Komdotkom

Wow, 395mm under an 18 will be tight AF but will be incredible. 36mm or 38mm?

Nice job on the wiring mate. I feel your pain on the bulkhead connector, I f**ked mine up (looking at it backwards) and had to repin one side of a 61 pin autosport connector. Then triple check it.

Jesus, that's a big diffuser. Planning to come East for some events at SMSP before WTAC 24? Out of interest, do you rate the Motorsport ABS? While I'm needlessly upgrading mine I have been considering it but $12k is a lot of cash.

I sold the Nismo LSD to Fatz for one of his fleet and am using a Cusco instead, this needs GTR stub axles which are made of whale tears judging by the price. For the 3.5 ratio I'm getting a set of gears from Neat, I'm also building a 3.7 for Winton just in case. The 350Z conversion is not as simple or as good as you'd hope. The front mounting 'ears' on the diff case are not in the same position from a height point of view so you end up with the diff hanging down much lower than a 'normal' R200. This creates some dramas with driveshaft angles. A guy I know has this setup in his S14 and needed to get GTR driveshafts to make it work which are also made from whale tears so it ended up being a very expensive conversion. Although the gears from Neat are $2k for a set, it probably would have been a better option with the benefit of 20/20 hindsight.

Hmm, if they did reverse rotation I'd be all over one I reckon.

Any idea on pricing? They do some nice high PR small frame stuff too.

Thanks gents, your input is very much appreciated Clearly I'm not smart enough to work this out, who do you engage as a consultant to spec a turbo for something like this? I wouldn't know where to start looking for the right kind of boffin for this.

I've got a bit more information from the owner about the turbo and it appears to be quite a strange hybrid. It was built to be similar to the GT2860R Rally which is a turbo which was designed specifically for rally cars on a 34mm restrictor. This is great in theory but when you overlay the choke line on the compressor map all of a sudden things are looking less good. 36 lb/min for a 38mm restrictor I think is on the money. I think my question now becomes do you tune the wastegate position to be keep it just below the choke point of the restrictor and taper shaft speed as rpm increases. I'm assuming that once the orifice chokes the flow gets ugly and we also see a vacuum in front of the compressor blades which is not great. Or do you just smash as much boost in there as possible and make it choke as soon as possible? My thinking is that the turbulent flow and vacuum in front of the compressor is NFG but I don't have any experience with this.

Sorry, I should have mentioned this is God's Tractor Engine, SR20DET (not VE)

Thanks for your insights @Lithium, much appreciated. I was thinking G25-550, at least they're good at high PR's unlike the GTX2971R which is surprisingly poor. It's currently running an IWG (I know I can't believe it either) so I'll see if we can get a Mamba .64 rear for the GTX29 on a V-Band and see how it goes.

I had a crack with matchbot earlier but without having much information on what the intake restriction is I was getting some pretty wild numbers. It still generates 30psi MAP so I'm assuming it's still spinning pretty hard, or is this in fact choked up exhaust gas? This has all come about because the engine is apart at the moment and the intake ports are covered in partially combusted E85 jelly stuff. As soon as the air becomes supersonic through the restrictor and it chokes the PR is going to spike massively, is the object to bypass more air through the WG to keep the compressor right on the edge of the restrictor stall?

I want to add a map sensor between the restrictor and the compressor to see what that looks like, not my car though so that's up to the owner.

It's a very difficult thing to get right. When the car had a smaller turbo on it (GT2860R .64) it would make more power past peak torque with the WG open. The current turbo GT2971R (not a typo) .86 does not, but that seems mental to me. All that air can't be going through the turbine without EMAP being 11ty billion PSI. I was reading an article about the old WRC compressors and they were saying that they ran a larger overall wheel but with a smaller inducer to allow for a 7 degree taper from the restrictor. The turbine was shallower/thinner but had a larger exducer to work at higher PRs. Car makes 220 ish kw on E85.

While this isn't strictly a Borg Warner turbo question, does anyone know if you can use the very helpful Matchbot software to simulate a turbo restrictor? It's got a line item for inlet air restriction which is for airboxes/filters and so on but if I ramp up these numbers to suit a 38mm restrictor does anyone know if the software will model correctly?

Anyone want a new Nismo GT Pro for a GTR? Doesn't look like I can make it work with 3.7s, needs a 4.xx ratio

So the 3.5 had just a bit too much rust pitting on it, so I've gone with a 3.69 which appears to be from an S15. I stupidly purchased a Nismo GT Pro for an R32 GTR so that I could use some 6x1 shafts (to hold the massive RB20 torque) but now it appears that the taller ratios have a smaller pinion and hence a different offset of the crown wheel and LSD. This has resulted in the gears and LSD being fine, but the side flanges don't fit. One side is 8mm too long, the other is too short and the circlip grooves are totally wrong. Any suggestions to make this work would be appreciated. I can't find much info on the side flange dimensions, the ones supplied with my diff are 38220-05U01, 148mm overall length.

And then?

I can't see the video of this laying 11's up the street, can you upload again please.

Same here, no cracking but my cage also goes end to end.

You can change the oil but I'd avoid full synthetic until you've done a few more km. Chrome or iron rings? If they're iron go for it they'll be fine, chome just a bit longer

Good work mate, especially when you've got the spicy flu. Leave the running in oil in there for a bit longer, change the filter if you're worried. I like to get 500km on them with mineral oil before changing to synthetic.

You forgot jet ski's and neck tatts.

At least you know how to change it if it's not enough! It's a pity they aren't accessible without removing the sump (and the engine)

It's only money. This arrived for mine yesterday

I did mine in the BMRS crimp on stuff, the -16 fittings for the dry sump were quite expensive. Just wait until the 18 " jellydonger arrives!