SaabCentral Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
453 Posts
Discussion Starter #1
Hi there, I've been having a very strange boost problem with my SPG. Its got the stock TE05 and I remember this used to pull pretty hard from about 2000rpm but after a few mods it doesnt pull like it used to. Ive got a 9k i/c and the JT 3" exhaust. The turbo is simply not spooling up like it used to. I dont really push it in first, but in second the turbo will not hit around 1 bar until 3500rpm and in third through fifth the turbo will not spool up until about 3000rpm. It will start to make boost before 2000rpm it just takes forever to build boost. This definately isnt right, so does anyone have some thoughts on why this could be happening? Could it be as simple as the wastegate staying open a little, but why would that change with the cars speed? Could the intercooler piping be blocked? It seems very odd that this little turbo would take so long to spool up, so if anyone has any ideas that would be great. Thanks a lot,
Phil
 

·
Banned
Joined
·
7,270 Posts
well some people say the FMIC mod adds pipework to the intake tract so it will take longer to fill the tubes. I think it wouldn't really make that much of a difference though.

Maybe there's something else going on? Maybe you have an hole somewhere - between gasketts.
 

·
Registered
Joined
·
4,222 Posts
Would the larger bore exhaust be a contributory factor? On cars with APC systems, larger bore exhausts do cause a pressure drop on the exhaust side, which leads to a laggy feeling until the basic boost is adjusted. Do you have APC? On your car, the bore of the intercooler pipework shouldn't be problematic. Is it really laggy, or does it just act like an old Garrett turbo now? :cheesy:
 

·
Registered
Joined
·
453 Posts
Discussion Starter #6
I had a set of pipes made for the intercooler so there arent any holes in it and it seems like its as short as it could be. It does kinda feel like my friends 900t with the Garrett turbo but I'm still confused why this is happening for different gears. In second gear it takes a noticebly longer time to spool up than in third gear. Im going to take the hose off the wastegate actuator and see if this changes the behavior. But Im still confused why it changes in regard to what gear I am in. It almost seems like the wastegate is bleeding off just a little of exhaust gas but once it hits 3000rpm theres enough gas to spin the turbine.
 

·
Registered
Joined
·
4,666 Posts
The spoolup will always be longer in the lower gears as there is less load on the engine. Taking till 3500 to make boost does seem a little long though, as my T3 hybrid will reach full boost before then and I have a substantially larger IC than the 9K unit.

First thing I would check is the basic boost level. Fitting the 3" DP will have increased the drop across the turbine which will have the effect of making the wastegate blow open more readily.
 

·
Registered
Joined
·
109 Posts
Im with Alex on this one - check base boost level as both the downpipe and FMIC can cause it to drop. I have the same on my car and TE05 spools from 1800 rpm and hits max at 1.3 bar at 2600. After you´ve checked base boost try adjusting p-pot. I´ve experienced apc needs to be adjusted after changing hardware. 3500 rpm is way too late for maxboost with that turbo.

cheers

Svante
 

·
Registered
Joined
·
453 Posts
Discussion Starter #10
My APC system was acting very strange so I have temporarily set up a MBC so this is all without an APC system. I will try to check the wastegate actuator but the last time I checked it was as tight as I could make, I think if I shortened it anymore the turnbuckle would not fit on the wastegate. This is Forge's heavy spring ('10-15psi' they called it) but I cant see how this would make a difference in spool up.
 

·
Registered
Joined
·
453 Posts
Discussion Starter #12
If I had the MBC backwards would this have any effect on spool up, Im going to go out and check after dinner but this is just an idea...
 

·
Registered
Joined
·
2,180 Posts
MBC's are a bit dangerous on C-900's because they have no knock protection what so ever, and if the engine is knocking, it will not pull the boost back one bit. the distributor is set at it's stages (16 deg BTDC, or retarded about 4 degrees) so it's not going to pull the timing back either.

just a word of warning, those MBC's can be hard on an engine.
 

·
Registered
Joined
·
453 Posts
Discussion Starter #15
Yes the MBC is a temporary thing until I can get this spool up problem sorted, I just thought It would be much easier to troubleshoot if I could eliminate the APC as a possible culprit. I am making sure that I dont boost any more than 12 psi to keep the engine well.
 

·
Registered
Joined
·
453 Posts
Discussion Starter #17
Alright, I wound in the actuator arm a bit and the problem is fixed. Now to get my APC back...
 
1 - 18 of 18 Posts
Top