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Discussion Starter · #1 ·
I measured the boost pressure on my '96 2.0 LPT (auto) tonight. The scale on the gauge is a bit cramped due to the fact that it goes up to 2.0 bar (I bought it for my Aero). However, it appears to show boost pressure at 0.25 bar. Being extremely pessimistic as to the precision of the gauge, I would say it is definitely between 0.2 and 0.3 bar.

This sounds rather low to me. I'll check the bypass valve tomorrow, but I'm not getting any stalling, which I would expect with a faulty bypass valve.

Does anyone have the correct boost pressure spec. for this car? It is the later type of 2.0 LPT, with intercooler and no BPC valve.
 

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Hi Bill,

I guess that youv'e already seen the answer to your question on the performance thread. Anyway, the following was posted by gadgeteer:

NB: At 3.5bar std, your's seems to be a bit low. You will get some variation between cars. Maybe you are getting some leakage from a warn dump valve, etc.

Model Years Engine Type Intercooler? Balancer Shafts? Engine Management Standard Boost
2.0 1992-1993 B202E No No Bosch LH/DI 0.45 Bar
2.0 1994-1995 B204E No Yes Trionic/DI 0.48 Bar
2.0 1996-1998 B204E Yes Yes Trionic/DI 0.35 Bar
2.3 1996-1998 B234E Yes Yes Trionic/DI 0.30 Bar
 

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Discussion Starter · #3 ·
Thanks, Paul. I had seen that, although Abbott's information is a bit suspect. They say there was no 2.3lpt before '96 but SteveN assures me he has a '94 2.3 LPT, and naturally I believe him (maybe it's a trick... ). What else have they got wrong?

I also have another report from the owner of a '96 2.0lpt that his is at 0.45 bar. Perhaps it was modified before he got it?

I bought a more accurate boost gauge yesterday (£20 from Halfords). Only goes up to 10 PSI, while the other gauge I have is an in-dash gauge (I don't connect it permanently, though) that goes up to 2 bar. Anyway, this one says I'm boosting to exactly 0.30 bar. That sounds too round a figure to be a coincidence, but I think I might whack it up to 0.45 anyway. I'm driving this one round at the moment while I do all the repairs and service items (bought it for my dad), and get a bit embarrassed at times when I know the Aero would have "whupped ass (boy)" had it not been sitting in the car park at work.

The bypass valve holds vacuum and the boost doesn't seem to vary from almost cold to fully warmed-up. I calculate I need 5 turns on the wastegate actuator rod to add 0.15 bar (0.03 bar per turn). If this doesn't bring it up to 0.45 bar, I'll swap out the valve.
 

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Bill,

Apparently, 2L ECO's (post 1994 models) are limited on boost by the ECU to 0.6 bar. Therefore, the actuator rod can be adjusted to give around 0.55 Bar without hitting overboost cut off on LPT.

I've had mine wound up to approx 0.55Bar. Increase s not significantly noticable, but add this cheap mod to a few others like performance airfilter, through bore exhaust, Optimax and it starts to add up. Unless you go for the Dawes Device or Bleed valve, to trick the ECU into enabling higher Turbo Boost that the cut off limit.

I am thinking of fitting a Boost Gauge too, and want something I can mount in one of the dash console boxes without having to damage any fascia, etc. Is there an easy way to feed the cable from the inlet manifold through to the bulkhead and lower console boxes (i.e. below radio)??
 

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Paul,

There is no "easy" way to get a tube line from the manifold to the passenger compartment, only less painful variants...

The one I would go for is to utilise the bulkhead fitting that is actually intende for the FPT route- I'm 95% it was fitted to most models.

To get at it, you'll need to remove the glovebox and look up to the right. You should see a little white plastic fitting on the bulkhead that has a boss that you can slip a tube on to. This passes through to the engine compartment and you can thus avoid having to make any holes.

Just a point of info- I'd question the usefulness for the driver of a gauge mounted where you propose. Given that most of the time you want to see what it's doing is when you've got your foot on the floor, you probably don't want your attention too far away from the road! I've added my calibrated gauge to my FPT on the dash with a surface mmounted pod adjacent to the RH speaker. Other options for keeping it in your sightline include a pillar pod.

And just a thought- if as you say

"2L ECO's (post 1994 models) are limited on boost by the ECU to 0.6 bar. Therefore, the actuator rod can be adjusted to give around 0.55 Bar without hitting overboost cut off on LPT."

and the overboost cut off you talk about is the over-pressure cut off, unless you bleed pressure from the pressure sensor, no device is going to let you go above that level.

Good luck!!

Mark
 

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Discussion Starter · #6 ·
I couldn't get mine up to 0.45 bar, let alone 0.55. The most I could get was almost 0.40 and that's as far as the rod will adjust. I changed the BPV to no effect. I don't see anything else wrong, so perhaps the actuator is weak.

It's plenty fast enough that my dad will be impressed with it and perhaps I don't want it to be too fast anyway. Perhaps someday I'll try swapping the actuator.
 

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SteveN assures me he has a '94 2.3 LPT, and naturally I believe him (maybe it's a trick...[/b]
Also know two guys with identical '94 models.

Are we saying here I can increase the boost by 0.15 bar by turning the locknut on the actuator rod and be within my ECUs safety limits? I'm still thinking about uprating the actuator to a stiffer springed one and maybe .45 bar.
 

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Discussion Starter · #8 ·
Thanks, Paul.

2L ECO's (post 1994 models) are limited on boost by the ECU to 0.6 bar. Therefore, the actuator rod can be adjusted to give around 0.55 Bar without hitting overboost cut off on LPT[/b]
Could this be "post 1995 models", as I know the 2.0LPT changed significantly between '95 and '96. My '95 CSE 2.0LPT has a BPC valve and no intercooler while my '96 CSE 2.0LPT has an intercooler but no BPC valve.

Therefore, the actuator rod can be adjusted to give around 0.55 Bar without hitting overboost cut off on LPT[/b]
My '96 can't be adjusted to give more than 0.4 bar. Nothing to do with the cutout, all to do with the available adjustment on the actuator rod.

What year is your car? An Anniversary would be '97 or '98, yes?
 

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Thanks for the info on routing the Boost tube, Bubbles.

Bill J, mine is a 98 Anniversary, although made in 97 according to the registration docs, etc.

I am surprised that your 1995 CSE has no intercooler. My understanding was that the pre 94 models had no intercooler and the 94 onwards variants of 2L ECO's all had intercoolers.

My turbo boost was adjusted via the wastegate actuator by a Saab main dealer, who advised that there was normally no problem winding up to the 0.6 bar ECU boost limit. Haven't tried it on earlier models though.
 
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