that picture is from world street finals 2005. thats basically how everyone did it back then, it was when turbo guys were still figuring things out. most ecms couldnt control boost, or really much of anything beyond a set of injectors. MSD 7531 was the ignition box of choice back then. a lot has happened in 15 years.

 

Will have to put a nipple in the compressor port, I think it just has a blockoff currently.

Joe Nova bought 1 of the $200 ones off ebay and measured it against the VSR and it was identical from what he could tell. Even china getting knocked off by their own

 

And there were a lot of ecu's back then that could easily control boost and a variety of ways.

A lot has happened in 15 years....but 15 years also isnt that long ago either.

 

I just know how the drag radial and outlaw 10.5 guys did it back then. almost every turbo car at WSF that year had a similar setup.
the ams1000 revolutionized boost control in drag racing.

 

You have a link to the one he got or his results? Most of the ebay 7875's still have the .96 housing with 3" vband exit and are closer to $300-400 for the billet version. I think the 1.25 housing with 4" vband exit allows the VSR version to breath a bit better then most as the housing is a good bit physically bigger. Granted I also haven't seen any of the ebay 7875's make 900+whp like the VSR. But yes I've seen knockoffs of the 88 and other versions as well, bound to happen!

 

@AwesomeAuto which one did you get?

 

@AwesomeAuto Joe can you link me to the billet 7875 knockoff that looked the same? I think my back pressure issues have come to a head. It's going fat at high rpm regardless of pulling fuel. I think is just not breathing up top.

 

Joe didn't reply for 15 min.....so I bought one billet 7875 with a .81 AR on the turbine. Anxious to see the difference. I was shifting at 7300 today and it just feels out of breath. Should make enough power to break the clutch now

 

why wouldn’t you have gotten the larger .96 AR? Prob wouldn’t affect spool time and would allow better breathing up top.

 

Because rear mount....

 

Yes I know. Not sure how much the .96 would affect spool time but it would provide higher flow up top compared to the .81. I had a 76/65 .81 on my front mount and the 78/75 with .96 did not spook slower. I know rear mounts like smaller AR to help spool the cooler slower moving exhaust but how much of a difference is spool vs top end power with you spinning 7k+.

 

The AR does impact power some but shifts the powerband around depending on how big or small you go. However the size of the wheel has much more of an impact on flow so stepping up from a 65 to a 75 itself will make a big improvement. Going with a .81 seems like a nice compromise to make sure it still lights off quick enough for my taste. I'm used to building/driving instaboost stuff.

To be fair, this is my science project car as I've never spent time swapping around turbos in the past so this had been fun learning how different sized turbos operate on the same engine setup.

 

$260 billet 7875 arrives this weekend. Meth kit is working and I put in another failsafe. The led working on line pressure works too so I know I have flow of that light is on

 

do meth kits really fail that often? ive never used one but ive never had any part of my fuel system fail and cause engine damage. the only parts failure ive had is rocker arm stuff.

 

The fail-safes I put in place aren't just to guarantee that its on during a WOT pull......its to guarantee that it doesn't turn on when it shouldn't. i.e. the car is off and a relay or wire shorts and the pump turns on and you flood the car with WWF and start it up and hydrolock the motor. This scenario is real enough that many vendors includes notes about this in their install instructions/troubleshooting sections. The fail-safes they put in a basic kit are pretty lousy, but I completely admit that based on what I do for work I have to account for more fail modes than most would think about.

 

The $260 7875 is likely the exact same one that I had. I noticed that there are 3 A/R options now so they are obviously branching out.
I'm not sure if anything else has changed in those other than the turbine housing.

They aren't the same as the VSR V2, but the original gen 1. I compared it to a gen 1 cast VSR 7875 and couldn't find any differences other than a compressor wheel.
They had the same .96 A/R 3" V-band turbine housing as well.
They aren't the 11-blade billet wheel that the VSR ones use, but basically a billet version of the cast wheel.
The 11-blade wheel will move more air up top and are usually more efficient at higher boost pressures, but if the billet 6-blade does what you need, it'll do it while spooling faster too.

I'm about to pick up 2 more of them for another project so I'm anxious to try out the .81 A/R versions now too.

 

I didn't get any notifications? I'll have to check my settings.

 

I ordered the .81. Will snap some pics when it arrives.

 

The gang is together.

 

what other ar options are there?