stian

Yeah! Thanks a lot to Harald & Inglar for the garage-tour and R&D advices... Some insane projects coming to life in that garage! You guys are completely nuts... Very impressive indeed!!

Sounds great! I will see how much I have time for until next season, but most probably I will stick with the existing setup for next year, and then upgrade (downsize) the brakesystem for next year. But lets see what happens... I will at least add a bias-valve and a larger master cylinder.

Let me know if you make it over and I will take you on the grand-tour of town I did go to Vancouver last year. Great place & awesome skiing at Whistler.

It's a custom modified Greddy aftermarket intake for the Nissan 200sx. The 65mm throttle body comes from the Nissan Primera GT ( Infiniti G20 in the states?). The intake was adapted to fit the Miata-engine by a previous owner, so I can't tell you too much about it I am afraid. I can send some close up shots if you want...

Hehe - I am already wondering if I can live with the delay in spool from the GT30 vs the 28-series, so I am not sure if the GT35 will help I am not aiming for max top performance (only) - I want something that gives good throttle response on track with some sort of reliability... I am sure 500whp will be more bust than reliable.

I've done some flowcalculations of the various turbochargers I've been debating, and will post them here shortly to get your feedback on it... Maybe I should do one for the GT35 too - just for the hell of it

stian

I've done a bit of calculations, according to Graham Bell's formulas, in order to better understand what would be the better turbo to select for my project. I calculated for 15psi & 22psi from 3600-7200rpms, then I did one for 25psi @ 7600 and one completely over-the-top at 30psi.

After going comparing all the compressorcharts, there are a few of the smaller (pre GT30) turbos that looks very promising. One is the new Garret GTX2867R. The first batch of these turbos are shipping very soon, so I sent some emails to ATP to get their opinion about it and they were extremely enthusiastic. It is promised to spool as well as the 2860RS but will deliver a whole lot more on the top end. See the comparison charts here. They could also ship it with a T3-turbine that could fit my existing downpipe. Here's the flowchart:



Not too bad at all!! No issues with surge and even up to the higher boostlevels it operates inside the most efficient area of the compressor, hitting the sweepspot at the end of the RPM-ranges. Would be awesome to see full boost closer to 3000rpms and yet reaching well above 300whp! I am a bit surprised that this turbo has not been mentioned either here or at M.net! Am I missing something here - apart from the fact that it's a fairly new device..? Will be very interesting to see how it compares in real life, once we see the first builds on the dyno.

The BorgWarner EFR6258 also looks very very promising. This seems to be the one to beat - at least when it comes to delivering at the lower rpm-ranges. Will be interesting to see once more people finish their builds and show some dynoplots with higher boost than the 12psi that "fresh38" was producing. Even then he produced 270rwhp on a more or less stock engine!!! Very impressive.



Edit: My first calculations were a bit off on this turbo, as I didn't scale it correctly. This now looks even better! Seems like the compressor is able to give 20psi all the way from 2800rpm to redline

Some other alternatives are also attached with overlayed flowcalculations, including the suggested GT35 that for sure will fit really well

To be continued...

stian

A while since my last post since the car was taken apart to weld some exhaust leaks and make a proper threaded fitting for the EGT sensor which the previous owner had made a half assed attempt to weld into the turbinehousing

Has since then been waiting for the snow and ice to clear off the road so I could take it for a spin. Today we had -6c (21F) but the roads were at least dry enough to brave a little testdrive. The fixed leaks was successfull and I got 2-3psi more now than before, so it pulls way too hard for the roadconditions to give me any traction. Turbolag is still HUGE, so the damaged dinosaur of a T3 must go. The quest for the proper replacement solution continues...

Now, I have a few questions regarding my hybrid RX7 FD3S tranny. The previous owner who fitted it, cut and welded a Miata bellhousing to the RX7-box and made custom fittings to bolt it to the PPF:




First of all the speedocable has snapped so I need to replace it. It looks like a standard Miata cable, right? So I guess they must have changed the drive-gear inside the transmission to make it read correctly on the Miata... Anyway, the sharp bend they made to the cable, probably caused increased friction so that it eventually snapped. Will see if I can get one of those angle-adapters so it does not happen again. Anyone who has one on the shelf?




Last question is related to a rattling noise in idle. The audio comes and goes as I press the clutchpedal:

What could be causing this? Throwout bearing? Transmission bearing(s)? Clutch fork touching something it shouldn't?

m2cupcar

iTrader: (5)

I vote the latter- in the bell housing- like rubbing diaphragm springs. Don't you have some places to peak through into the bell housing? fork boot maybe? That's where I peered in with one of those flexible LED lights to see my clutch disc in pieces. I assume nothing has changed in (driveline) drivability.

stian

Choice of turbo has been made, and I will attempt to go smaller and see what can be done with the GTX2863R with .63 A/R T3 hotside. Installation will hopefully happen within the next 2-3 weeks...

Also picked up oilcooler, tons of AN-couplers/hoses and some other bits and pieces.

stian

The new GTX2863R turbo is in place - and has been for a while now... Sofar I am running more or less on my old map, so it's far from optimal but things are certainly working much better than before!! I now have full boost (18psi for now) at 3800 which is 1500rpm sooner than the old Turbonetics thing. Also no more oilsmoke and noises. However, I am wondering why my boost curve rises so slowly from 1750 to 3000? Especially compared to the Cueball's 2860-setup, which seems quite similar to the hardware I'm running... Could it be cam's that needs less overlap?

I am going to the dyno later this week to get it properly tuned, so will post back the results and add my boost-plot once its done.