LPT Vs "Normal" turbo on a 900 classic

I don't think LPT was offered for the classic 900. What part of the world, and do you have a specific car (which year) in mind, or is this more of a general background question?

Dave Hinz

in article dgvoc.99$V44.95@newsfe1-win, Ash at ash snipped-for-privacy@hotmail.com wrote on

12/05/2004 20:53:

Hi Ash,

Simply put, the LPT boosts up to around half a bar of boost - hence, Light Pressure Turbo. The LPT is only an option with the 16V models - the full turbo models could be 8V or 16V, usually referred to at the T8 and T16 models around these parts.

The "normal" turbo will boost higher (typically 0.6? bar for the T16, 0.75 bar for the T16S/SPG or 0.85 bar for the Carlsson/Ruby models) and has the benefit of the APC system, which can be regarded as an electronic boost controller. The theory is, APC will provide the optimum performance for the car given the vast number of variables - ambient temperature, air pressure, fuel grade, etc. It is an excellent knock protection system. LPT cars do not have this.

APC is well worth it, but I've not heard anyone grumble about their LPTs. They're different cars and each have their merits - both are very customisable. Take a look at

for wads of informationabout the APC system ... And tuning it :) Paul

1989 900 Turbo S

in article snipped-for-privacy@uni-berlin.de, Dave Hinz at snipped-for-privacy@duck-creek.net wrote on 12/05/2004 21:01:

- look at MY1990 :) They're the Mitsi turbo without APC - the turbo is controlled traditionally by the wastegate actuator that simply takes a pressure from the turbo, or manifold.

Paul

Hm, I'll be darned. Never run across one of those, maybe not for the USA'n market?

Dave

in article snipped-for-privacy@uni-berlin.de, Dave Hinz at snipped-for-privacy@duck-creek.net wrote on 12/05/2004 21:09:

Yeah! I doubt a "balance between performance and fuel economy" would've gone down well over your side of the pond :)

Over here, they're very popular among Saab tuners. They can be upped from

145 BHP to around 185-200 BHP pretty easily. Just wind up the wastegate actuator and add an intercooler. As you can imagine, the engine bay is pretty sparse, so there's loads of room in there for intercoolers, water injection systems, etc. I know of some that have had APC (or parts of it) grafted in to monitor knock via a dash mounted LED (pin 19 on the 25 pin box IIRC). Knock is thus controlled by the foot! I would regard full APC as the better option for uprated models, but ...

Paul

Then read this first;

Yes it was! A friend has a 16v 900S (LPT - Low Pressure Turbo) there is no intercooler or boost guage I have an 8v 900T (FPT- Full Pressure Turbo), is has an intercooler, a boost guage and APC (Automatic Pressure Control).

------ MH '72 97 '77 96 '78 95 '79 96 '87 900T8

Thanks all for the info. So i guess the LPT has less Umph then the FPT?

What are your thoughts on this...

1990 Light Pressure Turbo 145bhp 1991 Light Pressure Turbo AERO 145bhp source "SAAB 99 and 900 The Complete Story"

Here in Japan, LPT had been sold between 1992 and 1993 in the name of

900S. At the time, in Japan, the 900 line-up was as below.

"900I(normal aspiration)":125hp "900S(LPT), 900S cabriolet":145hp "900turbo(HPT),900turbo cabriolet":165hp "900turbo16S(HPT), 900turbo16S cabriolet":165hp with special suspension

900turbo16S seems almost correspond to SPG in the States. All models are controlled by not BOSCH ECU but LUCAS ECU, and this line-up is basically the same as Europe one.

The boost of LPT is limited to 0.45bar without APC or intercooler but the other parts including ECU are common to the "normal" turbo except the "over pressure switch" that cuts the fuel at 0.6-0.7bar in 900S but

0.9-1.0bar in 900turbo. At first, you must be able to install easily the intercooler and piping into your 900S without any special adjustment. The problem is the APC. The APC seems to be also installed but it is not so easy. The easy alternative is EVC (a kind of boost controller) by HKS or any other manufacturers, though I am not sure you can get this device out of Japan. The EVC has the almost same machanism as the APC (in other words, the APC is the original and primitive model of the EVC) except the knowking sensor, but can control the boost more quick and linear than the APC and you can set the boost level up as you like.

The boost of 900turbo without any tuning is limited to 0.9-1.0bar as I mentioned above, but in actuality it boosts up to about 0.7bar at most under the good condition. So you might be able to feel more power than 900turbo by the EVC's quick response even if you set the 0.6bar boost considering a little overshooting. If you want over 0.7bar boost, you must adjust or replace the overpressure swith for 900turbo (you can make an access to the part by removing the under panel from driver's side at left handled car). If you want over 0.9-1.0bar boost, though I do not recommend considering the total and sure balance, you must resolve the problem of knocking (EVC does not have knocking sensor) and need total tuning including the fuel system etc.

One more important thing forgot. I recommend you introduce a turbo gauge for monitering the boost exactly.

Looks really nice, and has an Aero kit as well. It is very similar to the one my friend has - a 1992 or 1993. He paid around

10000 euro for it, Italian import into NL. Looks like UKP1700 is a bargain but there are 5 more days to go.

-------- MH '72 97 '77 96 '78 95 '79 96 '87 900T8

"MH" skrev i en meddelelse news:c7u2dc$31l$ snipped-for-privacy@news2.tilbu.nb.home.nl...

APC = Automatic Performance Control

Just to clearify. ;o)

M.v.h.

OK, my owners manual (in Dutch language) is not clear on that. In the APC section it only mentions 'turbodruk regeling'.

mvh Martin H.

----- MH '72 97 '77 96 '78 95 '79 96 '87 900T8

in article 4rwoc.114$V44.68@newsfe1-win, Ash at ash snipped-for-privacy@hotmail.com wrote on

12/05/2004 22:13:

To be fair, it seems a little high for an LPT without body kit and no leather. That said, it's in great condition - black is a bad colour for keeping shiny. If it's pristine otherwise, it might well be worth it - you can source leather interior and the Aero bodykit for scappers.

My 0.02 UKP :)

Paul

1989 900 Turbo S