2005 GTO LS2/T56 RPM For Drivability
11-20-2018, 12:55 AM
#1
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2005 GTO LS2/T56 RPM For Drivability I need to choose a rear gear, and am wondering what a safe highway RPM is for my car. 3,600 pounds. I plan on a lot of highway/interstate driving. 5th gear for commuting and fuel economy, and.6th gear for open interstate road trip.
By "safe", I mean high enough not to lug the engine or have the MPH drop drastically on small inclines. I dont want the RPM too high because of annoying engine noise, economy and needless wear on the engine.
The engine will be freshened, but basically stock.
thanks for any questions, advice or resources.
By "safe", I mean high enough not to lug the engine or have the MPH drop drastically on small inclines. I dont want the RPM too high because of annoying engine noise, economy and needless wear on the engine.
The engine will be freshened, but basically stock.
thanks for any questions, advice or resources.
11-20-2018, 09:59 AM
#3
With transmission ratios of
2.97:1, 2.07:1, 1.43:1, 1.00:1, 0.84:1, 0.57:1
3.42's aren't bad, but with GTO's ~3600 pounds plus full gas tank and driver weight, I would ideally want 3.73's in the rear. Isn't 3.42's to 3.73's is big change.
This would increase rpm by slightly.
I'm a fan of gears and my 3rdGen & 4th Gen with T56's both have 4.10's but they 2.66 1st gears. 2000 rpm at 70 mph is very manageable. Actually helps make mod's like cams more manageable. The accelerated engine wear for highway driving is basically irrelevant because the engine turns about the same rpm on the highway as a 4L60e.
Final drive rear gear 2.73's & 4L60e .7 4th gear = 1.91
Final drive rear gear 3.23's & 4L60e .7 4th gear = 2.26
Final drive rear gear 4.10's & T56 .5 6th gear = 2.05
GTO
Final drive rear gear 3.42's & T56 .57 6th gear = 1.95
Final drive rear gear 3.73's & T56 .57 6th gear = 2.12
Final drive rear gear 4.10's 's & T56 .57 6th gear = 2.33
2.97:1, 2.07:1, 1.43:1, 1.00:1, 0.84:1, 0.57:1
3.42's aren't bad, but with GTO's ~3600 pounds plus full gas tank and driver weight, I would ideally want 3.73's in the rear. Isn't 3.42's to 3.73's is big change.
This would increase rpm by slightly.
I'm a fan of gears and my 3rdGen & 4th Gen with T56's both have 4.10's but they 2.66 1st gears. 2000 rpm at 70 mph is very manageable. Actually helps make mod's like cams more manageable. The accelerated engine wear for highway driving is basically irrelevant because the engine turns about the same rpm on the highway as a 4L60e.
Final drive rear gear 2.73's & 4L60e .7 4th gear = 1.91
Final drive rear gear 3.23's & 4L60e .7 4th gear = 2.26
Final drive rear gear 4.10's & T56 .5 6th gear = 2.05
GTO
Final drive rear gear 3.42's & T56 .57 6th gear = 1.95
Final drive rear gear 3.73's & T56 .57 6th gear = 2.12
Final drive rear gear 4.10's 's & T56 .57 6th gear = 2.33
11-24-2018, 11:22 AM
#6
I'm running 3.73 and on the highway I wish 6th was just a little be taller. The RPM to hit your goal will depend on your motors torque curve. I use this site to go over all possible changes. http://www.grimmjeeper.com/gears.html