So I haven't really driven my car since I finished installing the turbo. I recently went with a turbonetics to4e turbo non-bb 55 trim .70 compressor .81 turbine. I am also running a reverse y pipe, and still a turbo noob. The thing is not seeing any boost before 3.5k rpm, and then close to 6 psi near redline. Ive been looking for some injectors, but other than that for fuel delivery, I have a walbro fuel pump, afpr, and cartech fmu. I know this is kinda vague but any light on the situation would be appreciated.

Lorenzo

 

What gear were you doing these tests in?

 

mostly 1st and 2nd and sometimes 3rd. Im also getting a cel from the map/baro switch, related maybe?

 

With that turbo your not gonna see boost real early. The turbo is gonna spool much differently depending on what gear your in and what rpm you start from. You could also have a boost leak which would add to the late spool.

Just so we are on the same page, try going WOT in 4th or 3rd gear starting at 2.5K rpm's. Tell me when the first bit of boost starts and when it peaks. Boost should not keep increasing till redline, especially if you are just going off your wastegate spring.

 

1st and 2nd are not appropriate gears to test in. My car never reaches peak boost in 1st or 2nd gear, at any point. If I have my boost controller set at 13psi, I don't see more than 9-10psi in 1st and 11-12psi in 2nd. 3rd is ok, 4th will be earlier, 5th will be even earlier.

I don't think there's anything abnormal with what you're describing now that I know you were testing in 1st and 2nd. Frankly, reverse ypipe setups suck when it comes to spool and lag. The only reason to use them is because they are easy to plumb, but performance wise they are the bottom of the barrel. Any given turbo will see faster spooling and less lag with a more direct exhaust routing than a reverse ypipe, but it's something you've got to deal with if you want the ease of turbo placement that the reverse ypipe setup offers.

 

Well I have some 2.5" and 3" piping so I may just switch to a forward y pipe. Boost does come much faster in 3rd and 4th gear. Thank you for the help

 

are u running true 3" all the way back and are u using a cat?
u also may have a small boost leak..

 

try using a boost leak tester http://www.boostpro.net/prodz32tester.html
i have this one... after using it i found out i had a leaky bov.. anyways gl
btw what kind of numbers are u putting down/?

 

I dont have a boost leak. I didnt look in the link but i did use a piece of 2.5" aluminum piping, a valve stem, and some rtv, and didnt find a leak (Inline with intercooler piping). I havent dynoed yet so I dunno on numbers.

 

Do a 4th gear roll from 1500 RPMs. If you cross the positive pressure threashold by 2500-3000 RPMs and get full boost by 4500 RPMs then you most likely have no problems, except for too large a turbine housing A/R (IMHO).

I have used a 0.81 A/R and 0.68 A/R p-trim on a 5L V8 (and got 9 PSI at 3100 and 2800 RPMs respectfully), and I think that those are just too large for good boost response on a 3L V6 (but will yeild very low back pressure in the upper RPMs...it is a tradeoff).