OTOH, I did confirm the factory baro sensor does in fact have +5v. The purge valve is what I pulled power for the EBC from. So the next question is, why would I want a 3 bar GM map from DIY, when there are 4 bar gm map sensors with pigtail for cheap all over the place? Chinesium not so good here?

I have one of the "chinesium" map sensors and while I have no experience with the 3 bar that DIY sells, I can tell you that compared to the MPX line of sensors, it's output is not nearly as steady. Just sitting exposed to atmosphere the fake GM sensor wobbles around considerably more. I would trust it as a baro sensor, but wouldn't want to use it as my main MAP. I assume the one from DIY is from a more reputable manufacture and therefore have a higher QC.

at 240kpa+, you definitely don't want the sensor to "guess" your manifold pressure lol

Noted. I may want more than 29 psi though...

@Reverant, what 4-bar sensor would you recommend?

Ok, pulled turbo apart to change to .64 housing. What I was told was a 2860r is actually a 2871r. Welp, now I have more questions than answers...

The shit Chinesium turbine housing I was sent (not the garrett I asked for) has a serious breathing problem at high revs. I can't get less than 22.7 psi above 6000 rpm. Oh well, this may be as good an excuse as any to swap manifolds and downpipes to get rid of this FM stuff. It sucks a lot to remove because of the rear upper to lower dp nut that fouls on the 3" pipe.

Anyway, 318/284 is okay. Not really what I expected from a GT2871R but I think I need an airbox to keep the IAT below 100*F and a better flowing hot side.

https://cimg1.ibsrv.net/gimg/www.mia...1612b0bee4.jpg

And a comparison between .64 and .86 housings. You may as well throw it all out past 6k as the boost is not consistent.

https://cimg4.ibsrv.net/gimg/www.mia...b040376755.jpg

the fact that you were diagnosing all this time and didn't even know which turbo you have, seriously makes me doubt........well just about everything you're doing. no offense at all

I take your assessment under advisement. I suppose I was wrong not to measure all the wheels when I was swapping turbos on the side of the road at Fontana Village Resort at the Dragon.

For real though. I am still down on power and now I am finally seeing appreciable knock in high RPM, so close to whatever the limit is for Iowa 93 octane fuel.

:vash: That damn trip messed a lot of us up. What does it drive like?

It's FAST and spins a lot on new RS4's. I need to get a better housing, on wastegate spring only it spikes to 10 psi and creeps to 23.

Well, I had a heck of a time with that stupid chinese housing. I bought a genuine Garrett .64 ni-resist housing which actually comes with the divider and a low pressure channel cast into it to help mitigate creep. I had to cut out the divider from the FM cast upper downpipe but I have never liked that part anyway. After the genuine housing was installed, I had 11 psi more or less solid to redline on wastegate can only. I also swapped the inlet from the 2.5" bolt on adapter to a 3" adapter. I am NOT a fan of this stupid sr20 style compressor housing and I will be swapping it soon, more on that later. I did a couple pulls after rebuilding my EBC bias table and got a VD graph of wastegate vs 21 psi. (I was having trouble getting some sort of artifact in the 4th gear high boost pulls, so I used 5th). I had the top down, so that is likely why the fall off up top. It does not have any large drop in power I can feel in high rpm, but it still needs to go to the dyno for final tuning. It did trap less mph than I thought it should have last time at the track.

https://cimg5.ibsrv.net/gimg/www.mia...4224f226a0.jpg


Just for shits and giggles I did a pull under a bridge near my house. The new intake inlet for the compressor housing makes the Turbosmart valve sound like a Tial Q. The car is now hitting the surge line, which you can hear in the vid. I am going to have to swap the compressor housing for an anti surge one over the winter. I will also be addressing the worn out stock 150k mile head and possibly tossing in some new slugs and a hone. The thing is using a lot of oil and sounds terrible cold.

Anyone have any hypotheses on what is could be holding back the top end? It has always has less top end power and a lot of torque fall off than other similar cars. It has a 3" turbo back exhaust and a square top. Maybe the Rev basemap has too much VVT advance up top or?

VVT should be going to 0 advance at redline.

0 advance from zero point? or zero absolute? I know that 0 on the map is a bunch of retard from zero point.

Full retard. The table should be setup where 0 is full retard, and 47 (or whatever the max range is) is maximum advance

Why full retard? Wouldn't it make more power advanced a little bit up top?

https://cimg4.ibsrv.net/gimg/www.mia...597d10ddc1.png

Anyone got a big hp turbo car that can help with this vvt table?

Didja try what Aidan suggested?

No, I never got an answer. I'm working on the car a bit in the am and I'll go out and do some pulls tomorrow. Still looking for more info on the theory of vvt with turbo...