Things that can cause late transistion.
#1
Autocrossed. I got CONED!
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Location: Lake Charles, LA
Posts: 629
Likes: 0
Received 0 Likes
on
0 Posts
Things that can cause late transistion.
Can someone give me a list of the parts of the turbo control system that could possibly cause an extremely late transistion to secondary at anywhere in between 6,500-7,800rpm?
I've replaced the one-way check valve to the pressure tank as somone had suggested in another thread, it seemed to make the transition consistent at least. I've tried 3 different solenoid valves for the charge relief solenoid until I finally found a good one. I've tried 2 different CRVs I had laying around and that also helped a lot. But the late transition is still there.
Thanks.
I've replaced the one-way check valve to the pressure tank as somone had suggested in another thread, it seemed to make the transition consistent at least. I've tried 3 different solenoid valves for the charge relief solenoid until I finally found a good one. I've tried 2 different CRVs I had laying around and that also helped a lot. But the late transition is still there.
Thanks.
#3
Autocrossed. I got CONED!
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Location: Lake Charles, LA
Posts: 629
Likes: 0
Received 0 Likes
on
0 Posts
I'm guessing the precontrol actuator you check with the KOKO process right? Solenoid probably has about 100,000 miles on it but I just replaced all vacuum lines with silicone about 3 months ago and everything is hooked up right and not leaking.
Thanks.
Thanks.
#5
Autocrossed. I got CONED!
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Location: Lake Charles, LA
Posts: 629
Likes: 0
Received 0 Likes
on
0 Posts
Well since I don't have an assitant at the moment, I'll probably end up taking the pre-control actuator off of my old set of twins and seeing if it makes a difference. If I wanted to replace the pre-control solenoid I'd probably have to order it since I don't think I have solenoids of that type laying around.
Thanks guys, at least it's narrowed down for me now.
Thanks guys, at least it's narrowed down for me now.
#7
Autocrossed. I got CONED!
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Location: Lake Charles, LA
Posts: 629
Likes: 0
Received 0 Likes
on
0 Posts
Instant 11psi on primary
8psi at transition at 6,500-7,800rpm
Instantly back up to 11psi and pulls really really good.
Engine related mods are mild streetport, hose techniques silicone line kit, RX7store 3" downpipe & high-flow cat, 2.25" cat-back into an OPAK racing muffler.
8psi at transition at 6,500-7,800rpm
Instantly back up to 11psi and pulls really really good.
Engine related mods are mild streetport, hose techniques silicone line kit, RX7store 3" downpipe & high-flow cat, 2.25" cat-back into an OPAK racing muffler.
Trending Topics
#8
Racecar - Formula 2000
Instant 11psi on primary
8psi at transition at 6,500-7,800rpm
Instantly back up to 11psi and pulls really really good.
Engine related mods are mild streetport, hose techniques silicone line kit, RX7store 3" downpipe & high-flow cat, 2.25" cat-back into an OPAK racing muffler.
8psi at transition at 6,500-7,800rpm
Instantly back up to 11psi and pulls really really good.
Engine related mods are mild streetport, hose techniques silicone line kit, RX7store 3" downpipe & high-flow cat, 2.25" cat-back into an OPAK racing muffler.
If that scenario is true, you are feeling something other than "transition" at the 6500-7800 boost hesitation.
#9
Autocrossed. I got CONED!
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Location: Lake Charles, LA
Posts: 629
Likes: 0
Received 0 Likes
on
0 Posts
I'm using the stock control and there are no other symptoms besides this late spurt of boost. And I have no boost leaks (courtesy of Fighter's Garage pressure tester). I'm thinking the precontrol solenoid as SLOASFK said, I just swapped out the actuator and it didn't help so I put my lower mileage one back in.
#10
Sounds to me like a possibility is one (or both) of the turbo control solenoids. It takes both vacuum and pressure to work the turbo control actuator which allows exhaust flow to the secondary turbo. Often one of these (more often pressure) is not working properly and therefore it takes much longer than it should for the turbo contol actuator to move. This is a pretty common problem. This can be checked by t-ing into the vacuum and pressure lines going to the tubo contol actuator and looking for vacuum and pressure (respectively) to hit at about 4,500 rpm (under full throttle). Hope this helps.
--Jeff
--Jeff
#14
Racecar - Formula 2000
OK. Dumb question: is what you see at your "transition" really 6500 RPM? Is there any possibility the tach is screwy?
#15
Cheap Bastard
iTrader: (2)
The stock ecu will dump some extra fuel at high rpm (under hard acceleration) when it sees the engine as not fully warmed up. This fuel dump will cause a hesitation. The stock ecu may see the engine as not fully warmed up if coolant temps are under 200 degrees.
To the thread starter. Try warming your car up to 210 degrees, and see if the hesitation persists.
Thread
Thread Starter
Forum
Replies
Last Post