Murray_Calavera

That is a good point. The closest thing I can think of is this episode of Might Car Mods, where they made 425KW with the exhaust valve closed, then opened the valve and made the same 425KW. (around 19 min into the video). I would think having the exhaust valve closed would be more restrictive then say going from 100 to 300 cell cat? But yeah I'm still guessing.

Has anyone seen dyno runs back to back while cats were swapped to see their impact? I would strongly consider putting in a better cat (I'm using 100 cell too) if I could be sure it wasn't having a large impact on performance. Side note, @Dose Pipe Sutututu what are your thoughts on building a 1 series 135i? The entry price seems pretty reasonable for the earlier models and look like a pretty good base to start working from. (But then again I don't know anything about BWM's and I'm basing this off looking at a spec sheet and car sales prices lol)

What a fantastic idea for a street car. Why don't you also bin the air conditioning, heater core and all their associated parts as well? You might almost find another 20kgs there too! If it is a street car, I don't think there is any realistic way to reduce the weight in a meaningful way while still retaining pleasant street manners. The OEM wasn't trying to add weight for fun, they don't like weight either - yet the car you have is the best they could manage while still being a pleasant street car. If your reason for lowering the weight is to improve performance, then just do that. Add power, sort the suspension and run the stickiest tyres you're prepared to live with. An R35 GTR probably weighs more then your car... Probably performs a little bit better too.

That would make a lot more sense. If that car that the OP linked there was a NA RWD Stagea, the weight reduction numbers would line up perfectly, a whole 20kgs of interior removed brining the car to 1500kgs.

Has all the obvious stuff been done, wheel nuts are tight, you've put the car on jack stands and given the wheels a good shake and inspected all the suspension components to ensure everything is nice and tight?

If you stripped out the entire interior, and I mean everything, it would not even weigh 220kgs. Whoever this 'guy' is that claims to have achieved 1500kg while still having you know, a dash and at least a drivers seat, is clearly full of $hit. So rather then just referring to some 'guy', I'll talk from personal experience. I stripped my swift down to a dash and driver / front passenger seat. When you look up, bare metal. When you look down, bare metal, when you look back, bare metal everywhere. It saved fk all weight. I weighed stuff as it came out. I saved maybe 20kgs? Turns out plastic trim pieces and foam seats don't weigh much. Go figure. Sound deadening and carpet was around 10kgs. My R33 is half stripped. Everything from the driver/front passenger seat is stock. Look over your shoulder, everything in the back is bare metal. The only reason I did this was to fit a half cage and make adjusting the rear coilovers easier. I had learnt from my previous experience that there is fk all weight to be removed from inside the car and it is not worth doing.

Just as a visual. When you turn this - Into this - You save about 300kgs.

So you want to pull 220kg to 320kg worth of material out of the car? That is an absolutely huge range, kinda like saying you want to make somewhere between 400kw to 1500kw from the motor. As you start to pull weight out of the car, every next kg gets harder and more expensive to achieve. Even on your conservative, 220kg weight reduction goal, it's 100% not realistic. Even if you said you were happy to spend $100,000 to achieve that goal it wouldn't happen... Unless you turn it into a death kart. Then sure I'm sure you'll find 220-320kgs of material to cut out.

Absolute worst case, you could ship your box of parts to a specialist workshop over here who you can be confident will do a good job.

It would be so much cheaper to just buy an evo or similar light weight car. Removing weight to the point that it is noticeable in the way the car drives will be an eye watering expense.

Have you not read the ecu wiring diagram/pinout?

Can you overlay his/your data with the Garmin to see where you are losing time?

That is a super open question, really comes down to your goals and budget. It's very easy to say buy an Artec manifold and a Garrett G series turbo, but unless your happy to spend about $6,000 on those 2 parts alone, well your not going to get very far lol. Maybe have a look at RB25 turbo results thread for inspiration.

We are talking about fitting an aftermarket part, you do what is needed to make it work. If the rod needs a bend, bend it. If it's the wrong length, get the correct length rod. If you don't want to do any of this, pay for a kit that is bolt on - https://gcg.com.au/actuator-assembly-nissan-rb20det-rb25det-billet-dual-port-xtrwga-bdp-rb25.html Obviously though that kit is for the stock turbo, you change the turbo you'll need to change the wastegate setup to suit the new turbo. As for what wastegate you should get, the only real reason for getting the Turbosmart wastegate is to be able to change your base spring pressure. There is a very strong chance you'll never need to do that. Lets say you buy a Hypergear high flow turbo and you want to run about 18psi. You can tick the box for the higher pressure actuator and that's it. You don't even need a boost controller and you have your 18psi. Say you want some adjustment. You buy the same Hypergear high flow turbo, but this time you get a 14.7psi wastegate spring. With a 3 port MAC valve you could theoretically take the boost up to about 30psi with that setup. Not happy with that range of adjustment? You could get a 7psi wastegate spring, use a 4 port MAC valve and take the boost up to about 30psi. So now you can run anything between 7psi and 30psi without changing your wastegate spring. My advice is if you don't know why you want to change the wastegate base spring pressure, don't buy the expensive Turbosmart wastegate. Have a think about what the min and max boost levels you would like to run, then buy a wastegate/spring/MAC valve that supports that goal. If I had a crystal ball, I'd probably see you buying a Hypergear turbo, using their high pressure actuator, using an aftermarket ECU and a 3 port MAC valve for boost control.

Sounds like there is some shenanigans going on with the boost control solenoid. The wastegate spring is 5psi and the factory boost control solenoid takes it up to 7psi when over 4500rpm. I would be very surprised if the play in the wastegate was causing these issues. Not enough preload on the wastegate generally just means a bit more lag and doesn't impact on the overall boost level. The universal kit comes with a straight rod, vehicle specific kits will come with a bent rod if required. Have a look at the IWG75 kits to suit an evo for an example. My wastegate isn't on the stock turbo though, so my setup won't be the same as yours. I'm using the straight actuator rod, but if you need a kink in the rod for your setup, this can be solved in about 5 seconds with a vice and a hammer. Having said that, I don't think there is much value in putting this wastegate on the stock turbo. If the wastegate failed, you'd just replace it with another stock one. The reason for running the Turbosmart wastegate is to have more control over the boost levels, but with the stock turbo you'd never run it over about 10psi anyway and the stock wastegate will allow you to run that very easily with a boost controller.

So you have the stock rb25 turbo? So I'm guessing what the guy was trying to tell you is the wastegate doesn't have enough preload on it. Have a look at this video to see what I'm talking about. When you say you've got issues with the boost dropping off, how much boost are you running and how low does it get in the top end? As for what I'm using, I use a Turbosmart IWG75 on a Hypergear turbo.

@The Bogan Sir, your dataz are ready. I included oil and coolant pressures as well because why not lol.

Hopefully after the TCU is installed you won't feel the need for a 3rd set of wheels.

What ECU are you going to use? Are you going to install all of the supporting mods yourself and then pay a workshop to tune it?

Would you be interested in picking up those skills? It's not hard, it's just a practice makes perfect thing and having good quality crimping tools makes an insane difference. I feel pretty confident that we could talk you through what tools you'll need, how to get this bad boy wired up and tuned.

Fk me, looks amazing Yeah, I was in NSW before but in QLD now, it's so much easier legally putting a built car on the road here compared to NSW it's crazy how different it is.

Please post up your results and some build pics as it goes. It sounds like it will be very nice

haha well you've already put aside the $2,500 that I mentioned, I hope you still have quite a bit of change left. Fingers crossed! I expect that you will pass emissions first go. Yes you are correct, the standards that you need to meet are based on the year the vehicle was manufactured. It sounds like you've got all your ducks lined up which is good.

No worries, I'll get the data up this week some time.

Almost perfect list. Small correction, the emissions testing needs to be done before the engineer can sign off the car. They are certifying that the car meats the Australian Design Regulations based on it's year of construction, they will need to view the emissions printout to be satisfied that this is the case. I agree, skids are an important part of the engineering and registration process.