rotarymandan

iTrader: (15)

I think there was a set of BNRs for sale in the 3rd Gen parts section... you'll probably have to search though, I was looking at them a month or two ago, but I don't think they ever sold.

tom94RX-7

iTrader: (5)

I think compressor surge definitely killed my turbo, I was playing with the bov and the adjustment screw today. Where I had it set, the bov would only open up about 6mm, I had the preload set too much, the screw was turned in too much, too hard, I guess this would explain why it was quiet too. So I turned out the screw and realized how the screw effects how far the bov opens to let out the boost pressure. With the screw turned out far enough to allow the bov to fully open up all the way, I actually can't really feel much of a difference in the force it takes to push open the bov with my fingers. So when I get my car back together I'll leave the screw out to allow the bov to fully open, and then just make sure there is no boost leak.

See the picture attached to see what I'm working on now, T04R single turbo kit!

rotarymandan

iTrader: (15)

What are your goals for this setup? If you were in the 10s with the twins you have to be hoping for some really fast times now!

tom94RX-7

iTrader: (5)

Low 10's or even high 9's would be awesome, but I don't really know how much power it will take to get there. I think I could have got a 10.7 with a perfect pass with the twins, so something close to high 9s would be nice. I'll put the 850 primary injectors back in and will have lots of tuning to do, I was about maxed out with 550s and 1680s, I was seeing 95% injector duty cycle with the amount of boost I was running with the twins. If I run that much boost with this single turbo I assume it should make a good bit more power.

Liborek

I don´t believe that surge kiiled it. Surge - true surge occurs at load and on the left side of compressor map. You were operating rather on the right side with very high shaft speeds - overspeeding.
Yes, there is surge condition when throttle is closed, pressure remains for fraction of second and flow goes almost to zero - which drives operating point beyond surge line.

I´m bit disappointed that you went for quite big single. It would be nice to see how would perform some smaller single, like Borg Warner S256 and such

All the best, hope you´ll max it out

Narfle

iTrader: (16)

I think this is interesting if you follow the BOV/No-BOV debate. It may or may not be the root cause of what happened. But, I'm inclined to believe a proper functioning bov would have saved that set of turbos.

Don't confuse me with the facts. My mind is made up

tom94RX-7

iTrader: (5)

Thanks for your thoughts on this. I like to think that my bov setup had something to do with it, because I had only been running this bov setup for a short time with this last set of turbos (greddy bov too tight, didn't open far at all, and stock bov removed). Prior to this I had 3 other sets of turbos that ran the same amount of boost for a much longer period of time, with the greddy bov that was not adjusted so tight so it opened up more and the stock secondary bov was hooked up too, and I didn't have a problem like this before, it could be a coincidence or it could be related.

I didn't want to get a smaller single turbo and barely make more power than I made on the twins, I wanted to have more power potential. I chose to spend the money on a single turbo and I wanted to make it worth the extra cost. Thanks.

limepro

iTrader: (2)

This makes me sad, wanted to see what you could do with the bnr's.