High altitude performance of V6?

[Dennis]

I'm new on the forum, but I've been lurking for a week or so. I've finally decided to buy a 4Runner after driving some of the competing off-road-capable mid-size SUV's. I'm going to get a Limited, but I need advice on the engine.

The V8 versus V6 thing has probably been beat to death here, but it is hard to find the appropriate threads because Search doesn't work on two-letter words, i.e. "V8" or "V6"! I've driven both engines myself and I think the V6 is great, except...

I will be driving a lot at high altitude as my house is at 6000 feet. I can't get a test drive at that altitude and I'm worried that the V6 might not have the beans I'd like up there. Can anyone tell me how their 4Runner runs at that kind of altitude--and above?

I'm trading up from a Grand Cherokee with a 4.7 liter V8 which has power and torque ratings similar to the Toyota V8. I judge it quite adequate at high altitude. I'd love to get the V6 mileage, though, especially since I'll be stepping up to premium gas.

 

[srpage]

I live in Reno at 5000 feet and have an 03 V6 4X4 and I feel it has plenty of power for my needs.

I have 30,000 miles on it and have driven all over from sea level to over 9000 feet and it has plenty of go. Mine has the 4 speed and if you are buying a new one with the 5 speed it should actually be a bit peppier with the extra gear.

Realistically I believe you will be losing some torque coming down from the Jeep 4.7 litre V8 and you have to decide if you can live with that.

You might want to consider test driving a 4runner at Carson City Toyota as they are at 5000 feet and let me test drive mine up to Spooner summit.

Why are you going to premium gas?

 

[Dennis]

My house is an hour away from the dealer, so it isn't really reasonable to take that kind of test drive. Reno is, in fact, at 4500 feet and is a fairly close altitude neighbor.

I'm very happy to hear from srpage, since he actually has a V6 that he uses in my neighborhood. Sounds like it might work for me.

The premium gas thing, by the way, is because Toyota recommends premium. Jeep recommends regular. I realize that the 4runner won't gag on regular, but it seems smart to go with the recommendation.

 

[Iowa4Runner]

My house is an hour away from the dealer, so it isn't really reasonable to take that kind of test drive. Reno is, in fact, at 4500 feet and is a fairly close altitude neighbor.

I'm very happy to hear from srpage, since he actually has a V6 that he uses in my neighborhood. Sounds like it might work for me.

The premium gas thing, by the way, is because Toyota recommends premium. Jeep recommends regular. I realize that the 4runner won't gag on regular, but it seems smart to go with the recommendation.

Just a side note, it's quite possible you'll find that your 4Runner runs the same on regular as is does on premium. High altitudes make detonation less likely so even with regular octane your engine probably won't need to retard the ignition timing to control pinging. And when that's the case, higher octane fuel will give you zero benefit.

Toyota's recommendation isn't for engine reliability, it's to reduce the chance of detonation related performance loss. They recommend 91 octane for my '04 V8 and after a series of semi-scientific tests, I concluded there was absolutely no difference in 91 vs. 87 octane under the test conditions.

Just my $.02

 

[RonMAIDEN]

3rd gens do fine up here at 6000 and even up at over 8000 so I'm sure the 4th gens with 50 more ponies are fine since 50 more ponies in a 3rd gen would be nice.

 

[greasefingers]

I found the same thing with my '04 V6 4Runner. I have an OTC scanner that has live data stream capabilities and I connected it for several tanks of gas (with 87 octane) to see if I could get the knock sensor to pull back timing. It never happened though--even if I drove full-throttle up a steep hill, the engine never experienced any detonation at all with the 87 octane fuel.

That kind of data is exactly what I have been looking for. Thanks Hitman and Happy Thanksgiving

 

[OUTRNNR]

I've been putting 91 octane in my '05 V8 and am not sure if I have noticed a difference in performance. Does anyone know what the compression ratio of the V8 is? I would like to compare it to the V6??

The reason I wonder is if they are around the same, I will start putting 87 in now that its been basically proven that the 91 makes no difference.

In CO, regular unleaded is 85 octane, mid-grade is 87 octane and premium fuel is 91 octane. As Hitman said this is because altitude deters detonation.

Thanks everyone and have a Great Thanksgiving. GO BRONCOS!!!

 

[bonedoctor]

4Runners at high altitude

I have a 2005 V8 Limited (purchased in flatland Missouri) with just over 8K miles and live in Aspen, CO. The town is at 7900 ft and I've had it up over Independence Pass (about 20 miles south of Aspen on CO 82) which is a little over 12,000 ft. Haven't noticed any problems and I'm very happy with the vehicle so far. I run the cheap (yeah, right!) 85 octance stuff since gas here is over $3.00/gallon in Aspen, but a little cheaper downvalley towards Glenwood Springs. Oddly enough, my Kawasaki Vulcan Classic cycle with a single carb that's been rejetted to a big 'ol jet while in Missouri and running Vance and Hines longshots pipes with baffles even runs pretty well out here. Was convinced that it would be way far rich. Apparently bikes come from the factory fairly lean, so it's not a rich as I thought it would be. My Yamaha FZ1 with four carbs (untouched) runs fine, too. Both have been up and over the pass at 12,000+ feet. I do run the CO premium (91 octance) in them, however.

 

[Koz]

The V6 4Runner has more HP then the Heep's 4.7 V8 and would be fine for your needs. The V8 has more HP and torque and will help if you intend to tow.

Koz

 

[greasefingers]

Does anyone know what the compression ratio of the V8 is?

The v6 comp ratio is 10:1
The v8 is 9.6:1

Once the variable valve thingie came about (I think it 2005 ?) then the compression ratio went up from 9.6:1 to 10:1 for the v8. I do not know if it also changed for the v6.

 

[Pribilof]

I have 39k miles on my '04 V6 4x4. I live at 5200' and use 87 octane gas. I have driven west on I-70 through the mountains all the time and think that unless you're towing a lot or towing heavy loads there is no need to get the V8. I towed a trailer with two sportbikes on it from Denver to Vail and didn't feel like I really needed any more power.

 

[GYoter]

Dennis, for what its worth when i drive around Truckee i barely notice a difference in power from here in sac. Even when towing i have plenty of oomph. My manual recommends regular gas, as i thought the V6 manual also did. I guess that changed? Ive driven my friends 04 v6 up there and i never thought it didnt have enough power. Anyways i think either engine would be plenty powerful for you. I am partial to the V8 tho.