Looking for someone with big boost rx1

[yamahacat69]

Hi guys I am looking for info I am running around 35-40 psi had a 5558 turbo now 68?? Forget the actual size but it’s big. Trouble I have now will not spool it up past5 pounds on the 2 step,,5558 no problem shoots up to 10 pounds no issues. Any advice will be great or do you know someone who ran big boosted rx1s ,,it’s still carbs
Thanks

 

[mbarryracing]

Bigger turbo's take longer to respond and spool. Bigger is not always better.
Hard to play catchup in short drag races with big power when you are slower in 60 feet...

If you haven't changed anything on your ignition or fuel system (or fuel type) that would affect the 2-step and result in a drop in psi of about half, other than that increase in turbo size, chances are the machine is still flowing the same exhaust flow on the 2 step as it was before but now there is less exhaust restriction , not as tight so less back pressure to create the combustion in the exhaust pipes that pushes the turbo...
Turbine housing AR too big now?

 

[rx1 fern]

What’s the turbo setup you have on your sled . I run a custom made turbo setup on mine also with precision 5558 turbo and this new setup spools fast and pulls hard . I’m running msd mc4 on my rx1 . Can you tell me your carb setup . Where your needle clips are and what main jets you run . With my setup I’m running 220 mains . I also made a bigger intercooler for my setup . What are you using to build boost . Thanks