Jwt Ecu

[Qdog]

Those of you with JWT ECUs, does it make a difference when you're not hard on the throttle & below 4k rpm ? A racer I'm not, but I would appreciate better throttle response and more low/mid range torque. OK, and that high rpm zoom once in a while ! I find with the original (92) ECU Q there is rarely enough road to get very far into the pedal. Should have bought another 4 cylinder Volvo (with automatic). 0 to 60 ..... yes, eventually.

[PalmerWMD]

I have the JWT ECU but I also have the TCU.

If all you are looking for is imrpoved drivability and not quarter mile times you should have a look at getting the TCU instead.

First gear start and hold the gear a bit longer.

Fred...

[911/Q45]

I feel more of a difference at part throttle and moderate rpm than I do on banzai runs. The TCU is definitely a factor too.

[fxjackso]

With both TCU/ECU I agree with 911/Q45. The combination is especially good under brisk but not all out acceleration. I don't know what Wolfe could do to make full throttle more full.

Fred (or call me Q45/911)

[aaacomp]

I have had a G-force , JWT , and home brew ECU's.The timing and fuel mapping change at 2800 rpm. That's not going to improve you take off.. Several choices,, 1. TCU first gear take off 2. Lower gears 3. Supercharger. All three will give you more low end take off. The 4:08 with the TCU would make a difference.. What tires do you have stock ? 15", 16". I'm now working on a Nitrous Oxide kit for my car, but that is not for low end take off either. It's only safe at WOT and preferrably with a controller......:thumbup

[Q45tech]

Generally all ecu software mods can't do much below 2750 rpm and even then gains are slight till you get closer to the peak torque rpm 3500-4000 rpm.A little might be gained at 3000 say 4%.Most factory ecu hold what they got after the HP peak rpm [5500-6000 rpm]........this is where additional optimization occurs up to redline or a new redline.

By taking out almost all of the build in safety reserve [not running super extra rich] 12.9 AF perfect say 11.8 vs 10.0 AF factory they gain HP by advancing the timing as the VE falls [air flow per gulp declines] say 1.0 degree every 500 rpm.....the optimum 22 @4k goes to 28@7k.

Once you get out of 1st all the acceleration takes place in 4,000 to 6500 rpm range in 2nd and 3rd.

Most restrictions on an engine don't begin to occur until the torque peak rpm [the rpm by definition were the engine is most efficient in creating power].

Idle to 3,000 rpm is especially difficult for high reving engines.No intake or exhaust mods will do anything constructive only redesigning the cams and valve size to lower the efficiency at high rpms will enhance the low rpms.

Companies like MB have been increasing the displacement [5.0/5.5] and are using 3 valves to try to tilt the performance lower in the rpm range much like older US V8.....taking the middle ground between the two extremes........but the peak torque [68 lb/ft per liter]never achieves the 75 lb/ft per liter of a 32 valve engine.......the new Corvette achieves this [68] with 2 valves.

[Jberger]

Hmmm, part throttle? I've never tried that!Guess I'll try it today so I know what you guys are talking about

Honestly, because I had them both changed at once, I can't say how they work independantly, but the combo makes the car significantly more fun to drive!

[mccluredude]

I'm a new owner (94 Q45t).. picking up my car tonight, and I'm already dreaming of more power. I'm sure you relate. I've searched the archives of this forum with moderate success.

Does anyone have stats on these mods? I've read a lot about the JWT ECU and TCU upgrades, but they're not explained very well on the JWT site (or anywhere I could find for that matter).

Anyone have before/after dyno or tracktime stats? Gtech even? Seat of the pants evaluations are also welcomed.

I'm curious how much more power (HP and torque) the ECU mod would generate on a 94Q (I did read a post by Q45tech that said you can expect 24hp increase on a 94Q, which I would love). Does it bring peak torque down in the RPM range? What are the drive-ability differences?

Also wondering if the TCU would add too much wear on a stock 94Q transmission with 150k miles? If 94's start in 1st anyway, is there a significant benefit with this modification or should I leave it alone?

thanks a million

[PalmerWMD]

I can't answer all your questions just a couple:

ECU:-No loss of torque-Need to be more carfefull about staying with premium only-Keep cooling system in top shape as (IAW Q45tech) some safety reserve is taken out- durabilty problems seem nil, many Q owners have put a lot of miles on their car with teh ECU and no ill effects even with frequent use of max power

TCU:

-I am not sure how significant the TCU would be on a 94 as you have first gear anway as you mentioned.It's suppsoed to make shifts firmer/quicker but I am not sure how significant that effect is as I have trouble feeling it, the shift pointsd also seem to be affected only minutely (if at all) from my experience with Q's w/ and w/o TCU.

If I had a 94 I woudl skip the TCU and just get the ECU (plus a 4.11/4.08 rear diff).

Fred...

[mccluredude]

Thanks Fred, very much appreciated.

I need to do the basic maintenenace procedures first, (fuel pump, transmission flush, brake flush, differential fluid, cooling system backflush) but I'm on the lookout for more power wherever I can get it as long as it doesn't hurt driveability or reliability).

Have a great weekend everyone.

[Q45tech]

The JWT ecu mods do nothing unless the car is at WOT [accelerator pushed to the floor] except change the rev limit which could in theory be achieved in low gears at less than WOT.They do remove 2-3 degrees of sudden tip in throttle retard which helps normal acceleration FEEL a little better on highway.

The factory non WOT software is the results of thousands of man hours of fine tuning no aftermarket company would even attempt to out guess the factory in normal driving......it would cost $500,000 of testing to find you couldn't make it better.

They squeeze every possible MPG out of each situation to avoid the gas guzzler taxes.......the idle/cruise is so lean the engine barely runs smoothly if perfect......all you can do by software mods is use more gasoline.Remember a 21.500000000001 not a 21.49999999999 is 22 mpg

They are limited to 0.05 millisecond adjustments of the injectors and they always choose the half of 1% leaner setting at cruise on the theory that as the engine [runners, throttle body, air filter] gets dirty the air flow will decrease and the engine will get slightly richer ------ a safe move.

[AGM]

aaacomp,

Do you have a TCU for a 1990 Q45

Regards

AGM

[Q45tech]

The best rear wheel difference I have seen on a factory vs JWT ecu is a 9-10% improvement roughly 20-22-23 HP [at 5500 and at 6,000] and the torque starts increasing from 3,000 [about 4] to a peak of 24 at 4,000 declining to 21 lb/ft at 6500.You take the cube root of the increase 10% roughly 2.2% to derive the acceleration decrease in quarter mile times~~ about 0.3-0.4 seconds .........since the bulk of the 0-60 is taken up by the 0-30 time and little can be improved below 3500 rpm [below 26 mph]......all you get is 0.2 at best here................the major impediment is the 1st to 2nd shift time of 1.0 second [or bad trannies 1.5-2.0 seconds.

Once you are in 2nd [50 mph] the slower acceleration to 85-93 or 98 mph in the case of JWT ECU, means improvement is feelable since you stay in that gear for up to 9 seconds......50-80 mph takes at best 5.5 seconds usually more like 6.0 seconds or 7.5 seconds in some really bad units. The transmission is out of the picture here once the shift takes place.

Each extra HP is expensive, the most bang for the buck is ecu, after that the exhaust [may 5-8 HP] for roughly the same money.

Popcharger besides their downsides can do little [except create noise] because the intake /filter is already so efficient [only 13" [12" K&N] WC at the MAF output [7.5"WC after the oem filter][6.5" with a K&N dropin].

If you want more than 0.2 seconds zero to 60 improvement you must change the rear diff gearing or add Nitrous or do both!

[1qckser]

Dennis what type of exhaust mods are you doing to get the 5-8 hp, just curious, Thanks

[Q45tech]

The loudest any human being can stand without their ears bleeding should be good for 8. Compliant California noise ordinance mods might be worth 3-4.We have driven Q with the entire exhaust system removed [nothing rear of two cats] on a few occassions! Ear plugs required sounds like NASCAR.

Using a large [size of trunk] externally driven [by another motor] vacuum pump might worth 20.

Special designed BIG headers with 180 degree phasing might also provide 20 or so at the single tune point.

There is a big range between 320HP streetable and 450 full race engines..............but notice that the torque almost always falls between 75 and 80 lb/feet per liter even though it moves up from 4,000 to 5500 rpm and falls to the useless level below 1200 rpm.

How many want a racing engine where the minimum idle speed is 1300 rpm all the time [after warm up] and of course burns more than twice as much at idle or on the highway just to stay running [lopey].

Nissan subscribed to a no more than 1% and 2% degradation on the intake and exhaust respectively.......these are the potential gains available from prior to MAF and after the CATS.

[Sopdadope]

AAACOMP,

I've sent a few emails to you and they've gone unanswered....we need to talk.

[1qckser]

Do you still have the parts car??, if so can you e-mail me as too how I can purchase some parts from you, I left a few post but nevr heard anything, Thanks

[1qckser]

So what type of exhaust are YOU running, just curious as to the the backpressure levels you measured with your own system, also the DB levels? Thanks