Those new walbros going to be a drop in upgrade for you?

 

More interesting stuff, looks like the 76mm compressor wheel may just be a better option, period.

Heres the Logs and what I noticed.

First the 72mm/Q, locked 3rd gear pull, right at 15psi takes 3374 RPMS, using 48% injector and a 11.24 Air/Fuel.

Second is 76mm/Q, locked 3rd gear pull, 15psi at 3407, using 52% injector and has a 11.46 Air/Fuel.

Conclusion, almost dead on spool, but the 76mm is using more injector at the same RPM/Boost and even with the more injector is still running leaner.

76 = no extra lag, moves more air and needs more fuel, thus making more power throughout. Also something to think about when getting closer to max efficiency the the 72 wheel will be putting out higher discharge temps.



72MM



76MM

 

I think that is likely due to an inconsistency with the wideband reading. They are never exactly the same readings under identical circumstances. If you did 10 pulls back to back with each turbo to average your WB results, you'd probably find that they are the same Unless you changed your tune for the new turbo.

 

Possible I agree. However what about 4% more injector at the same RPM/MPH? Take away that 4% and that wideband gap would grow further as well.

I'm on the wagon the 76MM@15 is flowing more volume of air then a 72MM@15. Then account it's at the same Engine speed, seems like a win win.

Thoughts?

P.S Why does your sig grill have to be all up in my space?

 

Lookin good Rob Let me know how those dual 400's turn out, i'm sending my bucket to lonnie's soon for twin 255's but you got me thinking i need to go MO BIGGA! Lol, i gotta set of 106lbers to feed

 

all this on 18*?!?! bump that **** up!

glad to see youre still making progress with that thing! everytime you go to the track it just gets more and more impressive and it doesnt even seem like youre beating on it too hard or anything! very nice sir!

 

At the same RPM and displacement, volume is always a constant. With the bigger compressor however, density can remain higher as RPM climbs. Also something to take into consideration is how you climb into the compressor map. The slower you roll into it, the more time the turbo has to build boost and maintain as much volumetric efficiency as possible. Big compressor just means more of a beast at the high end
I did notice the sig thing too...just waiting for someone to say something lol

 

Thats pretty awesome i thouught you'd have the NNbs Intake, but idk know much about turbo but on mine Nbs intake and Pigtail helped don't know on a set up like urs? Keep Up the Good work bro on them Small Cubes

 

It's the 32* air temp difference. Even though the manifold pressure is the same, the air charge is denser on your latest scan. The air density could also account for the slightly faster spooling of the 76. For an apples to apples comparison, you need to do both scans in equivalent weather.