1997 Q45 Ecu

[zinkie13]

Hello all....I have recently aquired a 1997 Q45 and was hoping to make some performance upgrades. I have looked into chips mods but i cannot afford to not be able to drive my car while the chip is gone. Is there anyone out there that knows where i can find an extra one or an already modded chip? Also, what other modifications are out there for this model?

[maxnix]

Welcome Zinkie. You have a great car, but it is OBDII. The best you can do is keep it in top stock condition. Reading the previous posts will educate you on your car and the modifications available to it that work.

[Q45tech]

OBD2 will [can respond] to more air flow [as there is usually a 5-10% calculation margin to work at sealevel in 32F weather....when the air is very dense.

Other than some light boost supercharging or very loud exhausts not much you can do.........nitrous would work ok up to 75 shot.A 4.083 diff gear vs the 3.694 yields a 10.5% [x.8=8.8%] increase in gear multiplied torque ~~~ net a 2% increase in acceleration...0.3 seconds decrease in 60/quarter mile time whereas the nitrous will be around 1.0 seconds without the diff gear change.

[zinkie13]

Thanks for your help.. I will look into the nitrous application. Do you have any specific Nitrous kits that you believe would work best for my car? Also, where would be the best place to purchase it?

[zinkie13]

The main reason i wish to speed up my Q is because i'm used to the first generation........and most recently the power of the newest Q. My step dad has had a 93, 97 and now a 2003...and all three are still in the family. I have the opportunity to get my hands on any of them any time. I haven't been able to drive the newest one as much as i'd like to...but from what i've seen, it's pretty amazing. I just hope i can get mine to get a little bit closer to the power of the 93.

[Q45tech]

The 97 tried to compensate for the lower power by changing the diff ratio from 3.538 to 3.694 = 4.4%........but that didn't equalize the 9% decrease in displacement nor less than optimum power produced from the emission friendlier detuned version.

The smaller displacement was an attempt to improve the gas mileage to compete with the smaller Lexus V8 [at 4.0 liters]....dollar short and a day late as they say since Lexus sneeked in the 5 speed in 1998 along with better tuning giving the Lexus a big advantage in 0>60 mph acceleration.

[zinkie13]

OBD2 will [can respond] to more air flow [as there is usually a 5-10% calculation margin to work at sealevel in 32F weather....when the air is very dense.

Other than some light boost supercharging or very loud exhausts not much you can do.........nitrous would work ok up to 75 shot.A 4.083 diff gear vs the 3.694 yields a 10.5% [x.8=8.8%] increase in gear multiplied torque ~~~ net a 2% increase in acceleration...0.3 seconds decrease in 60/quarter mile time whereas the nitrous will be around 1.0 seconds without the diff gear change.

How much would it cost to get the gear changed? Also....would it have any adverse affects on the car?

[Q45tech]

Fuel consumption [per hour/minute/second] is a function of volumetric efficiency times displacement times rpm.

So increasing rpm consumes more fuel roughly in the same ratio as the diff gear increase.

Engine life is a function of rpm hours, unfortunately doubling the average rpm - sextupules stress and wear...[if an average engine speeds most of its life at 2,000 rpm average, the the same engine [5,000 hrs] might last 1/8 as long at 4,000 rpm [625 hours]...........once you rise above the torque peak rpm the wear accelerates by a factor of something like 100 times..........so at 8,000 rpm [if the engine survives- 6 hours would be the life].Roughly what they get from NASCAR engines.

Over the narrow range of 2,000-2,400 rpms one might use the gear ratio increase times the the square root of two [1.414] as a extra stress factor so a 10% increase might yield a 14, 15% lower life in hours. 5,000 hrs dropping to 4,250 hrs .....like 250k decreasing to 212k miles.

Years ago [before 4 speed AT] most V8 engines ran at 2,400 rpm at 60 mph cruise, today with overdrive ratios 2,000 rpm is more the norm........this 17% reduction in average rpm is probably responsible for a great part of the increased longevity in miles current engines enjoy.

Unfortunately you need a certain minimum displacement to pull a heavy car with reduced rpm.

[BadQ45t]

I have a 97' and my dad has a 92' and the older car is faster. I think that doing a rear end or nitrous on this car is defeating the purpose of that car....I'm just leaving it stock. So Q45tech, are you saying the car being 400-500 lighter is bullcrap, I read several reviews and drove a 96 and for sure there was not much difference if any between those two models.

[Q45tech]

The 97 was a little lighter but it took this plus a higher reving 4.1 liter engine [via 3.694 diff gear] to even get close to even the 96 acceleration [which was slower than the 95-94].The 90 got to 100 in 16.7 seconds vs 20 secs for the 97.

[zinkie13]

Q45Tech.....I am considering changing the diff gear like you had previously mentioned. Who should i talk to about doing the work for me and what should i ask them to do? Do you have any idea what the price range would be?

[Q45tech]

Changing the diff gears is work for an expert because various mesh and lash settings need to be just right - perfect otherwise the diff willl howl, clunk , and wear out fast.

I would think 6-7 hours [$450-$500] plus gears and new bearings would be about right.

The 97-03 have a different design housing from the 90-93 and 94-96................4.083 was the gear set for the 300zx non turbo manual transmission.

[zinkie13]

soo.....i'd just take my car to my mechanical expert...and say i'd like to have my diff gear changed to a 4.083 and to make sure they make the mesh and lash setting perfect?

[BadQ45t]

I sure wish someone would just do a supercharger for this engine, for as much as the engine gets bashed the damn thing is smooth as silk and feel nearly "electric" it is so smooth. Another 50 hourse out of a supercharger and yee haa. Meanwhile, the car isn't exactly underpowered and gets good gasmileage, at least in comparison to my dads 92.