Miata Turbo Forum - Boost cars, acquire cats.

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this is why most people call us crazy.. :bigtu: drives 18 hours to purchase a car he has never seen in person. but it looks like a good deal :)

glad to hear nobody was harmed by the accident! this must be so frustrating and i feel with you after putting so much effort in two cars.

also from germany i know the situation with rising prices for the NA models. really good cars are rare - and expensive.
I didnt find a REALLY good one up to 6000€ and then i bought a rusty 300€ BRG 1.6 90hp NA, sold the allweathers and came out close to 0€ for the car itself.

expect a build thread next month trying to turn a rusty shitbox into a proper car with a turbocharger :party:

Yeah, either start with a very good or very bad base. I don't think there's much point in buying a mediocre 3k car where sills and wheel arches need doing, plus a decent 2500€ paint job.

The thing is: when going turbo you'll be chasing ends anyway. That's why I wanted to have the chassis sorted.

Nice to see you going on! Nice find with the "rust-free" white car - a very rare thing over here...

i removed the plastic sill trim and was surprised not to find even the slightest sign of rust. Later I discovered a tiny area on teh front right fender - it's the typical spot where dirt collects over the years and attracts humidity. It's fixable. All in all it looks like an honest summer-only car that was kept dry in a garage, but not particularly caressed. Only surface rust on the axles, but dirty in a few spots.

Quote:

Originally Posted by Eunos91 (Post 1423347)

however, my turbo sucks. It is the biggest disappointment throughout the whole build. The boost lag is gigantic. Really, it feels like "no...nothing...nope...sigh...oh wait...yeah there's something... Oha.... BAM!"

given this is the bee's knees EFR turbo on a VVT engine, the turbo lag is really horrible. There's nothing happening until 3000 rpm, and 200 kpa are only reached at around 4050 rpm. Max. boost of 230 kpa shortly afterwards.

I went looking for causes. Swapped the external BOV for the proprietary EFR internal BOV. Nothing. Wired the wastegate shut. Nothing. Ran the wastegate with the signal line unhooked. Nothing (for whatever reason it hit the overboost limiter!?).

so a leaking BOV, a blown open wastegate and a faulty solenoid were ruled out. Then I checked the turbo. Back when I received it from the vendor, the ID plate said "EFR-6758-0.85-WG“. This indicated it was indeed the wrong A/R (0.64 is what you want). However on the same plate the part number said 179388, which would translate to an EFR 6758 with a T25 flange, internal wastegate and the proper 0.64 A/R.
https://cimg1.ibsrv.net/gimg/www.mia...aa047d904.jpeg

oddly on the packaging it even said" EFR-6758-0.64-WG“. So it looks like there was a 0.85 A/R EFR with a mixed up part number plate in a sealed box of a 0.64 A/R turbo. Coming sealed directly from the official distributor for Germany, Austria and Switzerland, I suspect the mistake was already made in the factory. If it really is a 0.85 turbo, that might explain the late spool.

Shit.. i think this happened to me!

Bear in mind that I temporarily put in a 6258 0.64 and the spool was identically slow

Quote:

Originally Posted by Eunos91 (Post 1483405)

Bear in mind that I temporarily put in a 6258 0.64 and the spool was identically slow

That's very weird and doesn't make sense

From what I've seen the 6258 should be spooling up by about 3.8k RPM, and the 6758 should be around 4.2k RPM - Your graph looks about right. My spool issues which caused my spool to slow down by about 1k was related to VVT.

Can you tell what caused what? I.e., maximum advance improved or slowed down spool?

his car was running fully retarded vvt
once he set up the range and car was able to actually control vvt advance properly, it was fixed.

So, finally the project has seen some progress. The bodyshells are swapped, and I gave the damaged rolling chassis to a friend who will bring it back on the road. In the meantime I have been working on the new car, albeit not as much as I had hoped to. I rented a workshop for two days to swap the drivetrains. A couple of friends came by to watch, drink beer and help. I then trailered the new "car" (rolling chassis with engine and gearbox) to the underground parking spot of my apartment. Working there is semi-legal, so I try to do most work when nobody is watching.

- new diff carrier is in
- rebuilt sport brakes are in, including a best-of-Miata-brakes consisting of an NBFL sport brake booster and master cylinder, NA brake prop valve with an extra shim and a T-fitting to make the MC work with the non-ABS brake system. Big efforts were made to ensure minimum modifications to the brake lines before and after I swap to the NBFL ABS system and brake prop valve
- cleaned and repacked hubs, installed ABS uprights
- revised ducting to the coolers
- brake cooling ducts which were a PITA to fabricate and nobody will ever notice

https://cimg1.ibsrv.net/gimg/www.mia...b468a0807f.jpg
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Your work makes me feel lazy.

Good job; and I really like the ductwork! What did you use for trans tunnel insulation?

Like the brake ducts coming out of the sides, that's neato.

Why didn't you cover the area between the radiator and the oil pan? Is a splitter going there? All the air that flows under the intercooler/radiator ducting sheet will smack right into the harmonic damper area and provide lift and drag as it stalls. It isn't obvious unless you look at it with a straightedge, but the radiator is about 2-3 inches higher than the stock bumper height and the natural air flow path is right into the front of the block if you you don't seal it off (as the oem pan does).

I do run the stock undertray in a trimmed down version. You can see it in the last pictures.

No splitter for me due to legal reasons. However, I'll add a GV lip, KG works ducktail and a flat underbody. Sneaky stealthy aero FTW

Quote:

Originally Posted by HarryB (Post 1484150)

Good job; and I really like the ductwork! What did you use for trans tunnel insulation?

It's 4mm of adhesive fiberglass with an aluminium top layer. I had run out of material, that's why I had to use so many tiny patches.