Petrol 2wd TURBO tech

[isuzurover]

I recently acquired a saab 900 turbo (only my 2nd non 4x4 ever).

It has a 2.0L, redline 6000 rpm. Mitsubishi TE05-12B turbo (Garrett T3 flange) oil/water.

The car is a rocket at high revs, but the turbo does nothing below 2500 rpm. I am thinking a VNT might be the go... Any recommendations???

http://www.nysoc.com/albums/album43/P0011582.sized.jpg

[Dougal]

VNT's don't seem to like petrol engines. Chrysler did it 25 years ago and then no-one else touchd them.
Porsche finally did it only a few years ago.

A more modern BB turbo would be a good upgrade. But most petrol's are turbocharged for top-end power rather than low-mid range. A better BB turbo will wake up sooner but beyond that anything you do to get more low end will reduce the topend.

Are you okay with that?

[justinc]

Ben,

Saab have put a long time into research and Development, and depending on whether your 900 is an early model with KJET or later model 16V with L jetronic injection,(What year is it?) depends on the possibilty of modifying for more output. Saab have attached a lot of in built engine protection to their later EFI engines, the B204 (2litre) and B234 (2.3litre) are easily capable of 400 to 500,000kms, in turbocharged form. They do this with knock sensing and boost / ignition control, and it is very good at conserving engines. I would say that adding a VNT will upset the factory management to the point that the ECU will take over and bleed off early 'detonation causing' boost and advance as this is what it is designed to do. I would look into the addition of a megasquirt, Haltech, Motec or Wolf system to overcome this. Then yes it is a very good idea fitting a VNT as long as careful mapping is employed. Water injection will work well, as will a larger intercooler and you'll obviously have to use a high octane fuel.

Good engines, pretty well unbreakable actually:)

JC

[isuzurover]

Dougal - for overall driveability around town, I would be happy to lose a bit of top end.

It seems some of the saab guys have been playing with VNTs...
https://www.aulro.com/afvb/images/imported/2010/05/1102.jpg

JC - it is the 2.0 16V. As you say the APC system is highly advanced, however the turbo boost control is fairly simple, and should be able to work with a different turbo.

It seems though, from reading on the saab forums, that either the (unumbered) boost guage on mine is reading incorrectly, or my turbo is not working 100%. I will make sure the turbo and APC system are working as they should first.

[Bigbjorn]

They are very good cars but need a lot of maintenance, done on time, and preferably by someone who knows them well.

Eff all resale value once a few years old like most of the complex and maintenance heavy Euros.

[Dougal]

Dougal - for overall driveability around town, I would be happy to lose a bit of top end.

It seems some of the saab guys have been playing with VNTs...

Got any more info on that turbo? Looks like a wastegate and VNT actuator on the same unit?:eek:

BTW if you want to experience the opposite turbo petrol experience (small turbo that's always working) go for a drive in a VW 1.8T. Sadly the one I got to drive was auto, manual would have been waaay more fun.:angel:

[isuzurover]

Got any more info on that turbo? Looks like a wastegate and VNT actuator on the same unit?:eek:

Not much:
Possible newb questions? - SaabCentral Forums


They are very good cars but need a lot of maintenance, done on time, and preferably by someone who knows them well.

Eff all resale value once a few years old like most of the complex and maintenance heavy Euros.

Fortunately this one has been regularly serviced by a saab specialist. It has been very reliable so far (for me and the PO, who is a mate). And the price I paid can't sink much lower!

When new they were comparable to a 911. They are a very nice car to drive, and apparently had more output than the claimed 185bhp.

[Dougal]

They are very good cars but need a lot of maintenance, done on time, and preferably by someone who knows them well.

Eff all resale value once a few years old like most of the complex and maintenance heavy Euros.

Didn't know landrover owned Saab.:eek:

[isuzurover]

Didn't know landrover owned Saab.:eek:

lol.. :D


Btw - the guy had the turbo "made specially", and doesn't know which model VNT it is based on. It seems an interesting idea though, the Saab APC system still has full control...

[Dougal]

lol.. :D


Btw - the guy had the turbo "made specially", and doesn't know which model VNT it is based on. It seems an interesting idea though, the Saab APC system still has full control...

Presumably the wastegate would be to cut out boost spikes. No problem on a diesel but leaning out a petrol can be disastrous.
Let us know how he gets on.

[isuzurover]

Presumably the wastegate would be to cut out boost spikes. No problem on a diesel but leaning out a petrol can be disastrous.
Let us know how he gets on.

The saab has a fairly nifty system for boost control. The standard wastegate setting is very low (e.g. 4psi). There is then a system to bleed off pressure in the wastegate actuation line, to increase boost, provided the knock sensor etc report all is well...

https://www.aulro.com/afvb/images/imported/2010/05/1063.jpg

The APC controller also has various ramp functions built in for the rate at which it will allow boost to increase or decrease under various conditions.

[abaddonxi]

Lovely cars, Saabs, but woeful offroad.:angel:

[isuzurover]

Lovely cars, Saabs, but woeful offroad.:angel:

They make quite good rally cars though...
https://www.aulro.com/afvb/images/imported/2010/05/1061.jpg

[abaddonxi]

Large component of driver error in my case.

[Dougal]

The saab has a fairly nifty system for boost control. The standard wastegate setting is very low (e.g. 4psi). There is then a system to bleed off pressure in the wastegate actuation line, to increase boost, provided the knock sensor etc report all is well...

I think nissan do the same. I've never owned one but their turbo petrol cars have a solenoid in the wastegate line.

[isuzutoo-eh]

I've been talking to a friend about these turbos, he loves his 900 turbo, for my 4BD1. I know basically nothing about turbo-ing engines. Would this knock sensor system be effective in a diesel engine? I can probably get the saab bits for cheap.

[PhilipA]

As mentioned by one of the er "British" posters, I have found a lot of low end to be gained in petrol turbos by freeing up the exhaust immediately out of the turbo.
I had a Charade turbo (don't laugh now) and a Porshe 924 Turbo , and my son a Cordia Turbo . I am pretty intimate with turbos ( and Dynamic Turbos Ltd) as a result.

I had a great low down gain from a large contoured dump pipe from the turbo instead of a right angle bend they had into an empty cat housing (84).

My son also gained quite a bit from a boiler tube exhaust manifold into the turbo in his 84 Cordia pre emission which was FAST. BUt they usually are buggers of things to fit as they often don't allow for such things as actually bolting the turbo on the flange.LOL.
Both will help with quicker spool up but not increase waste gate pressure.
Regards Philip A

[isuzurover]

Would this knock sensor system be effective in a diesel engine? I can probably get the saab bits for cheap.

Diesels are less sensitive to knock than petrols. Knock in diesels is unlikely to (rapidly) destroy an engine like it will in a petrol. It is unlikely that a petrol knock sensor would work in a diesel due to the diesel "clatter".

On top of all that, extra boost (in general) in a diesel will reduce EGTs, whereas extra boost in a petrol (without sufficient fuel), will increase EGTs.

In short, turbo diesels and turbo petrols are very different.




As mentioned by one of the er "British" posters, I have found a lot of low end to be gained in petrol turbos by freeing up the exhaust immediately out of the turbo.
I had a Charade turbo (don't laugh now) and a Porshe 924 Turbo , and my son a Cordia Turbo . I am pretty intimate with turbos ( and Dynamic Turbos Ltd) as a result.

I had a great low down gain from a large contoured dump pipe from the turbo instead of a right angle bend they had into an empty cat housing (84).

My son also gained quite a bit from a boiler tube exhaust manifold into the turbo in his 84 Cordia pre emission which was FAST. BUt they usually are buggers of things to fit as they often don't allow for such things as actually bolting the turbo on the flange.LOL.
Both will help with quicker spool up but not increase waste gate pressure.
Regards Philip A

Thanks Philip, The dump pipe and start of the exhaust seems quite large and free flowing. However I will see what can be done further.

[isuzutoo-eh]

Thanks Ben, i'll cross that set up off my list. Sorry for the hijack

[LandyAndy]

Recently had to chase Ben accros the city to pick up my prawns in peak hour traffic.
Dont like city driving at the best of times,but a chipped D2TD5 was more than up to the chase.Nobody got between us:twisted::twisted::twisted:
Nice buy Ben,didnt get around to talking about the SAAB.
Andrew

[isuzurover]

Recently had to chase Ben accros the city to pick up my prawns in peak hour traffic.
Dont like city driving at the best of times,but a chipped D2TD5 was more than up to the chase.Nobody got between us:twisted::twisted::twisted:
Nice buy Ben,didnt get around to talking about the SAAB.
Andrew

I was driving slowly so you could keep up Andy ;)

The saab has a 0-100 time about half a stock td5 disco...

[LandyAndy]

Mine aint stock:p:p:p:p
But she isnt no boy racer either.Can win the traffic light GP easily if one is in a hurry,not my driving style.
Andrew

[isuzurover]

Mine aint stock:p:p:p:p
But she isnt no boy racer either.Can win the traffic light GP easily if one is in a hurry,not my driving style.
Andrew

Yeah, I try to drive sensibly as well - if only to avoid the donations to the police charity ;)

The saab will do ~8s 0-100 and 16s quarter mile stock (which mine still is) and has a top speed of 125 mph.
I recall the fastest time for a stock TD5 is around 15s 0-100, and a top speed of ~100mph?

So if you have double the stock power, and/or I have 50% of mine, then we would be evenly matched. But of course the disco goes much better offroad - or with a load of firewood on!

[LandyAndy]

Mate if I realised that you were going home again after the prawns,you could of had the pleasure of driving her thru the city and back!!!!
I reckon you would have enjoyed the task!!!
Love the sound of Tombies TD5 VNT upgrade 208HP:eek::eek::eek:
Andrew