1994 Infiniti Q45 Rear Mount Turbo full writeup w/pics

[95eEra kid45Q]

hey bro i have a 95 q45 my name is edwin im from durango, co. i was woundering what kinda pipe kit did you use for your intercooler turbo intake setup what did you use...? im learning as i go and im learning real quick im puting an intake in it right now an im really interested in what you did with your car. whats in it? if you dont mind?

[95eEra kid45Q]

yo im next bro. im in the process of building up my q45 95. im trying to go with that rear turbo set up i need help finding the right parts unsure of what parts i REAlly need as for piping an stuff not sure what kit to use any help guys thatd be awesome.

[qsiguy]

There is no kit available for what I've done. It is all custom fabricated. If you read the entire thread you should have a pretty good idea about what you'll need to do.

On another note, I've been chatting with another guy that is doing a remote mount turbo in his Q45. He is making great progress. He sent me a few photos but I'll wait to post as he may join NICO and I suspect he'd want to make his own thread about his build.

Not sure if you're talking to me about the 5-speed swap but it's definitely on my wish list. If the budget allows the 5-speed swap would be an awesome upgrade for me. If I blow up my current auto trans that will certainly push me in that direction as well
Modified by qsiguy at 12:48 AM 9/10/2009

[95eEra kid45Q]

hows your rear mount working for still running solid..?

[95eEra kid45Q]

yes my rear diff is on the first of my list looking for a 4.08 gear. i haved a 3.8...??? i think it is.

[qsiguy]

My car is still running pretty strong. I have some typical maintenance issues to address, steering bushings, etc. Now that the temperatures are coming back down I'm starting to tune again. Had a safe summer tune on it for the last 4 months or so.

I may, at some point put my OEM rear diff back in. I'll post when I have my 4.08 diff up for sale. I just think I preferred the higher gearing with the turbo and also for highway cruising.

[bimmersupercharged]

Hey Shane, Just dropping a note to say thanks again for chatting on the Q turbo build. I will be addressing the few issues I had and getting some finished pics soon. Then after a little driving with 4psi I will run up to 8-9psi where I will be in need of some tuning (hint hint) haha, very anxious to put the finishing touches on this build. Thanks, Richard

[qsiguy]

Welcome to NICO Richard. Looking forward to seeing your finished product!

Yes, you heard right people. There's another rear mount turbo'd Q in the works! I've seen a few photos and Richard is making huge progress. I'm going to let Richard post his build so you'll have to wait for photos...

[prtrillaboss]

pretty cool setup you made, sounds pretty nice any new video?

[qsiguy]

No new video's for a while, there are several on YouTube, Streetfire.net, and a couple on Photobucket.

[buttons]

I was looking for a cheap project car thats something different from the standard turbo civic/ 16g dsm / etc. Saw your remote turbo Q45 and was sold. got a 94t last night and actually love the car.

I dont think im going to invest much money into the one I got -- would rather start with a cleaner example but man I love that VH45! i might focus more on the 5 speed swap -- especially if my transmission starts giving me fits. My ideal car was a BMW 540i 6 speed, these infinitis make the same if not more power -- and fraction of the price.

[redtopsdrop]

what is the purpose for going with such a large turbo? does it have to do with the amount of piping and distance from the engine?

[qsiguy]

The T70 isn't that big of a turbo. The reason for the size is the size of the motor and the amount of air it ingests. The only think that changes due to the rear mounting location is the lower turbine A/R. I went with this particular turbo after months of research and educating myself. The math I used was based on the Garrett turbo tutorials.

[LEMHEAD16]

What AR did you go with on the Hotside of that T70?

[qsiguy]

I went with the .68 turbine a/r. I don't think it would hurt for it it to be a bit smaller, would make for faster spool up. STS Turbo, who makes rear turbo kits, uses a .36 turbine a/r on their Corvette twin turbo kit.

[LEMHEAD16]

Thanks

[PalmerWMD]

QSI guy:

I been catching up on my NICO reading I missed in the last few years and I just wanted you to know yours is my favorite thread so far..

Fred...

[qsiguy]

I'm ready to put my OEM rear diff back in if I can sell the 4.08. I haven't pulled the Unitrax 4.08 yet but if anyone is interested I will get it pulled for you. I'm asking $400 plus freight for it. Not sure the exact weight yet. Let me know if anyone's interested and I'll get the shipping weight. I'd crate it up in a wood crate most likely.

Cheers.
Shane

.........I may, at some point put my OEM rear diff back in. I'll post when I have my 4.08 diff up for sale. I just think I preferred the higher gearing with the turbo and also for highway cruising.

[elwesso]

I see that's a TCS diff. Did the TCS system work with that? Not sure if you had a TCS car or not

[qsiguy]

Well my TCS had problems before so I'm not really sure if it would work or not. I doubt it though in it's current configuration because my ABS doesn't work because the gears on the wheel sensors have fewer teeth than my OEM diff. So I guess that's the disclaimer to anyone interested. If your vehicle is the same as mine the ABS won't work unless you relace the sensors and/or sensor gears to match the front wheels. Might be as simple as swapping with the OEM ones but I can't say as I've never messed with it.

Shane

[Heath]

I've got a buddy here thats a big turbo guy... He recomended using an STS rear mount setup if I ever get around to going turbo... Love your setup, its awesome. I'm going to have to go back and read pages 2-3 still...

[S13xCrazy]

Beautiful build! Love it! I got a kick out of looking at your pictures, the Y33 and G50 have nearly identical actual frames! Everything looks incredibly familiar. I actually just got my exhaust done today for my rear mount kit - should have it running by next Friday.

I could have missed something, but it looks like you were just running on the stock ECU in the beginning? What sort of steps have you done with tuning? Any piggyback or standalone?

[qsiguy]

Heath, the STS turbo system was my first exposure to the rear mount. Then I found out my nephew had one on his truck. They didn't have one for the Q45 and at the time didn't have the standard universal kit they have now so I designed, fabricated, and installed my own setup.

...I could have missed something, but it looks like you were just running on the stock ECU in the beginning? What sort of steps have you done with tuning? Any piggyback or standalone?

I do use the stock ECU but it has been extensively modified. The thread I'm posting below has a lot of information about what I did.

the-factory-ecu-thread-t345529.html

It's been rechipped and I used a Moates Ostrich emulator for most of my tuning to allow tuning on the fly. Now with the tune pretty much dialed in where I like it I have a two way chip installed that allows me to go between two maps. The only difference between the two is a timing advance on the stage 2 map.

Here's a photo of part of the mod I installed on my ECU. This is a socket booster with the socket and ribbon cable from the Ostrich emulator.

[Q-ZILLA]

Hey Shane...Have you been tinkering with the turbo-tune? I'm getting ready to put in Meth/Water Injection. You already have meth, I thought. Did my tune incorporate that or do I need to re-tune for meth/water inj.?

That 4.08 has TCS... How or what would I have to do to use it with my Q, no TCS?

[qsiguy]

I'm not sure what difference there is since it's got TCS. Maybe just the sensors? I don't have them hooked up anyway so I really don't think there will be any effect. I'm not the expert tho having not worked on a non TCS Q45 before.

I'm currently using the same two tunes I put on your ECU. I do have methanol injection but the pump went out and I haven't fixed it yet. If you you want more options from your ECU I've been thinking about doing an 8 way switcher with the same tunes for all except that each one will advance the timing in the load areas a degree or two. First program would probably be a little more mellow than your stage 1 now. This should allow for pretty precise tuning for different ambient temperatures, fuel types, methanol injection etc. If you are interested shoot me an e-mail and we can discuss the details.

Shane

[bundy26]

I don't know if you put it up already but did you dyno it and if you did what is the power increase.

[Q-ZILLA]

Shane, You know I'm always interested in the tuning... Couldn't I just take that rear-end to a shop and switch out the gears themselves into mine? I don't drive on the highway much, if at all, so I would like to get that from you.

[qsiguy]

I never dyno'ed mine post turbo. Not sure I will now that I have a ton of miles on it. It's not as awesome as it initially was. Maybe John will dyno his, John? His should be really similar to mine. Many guys have done dyno's after transplanting the VH45DE in to the 300ZX or 240SX. Jeff Taylor is one but wasn't able to find the thread on a quick search. If I remember correctly he was making about 450HP on about 6 lbs of boost. I'll have to dig around for the old thread.

[bundy26]

Looks tempting enough to make this a project for my A/C 2.5.

[qsiguy]

I don't think you should pull the guts unless the casing just won't fit. It's in a nice case with cooling fins. Up to you what you do with it if you buy it tho. If I sell it it's for the whole thing, not the parts to it.

Shane, You know I'm always interested in the tuning... Couldn't I just take that rear-end to a shop and switch out the gears themselves into mine? I don't drive on the highway much, if at all, so I would like to get that from you.