Need realistic 97 Q45 power...

[pasadenaQ]

I posted in another area about trying to squeeze more power from my 97 Q45. I have an extrude POP Charger intake, Upgraded EPROM, Stillen cat back, and I will be upping my rear-end to a 4.08 next week. There are no CA legal turbo or supercharger kits yet, so does anyone have ideas about how to squeeze more legal HP without boring, stroking, adding monster injectors or NOS? I also don't think that it is realistic for a Q45 to change all of the body parts to fiber in order to save weight (if you could even find the parts in fiber). What about Capacitive Discharge systems for a few HP? Any ideas would be hugely appreciated.

[PalmerWMD]

I think your 4.08 rear end will give you the greatest effect.

Of course it is always possibple to get a custom s/c kit, but spendy.Hmm, I wonder of its possible to drop in a VH45DE vs the VH41DE?

Fred...

[Chaz98Q45t]

Hey pasadenaQ - sounds like you've got that Q rolling pretty good. I'm attempting to to the saem with my recently purchased 98Q - I am thinking that the POP charger and / or EPROM upgrade is next. Which ones did you put on your Q? If I had to do one first would it be the POP or EPROM??Sorry I'm not answering your question - but instead am asking you questions...Thanks, Chaz

[pasadenaQ]

Have fun with your 98 Chaz! Hope to run ya some day. Wolf makes the best EPROMS for Q's but they no longer make them for the post 96's as far as I know. My EPROM was burned by JET and you can get it done through Stillen. My GTech computer was giving me 0-60 times in the high 6's before the mods. The POP and exhaust are all Stillen and I have not yet measured my new 0-60 times, BUT the car actually feels slower after the mods. I hope this isn't true. It has me prematurely wondering if the intake swap actually may have worsened the acceleration? I can't imagine that Stillen didn't test the air before they sold the item, but... For one, the new K&N filter pulls air from behind the left front light. This air may not exactly be cold enough. Also, there are 2 sensors that tap the inbound air. 1 is tapped into the stock induction cowl, and the other seems to tap into the inductor after it has passed through the filter. I imagine that these taps sense temperatures or something? Will the electronics be screwed up if the pre-filter induction sensor is now not really measuring anything? I hope that "Qtech" reads this posting. He seems to really kow his Q's.

[PalmerWMD]

BUT the car actually feels slower after the mods.

Pasadena:

That's entirely possible the Q factory intakes ,are pretty good to begin with.

As for K&N many here feel, that they can ruin MAFS, as well as the underhood air is much=warmer less power.

Actually your pre-mod numbers are very good, which means your (factory) set-up was running well for you.

A shorter rear diff is one of the best bangs for the buck in performance enhancement and you should be able to feel a clear difference and go Lexus hunting.

Fred...

PS: Check out my signature link, I cnat take credit for those mods Dr Birkmeier did them, he is founder of this site.

[VimyJ]

I hope that "Qtech" reads this posting. He seems to really kow his Q's.

Do a search on intakes, etc. You'll find some very interesting reading about "performance" intakes.

[BadQ45t]

Wow, our step sister following of 97-01 Q's is growing Chaz!!! I've got a 97' touring myself and love it. You think the chip did something. I though about it but Q45tech pretty much talked me out of doing anything with it.

In any case running more RPMs at speed is not something I want to do so I wouldn't personally change out the rear, but let us know what you find out there. I sure hope that some additional performance parts start showing up for our cars (like even Tokiko Blues for a start) since there are LOTS of them out there in comparison to other Q years.

[pasadenaQ]

Hey BadQ. All the reports actually seem to show that the 4.11 rear end will actually help the transmission last longer because it won't have to work so hard. I would have to think that this might be the same case for the motor as well. Of course, it could be argued that the type of person who adds a 4.11 is the type who will also rev the car more heavily so the wear will be more rapid. Either way, if I don't greedily squeeze more juice from my Q, then I will cause undue wear by slamming my head against the steering wheel if I don't clearly blow doors on Lexus and Bimmer dorks. I only wish that I could get my car to rev longer, but it just isn't in the cards for the available 97+ ECU/TCU's that I have read about so far (although I am sure that they exist).

Yeah. What the heck is with Tokico and other shock/strut manufacturers? Let's all cross our fingers and keep bugging the manufacturers with emails.

[eQlipse]

I have a couple questions:

What is an EPROM? Is it the same as the ECU?

What are the benefits of changing the gears? I know acceleration is one benefit.

I commute 50 highway miles one way to work. Would changing my rear end be detrimental. I'm sure mpg would suffer!

[911/Q45]

An EPROM is a portion of the complete engine control unit(ECU). A lower rear end ratio improves acceleration by letting the engine get into the power band sooner. It harms mpg and engine wear by allowing a higher cruise rpm. There may be slightly less trans wear due to more gear advantage on a standing start. Q45Tech says the drivetrain is carefully designed to work with the existing gear ratio, so change with care!

[BadQ45t]

I agree, I'm going to start to bug the shock manu's that they should recognize that we're going to need replacments soon and we don't want stockers.

What do you think you'll see in terms of change when you're cruising the freeway at 65MPH with that changed rear end? Wouldn't the extra RPMs have a negative effect on gas mileage and ultimately engine life????

Also, how are you changing out the rear end??? Is it a whole new unit? How much????

I've got my dad's old 92' Q so I think if I want to make one of the two a racer I'll do it to his and use mine as the cruiser.

[PalmerWMD]

The extra rpm may have an effects on lower ring life, but it will be easier on the bearings in most all drving situations.

Could easily be a wash as far as engine life is concerned.

The use of a very good, ie synthetic , oil could help minimze penalties (if any) in engine life.

Fred...

[Q45tech]

A 4.083 diffs 15.4% higher ratio will icrease same gear rpm by 15.4% so under 74.99 mph the mileage would worsen by that amount............ however the ecu tables above 2,500 rpm [normal 75 mph] are richer to protect engine so with a 4.083 this would now occur at 65mph so the 70 mph cruise might be worse than the 15.4% nominal decrease............never done the testing to see WHAT rpm the closed loop quits or is modified other than noted a injector duration increase above 2,500 of 5% then 10% at 85 mph which would be 74 mph with a 4.083.

In other words it maybe both the speed reading and the rpm or just the rpm table which controlls the richening! ????????Either way a loss of 3 mpg on highway is nothing to sneeze at.

Not to mention the probable 15% reduction in engine life 45,000 miles ? but most don't care if it last 250k or 300k.

[pasadenaQ]

Hey BadQ. I just spoke with a transmission guy and a race builder today about this issue and I still don't have an answer that makes me feel 100% O.K. yet. The problem for me is that IF everything else remains the same (shift points, etc.), then the car will indeed have higher revs for the same MPH. To me, it seems logical that this will also translate into worse MPG and greater wear on the engine (but quite frankly, the way I push the car, the engine will wear faster than normal anyway). But, the mystery part for me are the computer shift points. From what I have read (and I am not a Q transmission specialist so I don't fully know), the shift points are affected in many ways including tire RPM, differential RPM, foot stomp speed, etc. What I fear is that the 4.08 rear end will have my computer shifting faster to make up for the higher differential RPM's. This could have my Q shifting all the way to 4th gear before I even get past the other side of an intersection (jokingly exaggerated). On the other hand, if the rear end guys who built this thing for the Q know what they are doing, then they will also have shift point fixes as well. I recall reading somewhere in the forum about a guy who had his torque convertor worked on at the same time and tweaked the shift points. I will have to check back.

Regarding engine and transmission life, I suppose that it depends upon your perspective. In my opinion, the Q is too heavy to be pushing it from a standstill as hard as I am wanting to push it. That being said, then a 4.08 rear will help keep my transmission from woking as hard off-the-line. For me, the magic would happen if I could gain the 4.08 advantage off-the-line through the first 2 or 3 gears with over drive off, then have it behave responsibly in overdive at highway cruising speeds to reduce wear. Maybe that's "dream" is possible and what will actually happen, but I still have not yet heard anything that completely comforts me in this way. I'll keep working on it...and checking the archive postings here...

[PalmerWMD]

Dennis, we both know, most of what I know i learned from you and your posts, but plz consider this:

yes, the extra travel is extra 15% travel on the rings, but IMO that should not equal 15% less engine life.

this is why:reduced engine lugging around town due to the higher rear diff.

Also, didn't you once point out to me, that bearings are more of a limiting factor to our engines lives as rings?

The reducing lugging in town w/ the higher rear, the reduced lugging in OD on long interstate hills should all make this easier on the bearings right?

Also the reduced lugging should be good for ATF line pressures too right?On long interstate hills or in town, now with the 4.11/4.08 I donrt have to feel guilty about leaving it in "D" anymore.Also at the higher rpm teh oil pressure will be higher helping to squeeze more oil into the space between rings and cylinder walls (or at least at higher pressure).This should also help offset some of the penalty.

I wouldnt be surprised at all, if the life reduction of the rings is much less, than that which one would mathematically predict from the increased travel due to shorter rear end.Adding to that the pleasant side effects oif less luggin on engine and transmission and the only real draw back seems mpg's.Around town the mpg penalty should be small maybe comparable to leaving it in "3" vs "D" which I do all the time anyway.As for hiway driving, I will report in detail my consumption w/ a short rear diff.

Fred...