I just did a whole bunch of stuff to my car and now my primary turbo is very slow to spool up

things I did:
R&R engine
rebuilt turbos w/ turbo city rebuild kit
silicone vacuum hose
vacuum line simplification (removed egr, avc, etc.)
k&n cone filters

I'm only getting 5psi of boost by 3500rpm and it is very sluggish.

I tried the poor man's non-sequntial and built 12psi by 4000rpm (maybe a little sooner)

checked for boost leaks throughout the entire charge system

checked wastegate, pre-spool, charge control actuator, turbo control actuator, bypass/charge relief valves for proper operation

checked turbos for play or binding/rubbing
(similar "drag" on my primary turbo as my friend's WORKING RX-7)

we have checked eveything that we can possibly think of.

when reved to 6000 w/no load there is no boost, where as my friend's gets up to nearly 5psi by 4500rpm.

any other suggestions?

 

also, a few more things.

In non-sequential, it holds boost all the way up to 8k rpm.

all actuator rod lengths have been checked.

the charge control actuator was checked to see if it was leaking boost back into the secondary turbo area....that turned out to be a negative.

we ported the wastegate when we had the turbos out, but left a sealing surface of a couple of milimeters all the way around the wastegate, so i don't suspect that the exhaust is leaking around the wastegate. (not impossible, but not likely IMO)


I haven't taken it up to very high rpm in sequential mode for fear of me screwing something up if some stuff is not 100% correct.

i have a needle valve controlling prespool, but i have it completely closed so that no exhaust is being routed to the secondary turbo.

I have a AVC-R boost controller that works fine in Non-seq operation and nothing is being changed when switching back to seq operation.

I have an efini Y-pipe so boost leaks from that are unlikely.

if you want to know anything else just ask (we've probably tried it )

 

please help me!

 

bumpity-bump

 

Have you tried adjusting your prespool flap?
You may be redirecting TOO much exhaust to your second turbo before 4500rpm causing your primary turbo to slowly build up boost.

The prespool acts like a mini-wastegate.

This is one of the ways people get rid of the dreaded Boost Spike at 4500rpms with modded FDs. They basically redirect LESS exhaust to the 2nd turbo so that it doesn't create that crazy boost spike at transition.

 

yes, I have a needle valve to control pre-spool. right now I have it fully closed so there *shouldn't* any air getting by and opening the pre-spool door. I am going to go through everything again tomorrow and double and triple check everything.

just for further clarification, I would describe the turbo repsonse as similar to non sequential, even when it should be operating in sequential operation.

both of my turbos appear to be working properly (minimal shaft play, turn smoothly, no rubbing on the turbine or compressor), so I don't think it's the turbos themselves.

anything else that I could be missing?

thanks for the response

 

Of course it would. Think about it. Just like in non-seq mode, exhaust has to be directed to both turbos.

I also installed a valve at the prespool actuator. It made almost no differance. I had to manually adjust the prespool flap on the exhaust manifold.

If you did the poor man's non-seq mod, then you probably remember having to tie the prespool flap open by moving the rod attached to the shaft back towards the rear of the car. This basically allows much of the exhaust to flow towards the 2nd turbo. As a simple test, try wiring the flap closed (pulling rod towards front of car). All the exhaust will be shot towards the 1st turbo.

Of course, it IS also possible that your Turbo control actuator needs adjustment. That sucker also needs to stay closed rod pulling into actuator) to ensure no exhaust goes to the 2nd turbo.

 

thanks, the prespool door was open a crack!! problem fixed. here I checked everything else (much more in depth mind you) and it ended up being the simple stuff.

thanks again