[Evan(CA)]

I don't know where to post this so it's also in the general 5 series forum but this might be more appropriate. I don't care where it's posted and if the duplicate gets deleted but please leave at least one in the most appropriate forum. Thanks!

I apologize for my noob questions that are likely answered already and I am slowly researching on here more and more each day. However a thread of my own with my specific situation is nice to have.

I have always been a Z32 1990-1996 Nissan 300zx Twin Turbo Guy. I had a non turbo for my first car and literally 10+ in the subsequent almost 20 years now.

Given that, I am VERY familiar with turbo cars and wrenching on them. I have ALWAYS stayed away from the 96 300zx's because of smog. It's an absolute nightmare to find a shop that will let the visual stuff slide despite the actual numbers on the rollers being perfect.

How big of a deal is smog for you guys? I'm in California and boy does it suck for smog and motorsports in general.

I have only just recently started looking into modding this as I have so many toys. A 500whp 93 Z32, a 360whp 91 z32, 2009 Ducati 1098s motorcycle and more projects in between than I can remember. Everything from complete part outs to the uni-body and built all the way back up from there.

I am confident that I can do ANY mechanical work on the car but BMW's seem to "LOCK" their ECU's and force you to go somewhere with an OEM BMW scan tool. How much truth to this is there, especially when you start to mod?

Typically I'd start with standard bolt ons, air intake, full turbo back exhaust, off the shelf ECU tune. Manifolds are changed when the engine is out but downpipes are easily swapped in and removing the precats(1st set of cats) causes no issue in emissions despite having to actually run the car on the rollers at 15 and 25 mph. The main cats do need to be swapped back in for smog but it's quick and easy.

I know the turbo back exhaust has always been a headache for the 96 Z32's with pre and post cat o2 sensors. Do the aftermarket exhausts for the newer cars come with bungs for 02 sensors that negate this problem without throwing codes for the completely open exhaust?

Off the shelf ECU chips are generally thought of as garbage and a real tune on a dyno is the way to go. Are there any BMW specialist's in SoCal who do this?

Without creating noticeable turbo lag how big can you go with the sequential turbos? What's the ideal 1-2 punch? I don't mind it feeling like a turbo car to some degree as you would never know it's a turbo in it's stock form. Are upgraded recirc valves needed for upgraded turbos? Hell I don't even know if it's a MAF or MAP car that's how much I've actually researched modding the BMW as I NEVER thought I would.

However I'm between projects and was looking for a new DD. I was going to sell the BMW but I only paid 7800 for it with 114k and it's SUPER clean with m sport wheels I believe. So I can mod it or sell it for a profit.

Is an upgraded intercooler before upgraded turbos a waste? The cross-feed turbos on the Z32's and sequential set up here make them similar but at the same time apples and oranges to compare.

Are oversized charge and intake piping a thing with these? That's one of the biggest mods you can do on a Z32. Exhaust manifolds, turbos and 3" all the way back with 2.5" intake/charge piping. If you've seen a z32 engine bay that's as big as will possibly fit. They literally picked the engine first and designed the car around it so there is ZERO room to work so engine pulls are something that happens often but after all the proper deletes isn't very hard or time consuming.

I know the engine is fine for the power I want but what about the transmission and drivetrain? If I am going to blow up the autotragic I'll skip the project all together.

Do you use lightweight crank/flywheel/driveshafts at all? Those are other ways to easily free up HP and make the car more peppy with Z32's.

Don't flame me for asking for information I'm sure has been answered 1k times, I'm trying to find it as we speak but I am really just now getting serious about this.

I guess what I'm asking is where do things differ drastically and what are the work arounds, if any? Where do I start and where do I stop? I have no intention of this being my fastest car and don't want to sacrifice TOO MUCH reliability but am well aware that is part of the game.

This all really came about after deciding it's time for a new DD. It comes down to buying a new dual motor Model 3 and selling this for a profit, or modding this for a little (Subjective, I've had 9s cars & still have crotch rockets) more pep. Somewhere in between the 2 Z's 360whp-500whp would be nice. Closer to 500 as it's a big heavy 4 door sedan.

I'm not concerned about suspension, I have other vehicles for canyon carving. I simply want to have some fun while going about my day. A few stop light pulls and the need for just a flick of opposite lock when I want to around a corner. It pretty much does that now but wont pull through the slide if that makes sense.

[e4603]

I remember calling so many dealers back in 1996 looking for a pearl white & black interior 300ZX TT commemorative edition. Just didn’t work out at the time.
Yes, you should learn to use BMW specific software tools. Pretty interesting stuff but definitely not the old school carb adjustments type skill set.
2004 & newer cars will not pass CA smog with a ECU tune. If you want something fast & high tech, forget the turbos and get a Model 3 performance or a S plaid and win every red light Grand Prix while doing karaoke. Unless you want to wrench.

[95blkmax]

Welcome to BMW world! You certainly have GOLD sitting in your house with those Z32s (prior Nissan guy myself!). They were so ahead of their time that 30 yrs later a clean Z32s still looks contemporary!

I wish I could help you, but a lot of my answers would be non-applicable to the republik of kalifornia's stance on the automotive industry in general. Where I live I can basically do anything I want on my car. Most of your questions would really best be answered by a Cali resident. Anyway, here is what I CAN answer for ya...

- Not just BMW but all manufacturers (but especially Germans) have made diag'ing tougher to force folks to go to dealers for it. But thankfully BMWs have a massive aftermarket. You can do most of your diag with Carly (myCarly.com). It's an app that yo buy on your phone, and you use a separate OBD2 dongle (purchased on Amazon) that communicates with your phone via bluetooth. Carly runs function checks on ALL modules on the car checking for codes and reports them back to you. It has a ton of features you should research on your own, but very useful for a DIY'er. Do not confuse this with a standard OBD2 code scanner from the parts store. Those often only look at ECU/ DME functions. Apps such as Carly (and others) look at that, AND the other modules like Footwell Module (lighting, locks), CAS module (basically the immobilizer), IHKA (HVAC control), TCB (radio/ GPS/ Satellite signal processor), etc...

- Your 535 only has 2 O2 sensors- a Wideband O2 that is directly after the turbo but before the cat, and a secondary in the middle of the cat itself for cat efficiency duty. Both are located on the downpipe, so no 02 bungs are on the catback itself.

- You can do your own OTS tunes yourself with either MHD/ Bootmod3 (which are flash tunes). There is also a piggyback solution that is very easy to remove and wont affect your flash count (I don't know if Cali smog looks at that) but the Burger Motorsport JB4. I had it and it worked great! At some point I just outgrew it wanting more options and control so I went MHD full suite. Both all 3 are proven and reliable. If you want THE BEST power, you'd need to go MHD or BM3 and get with a custom tuner (of which there are a few- I personally use David Shoup).

- No sequential turbos for N55. No one bothers with that (plus no space and from a cost-benefit factor it doesn't make sense). It's plenty torquey down low. It just falls on its face after 4500 due to it's size. Even when I was full bolt on and custom tuned, the best I got out of my stock turbo was 372whp/ 478wtq. Most people "fix" this by going for a larger turbo lol. You got plenty of options on this. Be aware any larger turbo beyond a "stage 1" size(such as a Pure Stage1/ 500, or Vargas Turbo Stage1) will require custom tuning.

- N55 engine uses BOTH- MAF is just after your air filter box, and you have 2 MAP sensors- One on the charge pipe just in front of the throttle body, and one at the top of the intake manifold (under the air filter box). The N55 CAN run without the MAF signal and just use MAP sensors (but you will have codes for it and won't run right). Typically that's a custom tune thing if you go for a big top-mount turbo, the MAF gets deleted, then the tuner uses only the MAPs for tuning your maps.

- You should ABSOLUTELY upgrade the intercooler. Even at stock turbo and stock power, the IC is tiny and DOES heatsoak badly. Tremendously undersized from factory. You do not have to spend $1000 for a Wagner IC. I've been running the GPlus intercooler ($250-ish) for over 3 yrs now along with many others here with zero issues). No tune is needed for this either, just install and enjoy much more consistent IATs

- Yes, we upgrade piping as well. The charge pipe (from the intercooler's up-pipe to the throttle body) is a weakpoint of the N55, not just in size but also construction. It will explode on you right at the flange with the throttle body (even at stock power, lol). A larger one flows better but also will not explode on you down the road lol. You can also upgrade the boost pipe (most don't need this, but it's a nice upgrade to have if you're already in there replacing the intercooler. The stock one is flex-rubber thing that I did not like lol. The turbo inlet pipe is a BIG choke point, this I HIGHLY recommend you upgrade. Noticeable improvement. As for exhaust, a high-flow catted downpipe (or catless) is where you will gain a ton of power. Catback modifications are just for your ear's pleasure if you want to lol, do not expect much in the way of power here.

- Your car has the Car God's ZF 8HP, trust me it can take power as long as you take care of it. There is no such thing as lifetime fluid! Replace that crusty ol fluid! Go to FCP Euro and pick up a service kit with a ZF pan (filter is integrated to the pan) and LiquiMoly TopTec1800 fluid. Your transmission will love you. You can also flash in xHP which is a transmission tune. I've been running their Stage 3 for a few years and Im happy with it. Shifts and instant compared to stock. This trans CAN take well over it's rated torque if prepped correctly. I had 478wtq so at the trans it was well above that- with the stock turbo! I now have a larger turbo and it is still plenty happy.

- No options for lighter pulleys/ driveshafts. There are lighter 1-piece flywheels available, but yours is automatic so doesn't apply.

- I am happy with my H&R lowering springs on the stock M-sport struts. Plenty comfy, just stiffer enough, spot-on lowering.

I hope this helps you! We've all been in your spot at some point so I get it. Take a look at my mods and the link to my YouTube page on my signature below. It will shed more light into mods for you. Be aware though that I unfortunately started YT'ing yrs into owning the car so I took care of all the maintenance and basic mods long before, so the stuff there is more advanced. But someone with your background will easily catch on to what's going on there. Long live the VGs!