Q45 Throttle Position Sensor Options

[ADIDASilvias]

I posted this in the RB FAQ but it seems that thread is getting no love for anyone's questions, so I thought maybe this would garner more attention here. I really do think this is a possibility, and I think we could figure it out since this community has a lot of collective resources. If we find a definitive answer I'll post it in the RB FAQ for anyone looking for the same thing.

I'm in the process of building a RB25det NEO for my 95 S14, currently in the "drain my bank account" stage, before I get to installing everything on the motor and then finally swapping out the KA.

I purchased a "Greddy Style" intake for a decent price. Not some crappy cast eBay junk, but a precision machined billet flange and sheet aluminum construction intake plenum.

It comes with a 90mm Q45 sized throttle body that looks to be good quality from the photos, but that remains to be seen. Regardless, I am looking at TPS options since it is supposed to use the Q45 TPS.

The prices for the Q45 TPS are fairly high considering what they are and the prices of other units on the market. It leads me to believe that supply and demand are driving up prices with everyone and their brother putting Q45 TBs on every engine imaginable.

At any rate, I have searched my literal ass off trying to find an equivalent TPS that is plug and play or that works with minimal modification, and have determined the best bet is the TPS from an early 90s Maxima (V6). They appear to be the same unit, with the same plug, but I have read that the Power and Ground leads are reversed (Signal is still the middle pin).

So, does anyone know if I de-pin a Maxima TPS and reverse the Power and Ground leads if the TPS is now the equivalent to the Q45?

If it comes down to it I'll purchase a true Q45 TPS, but it would benefit us all if we could come up with another option. Maybe someone who works at an auto parts store could compare the two and make sure the plugs and bolting points are the same? They sure look the same from photos.

Anyone? Anyone? Bueller?

[KAT-PWR]

Look up voltage outputs for them

[Kingtal0n]

TPS doesnt need to be on the engine to start it and run it / drive it. Don't let it slow you down from starting.

What I am worried is, what sort of turbo/injectors you have. If you are using stock turbo/injector/ecu it will probably lose throttle response and torque due to the enormous plenum and throttle body. Do you see the OEM runners and tiny plenum it uses? thats all it needs for an OEM turbo.

[ADIDASilvias]

KAT-PWR - Any idea where I could find that info? I did a quick google search to no avail. Lemme see if NICOclub has a FSM... good idea!

KingTal0n -

I'm in the process of getting parts lists together, but injector wise, I am thinking no less than 700cc, probably more like 850. I am thinking Supra fuel pump for delivery.

For turbo I am thinking GT3076 or HX35, though I may suck it up and get a twin scroll manifold with an appropriate twin scroll snail shell. I have been looking at compressor maps and reading reviews regarding spin up on twin scroll turbos and I like the lower rpms for full boost. Though as fast as the engine revs it may be a non issue.

I am going with LS truck coils as well for spark.

Lots of info on the UK and AU sites regarding dyno and butt dyno results of various turbo pairings, I just need to find one that will do what I'd like without some ungodly price. I can see a grand or so for one, of which there are plenty of options, but pushing 2 grand on a few I really like is more than I want to spend on that portion of the build anyway. If it is turbo and manifold that's a different story.

I'd like to make around 400whp with a quick spin up, mostly for street driving with an occasional autocross track day thrown in.

[ADIDASilvias]

So here is the Maxima VG30E TPS voltage info. Looks pretty solid to me. What do you think?

Edit: Added the Q45 TPS diagram as well. Looks the same to me. I know the rotation is opposite on the Maxima TPS though, which is why I believe you can swap pins 4 and 6 and effectively have the Q45 TPS.

Also, I am most likely going to get a Power FC D-Jetro for stand alone engine management. I had originally planned for a Nistune Type 4 daughter board, but my engine did not come with an ECU, and factoring in Z32 MAF, ECU, Nistune board with software and communication cable the cost ends up towards $8-900. That's pushing L-Jetro cost, in which case I might as well spend the extra and go D-Jetro. Plus the hassle of soldering in the board kinda makes me lean towards the Power FC. The MAP sensor is a huge bonus for tuning, and I feel it would be worth the extra cost.

[600supersport]

I believe there are different Q45 TB TPS housing options and the one that worked for mine though I can't remember what year the TB was from; for around $50 brand new instead of the $140 for the Q45, I was able to go with an '01 Pathfinder TPS with the 2 connectors on the TPS plastic housing, not the detached/wired one like in those ^ diagrams. It fit pretty well into my TB housing, but it required me to adjust it all the way in one direction for closed to reach the 0.5v and It shows full functionality as far as voltage and scaling in the software from 0 to 100% throttle.

[ADIDASilvias]

Nice, I'll definitely look into that. I have an 02 Pathy with an AC 2" lift and 32s. It was for the VQ35 engine? I guess I can see if mine fits the throttle body when I get the intake manifold. It'll be a couple more weeks until I have it in my possession.

It doesn't really matter if I have to adjust it all the way in one direction as long as I can get it to read the correct voltage.

I'm not trying to cut corners with this build, but anywhere I can shave a bit of cost while retaining the quality means I can put the extra towards things like turbo, engine management, and various other areas where a couple hundred could make a big difference.

Thanks!