True Q45 horsepower figures

Post by **juju0990** » Fri Jan 30, 2004 1:50 pm

I have a Question to the 278HP rating how true is this ? Now I recall Japan had a Hp limit of 280 and use to underate cars to meet this goverment requirement. Has any one ever put there car on a dyno to see how much HP they were putting to the ground ?

Post by **qship96** » Fri Jan 30, 2004 1:50 pm

early q was rumored to have closer to 300 flywheel horsepower,but measuring on the dyno shows wheel horsepower,a totally different and lower measure than the way the factory advertises horsepower{at the flywheel} japan did have that crazy rule back then,yet the 1990 300zxturbo was rated at 300 horsepower from the factory,so go figure!

Post by **juju0990** » Fri Jan 30, 2004 1:50 pm

Yea i was just wondering if any one had any chasis dyno figures because the jump from 278HP to the current 340HP is a big gap, I think they are closer or over the 300HP mark of course in the best state of tune

Post by **qship96** » Fri Jan 30, 2004 1:50 pm

juju0990 wrote:Yea i was just wondering if any one had any chasis dyno figures because the jump from 278HP to the current 340HP is a big gap, I think they are closer or over the 300HP mark of course in the best state of tune

I think part of that "gap" is pure marketing,the new q has never lived up to it`s performance numbers,and unfortunatly cant beat the 290hp ls430,wishful thinking on the 340hp number maybe?

Post by **juju0990** » Fri Jan 30, 2004 1:50 pm

Yea they just did not do well in the marketing at all, Which is good news for people looking for a performace car for a little of nothing. I just picked up my 94Q 100,000 mint condition for $5000

Post by **qship96** » Fri Jan 30, 2004 1:50 pm

what a great choice!take a few days to read up on all the old posts for suggestions on maintaining your q ! probobly the best advise you will find is to change ALL fluids every year,and keep the q out of the hands of technicians that are unfamiliar with the q.

Post by **juju0990** » Fri Jan 30, 2004 1:50 pm

yea i am getting started this weekend, i am a fairly good with the tool box so its not much that i wont take on my self.

Post by **qship96** » Fri Jan 30, 2004 1:50 pm

have you fished around the spare tire area to see if the factory service manual is still there?

Post by **szh** » Fri Jan 30, 2004 1:50 pm

qship96 wrote:I think part of that "gap" is pure marketing,the new q has never lived up to it`s performance numbers,and unfortunatly cant beat the 290hp ls430,wishful thinking on the 340hp number maybe?

The same engine in the M45 can beat the LS430 easily. I tried to get one to run with me the other day, but he wouldn't take the bait!

Z

Post by **AZhitman** » Fri Jan 30, 2004 1:50 pm

Actually, the LS430 numbers are pretty widely accepted to be exaggerations.

I have driven one, and also have an LS430 kill (3 runs) that (I think) is chronicled in "Infiniti Speeding Stories" thread.

Some of our experts have indicated the EARLIEST Q's were around 307 hp, with power diminishing gradually down to 278-280 in 1995. 1996 showed a larger drop, and 97 saw another sharp decrease.

Post by **Q45tech** » Fri Jan 30, 2004 1:50 pm

The 90-93 Q actually had its peak HP at 5,600 rpm or two peaks at 5,500 and one equal or smaller peak at 6,000 rpm depending on air and engine temperature on the 3 chassis dyno graphs I've seen..........the RWHP looks similar on a chassis dyno.

The 90-93 approached 307 lb/ft not 307 HP, the 307 HP was with a JWT ecu and colder air intake and loud exhaust bumped this to 318 HP and 337 lb/ft.

Retuning the cams and intake on the 2002 engine resulted in peak HP occuring around 6400 rpm: 6400/5600=1.1428.......279 lb/ft at 6400 rpm is 340 HP ~~0.838 efficiency.

I'll bet they meet the torque [odd number 333 lb/ft] so they probably meet the HP [give or take the usual 3% allowed variance between engines as installed] [some are 330 some are 340 many are 335.

The closer the HP peak is to the transmission shift the less time you have to USE the peak power but the torque peak rpm is still at 4,000. Thus the range in gears is the same [4,000-6,900].

With automatics, heavy cars, and concerns for highway mpg you are stuck with a less than 4500 rpm torque peak with limits where the peak HP can occur.........Audi tried a trick a few years ago in the S8 [5,000 torque peak 6900 HP peak] to show for marketing purposes 360HP from 4.2 liters........they need a 15% higher diff gear to allow highway cruising without bucking on inclines..............the highway mileage dropped to 20 mpg ugh!

The newer 6 and 7 speed automatics will allow these higher rpms and thus the higher PEAK HP.

BMW is always a good benchmark of what is prudent and possible now that they have increased displacement to 4.4 liters..........325 HP@ 6100 rpm.....330 lb/ft @3,600........an extra 0.1 liter might be good for 8-10 units higher depending upon how you pivot the cams - favor higher torque or higher HP.

I surely wouldn't get concerned over 10-20 HP in a 4,000 pound car, pretty immaterial.

The problem is the transmission.Infiniti is way behind the curve with the 5 speed AT. The newer [6-7] AT use dual clutches instead of torque converters and disconnect the engine from transmission when stationary.http://www.autotechdaily.com/pdfs/T07-31~1.PDF

With engine technology peaking [until direct injection/electric valvetrains] it's all about who has the best transmission now..............

Post by **Q45tech** » Fri Jan 30, 2004 1:50 pm

"ZF introduced the world's first 6-speed automatic in BMW 7-series. Soon, Jaguar S-Type, XJ and Audi A8 also adopted the ZF transmission. Not Mercedes, because Mercedes is the only car maker in the world building its own automatic transmission (GM and Ford builds via their subsidiary, while other European car makers simply out-source from transmission makers). Mercedes used to be proud of its smooth 5-speed automatic, which is fitted to almost all its models from C-class to SL-class. However, being short of 1 gear, it is bettered by the ZF unit in acceleration, smoothness as well as fuel consumption. This will be changed from this Autumn, when Mercedes start producing a new generation 7-speed automatic transmission, called 7G-Tronic, to replace the old 5-speeder. Initially, it will be used by the V8 models only, such as E500, S430 / 500, CL500 and SL500.

With 7 ratios, expect it will take the lead again in the competition with ZF. More ratios means two benefits: 1) smoother shifting and acceleration because the ratios are closer from each other; 2) better fuel economy because of larger ratio spread between the lowest and highest gear. In the best cases, fuel consumption can be reduced by 0.6 litre / 100km while 0-60mph time is cut by 0.3 seconds.

The 7-speeder is barely any longer and heavier than the old 5-speeder, thanks to clever packaging and magnesium casing."

Post by **Q45tech** » Fri Jan 30, 2004 1:50 pm

I can't wait till some used owner abuses the transmission and hears at 101,000 miles: Oh, that will be $5,750 plus $1,000 in labor to put in a remanned.Current Infiniti owners cry at $3.5k for a 4 speed and $4.5k for a 5 speed.

Post by **elwesso** » Fri Jan 30, 2004 1:50 pm

If you wanna play you gotta play....

Ive wondered... Dennis, what do you think the reliability (overall) of the new generation Q45 will be compared to the G50.... I know the transmission will be more expensive to replace, but could we expect them to last longer???

Post by **AZhitman** » Fri Jan 30, 2004 1:50 pm

Dennis, as always, thanks for the clarification.

Dennis' knowledge > my "knowledge".

Post by **Q45tech** » Fri Jan 30, 2004 1:50 pm

On average I would think not, as the goals were to lighten the AT at everyturn to save weight. All versions [made by JATCO] use the same 100,000 shift design points and obviously this can translate to 200,000 miles or more life with excellant maintenance.Really depends on the torque reserve........there is none [unit rated at 333 lb/ft] in the M and Q application vs 20-25-30% with the V6.

100,000 shifts in city wall to wall traffic is a lot different from 100,000 shifts in a car used mostly on interstates.

What scares me is the new fillled for life ATF [or 100k] which ever comes first. Hopefully owners will flush at least every 30k but we know this won't happen........so the same reliability problems will show up buying used............but there are now better filters inside.

I was wrong it seems the 1998 Audi A8 transmission is $7500 plus a few thousand for install read the following similarities to Q problems and solutions:http://www.audipages.com/Tech_....htmlh ... items.html

http://home.t-online.de/home/f...e.pdf

Post by **elwesso** » Fri Jan 30, 2004 1:50 pm

Interesting items..... Good reading!

I have to ask... A lot of the new mfgs are going with the sealed case, so you cant change the filter and drop the pan (obviously).... What is the advantage to doing this?? I also hear its much harder, if not impossible to flush these transmissions....

I see the A8 transmission isnt the sealed type.. So what could be the advantage to having it sealed??

Post by **Q451990** » Fri Jan 30, 2004 1:50 pm

"you'll more than likely save yourself somewhere between $9-11K replacing your transmission."

Wow... Note to self - maintain 90Q as long as possible - it's a bargain to maintain!

Heath

Post by **Q45tech** » Fri Jan 30, 2004 1:50 pm

Every transmission I've seen has 2 lines to a rad or external coolers, so flushing is easy. You just must known what you are doing as without a dip stick it is not so easy to zero in on the exact refill amount or add a conditioner/lubguard.

I think they are sealed so owners or lubeyshops won't pour coolant, oil, or brake fluid in...........or buy some cheapo generic Dex III and overfill.

Bad technicans, lubeyshops, and owners destroy more cars than fail from natural causes.

True Q45 horsepower figures

True Q45 horsepower figures

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums