26 replies to this topic

[Mozen]

Hi dear forum friends!

We got a new consultant mechanical engineer at work, He used to work for Saab in the engine tuning department in Trollhättan Sweden.
He told me that when Saab planned for their new Saab 93 Aero, I think it was launched in 2006, they considered to use the Z20LET/Z20LEH engine. They ended up using a 2.8t V6 engine instead for that car.
(The engine block of our Ecotech Let engine is also used in Saab 93.)

Saab requirements for an engine were different compared to Opel/Vauxhall. Saab required a minimum of 100000 UK miles or 10 years without breaking down in their heavy load engine test rig while Opel/Vauxhall requires only 60000 for the same test setup.

In their test rigs the Saab engineers could only push the power of the Z20LET/Z20LEH up to 240 BHP while meeting their requirements. The problem were not the engine block itself or the turbo. Instead it was other internals that could not keep up with the temperatures generated under heavy load. Due to the safety margins Saab uses that meant that they would not be able to use more than 210 BHP in a commercial car with this engine.

This engineer recommended me to use an oil catch tank (which acts as a oil cooler and oil is always available in the oil pan for the engine) and consider upgrading internals for higher outputs if I would push it passed 240 BHP. Of course only if you want the engine to last longer than 60000 miles.

Another option is to use a full Saab engine instead like the guys at Swedish Trollspeed is building, 600 BHP, 442 lb/ft (600 Nm)
http://www.garaget.org/?car=88131

Do you have other knowledge/experience about this?

Edited by Mozen, 14 February 2012 - 11:49 PM.

[techieboy]

Can he get any data on the B207R engine? Would be interested to know what Saab themselves think the rods, pistons, liners, etc are capable of supporting.

[FLD]

Can he get any data on the B207R engine? Would be interested to know what Saab themselves think the rods, pistons, liners, etc are capable of supporting.

[Mozen]

Can he get any data on the B207R engine? Would be interested to know what Saab themselves think the rods, pistons, liners, etc are capable of supporting.

I will ask him!
I can't get an answer until next week due to travel though...

[techieboy]

Thankyou.

[Winstar]

In their test rigs the Saab engineers could only push the power of the Z20LET/Z20LEH up to 240 BHP while meeting their requirements. The problem were not the engine block itself or the turbo. Instead it was other internals that could not keep up with the temperatures generated under heavy load. Due to the safety margins Saab uses that meant that they would not be able to use more than 210 BHP in a commercial car with this engine.

This engineer recommended me to use an oil catch tank (which acts as a oil cooler and oil is always available in the oil pan for the engine) and consider upgrading internals for higher outputs if I would push it passed 240 BHP. Of course only if you want the engine to last longer than 60000 miles.

Another option is to use a full Saab engine instead like the guys at Swedish Trollspeed is building, 600 BHP, 442 lb/ft (600 Nm)
http://www.garaget.org/?car=88131

Do you have other knowledge/experience about this?

The LET and LEH are quite different. The LEH has stronger pistons and oil spray cooling jets to combat the heat at higher power level (my friend was the development engineer on the upgrade and i did the calcs to see if the LET oil pump had enough flow).

However it doesn't matter as the heat is only a problem when you need to meet the strict euroIV emissions to meet the emissions for our MOT's you can map the engine to run cooler and protect the pistons

[Mozen]

In their test rigs the Saab engineers could only push the power of the Z20LET/Z20LEH up to 240 BHP while meeting their requirements. The problem were not the engine block itself or the turbo. Instead it was other internals that could not keep up with the temperatures generated under heavy load. Due to the safety margins Saab uses that meant that they would not be able to use more than 210 BHP in a commercial car with this engine.

This engineer recommended me to use an oil catch tank (which acts as a oil cooler and oil is always available in the oil pan for the engine) and consider upgrading internals for higher outputs if I would push it passed 240 BHP. Of course only if you want the engine to last longer than 60000 miles.

Another option is to use a full Saab engine instead like the guys at Swedish Trollspeed is building, 600 BHP, 442 lb/ft (600 Nm)
http://www.garaget.org/?car=88131

Do you have other knowledge/experience about this?

The LET and LEH are quite different. The LEH has stronger pistons and oil spray cooling jets to combat the heat at higher power level (my friend was the development engineer on the upgrade and i did the calcs to see if the LET oil pump had enough flow).

However it doesn't matter as the heat is only a problem when you need to meet the strict euroIV emissions to meet the emissions for our MOT's you can map the engine to run cooler and protect the pistons

We mainly discussed the Z20LET, my misstake since I did not now that the internals of those two are different, I thought only there were external differences. It makes sense that you can get higher power out of the LEH engine in that case.

I stick to my earlier statement, with minor adjustment, that if you want to get more power out of your Z20LET engine than 240 Bhp it is recommended to do something about oil cooling and preferable upgrade critical internals, like pistons, instead of only changing turbo and intercooler.

[Mozen]

I understand what you mean with tuning the engine to run cooler, as example by increasing the fuel/air ratio so that some extra fuel is actually used to cool down the engine at high rpm. Still I am unsure how much resources companies like Courtenay has in terms of developing those tuned maps in order to ensure longevity of the engine in relation to performance. What do you think Winstar? Perhaps they have guys like you onboard which would help me to sleep better at night?

[FLD]

Humpty bumpty re B207

[tozey]

My VX is running at least 240 brake and is currently on 70k miles.and it was put to 240bhp by previous owner at under 10k miles, although it appears i may have a cracked turbo manifold, but hey so do a lot of standard Astras. Not sure what my point is here really, except that maybe its OK. And if you want monster power your not going to be surprised if it goes pop.

[snoopstah]

I don't pretend to know anything about how these things work, but it seems to me that a lot of it would depend on the conditions of the 'heavy load engine test'. If I was doing it (and having absolutely no experience, that's pretty unlikely!) I would be looking to exercise the engine in a realistic but worst-case scenario, as this is presumably used to estimate reliability, and hence likelihood of warranty claims and customer satisfaction levels. In the case of Saab, that would presumably involve testing with an ambient temperature as seen in their hottest sales regions, and with an engine load that would simulate a load being towed (as Saabs are commonly used as tow cars). The VX on the other hand, being extremely light-weight, seems to me unlikely to experience the same level of engine load. Bear in mind that a well-tuned VX on stock engine internals will reach 100mph in less than 8 seconds of WOT, it seems that for road use or even reasonable track use, the duty cycle of the engine is likely to be a lot less than a 'heavy load engine test' on a family estate car that's designed for towing. Unless you are using the car solely to do flat-out laps of the Nurburgring on the hottest days of the year, it's quite possible you'll never get close to the conditions Saab were simulating. As I say, this is quite possibly complete rubbish, but it seems unreasonable to me to extrapolate engine life-expectancy in the VX based on how the engine behaved when being tested by a manufacturer expecting it to work in a car weighing twice as much, rated to tow a further 1500+kg, and who sell their cars in places like the Middle East.

[tozey]

Actually i think what you just said sounds pretty bang on!

As I say, this is quite possibly complete rubbish

[fezzasus]

snoopstah has pretty much nailed it here. The severity that engines are tested at for development are much, much higher than the severity that would ever be experienced in the field. I can't disclose any exact test cycles but the general theme with all of them is high load, cycling revs and thermal shock over a massively long time period. Even a VX intended just for tracking will not get close to the load and thermal shock imparted on these engines. The logic behind the work is very different too; car manufactures want to ensure the engine is protected in every situation (extended servicing intervals, high load carrying, poor fuel quality) and will build in tolerances to ensure they don't get close to the edge, because the damage by warranty claims and bad press would be massive. Someone tuning their own engine is more likely to run it on good quality fuel, and ensure it is serviced regularly. Worse case, if they cause their engine damage they have no one to blame but themselves, and it cannot be linked to the manufacturer.

[nicollow]

Someone tuning their own engine is more likely to run it on good quality fuel, and ensure it is serviced regularly. Worse case, if they cause their engine damage they have no one to blame but themselves, and it cannot be linked to the manufacturer.

Hahaha, Id love someone to go to Vauxhall: "I tuned my VXT to 290bhp and its now blowing oil slightly!! I want someone to sort this out under warranty straight away!!"

Agree with pretty much all of the above

[Mozen]

I discussed the topic with our "Saab consultant" again. We both agreed that if you can disregard environmental aspects you have much more freedom to ensure a long life of the engine. As you stated the tests they make are mainly performed to ensure not to get any warranty clams etc. Saab also pushes their brand as a manufacturer of cars with high engine reliability. I asked him about the B207r and tuning capabilities. He said that that this is mainly the same engine as the 1.8t engine. The main difference between the 2.0 and 1.8 is the programming timings. The named 1.8 engine is actually a 2.0 engine. He said, also for the B207r, they found that it could not handle more than 240 Bhp. It was actually in a worse shape after test completed compared to the Z20Let when tuned for higher power outputs. Instead he recommends the B235R engine to get a reliable high performance tuning. (A budget version can be to use the B234 or B204 engine. I think he said the heads are different depending on model year. These engines can be converted to B235R engines.) Hirsch get 305 Bhp out of this engine without changing any internals. This is with warranty remaining. The guy who built the concept car for Saab Hirsch is a close friend of my “Saab consultant” and an old Saab engineer (http://iamotorcenter.se/). The concept car had ~350-360 Bhp reliable horse power. One issue with this concept car was that the components had to be relocated to get the correct air flow around them etc. This was too much for Hirsch since they would have to charge additional four thousand pounds only to relocate all the components. Instead they settled with the lower 305 Bhp. With this engine you only have to ensure that the engine breath well, air flow in and out of the engine and you can most likely get it reliable upwards 350 Bhp with our light cars. My consultant colleague also suggested that we use the Mitsubishi Turbo from the Saab 9-5 Aero rather than the Garret turbo. The reason is that Saab found that the Mitsubishi turbo is much more reliable with higher boost. Standard the “heavy” Saab 9-5 Aero, with Mitsubishi turbo, has 260 Bhp but the turbo is capable of much more. The Garret tends to crack on the exhaust side. Of course you have to remap the ECU. Let me know if you have other questions. Please remember that I am only the messenger, don’t kill the messenger.

[FLD]

Thanks for this, we appreciate your efforts!

[NickB787]

Thanks for this, we appreciate your efforts!

Thanks

[FLD]

Can I ask specifics around the B207 please? I suspect the 240bhp limit is down to the rods. Obviously a lot of us are looking to the saab block with its piston oilers and different oil cooler design for use with new rods / pistons etc. I'd be interested on finding out more about the block if that info is available.

[techieboy]

When I spoke to Maptun (never got an answer from Abbot), they reckoned the first limitation was the pistons themselves at a little north of 300bhp. From memory their 315bhp conversion needed required new pistons but rods were fine. Obviously this is all in relation to the engine being turbocharged and not supercharged.

[Mozen]

Can I ask specifics around the B207 please? I suspect the 240bhp limit is down to the rods. Obviously a lot of us are looking to the saab block with its piston oilers and different oil cooler design for use with new rods / pistons etc. I'd be interested on finding out more about the block if that info is available.

When I asked him about more specifics about the B207 he said that I would be better of if I called his friend. Is there some of the Swedes who lives close to Lidköping and can ask him? Otherwise I can of course make a phone call.

Some things I missed if it is unclear.
The B235R engine is the 2.3 liter engine.
The Mitsubishi turbo is used in "all" Saab with higher outputs, at least in those with more than 220 Bhp, also for example in the 9-3 black turbo edition etc.