Is there a difference in the 1990 Q45 engines VS all others.

[Infinitiguy19]

I have been told that the 1990 Q45 engines idle rougher than 199-1996 Q45 engines. The ECU's from a later car were swapped out and that did not fix the issue. What was revised in the 1991-1996 Q45's to smooth out the idle?

And do 1990 Q45 engines really produce more power or is it that the 1990 Q45's are lighter than the rest?

[qship96]

[quote=

And do 1990 Q45 engines really produce more power or is it that the 1990 Q45's are lighter than the rest?[/quote]



No more power . early pre production models given to magazines for testing showed 0-60 and 1/4 mile results that were never matched again after production 1990 models were released.

[jbracy7]

You have to remember that a 90 q45 is 22 yrs old,its bound to be a lil rough,I know they updated the something around 94-96 not sure what

[Infinitiguy19]

No more power . early pre production models given to magazines for testing showed 0-60 and 1/4 mile results that were never matched again after production 1990 models were released.

So it was the lightest of all Q45's built with a NICO ECU?

You have to remember that a 90 q45 is 22 yrs old,its bound to be a lil rough,I know they updated the something around 94-96 not sure what

A moderator who owns one told me this. He also knows another moderator who has one and has very high millage on his.

Point is I want to buy a VH45DE but I am having a hard time finding one and I need to know which is the best. But almost nothing goes right the first time.

[qship96]

Not sure why the 90 would be any lighter {or heavier} than a 91,92- as nothing really changed. Now the 94-96 is about 150 lb heavier due to thicker glass,better insulation, and more electronics. Even 150 lb, when talking about a 3850+ lb automobile, is really rather insignificant-unless you are talking about an all out race car to be used on the track.....in a lux 4 door sedan,it is peanuts. ANY q45 is really a pretty slow car anyway compared to modern vehicles with v8 or even v6 power......the 4 speed transmission and lack of high HP/torque compared to new vehicles is really apparant {go drive a g37/Altima/maxima/accord/camry v6 and you will understand.Test drive a m56 or other premium v8 ppowered sedan,and you will really notice how outdated the Q powertrain is!

[goody90q45]

I have been told that the 1990 Q45 engines idle rougher than 199-1996 Q45 engines......

My 90Q purred like a kitten at idle...with 256k miles on the engine. Sometimes I had to look at the tach while sitting in traffic to make sure the engine was still running. Your info sounds like an old wive's tale to me.

[GSUjinih]

Was there any particular brand of gas you used to get all those miles out of your Q? How often did you change you transmission fluid and what kind of engine oil did you use? Would like to hit the quarter million mile mark too!

[GSUjinih]

Any really differences between the engines with sodium filled valves compared to normal valves? Do the sodium ones last longer and/or better for valve seals?

Edit: I saw that the sodium ones are good for 1-2 degrees more timing at WOT.

[goody90q45]

Was there any particular brand of gas you used to get all those miles out of your Q?.....

I always use tier 1, 91 octane, usually Chevron. I also use a bottle of Redline S-1 fuel injection system cleaner in a 1/2 tank of gas every 3-6 months.

......How often did you change you transmission fluid......

This 90Q had 2 transmissions replaced under warranty before settling in at 100k miles. In the few years that I owned it I did a drain and fill (3 1/2 quarts) with every oil change (3000 miles religiously) using WalMart transmission fluid at $10/gallon. The previous owner who bought the Q new did the same. It's a little more expensive in my current Q since it has Mobil 1 synthetic ($9/quart) in the transmission.

...and what kind of engine oil did you use?...

Castrol GTX 10-40 exclusively in every car I've ever owned. I'm not sure the brand is as important as changing it every 3000 miles.