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2008 V6 SRX4
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Discussion Starter #1
Boston to Long Island NY, Friday, good weather, minimal traffic, 225 or so miles. Car was loaded pretty good with 2 adults and a baby. and enough stuff for a long weekend, including, car seat, stroller, a large 27" tube TV that I am donating to my brother in law (prob 75 pounds alone) and luggage.

From Trip computer: 68.2 MPH avg speed, 21.5 avg MPG, 225 miles, 3 hrs 20 minutes. a/c on for about last 1 hour of trip. Drive mode used was Sport.
max speed prob. 84 MPH

Tire pressure was 36-38 PSI per tire front and back. V6 AWD, ultraview, third row. Engine with 4000 miles

All in all I was pretty ok with that kind of milleage I think getting to the 23-24 HWY would be awesome and it maybe possible though not the norm. City MPG is still pretty crappy at 15-16
 

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2011 CTS-V Coupe A6 w/RECARO's
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I've only had one opportunity to check the highway fuel mileage on our 09 RWD V6 SRX. With no load (save myself) and not trying, I managed just at 22 MPG (hand calculated - the DIC reads about .5 MPG high).

I'll be taking the wife and daughter plus all our race gear to Indinapolis in two weeks to the Allstate 400. It's 260 miles from our house to our hotel. Since we caravan with 5 other cars it's hard o set the cruise and get decent fuel mileage, maybe that's why our 08 Accord EX-L with the 190HP 4 cyl only managed a real world 28 MPG.

If we can get the same 22 MPG with our SRX I'll be very happy.
 

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2008 V6 SRX4
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61 Posts
Discussion Starter #3
Return trip:
slightly more traffic though it never got to stop and go (thank God) too a slighlty longer route and took a short detour (about 8 miles) to get some lunch at the Niantic CT lobster fest. Car was a bit lighter than my last trip by about 75 pounds. Anyway here we go to the details:

according to DIC:
trip 254 miles
AVG MPG 21.8
AVG speed 59 MPH (due to traffic), top speed 82-84
going there avg speed was 8-9 mph faster
Drive mode sport and cruise control on first half of the way (wife drove the
second half without it cos it annoys her) :thehand:
A/C on most of the way.

Tire pressure was a steady 38-40 PSI all around. (goodyear eagle RSA)

About 120 miles into the trip I hit 23 AVG MPG and I think I would have had no trouble staying above 22 MPG to even 22.5 MPG had I drove the whole way but I did not, This route took us into some hilly territory so maybe low 22 would have been the best case scenario.

Also...you can run those RSAs to 44 PSI and if you drive mostly HWY I highly recommend you inflate them to 36 or so prior to your trip. In warm weather and 3-4 hour trips the pressure can increase 3-4 psi which puts you safely in th 40 psi range. I can verify it is much more pleasurable driving the car with more inflated tires than the 32 psi that is recommended. It all depends on your load as well so consider that.
 

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Cadillac
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San Antonio back to Houston 2 weeks ago avg 23.3 on the DIC running 70mph. Made only 1 stop. Thats with oil change weekend before.
2004 SRX V6 w/AWD.
28Kmiles.


Rob

NOTE: K&N filter seemed to make a noticiable difference in milage improvement since I changed to it last fall. Avg. 17.5mpg in town.
 

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2014 Standard SrX grey/black 2006 GTO
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why are guys running such high tire pressures? I know it must help fuel economy but the ride quality can't be great.
 

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2008 V6 SRX4
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61 Posts
Discussion Starter #6
AS I mentioned I am inflated to 35-36 psi front to back, while driving for a while in warm weather the pressure goes up by 3-4psi There are too many variables to really take into consideration when you talk about ride quality vs performance (suspension, load, tires, driver subjectivity and preference) but I can tell you this, on the highway running the higher PSI made the car feel more sure footed and less 'lofty' . I think cadillac has always geared their suspensions for touring/comfort so tightening up a component such as PSi does stiffen up the ride, but on a highway in good condition, this is highly desirable. city-wise perhaps the ride is a tad (unmeasurably) harsher but I never liked the lexus 'hovering thru air' ride anyway. I prefer to feel the road a bit more and have a more direct connection to the HWY. If a bi-product of higher PSI is better fuel economy then I will take that too...at the end of the day it is about what kind of 'ride' you prefer. The SRX is so heavy that a soft ride just makes it feel more sluggish...a tighter ride lets you feel a quicker reaction time between you and the road. I suggest you up your PSI and try it on your own....while I DO NOT recommend it, there are people out there running 44+ psi on their tires (goodyear SR-A and others) due to fuel efficiency needs and preference on other types of automobiles.
 

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01 740iL, 99 Z28, 06 SRX V8 rwd
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I got a DIC indicated 18.8mpg from Shreveport to Dallas in 100 degree weather with the cruise set at 78-80mph. 2006 2wd Northstar. Tire pressures set to 30 front 32 rear when "cold" at 85-90 degrees or so. Clean but not new AC Delco air filter. Oil fairly recently changed, Mobil 1 5w30. Fully loaded with 2.5 people and luggage. The .5 people seem to have the most luggage....

DIC has been within .1 to .3 when I have checked it against the manual calculation based on how much gas I can pump in.

I'm either doing a K&N drop in filter or a Volant CAI and will be interested to see if it makes a mpg difference. The SRX is handicapped by the fact that it's higher up and therefore pushes more air, so you just aren't going to get car mpg (for example, with the exact same driving style, I can get 20 something from the 7 and 28 from the Camaro). But it's about the same as our 99 4.0 I6 2wd Grand Cherokee, with 130 more horsepower, so I can't really complain.
 

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2008 V6 SRX4
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61 Posts
Discussion Starter #8
I have found the DIC trip computer to be fairly accurate and I do believe that it maybe off by .3 MPG give or take. I do not see that as a major deterrent from using DIC for MPG calculations so I will stick to using it.
 

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Cadillac SRX '04 AWD V8
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I have found the DIC trip computer to be fairly accurate and I do believe that it maybe off by .3 MPG give or take. I do not see that as a major deterrent from using DIC for MPG calculations so I will stick to using it.
Mine is 6% off. Tells me I am using less gas, but in fact I am using 6% more.
 

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2007 SRX
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Just completed a 3340 mile round trip from Phoenix, AZ to Penticton, British Columbia, Canada and back in my '07 RWD V6. Overall fuel economy was 22.2 mpg according to the DIC, marginally better (23.1) on the first leg of the trip. I attribute the drop to more interstate driving, therefore higher speeds on the way home. A/C and cruise were on for the whole trip. I was pretty impressed, considering all the hills and mountain terrain. Lost the ability to upshift and downshift in the manual mode mid-way through one afternoon, but all was working well again the next morning. The V6 left a little to be desired in the mountain passes, but I guess the trade-off is okay to get the better fuel economy. Very impressed with the vehicle overall on its maiden voyage.
 

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01 740iL, 99 Z28, 06 SRX V8 rwd
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Dallas to Santa Fe and back trip report:

Short Version: 16.8 to 18.7 mpg averaging 71.604mph there, 19.023 to 17.9 mpg averaging 73.32mph back. For maximum crusing range, ignore the gas gauge, use the DIC mpg and the DIC "fuel used" function + a map with accurate distances to the next town.

Long version:

2wd Northstar. As in my post above, Tire pressures set to 30 front 32 rear when "cold" at 85-90 degrees or so. Clean but not new AC Delco air filter. Oil is still the same batch of Mobil 1 5w30. Loaded with 1 person + a full cargo area of luggage.

Dallas to Claude, Texas 319.9 miles - running Shell 93 octane, avg speed 75.895 mph, 16.83 mpg manually calculated (DIC indicated 17.2 mpg). This stretch I experimented with no cruise control and there was some WOT passing on a hilly two lane section, and dicing through I-35 traffic to get out of Dallas at 7:00 in the morning.

Now we're at higher altitude, Premium Shell I filled up with in Claude is 90 octane.

Claude TX to Tucumcarri NM - 135.5 miles - no stop, so the mpg numbers from the DIC - 16.8 mpg - average speed for the Dallas to Tucumcarri = 77 on the DIC (which of course doesn't include the 6 min the car was turned off in Claude to get gas) and 75.833 actual average mph.

At Santa Rosa NM I'm so far ahead of schedule that I will have to sit and wait forever at the Albuquerque airport for the folks I'm picking up. So I stop for 28 min and check out the Route 66 auto museum. With that stop, the total trip time to the Albuquerque airport from Dallas = 8 hours 51 min - 633.7 miles 75.7 DIC average speed (again, not real, does not include stops) 71.604 real average speed. Santa Rosa to Albuquerque airport was 18.7mpg on the DIC - more downhill stretches once I crossed a mountain range.

Then there was a short hop to Santa Fe, but I don't have the full figures on that. Return trip has no airport component, straight Santa Fe to Dallas.

Santa Fe to Clarendon Texas 329.9 miles 19.3 mpg DIC 19.023 mpg calculated manually, average speed 77.34 mph manually calculated, 77.8mph DIC. Only pumped 17.342 gallons to fill up here. The best MPG of the trip, and also the best average speed, done on 90 octane Shell. I suppose going downhill from Santa Fe to Texas helps a lot here. Also, no traffic to speak of so there's more maintaining speed and less getting back up to speed.

Clarendon gas stop took 15 min due to a line inside the station. Now we're back on 93 octane Shell, but we're also on the leg that will conclude with Dallas traffic.

Clarendon to Dallas - 289.7 miles 17.9 mpg (DIC). Complete average speed from Santa Fe to Dallas = 75.6 mph DIC (again, doesn't include the horribly lengthy stop in Clarendon for gas) 73.32 actual calculated average mph.
 

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2011 CTS-V Coupe A6 w/RECARO's
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Follow up: We just returned from our trip to Indy.

We hauled 4 adults plus all our luggage and a big (heavy) cooler. Running between 5 and 7 over posted speed limits we got 22.2 MPG (hand calculated).

I was surprised how accurate the DIC was. After ZERO'ing out all the data then driving the 256 miles from the gas station to our hotel then to a near by gas station to fill up, the DIC also dispalyed 22.2 MPG.

I'm pleased by that fuel mileage as we carried enough stuff for our 2 day stay carried 4 adults in comfort, style and safety and still got better than 22 MPG.
 

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2008 V6 SRX4
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Discussion Starter #13
PLease indicate when you are using the Sports mode of the tranny or not, I do believe that makes a difference. It seems that I am getting some of the better milleage along with USAFRET. Interested to know what people's PSis for the tires are as I also think that makes a difference, and for the records, it appears to me that under heavy load or A/C usage the milleage in HWY appears rather unnaffected which is a goo thing, The car is so heavy anyway that 800 or so pounds of luggage and passengers probably does not take much more extra gas on the HWY (city would be different) Yah, for this car I may never use the hand fuel calc as I think DIC is pretty right on.
 

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01 740iL, 99 Z28, 06 SRX V8 rwd
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On the Santa Fe to Dallas run I used regular transmission mode exclusively. On the Dallas to ABQ run I sometimes used sport and manual - it didn't seem to make much difference when working between 79 and 89.

I only used manual in an attempt to get back into 5th gear while on cruise control - if you've got the cruise set, and a big hill makes the SRX think it needs to kick down into 4th, sometimes it isn't sure that it wants to go back into 5th for a while - I suppose it isn't sure you're done with the hill so it wants to be ready in 4th. Really, I was trying to use cruise on too steep of a hill and I ultimately solved this problem by using my right foot.

The Performance Algorithim Shifting now, that DOES work - it uses the yaw sensors and the throttle position sensor to determine when you are hauling ass through a series of corners, and holds the appropriate gear just like you would if you were rowing your own in a manual gearbox. Fantastic! I may have had to do a few laps around the ABQ airport while waiting for my passengers to arrive - you know, since the TSA doesn't let you sit idling out front anymore.
 

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2008 V6 SRX4
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Discussion Starter #15
kind of unrealted topic, but a week ago or so I drove my brothers :thepan:1979 BMW 323i 5-speed in the twisties and it was amazing....coming from the SRX and my 4banger rav4 it was unreal, the sheer power and throttle response was great. I may now be shopping for a BMW 325ix just to drive around for fun.
 

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2011 CTS-V Coupe A6 w/RECARO's
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PLease indicate when you are using the Sports mode of the tranny or not
In Drive with the AC system set to AUTO, tire PSI set to 34 Front and 33 Rear Cold. During the trip that increased to 37 Front and 35 Rear. BTW dealer serviced my tires with Nitrogen as part of their PDI.
 

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01 740iL, 99 Z28, 06 SRX V8 rwd
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To all who are not running the factory recommended tire pressures (30 front 32 rear, at least on my SRX - provided you aren't driving for "extended periods over 100 mph" which bumps you up to a higher recommended cold pressure), do you have a reason, and if so what is it?

I know there are plenty of reasons to deviate from the factory pressures, I'm just curious which of these reasons have caused you to run different pressures.
 

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2011 CTS-V Coupe A6 w/RECARO's
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To all who are not running the factory recommended tire pressures (30 front 32 rear, at least on my SRX - provided you aren't driving for "extended periods over 100 mph" which bumps you up to a higher recommended cold pressure), do you have a reason, and if so what is it?

I know there are plenty of reasons to deviate from the factory pressures, I'm just curious which of these reasons have caused you to run different pressures.
because I've used this technique on all my cars for the last 20 years or so, plus I like how the car feels (slightly more crisp). I do check my PSI and tire wear trends. I was able to routinely get over 30 MPG in my 2001 Corvette by bumping up the PSI from the factory rating of 30 PSI to 32 PSI and never experienced any abnormal tire wear.

But again one has to be careful, my my vette PSI's would climb to 35/37 PSI depending on ground temps and length of the trip.
 

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I just returned from a 1300 mile trip, Michigan to Baltimore and back. Tires set to 37psi cold (General Altimax HP, which states their MAX is 51psi). Got up to 42 psi during the trip. Running almost all highway, minimal stops and going just slightly over the speed limit (73 in Michigan, 68-70 in Ohio & Pennsyl.). I averaged 23.5 mpg (23.8 going there, 23.3 on the way back). I was running 89 octane and my recent oil change was Castrol 0w30 (German Castrol). Not bad for this vehicle I think. This is an AWD 3.6 V6 BTW.
 

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01 740iL, 99 Z28, 06 SRX V8 rwd
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But again one has to be careful, my my vette PSI's would climb to 35/37 PSI depending on ground temps and length of the trip.
My 30/32 cold increased to 37/39 (plus or minus 1) over the course of my ~300 mile between stops trip in warm summer temperatures. An interesting datapoint, but not anything to worry about.

Generally speaking, as long as your cold pressure is above the factory recommendation and less than or equal to the Max PSI on the sidewall, you don't need to worry about how high the PSI gets as you warm the tires up by driving. Both the factory recommended pressure and the Max PSI on the sidewall are "cold" pressures - meaning if you've got a 45psi max, and you inflate to 45 psi cold, you are still within the design specs when that psi rises as the tire heats up.
 
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