I've been searching for a graph of engine horsepower and engine torque versus RPMs for the 3.5 L engine in the new Maximas. Have had no luck. Was advised at freshalloy.com that there is a poster on this site who has these graphs for all Maxima engines.

Nissan seems to keep this information under "Lock and Key." When I bought my Dodge Ram pickup with 8L V-10 engine to haul my camper, I had no problem finding this graph -- Chrysler did not hide the graph.

Any help out there to provide this graph would be greatly appreciated. I've found in the past that it helps to know how "peaky" both the HP and the Torque curves are. My suspision from driving my new Maxima is that the torque curve is reasonably flat from about 1,800 RPM up to the peak Torque at 4,400 RPM. Because I'm still breaking my engine in, I've rarely been above 4,000 RPM. Will be soon, when it's broken-in.

 

Hi SilverMax_04,
that was me who advised you to come here :-)

Let me pore thru threads - there is a guys who has those charts in the signature

 

I think you are talking about STEVTEC. spelling may not be correct.

 

Yes, this is SteVTEC - I just did a lookup

 

My "engine tech buddy" found a graph for a "stock" 2002 Maxima -- but it's a graph taken at the driving wheels rather than at the engine. It is also of a 2-year older version of today's engine. It is still of interest, and can be found at this site:

http://forums.maxima.org/showthread....6&goto=newpost

I have the following comments about this graph for the 2002 Maxima engine:

The graph of torque at the wheels confirms my opinion of a reasonably flat torque curve (from 2,500 to just over 5,000 RPM the torque was at or just above 200 ft-lbs at the wheels). I note that the car they tested was a 2002 model Maxima. I suspect that the latest engine has an even broader flatness to it's torque curve, and that a curve of today's engine would find the flatness goes down to 2,000 RPM or even somewhat lower. The peak torque at the wheels for the 2002 appears to be in two places (3,500 RPM and again at 4,500 RPM). Nissan reports the latest engine has its peak torque at 4,400 RPM.

The HP at the wheels curve is also what I expected. It builds to a peak and then falls off, with the peak just past 5,000 RPM. The latest Maxima engine reports peak HP at 5,800 RPM.

A friend with a 2003 G35 reports his car seems to jump at about 4,000 RPM. The curve for the 2002 shows something happening at about 4,000 RPM as well.

This may be the only graph I see of HP and torque -- and this for an earlier version of this engine.

 

In my previous post, I ended up with the wrong web address for the site where they show a graph of HP and Torque (at the driving wheels) for a stock 2002 Maxima. The correct address is:

http://www.nissanperformancemag.com/june02/maxintro.php

Sorry bout that!

 

I can send you my dyno's of my stock 02 6 speed. My graphs confirm what you've written. Mostly flat SAE TQ (averages around 220 ft/lbs and varies by as much as 10) from 2.5K to 5.0K where it starts dropping. My peak SAE TQ was around 4.5K at 225.8 ft/lbs.

There is a TQ/HP change around 4K which is supposed to be due to the variable intakes changing. I haven't seen any dynos showing peak TQ at 5800. That would be pretty impressive. I'd be very curious what is changed to do make that happen. Hope this helps.

 

There is no difference at all between the engine in the '04 and the '02/'03, they are both the VQ35. Nissan says the rated output difference is due intake/exhaust changes. Furthermore, Nissan has been known to play fast a loose with the output ratings on the VQ35. For instance, the Altima which is rated at 240 hp puts down the same hp numbers as the Max which is rated at 255. I'd love to see a dyno of the 6th gen.

 

are you talking about HP at the wheels Jaws?

 

Yes, the Alty and 2k2/3 Max put down the same power at the wheels. It would be interesting to see if the exhaust/intake differences have actually bumped up wheel hp with the 6th gen or if Nissan is playing with numbers again.

 

well the 6th gen maxima may not loose as much power through the drivetrain.

 

I suspect that Jaws may well be correct. Nissan has tweaked the engine to get slightly higher "engine dyno" readings for the Maxima, but the "wheel dyno" readings may well be almost the same as for the Altima and also earlier Maximas.

Note that ajahearn reports that he has "wheel dyno" readings made for his 04 Maxima. It would be nice if he would share the graphs or at least some of the dyno points on these graphs of HP and Torque. Note, however, that ajahearn reports that the Torque curve for his 04 is essentially the same as the torque curve for the 02 that is shown on the web site (basically flat from 2,500 RPM to 5,000 RPM). Also note that the Nissan quoted peak "engine dyno" Torque for the 04 was 255 lb-ft at 4,400 RPM (not the 5,800 RPM that ajahearn quotes in his post -- the peak HP occurs at those higher revs).

 

It is the identical engine/gearbox. If I took the engine out of my car (2k2) and put it in my dad's car (2k4), there would be no difference. Hmmm got me thinking now...

 

I had a private post on this site about issues of HP and Torque that raises an improtant question: Are Chassis Dyno readings (at the drive wheel of a car) better than Engine Dyno readings (at the flywheel of the engine)? The message was private, so I'll not indicate who sent it to me. The issue is important, so I'll repeat the issue from this private post {my comments are in these brackets}:

"Manufacturer dyno plots for engines are set to match whatever their marketing department is claiming and not what the engine is actually putting out. So manufacturer crank dyno {at the flywheel} plots probably wouldn't be very useful. Chassis dynos are the best at telling the true output of engines."

I raised this question about engine vs chassis dyno readings with my engine tech friend (who I've quoted in other postings). The question I asked him was: "I always thought the marketing department waited until there was a graph of engine dyno output before 'claiming' the numbers. This message seems to think it's the other way around."

Here is his reply to this question.

I do not think I would agree with his assessment of the situation as being the universal truth. It is more dependent on what the series of events around the situation are. Chassis dyno testing reflects the composite effects of the complete powertrain which introduces another layer of variability on the performance measurement. Engine dyno testing is more controllable and repeatable and as a result usually gives a more accurate measure of the engines performance. In either case it is not uncommon to see a 3% variability in production engines {for engine dyno readings} and in some cases I have seen data indicating up to 10%. This is the result of variabilities in a mass production world.

Since some of the makers {auto manufacturers} have been burned in the past over inflated ratings, many of the makers are shooting for the lower end of the respective confidence band these days. I have been able to span well over the 10% range on several engines just by doing command overrides on the control system, something that increases the risk of failure when you are in a production environment, yet with the data available on an engine dyno becomes easy.

The bottom line is that if you want to know what an engine is really capable of, you instrument the heck out of it and run a full sweep on an engine dyno. That is the only way you can control all of the variables to the point of obtaining repeatability and correlation from test to test. Such control is simply not available on a chassis dyno.

What is claimed by marketing is a political issue that may or may not have an impact on the final {dyno test} number, I have seen it go both ways. In some cases a platform requirement comes from the vehicle group (more than 1/2 the time) and in other cases the vehicle group is solicited by the engine engineering group.

Even in the case of competitive evaluations by one manufacturer to another {one company analyzing another company's engine} the engine dyno is used to understand what the product does. Its just that the cost of testing a competitive product on an engine dyno these days is quite high and that is the primary driver behind the use of chassis testing for competitive evaluations, not accuracy of data.

The real question is who is doing the test and what level of attention do they pay to the details, that is where the accuracy of measurement takes place. In the world of engine testing 1% is a very small number to validate in terms of realistic confidence bands. This is normally repeatable on different dynos with the same engine only if someone really knows what they are doing and pays close attention.

Another way of putting it is that at several thousand dollars {an 8-hour} shift to do engine testing, it is a rare occurance to have months of time to sort out how to make that comparison and what the real number is. I have had the opportunity to participate in that process and it is quite daunting. Accurate numbers that represent an engine (BSFC, BMEP, Corrected Torque) are hard to get with high precision and repeatability under the best circumstances on an engine dyno. A situation that is much more difficult on a chassis dyno and normally not used for high accuracy and precision measurement of engine performance.

Feel free to pass this along.

 

thanks for the info silvermax.

 

not necessarily true...


http://forums.maxima.org/showthread.php?threadid=179293

 

Umm, you must be a journalist. My entire quote said that the changes are exhaust and INTAKE changes. The ENGINE is identical (I don't consider the intake to be the engine). Nothing in the thread that you referenced indidicated any changes to the engine itself.

 

how about the silent timing chain?

LOL

 

Supposedly the TC on the 2k2/3s is "silent" too. Although mine certainly rattles on the occaissonal start

 

okay, but your posts seemed to be implying that the 04 max would put down the same amount of power as the 02/03s bacause they have the same engine. each one of your posts seemed to ignore the fact that there actually is a difference under the hoods of the cars. you were talking like even though there is a change in the intake it wouldnt make any difference and the 04 would put down just as much as an 03 maxima and altima. but that isnt necessarily true.

that is just how i perceived everything you said.