Would it be possible to have a Q45T/A

Post by **Infinitiguy19** » Wed Apr 09, 2008 2:47 pm

What I mean is was it ever possible to have a Q45T/A with both the Touring and active suspension and Traction control as an options? Because if so that is the best G50 there could ever be and the rarest as well.

Post by **maxnix** » Wed Apr 09, 2008 2:57 pm

No, that is why one was not made.

Study the FSM and you will see why.

Post by **Infinitiguy19** » Wed Apr 09, 2008 3:17 pm

I was expecting you to say that but if it was possible we all know that would be one bad *** Q.

Post by **elwesso** » Wed Apr 09, 2008 4:16 pm

it would actually be possible, however youd have to retrofit the electronic SUPER HICAS used on other NISSAN cars vs the hydraulic HICAS used on the Q.

of course, if theres a will theres a way. IMO its probably not worth it.

Post by **Haitian_King** » Thu Apr 10, 2008 12:12 am

ppastos wrote:What I mean is was it ever possible to have a Q45T/A with both the Touring and active suspension and Traction control as an options? Because if so that is the best G50 there could ever be and the rarest as well.

Wouldn't that just cram more stuff into an already tight engine bay? I hear people complain about just the TCS stuff in there.

Reservoirs for TCS, Active, and HICAS?

Not to mention the addition of switches.

Post by **Infinitiguy19** » Mon May 29, 2023 5:42 pm

So many years later I have answered my own question. It is possible to have both active suspension and HICAS together in one car. The only reason it was not an option is the complexity and room. But I took a factory Q45t and added the active suspension from my old Q45a that a tree fell onto.

I took the whole car apart stripped the wiring harness to use just the active suspension part. Put it back together the tool apart the car to put in the wiring harness. The whole interior and both front fenders removed.

I also retro fitted a Mercedes Benz active suspension filter in the oem fluid tank. 3 micron vs 10 micron 250k miles on it. Also ran the ase 664 suspension controller through the car.

The rear subframe had to be lowered to install the hydraulic lines. And it also had to be lowered to remove the rear HICAS lines (worst part of the whole job) due to rust hole in line.

The factory power steering pump needs to provide more flow so I may drill out the flow control valve from 11/64 to 3/16. A hydraulic needle valve is on the HICAS solenoid pressure inlet line. Even turned way down the steering has a (pump catch) lag. I will see what that does worst case I put an accumulator near the steering rack in the front. The oem power steering pump seems overkill in this car. A lot of banjo (flow restrictor) fittings used due to space requirements?

But all in all it is pretty awesome to drive!

Post by **macgiver** » Wed May 31, 2023 1:18 pm

..............................Just let me know WHEN your driving that on the road .............

................uhh ..........I would love to SEE it ! ya

.....

Post by **3Q Jay** » Thu Jun 01, 2023 4:05 pm

Infinitiguy19 wrote: ↑
Mon May 29, 2023 5:42 pm
So many years later I have answered my own question. It is possible to have both active suspension and HICAS together in one car. The only reason it was not an option is the complexity and room. But I took a factory Q45t and added the active suspension from my old Q45a that a tree fell onto.

I took the whole car apart stripped the wiring harness to use just the active suspension part. Put it back together the tool apart the car to put in the wiring harness. The whole interior and both front fenders removed.

I also retro fitted a Mercedes Benz active suspension filter in the oem fluid tank. 3 micron vs 10 micron 250k miles on it. Also ran the ase 664 suspension controller through the car.

The rear subframe had to be lowered to install the hydraulic lines. And it also had to be lowered to remove the rear HICAS lines (worst part of the whole job) due to rust hole in line.

The factory power steering pump needs to provide more flow so I may drill out the flow control valve from 11/64 to 3/16. A hydraulic needle valve is on the HICAS solenoid pressure inlet line. Even turned way down the steering has a (pump catch) lag. I will see what that does worst case I put an accumulator near the steering rack in the front. The oem power steering pump seems overkill in this car. A lot of banjo (flow restrictor) fittings used due to space requirements?

But all in all it is pretty awesome to drive!

Congrats on actually making this happen!
Paul and I discussed his progress, and issues several times over the course of his extended conversion. I probably would not do it (too big a project for me personally at this point in life amongst other reasons), but he did prove that it can be done.

Personally I've always admired the HICAS, although I've not owned one.

Post by **Q451990** » Thu Jun 01, 2023 8:44 pm

Paul finally brought the goods on one of his "I think this can be done" idea posts. Awesome work man!

Post by **Infinitiguy19** » Fri Jun 09, 2023 4:12 pm

I hope vstar650cl sees this.

So the only problem I have so far is the speed sensor input doesn’t work going to the active suspension computer. I used some of the signals going to the HICAS computer. I made a jumper harness and put it between the HICAS computer and some of those inputs feed the active suspension computer.

The speed sensor part of the active suspension computer reads 0 mph when I am going 20 mph. The HICAS computer reads normal. The HICAS computer gets it input from the speedometer then a “adapter connector” then that’s goes to the HICAS computer and the data link port. But every car that has HICAS (240sx, 300zx, j30 and Q45) all have a “adapter connector”.

The voltage according to the book is supposed to fluctuate from 0-5 volts. When in reality it’s 0-10 volts checked with a fluke multimeter. Both active and HICAS computer want to see 0-5 volts fluctuating from the speedometer for speed sensor input.

I could try to run a wire from another module (ecu, tcu or bcm) and see if those actually see 0-5 volts.

Why is the HICAS computer seeing up to 10 volts almost?

Why is there a adapter connector between the speedometer and HICAS computer only?

Post by **VStar650CL** » Fri Jun 09, 2023 8:38 pm

Usually with a pulse or PWM signal Nissan will list the voltage as a voltmeter would read it, which is to say an average. That might imply the signal is supposed to be 0~10V with a maximum 50% duty. I'm gonna have to look up the systems to try to sort that out and figure out what your hybrid system wants. Speed signals aren't usually rocket science and there are adapters out there for changing signal ratios arbitrarily, but Nissan FSM's don't usually call out what the basic ratios are. For instance, try looking up the number of teeth on a CKP reluctor. You may find it indirectly in the ECM reference values, but more often you won't. The FSM will just tell you to read the engine speed from the ECM. If you want to know what the crank sensor actually puts out then you count teeth and gaps. So your answers may not be out there without a little educated experimentation.

Post by **VStar650CL** » Sat Jun 10, 2023 6:22 am

Okay, it seems clear from the WD's that the HICAS uses the same VSS signal as the ECM and the Consult port, while the PSCU is getting a signal that's modified somehow in the cluster and outputted on a different wire. The PSCU signal comes from pin 35 in the speedometer, a Yellow/Green wire. That kind of pass-through signal modification was common on the older stuff, I seem to recall the 300ZX's had three different VSS signals coming out at different rates for different systems. In any case, the pin 35 wire may not be present on the '93 HICAS, and it's possible the '93 cluster isn't even producing a signal for it. So I'd suggest you begin by using your multimeter to see if it looks like there's a VSS signal on pin 35 when the wheels are turning. If so, you should just need to connect that pin to pin 7 on the PSCU. If there's no signal then you'll need an aftermarket adaptor to tap the regular VSS signal and experiment to find out the signal rate the PSCU wants. If that's the case, my buds at Widget Man make a very nice Speedo Corrector with sweep adjustment that you could use for it.

Post by **Infinitiguy19** » Sat Jun 10, 2023 6:48 pm

1994 Q45 service manual Page ST-59 shows “adapter” (E77) between speedometer and HICAS computer. Can I move the adapter to the trunk instead of under the LF fender? I want the adapter to still be between the HICAS computer and speedometer. But i want to use the HICAS speed sensor signal for the active suspension computer.

I will see what kind of signal I get with the adapter removed from the circuit.

I also thought of trying a resistor between the HICAS speed sensor signal and active suspension computer. That’s will keep the signal 0-5 volts. Maybe?

The HICAS computer is the only power steering computer in the car. Either you have HICAS or you have a small power steering computer near the cruise control computer.

The non HICAS cars still have a wire going to the consult port and power steering computer. But no adapter between them.

Why did they use three different speed sensor signals in the 300zx?

Post by **VStar650CL** » Sat Jun 10, 2023 9:07 pm

I don't think the issue is the signal voltage, it's the signal rate. My recollection is that the cluster on the Z's outputted 3 different rates, IIRC one was for the ECCS and another for the cruise, and I forget the third. Been a long time. The point is, there was only one VSS, the cluster processed those signals into three different rates (pulses per mile) required by the different systems. In your case, the feed for the PSCU came from a different pin on the cluster than the main (ECCS and HICAS) signal, which probably means the PSCU wants a different number of pulses per mile than those other devices.

Post by **Infinitiguy19** » Wed Jun 14, 2023 4:43 am

So do you think I can change the signal rate for cheaper than a Dakota digital control module or should I just buy one?

I am kinda wishing I ran two more wires while it was all apart. One from the cluster and another from the transmission computer.

Post by **VStar650CL** » Wed Jun 14, 2023 5:42 am

If the cluster is outputting signal on pin 35 then I'd bite the bullet and run a wire. If not, these are cheaper than a Dakota and should do what you need:
https://www.ebay.com/itm/143554785386

Post by **Infinitiguy19** » Mon Jun 19, 2023 6:19 pm

I will try your product out for sure thanks!

So the accumulator pressures are as follow.:

Return accumulator: 7 psi
Main accumulator: 580-652 psi
Pump accumulator: 710 psi
Shock accumulators 217-246 psi from the Toyota celica SAE paper. The uzz32 soarer site says: front 254 psi rear: 218 psi.

I am no liable for any damages. I got this information from SAE papers and online sources.

Post by **Infinitiguy19** » Sat Oct 21, 2023 8:58 pm

Link with some pictures.

https://www.facebook.com/groups/6159052 ... tid=W9rl1R

Would it be possible to have a Q45T/A

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