Titan in Truck Trend Mag

[GETSOMZ28]

All, the Titan has been added to Truck Trends long term testing in the current issue (Sep/Oct 2004 pg77). Seems like they like it so far, but one thing strikes me as odd...they say the Titan requires premium fuel. Thats not what my manual says, so I am not sure why they would say that?!? I am interested to hear the updates.

[virnoche]

I got news for you.......TRY IT!!! mine feels like a new motor with premium vs regular fuel!
I reckon they are referring to the performance more than an actual necessity.

Premium even sounds better......lots more power......and fuel economy for mine went to 15 with mixed driving from 14 with regular.

[BiXLL]

I am skeptical as it goes against everything I have ever been taught about engines/octain/performance. I am going to run a tank of premium through it though just for ships and grins.

[Titan4x4Aggie]

Originally Posted by BiXLL

I am skeptical as it goes against everything I have ever been taught about engines/octain/performance. I am going to run a tank of premium through it though just for ships and grins.

I am also skeptical. Higher octane fuels are more refined and subsquently have a higher resistance to knocking or detonation. They also have a higher flash or ignition temperature, which means it takes a hotter flame to completely burn the air/fuel mixture.

What does all this mean? It means high octane gas does not burn as completely or efficiently in a low-compession engine. Expect to lose horsepower and gas milage, and waste money.

I run 93 octane in my turbo rx-7, because if i dont it will detonate. But I ran 87 in my n/a rx-7, because it had lower compression and got more hp out of the cheap / low octane gas.

[DallasTitan]

Originally Posted by virnoche

I got news for you.......TRY IT!!! mine feels like a new motor with premium vs regular fuel!
I reckon they are referring to the performance more than an actual necessity.

Premium even sounds better......lots more power......and fuel economy for mine went to 15 with mixed driving from 14 with regular.

As much as I hate paying more than 2 bucks a gallon for it, I have to agree with you.
I did a test of the 93 octane last 2 weeks.... man what a difference!
It feels like I just dropped $1000 on a Volant and Banks exhaust to get this much more power!
I just don't know if the computer would quickly adjust back to the old fuel/air mix if I have to go back to the old knocker(87 octane).
We'll see.

[BiXLL]

Originally Posted by Titan4x4Aggie

I am also skeptical. Higher octane fuels are more refined and subsquently have a higher resistance to knocking or detonation. They also have a higher flash or ignition temperature, which means it takes a hotter flame to completely burn the air/fuel mixture.

What does all this mean? It means high octane gas does not burn as completely or efficiently in a low-compession engine. Expect to lose horsepower and gas milage, and waste money.

I run 93 octane in my turbo rx-7, because if i dont it will detonate. But I ran 87 in my n/a rx-7, because it had lower compression and got more hp out of the cheap / low octane gas.

I changed my mind when I went to fill up this morning. I just can't get past what I have always been taught regarding octain and compresion level. I really think you guys are talking yourselves into it running better because you are paying more. It is a waste of money!

[virnoche]

Being that I used to build engines for my exepensive passtimes I am quite familiar with the physics behind octane and compression. What exactly is 'LOW' Compression?

We had a pretty oversimplified rule of thumb when we had interchangeable domes and Klotz additative for out machines. Dont laugh but it worked well for us. move the decimal in the octane one postion left and that is roughly the highest level of compression we would run with THAT octane. Funny thing......our race engines ran in the 10-11 range and so did our fuel. We either started with aircraft fuel 102 octane and added from there or used pump premium and added from there.....

All I know is that it worked well for us as a general rule.

[BiXLL]

Virnoche, I too am very familiar with changeable domes, race gas etc., I have built and raced jet skis for the last 15 years! So with all your "experiance", are you telling me that our Nissan 5.6 is a high compresion engine? Or maybe the computer teaches itself to adjust to run better on high octane gas?

[virnoche]

BiXLL-

I don't know WHAT the compression is in the Titan and that is why I asked you what you considered LOW compression. Usually....you can research this yourself 32 valve engines are around 9 to 1 and most manufactures that have them DO INDEED recommend premium pump fuel.

The reason I switched to premium is the following.....while pulling out to pass one day I noticed a very slight nock and an immediate reduction in power. The next fillup I didnt even hesitate to go with premium as I have been down this road before.

I know what the manual says for the Titan but did you ever think that this was done for a simple marketing reason? Think about this....Nissan is no dummy when it comes to building phenominal engines. They know exactly how good there engine management system is so they know full well that regular fuel will not in any way harm the engine so they say you can run it........

Now think about this......had they required PREMIUM fuel how many sales would they have lost because of this fact??????

Just some food for thought.......I know for sure mine reacts much better to premium so that is what I will give it!!!

[Mike H.]

I too have noticed the same thing. Noticably better with 91/93. More peppy down in lower RPMs to me. I stopped doing it though when the liquid gold prices exploded. I have even noticed a slight improvement going to 89, but not worth the $0.10 more.

[virnoche]

Here's a great article I found that seems to verify our old school method of octane matching with non-engine managed systems:

http://www.faqs.org/faqs/autos/gasol...section-1.html

Also read farther down where it deals with engine management systems.......

Good article!!!!

[SupraTitan]

Originally Posted by Titan4x4Aggie

What does all this mean? It means high octane gas does not burn as completely or efficiently in a low-compession engine. Expect to lose horsepower and gas milage, and waste money.

This is not true at all. Premium fuel burns more effeciently than lower octane do to a more ignition advance being allowed to be run. This in turns creates less cylinder temp(heat is wasted energy) and lower egt's and you will gain power and mpg.

The Titan brochure actually states that premium fuel is required. In the specifactions section it shows the engine model. Next to it is a little box with a small number that corresponds to the info on the bottom that states premium fuel is required. Thought that was strange since the manual does not say anything.

[IMADOGMAN]

Originally Posted by virnoche

BiXLL-

I don't know WHAT the compression is in the Titan and that is why I asked you what you considered LOW compression. Usually....you can research this yourself 32 valve engines are around 9 to 1 and most manufactures that have them DO INDEED recommend premium pump fuel.

The reason I switched to premium is the following.....while pulling out to pass one day I noticed a very slight nock and an immediate reduction in power. The next fillup I didnt even hesitate to go with premium as I have been down this road before.

I know what the manual says for the Titan but did you ever think that this was done for a simple marketing reason? Think about this....Nissan is no dummy when it comes to building phenominal engines. They know exactly how good there engine management system is so they know full well that regular fuel will not in any way harm the engine so they say you can run it........

Now think about this......had they required PREMIUM fuel how many sales would they have lost because of this fact??????

Just some food for thought.......I know for sure mine reacts much better to premium so that is what I will give it!!!

SERVICE DATA AND SPECIFICATIONS (SDS)

EM
SERVICE DATA AND SPECIFICATIONS (SDS) PFP:00030
Standard and Limit EBS00I3B
GENERAL SPECIFICATIONS
Cylinder arrangement V-8
Displacement cm3 (cu in) 5,552 (338.80)
Bore and stroke mm (in) 98 x 92 (3.86 x 3.62)
Valve arrangement DOHC
Firing order 1-8-7-3-6-5-4-2
Number of piston rings
Compression 2
Oil 1
Number of main bearings 5
Compression ratio 9.8
Compression pressure
kPa (kg/cm2 , psi)/rpm
Standard 1,520 (15.5, 220)/200
Minimum 1,324 (13.5, 192)/200
Differential limit between cylinders 98 (1.0, 14)/300

[BiXLL]

Virnoche, you have brought up some very good points so far as marketing. I remember the early Nissan manuals actually did call for premium fuel also. You could be absolutely correct in thinking perhaps it was changed to make the vehicle more marketable. I am going to do some digging and see if I can't come up with just what the compression is on the 5.6.

Good discussion!

[BiXLL]

Originally Posted by SupraTitan

This is not true at all. Premium fuel burns more effeciently than lower octane do to a more ignition advance being allowed to be run. This in turns creates less cylinder temp(heat is wasted energy) and lower egt's and you will gain power and mpg.

The Titan brochure actually states that premium fuel is required. In the specifactions section it shows the engine model. Next to it is a little box with a small number that corresponds to the info on the bottom that states premium fuel is required. Thought that was strange since the manual does not say anything.

How can you say that? Without going into the computer and retuning it, it will not automatically advance the timing! The computer doesn't know that this time you put high octane gas in it! Therefore the quote you responded to is absolutely correct!

IMADODGEMAN, you posted as I was making a post. If that compression figure you have listed there is saying we have a 9.8 to 1 ratio, then this motor very well could do a better job with higher octane fuel! 10 to 1 is where we always made the change, so it is right there! However.....if Nissan detuned, or retarded the timing in able to accept the low octane fuel, would the higher octane fuel be of any value to the motor? (I don't know, I am asking)