rrett t3 turbo

Hi i have a 1990 saab 9000 cd 2.0 turbo with a garrett t25 turbo on it can i run the t3 after the t25 so it wll be twin turbo the t25 will be the lowend and the t3 will be the highend boost. or is it better to just run the t3

and where can i get a good t3 turbo

Reply to
es
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Best to leave it as it is. A bigger turbo will have bigger turbo lag.

Reply to
Johannes

Do you have any idea what would be involved in doing this?

More to the point, do you know how crap the car will drive if you do this?

Reply to
Grunff

yes i do know what i need to do to do ths and i think if i just go with the t28 turbo is will spool up fast and will have good topend too

i just hate how the turbo feels like its not there after 2nd or 3rd gear

Reply to
es

It should drive pretty well, just more lag. I've got a car with a T3 and like it, though it's not a 9000.

Reply to
James Sweet

No, I'm referring to "can i run the t3 after the t25 so it wll be twin turbo". It would not drive well.

Reply to
Grunff

Agreed Grunff.

If someone really wanted to go twin turbo - you might get away designing a custom split header and IC intake so that one turbo spooled up earlier than the other and then didn't back flow into the smaller turbo.

To do this - you would really have to do some heavy work on which pair of turbo's you would need to pull it off. T3 and T25 wouldn't be it. Personally, I think you would want to match a smaller pair that simply had different boost controllers for the same affect.

You would then have to custom chip all the computer controllers from fuel rates to waste gates to account for the higher rates of pressure so as to stop the car from cutting back ignition to account for what it would perceive as being an over boost situation. You would need to build some sort of airflow kit to bleed off the extra heat under the hood too.

Common wisdom on the greater problem is to swap out the intake cam with a

2.0 N/A intake cam (which is claimed to increase lower end torque in turbo engines). Go with a 3 inch exhaust system from the turbo flange to the tailpipe, changing out the turbo after talking to Maptune about which chip and turbo to accommodate the new curves. This will impact total top end - but - will give you earlier and stronger boost through anything to 110mph.

Personally - I think you might be better off simply going with a fresh stock turbo, a more open exhaust, bigger IC and new chips first (don't forget to pull the AC unit) - and then see where that takes you.

Be warned, there is *a lot* of kit on both sides of the crank stubs that needs uprating as befits your engine modifications.

Reply to
Dexter J

designing a

earlier

simply had

(don't

OK i think i will go with the one i got right now and just 3" down pipe. will it be better if i get the intake manfoled from the newer 2.3 turbo saab 9000 engein. where can i get one of thoes and i have a M boost controler right now what do u guys think i should run for psi im at 14 right no. i heard it would be better if i run the fiul presher regulater from a non turbo saab is that true. i just wont to have a better topend on the car what is the best way to do this bcs the lowend is really nice as is. later when i get the t28 in there it should be really nice does enyone know where i can get a good t28

THANKS

Reply to
es

I'm not sure we are on the same lines here.

Top end on a stock SAAB turbo is well and above *anything* you will ever likely use unless you live in a place that doesn't issue 'reckless endangerment' tickets or are retiring the machine to racing exclusively.

If you are simply looking for more total boost - and you are not Trionic under the hood - get a manual boost controller and dial back when the waste gate opens.

I believe your stock turbo is good for the better part of 19 or 20 psi. But - and this is very important - your engine management computer will cut off fuel when it senses the inevitable engine knock this will cause (the car will 'buck'). And let me assure you, the stock SAAB engine protection system (the chip) is very conservative in this regard..

You can get a feel for this by removing one of the BPC controller hoses to the waste gate - which will allow your car to boost well above the noted red-line on the dash. Hit

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for details - beware you can easily still blow up your turbo/engine if you are not very careful when you do this.

The real strength and objective of the SAAB Turbo is to provide much quicker 40-90mph acceleration rates (or more accurately - 2,500 to

4,000+ rpm rates) without eating the pistons as would normally be the case in manually controlled Turbo systems. For whatever it is worth knowing, basically, when you pull out to pass in a stock SAAB turbo in good working order - you are making roll on acceleration rates that are competitive with Ferrari.

Where most folks have trouble with turbo systems (SAAB or otherwise) is the spool up (or lag) when they plant their foot. This is overcome in 5 speed cars by downshifting - then planting the foot while turbo inertia is already overcome. You can also do the same thing by spinning up the turbo before dropping the clutch at start up. This, however, is not a wise thing to do in a 9000 as it tends to eat transmissions pretty quickly. You can pull it off in an automatic as well - but you will eat the transmissions even more quickly.

This is where different kinds of Turbo's do different things. Bigger, thereby heavier, turbo units take more time to spool up - but can provide higher total boost pressure without wearing out too fast. Smaller Turbo's provide less total pressure - but spool up faster without wearing out too fast.

Hence, while your total boost on a Low Pressure Turbo (LPT) is lower - the effect is that the Turbo delivers more 'tractable' power more quickly from lower RPM ranges. It feels very much like you always have two extra pistons under the hood without the lame timing belt problem. However, it also feels like you are pulling more weight when you are driving given lower total pressure.

In my Aero - I have the larger turbo (and several other factory issue controller uprates) which should safely top out in the 225hp range. But I also have some evident lag, I have to wait a moment for the power to come fully on. To use the Turbo to it's full effect - I would use the driving techniques outlined above if I still felt the need to impress the kids. Which, oddly, I don't anymore now that I have the Aero. Life is odd that way I suppose.

Anyway, - mostly I use the turbo to avoid hill climb downshifts (I wait) - or to make a quick pass (I downshift) - or to blow up on ramps (just for the fun of leaving the Corvette or Mustang or Bling-Bling'd Rocket behind me wondering if something has gone terribly wrong under their hood). I'm also planning to take up slalom racing again - which is mostly just for the relaxation.

So, if you are looking for better overall start-up acceleration without going to a smaller turbo - you open up the exhaust to 3 inches (and not just the down pipe - you have to work all the way out to the end of the exhaust system) and you should look at a better air-filter. You remove the AC condenser so that the stock IC doesn't heat up as quickly - or - you remove the AC condenser AND put a larger IC in to keep it even cooler. Everything after that on the intake that is more than ample to deal with the more rapid increases in pressure (assuming you have an intake system in good working order - no rotten rubber or dried out seals).

Next step is to talk to Maptune for a better chipset. Once you have decided on the chip - go with the recommend turbo for the chip. You will be uprating your injectors and fuel regulator accordingly to avoid lean out (ping/knock) - which will kick in the engine protection system at exactly the wrong time.

Finally, you will be looking at a better clutch and very likely a transmission rebuild - go with a really serious builder on the latter item if you are breaking into the 250+hp range. You will also want to look at what is attached to the drive pulley on the other side of the engine (water pump, power assist items) - because they will suddenly be operating in sharper curves than they have been.

For example, a lot of folks seem to start blowing their cabin heater core after a serious uprate. Is this just age or more rapid changes in pressure? I'm not sure, but it makes sense that some attached systems are rated for certain parameters if you think about it.

My personal take is that there are truly monster figures to be pulled out of the SAAB Turbo without nearly as much work as you would have on most other brands. On the other hand - the great appeal of the SAAB Turbo is that it pulls very respectable figures *safely* without a lot of work. The trick, at least how I will probably go, is to *gently* uprate the overall car to better apply the power it came with.

Provided with all the usual disclaimers and limitations.

Reply to
Dexter J

Ah, yeah twin turbo is not quite so simple, most guys I know who've had sequential turbos converted them to a single turbo as soon as something went wrong.

Reply to
James Sweet

I haven't checked on a Saab, but generally when it bucks like that, it means there's a simple overboost pressure switch which cuts off the fuel pump, it's got nothing directly to do with knocking. Can't be good for the engine to hit that often either.

Reply to
James Sweet

On older C900 or 99T's - I think you might be correct, but don't actually remember.

However, I'm pretty sure all 9000's cut out based on knock and/or resistance. It's tied into the Trionic system that adjusts for different fuels on later models. On pre-Trionic 9000, its tied directly to the knock sensor with feedback from the ignition coil (I think). It is all interpreted by the main engine computer in both cases.

In my 1989CD model - the system was cutting out fuel because of a problem with the distributor. It would start arcing (missing) at higher RPM - which was interpreted as knock by the system, at which point it would start *violently* bucking. In my 1993 Aero - I'm sort of locked into base boost for the moment (cruise control problem we think), so I've not been able to run it into cut-out as yet.

Perhaps next weekend if everything goes as hoped this week.. :) ..

There are several interesting posts floating around regarding certain kinds of engine noise (timing chains - oil pumps) that can trigger a fuel cut out because of the internal block harmonics involved.

Personally - I think it's a better (if more annoying and limiting) system overall. By interpreting sound and/or resistance - you can cut or adjust fuel rates for many reasons and much more quickly. 2,500RPM means that any lean or rich condition you are experiencing may be happening 41.6 times a second. Sound and electrical resistance is a better way to gauge this if you ask me.

In a purely over boost based system - you can simply change out the switch to change the cut out. In the CPU governed system - you adjust all the parameters so as to allow for when the cut out happens. Same thing really

- just different triggering sensors and greater latitude.

The SAAB system allows for changes in fuel octane rates, altitude AND boost because it can adjust the ignition curve and fuel rates slightly depending on feedback from a couple of systems. Cut out is the last stop along the line.

Works too - I honestly do get better mileage on higher octane fuel with Trionic than I do on pump regular, but I loose performance as I move down the pumps. The same was true of the 1989CD - except that it worked on mid-grade instead of high-test.

If there is any serious complaint on my part, it is that the software controlling the Trionic 5 system is essentially closed source (no OBDII for us). Although, by Trionic 7, I think it is fully OBDII compliant.

Reply to
Dexter J

right now i am running a turbo xs manual boost controler (its the dual stage one) and it i working really nice but do u think i should just go with the apc.

what should my stock boost psi be ?

what do u think my engein can handle safly for psi?\

Reply to
es

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