Comparison Test: 2007 Half-Ton Pickup Trucks
#41
PT's Slowest Truck
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Originally Posted by agreif
One thing I noticed is that Yota is running 10.2:1 compression on "87 or higher" fuel for that 5.7. So is this going to be like the escalade motors where they test and publish numbers with the 93 or 91 octane, but then if you run the 87 is detunes it quite a bit? If they are getting those numbers on 87 I'm gonna be damn impressed. Just funny because the escalade at 10:1 compression calls for 89 octane. I just want to know if Yota is that good or if they are slightly misleading (IMO).
Even on the little econo boxes it looks like Honda and Toyota are able to push their static compression ratios higher than GM is able to, yielding equiv power and better gas mileage. Sorry, I'll get off my stump now.
Even on the little econo boxes it looks like Honda and Toyota are able to push their static compression ratios higher than GM is able to, yielding equiv power and better gas mileage. Sorry, I'll get off my stump now.
#42
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Originally Posted by budhayes3
I believe that they can get away with the higher compression due to their VVTi (Variable Valve Timing w/ intelligence)...aside from being able to increase valve lift, it also bleeds off pressure.
#43
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Originally Posted by agreif
So their static CR is higher, but they aren't getting as high of a dynamic CR due to bleed off? If I'm understanding you correctly, I am hearing that if you set up GM valving and Yota valving on the same engine (same static compression ratio) the dynamic on the Yota would be lower than the GM, allowing for lower octane, right? So with variable timing, the static ratio is a bit misleading for an apples to apples comparison?
#45
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Originally Posted by NegraRCSB2X4auto
man gm get you head out of you aaa and just let us order rc trucks with what ever motor you have ls7 would befine.
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Originally Posted by nonnieselman
Is this TRUE??
That just sounds stupid... so there is no point in puttin it to the floor? Ive got to find someone and get the stock tune to look at it..... Thats just odd.
That just sounds stupid... so there is no point in puttin it to the floor? Ive got to find someone and get the stock tune to look at it..... Thats just odd.
Trust me, its true. I'm not a tuning guru, so I don't know all the terms and ins and outs, but when Wheatley tuned my 4.8, there was a definite 4 second lapse after flooring it, before the ECM would fuel the system and then it would hammer down.
We picked up a 6 tenths gain 0-60 just with an 87 octane tune and removing 50% torque management. I should be going back soon to have him update it to a 93 tune and about 25% more TQM out of it.
Other noticable thing I see, is look at the torque numbers--most noticably, the where it peaks out on the powerband, the silverado peaks out with less torque at 700 rpms higher than the tundra and 900 rpms higher than the titan.
Last edited by BLACKND; 07-13-2007 at 05:02 PM.
#50
I have a gut feeling the 5.3L is faster than the 6.0L in the 2007 chevy trucks I think my 2005 GMC 5.3L running on E85 ethinal 105 octain or possibly on gas will beat a new tundra. The 6.0s seem a lil more slugish off the line than a 5.3l. Im dying to race a tundra, titan even if I lose.