Engine Question on T4R versus GX

[BDL]

I have what is probably a dumb question, but I searched and didn't see it addressed. Why does Toyota assign different horsepower and torque ratings to the T4R and the GX? And why does the GX supposedly take 91+ octane versus 87 octane fuel for the T4R?

Did they just test the GX on premium and get better figures? I understand that the engines are basically identical.

 

[steh-fan]

Are you looking at an American GX manual?
Octane Rating 87 is 91+ in all other countries (different ways to calculate it).

 

[BDL]

Yep, I'm looking at the US manual for both. The T4R manual calls for 87 octane (91 research octane, whatever that means) whereas the GX calls for 91 octane (96 research octane).

All of the manifestations of the 4.7L engine - T4R, GX, Sequoia, Tundra, etc seem to be rated a little differently.

 

[steh-fan]

(91 research octane, whatever that means)

Some clue you could find here, if you want:

http://en.wikipedia.org/wiki/Octane_rating


Maybe it is just when you buy premium cars that you have to use premium gas...

 

[Boston_Runner]

The GX use to only recommand 91 octane, the 08 now requires 91 octane. Not sure what the diff. is, but just because an engine is mechanically the same, that doesnt mean the electronics is the same.

 

[Thai]

If you just spend $55,000, then do you want to find out that a 4runner makes the same power?? Nope.:

 

[steh-fan]

The GX use to only recommand 91 octane, the 08 now requires 91 octane. Not sure what the diff. is, but just because an engine is mechanically the same, that doesnt mean the electronics is the same.

Indeed, the GX engine uses different spark plugs (with a smaller gap) and also have different coils.

 

[Uneek]

All of the manifestations of the 4.7L engine - T4R, GX, Sequoia, Tundra, etc seem to be rated a little differently.

This was true with the also 2JZ-GE, the 3.0 I6 used the Lexus SC300, GS300, IS300 and the naturally aspirated Supra. IIRC, the SC300 were rated at 225hp, but and the GS300 and Supra at 220hp. The five extra horsepower was at 500 RPMs higher. The IS300 on the other hand was rated at 215hp, but it was due to a more restrictive exhaust.

I say the GX has more HP is because it uses premium fuel. I don't think there are any variations in its (GX470 and 4Runner) intake or exhaust setup like with past Toyotas and Lexuses models that shared the same engine. And beside most premium/luxury brands vehicles require premium. It's probably for that warm and fuzzy feeling for a Lexus owner.

My two cents.

 

[rx900]

According to a Lexus mechanic I asked once, the difference is the catalytic converter. The CC in the Lexus is different than the one in the V8 Toyotas (Sequoia, 4Runner, Tundra).

Plus for the GX, it was recommended 91 for the 03 and 04s but once they switched to the VVT-i engine in the 05, 91 became required.

 

[TeCKis300]

Why does Toyota assign different horsepower and torque ratings to the T4R and the GX? And why does the GX supposedly take 91+ octane versus 87 octane fuel for the T4R?

The basic reason you point out is the major reason for the hp descrepancy. Octane allows for more compression before pre-ignition and knock although the GX and 4R have the same static compression. This allows them to tune more aggressively by advancing timing for more dynamic compression.

There might be very very minute detail differences on the whole between the models, but they are almost for all intents and purposes mechanically identical.

And to rx900...'05 4runners received the same vvti upgrade w/o the octane requirement.

Irrelevant of the different ratings...just know that your V8 4R is the faster and more agile vehicle between the vehicles. The GX is quite a bit heavier due to it's luxury laden nature.

 

[rx900]

Correct. The 05s and newer 4Runner (V8 models) received the VVt-i upgrade also, BUT as I mentioned in my first sentence, the Catalytic Converter is different from what they put in the Lexus vehicles versus Toyota...




GX may seem heavier but it has practically the same power as the 4Runner and it's more stable to drive, especially on those long road trips where there's a segment of the highway with gusty winds Not to mention cabin space. I still appreciate the cabin space that the GX offers but the 4Runner doesn't

 

[DrVolkl]

So what's the final verdict? My '07 has 91 octane warnings all over the place.

I think I'll just play it safe and use the high grade...but it sure would be nice to use 87 or even 89 once in awhile.

 

[Huskey4Runner]

Doesn't a higher octance help the engine stay cleaner. I just got rid of an Acura for my 4Runner and it required 91 octane. The way I see it it's really not that much more expensive. It's $.20 extra per gallon over 87 rated Octane, at 5 gallons that's a dollar, and the most gas I've been able to put in my 4Runner is 19 gallons. So, $4 extra (one froofy drink from Starbucks) is worth it to me to have a cleaner running car, especially in the long run. Just a thought...

 

[DrVolkl]

Doesn't a higher octance help the engine stay cleaner. I just got rid of an Acura for my 4Runner and it required 91 octane. The way I see it it's really not that much more expensive. It's $.20 extra per gallon over 87 rated Octane, at 5 gallons that's a dollar, and the most gas I've been able to put in my 4Runner is 19 gallons. So, $4 extra (one froofy drink from Starbucks) is worth it to me to have a cleaner running car, especially in the long run. Just a thought...

You are completely correct... I often forget how little it really matters.

 

[SubSonic]

If you just spend $55,000, then do you want to find out that a 4runner makes the same power?? Nope.:

LOL! That's funny, but true. Take the 1970 Chevy LS6 (454). They rated its HP less in the '70 Chevelle than they did in the '70 Corvette, and the engines were identical - but the cars' prices were not. The car model dictated the HP difference.

Of course it can be argued that there were 2 454s available, and there were, the LS5 and LS6. But the LS6 was the bomb, and I am not certain if the lower HP LS5 was available in the Corvette which is why I speak specifically about the LS6, which *was* available in both models for that year.

 

[Forenaftrunner]

Re: Re: Engine Question on T4R versus GX

Irrelevant of the different ratings...just know that your V8 4R is the faster and more agile vehicle between the vehicles. The GX is quite a bit heavier due to it's luxury laden nature.

I find my wife's GX470 to be significantly quicker than my V8 4runner (Both 2008 models). I use regular gas in both. Hers feels a good 0.5 - 1.0 second faster in the 0-60 sprint, and on the highway it feels like there is much more passing power.

It seems like the minor difference in claimed HP would not be enough to create this perceived difference. Is there any difference in the gearing or final drive ratio between the two?

 

[Will816]

The difference is that the HP/torque ratings on the Lexus are not SAE approved. If you look at the ratings on the 2005 4Runner with the V8, it is the same. This was back before Toyota revised its power ratings to comply with SAE standards. Also, the 03 and 04 models make the same numbers, but this was the V8 that had a lower rev limiter and no vvt-i.