubt they had to drop compression .2 just to run on reg gas. there are many engines with 10:1 or even higher that are designed to use reg.

Here is the article. My bad, it was 10.5:1 originally.

http://www.findarticles.com/cf_dls/m...le.jhtml?term=

[bighawaii]

pretty nice writeup, goin to my favs lol. thanks

[juma]

I just read through the big brochure and it says the Titan is premium fuel. So, it probably has maps for regular through premium. You want more punch, gas up with super. juma

[Austin]

Originally Posted by juma

I just read through the big brochure and it says the Titan is premium fuel.

The Titan runs on 87 AKI unleaded fuel.

In which brochure do you think you saw a reference to premium unleaded fuel as a requirement?