1970 Plymouth Sport Fury 383 EFI OD, now adding twin T3's

[furious70]

So far my impression is these turbos are NOT too small for this application. It's so eager to downshift it's hard to tell, but giving it a 1/2 throttle squeeze in drive brings on the boost pretty quick, but it is not instant or light switch. It feels just like I'd want it to really, so it may all turn out quite well. Because of the downshift it's hard to tell yet where the boost threshold is, but it seems to be somewhere around 2200-2400.

I did weld in a bung to do back pressure testing, I want to do that this fall as well to see where it's at.

[furious70]

This car is no 700hp freak, but it's a pretty satisfying drive right now Beat on it a bunch and logged this weekend. Have some detonation above 4000rpm that need to cure. Did some back pressure testing, looks like it's probably around 2:1 until 4000rpm then approaching 3:1. The needle bounces so much it's really hard to tell. I can be rolling about 10mph in 1st, nail it, and after a 1-2sec the turbos will spool and it will boil the tires, which is the kind of shananagins I was hoping for. Will be interesting to get to a track next year, it certainly drives like a 'big' 440 now but with the mellow little 383 the rest of the time. IF I can eventually drop down into a smaller cam and add more boost I'll be quite happy.

[furious70]

Back pressure testing

at 5-6psi
under 3500rpm back pressure stayed below 2:1
~4000rpm 3:1
~5000rpm 4:1

these turbos are very responsive on the street but the are definitely choking it up top. Seat of the pants rev time from 4-5000rpm is not that great. Maybe stage III wheels would be enough? Probably time to call a professional now that I have data....

[furious70]

Short, and with the car just in drive as I didn’t have a hand to shift and hold my phone :P Had to feather the throttle in the one of course which caused upshifts.

http://youtu.be/8xRVnuzum0o

http://youtu.be/KvAUD-9BJLU

[chargerwayne]

It was nice meeting you last week in Roselle . I heard Furious as you left and she sounded sweet. Wayne

[furious70]

It was great to meet you too!