So with all of the recent turbo talk about folks searching for the "perfect" VGT turbo for 175/75 injectors, I decided to try and build a turbo based on some similarities that I noticed from (what seemed to me to be) "higher than normal" HP rated non-VGT turbo options. I had to have a custom billet wheel made as well as a couple of different turbo parts to make this turbo work. Nevertheless though, the testing so far seems to be going VERY well and this turbo has far exceeded my expectations for performance from a 10 bladed GT37 turbine wheel. The long and short of it all is that this turbo uses an ~67x88, 11 blade single plane, compressor wheel and a 10 bladed, GT37 turbine wheel and is dubbed the "NB6766V" for now.
So far, I have been driving my truck with this turbo on it now for just about 2 weeks. My tune that I am running is Eric's Xtreme X that I had written for the Stage 3 (LOTS and LOTS of fuel) and I haven't bothered messing around with any revisions with it so far. Cruising on the flat ground with this turbo at 70 mph, my boost is about 4 psi and my EGTs are 690-720F; cruising at speeds of 45-55 mph, my EGTs are about 550-600F; and at speeds of 40 mph and under, my EGTs are usually below 500F. This turbo runs about 2-3 psi less EBP under cruising and acceleration conditions (I haven't been able to watch EBP on WOT yet as well as smoke due to traffic). At WOT, I was able to get the turbo to hit 42 psi and hold 39 psi of boost, where with the exact same tune and the MadMax, I was only able to hit 34 psi of boost. Furthermore, at every boost PSI that I checked, this turbo had a higher MAF reading than either the MadMax that I tested, the Hybrid, or the Stage 1 (never did MAF readings on the Stage 3). I don't believe or trust MAF readings as far as knowing how many lb/min or gm/s of air I'm moving, but I do use it for seeing if I am moving more or less air than other turbos. My EGTs at WOT were 1490-1500F. With the Stage 3, my EGTs were 1470F on the same tune at about 39-40 psi of boost (as that was about all I ever got from the Stage 3 and this tune). The MadMax really ran out of air up top (as shown by the dyno results from Adrian) and yielded EGTs of 1650F at the same speeds.
Here are some pictures of the wheel. Since this turbo most closely resembles the MTW Stage 2 turbo, that is what I am comparing it to. The first pic here is the cast wheel of the GT4088/Stage 2 turbo.
Here is a pic of the billet wheel used in this turbo.
So the next steps for this turbo are to see what sort of power level can be had from it as well as some different turbine wheel options (bigger turbine) to see how that changes the performance of the turbo. If I can get some better weather here and some more free time, I will update this thread with EBP numbers.
As of right now, this turbo is ONLY a prototype. We still have a ways to go with it in terms of gauging it's performance, longevity, and parts availability. However though, I am simply blown away (no pun intended
) by the performance potential exhibited thus far by this little turbo with my 190/100s and it has made my truck an absolute pleasure to drive. The MadMax was a blast to drive too and I didn't think low end power and response could get any better, but I have noticed no low end power loss and have definitely gained air flow through out the entire RPM range (as indicated by the lower EGTs). How much did I gain?? Only a dyno is probably going to be able to tell me that. Nevertheless though, I feel like I finally have a turbo that can really have a chance being used to tow heavy with my 190/100 injectors. I think that as long as this turbo produces solid dyno results, it should be an AWESOME little turbo.