I am about to pull the trigger on a YSi headunit. In the process I'm also going to be swapping my mini race bypass valve for a mondo bypass. Just wanted to double check, I should be able to take off my V2 headunit and replace with the V7 YSi correct? I would imagine I can keep all piping the same, but I would probably need different reducer size couplers correct? I'm currently running 8 rib setup, 10% overdrive, and a 2.95 blower pulley and was pushing 17psi out of the SI. If I were to keep the same pulley combo, would I even see any gains or do I need to step down to a 2.8 or so for noticable gains? My last dyno pull we were able to take the car to 6400 rpms, but it wasnt making any power past 6k as it just flatlined and appeared that the SI was just pushing hot air at this point...

 

You're deffinitely pushing the efficiency boundaries of your current blower.

What is your injector pulsewidth at? Keeping the same size pulley with a bigger blower is obviously going to increase airflow... make sure your injectors can handle the extra fuel output to compensate.

If you just want to fix your powercurve then it's possible that just upgrading your cooling unit could help you a lot.

I'm basically just guessing at this point though. If you post a data log I could help a lot more.

 

Thanks for the reply.

Not exactly sure what my pulsewidth was at...I dont think I'm close to maxing out my fuel setup (sumped tank, dual 300lph walbro pumps, inline fuel filter, twin -6 feed lines each feeding an edelbrock rail, adjustable fpr, 60# injectors), but i'll try to find out

When you say "cooling unit", are you referring to intercooler? I have a Paxton fmic, which from the research ive done is an extremely efficient i/c setup. I have an AIS stage 3 meth setup installed on the car, but never sprayed. The car will be going to Dez for tuning on meth once I can set a date in stone with him in the spring.

I think 18+psi and spinning the blower as hard as I am just becomes inefficient at a point.