Your probably sick of this Question

[buckejit]

Hi Everyone,

I have just converted my 2001 Saab 9-3 2.0t HOT, £1150 Stag 300-4 with Flash Lube (Its got 110k on the second engine as the last owner who has had it from new stopped getting it serviced properly and it slugged up and blew up the engine ( That taught them a lesson I bet) The car actually has 180k on the clocks and she is still a solid as a brick..









Anyhow I have just done a few calculations. I do a 70 mile round trip a day to work and I was getting 32 mpg on petrol. I have a 60 ltr terodial tank and I was able to get 50ltrs into it on its first fill I got 264 miles from that fill which if my maths is correct works out to be 23.9mpg on gas, That IMO is Terrible. The only thing I hope will make it better is that when the guy installed the kit he told me in order to get it to run smoothly on LPG he had to adjust the gap in the plugs and change the brain settings to adjust for the plugs being in Bad condition he said !. I have just ordered up some NGK PFR7H-10 plugs so I can give the system teh best chance of running well.

1. So what I am asking you guys will the new plugs and the system adjusted to suit make the car any better on the Gas MPG.
2. Is 23mpg what would be normal for a 2.0t engine.
3. And My car is an AUTO and my gears seem to reving higher than when the car is on petrol which I think is the reason its burning more LPG, when he adjusted the brain to suit the bad plugs will that have affected the gearbox in any way ?

Thanks In advance..

Darren

[Tubbs]

Really, and worse case. The mpg should be around 25 and thats low. 20 % less. But really that's on a mixer and not an injection system. You should be hitting 28's I would say.

[buckejit]

Really, and worse case. The mpg should be around 25 and thats low. 20 % less. But really that's on a mixer and not an injection system. You should be hitting 28's I would say.

I forgot to say that 85% of that drive is on Duel Carriageway @ 60 mph
The car has also just had a New PCV kit fitted and New Air filter. New plugs going in on Wednesday night and the car is then going for its First LPG service on Friday.

[Gilbertd]

Which engine do you have? I suspect the old Saab B204 in which case you don't need Flashlube, they'll go on for at least 300,000 miles (as long as they don't gum up when they are in a 9-3, not a problem in a 900). My old one was a '96 900 XS non-turbo but the same lump. That used to do anything between 190 (around town) and 260 miles (on a run) on a 46 litre fill and that was thrashing it mercilessly (only 125 bhp so you had to). I once got 280 miles out of a tank but that was on a 90 mph thrash across Europe and running on Propane/Butane mix. So unless you drive like a granny (and if you do, why did you buy a HOT in the first place?), I'd say it's about right. I think your petrol figure is wrong, is that from the trip computer (mine used to tell me I was doing nearly 40 mpg but I wasn't!) or from real world checks?

The gumming up on the 9-3 was down to two changes when Saab altered things from the 900 to the 9-3. It's the exact same engine but they changed the PCV arrangement to meet Californian emissions and moved the cat to under the sump. There was a mod that should have been done to the PCV system as long as the car was serviced by a Saab agent and the overheating of the sump from the cat was the reason they changed the recommendation from semi to fully synthetic oil.

[buckejit]

Which engine do you have? I suspect the old Saab B204 in which case you don't need Flashlube, they'll go on for at least 300,000 miles (as long as they don't gum up when they are in a 9-3, not a problem in a 900). My old one was a '96 900 XS non-turbo but the same lump. That used to do anything between 190 (around town) and 260 miles (on a run) on a 46 litre fill and that was thrashing it mercilessly (only 125 bhp so you had to). I once got 280 miles out of a tank but that was on a 90 mph thrash across Europe and running on Propane/Butane mix. So unless you drive like a granny (and if you do, why did you buy a HOT in the first place?), I'd say it's about right. I think your petrol figure is wrong, is that from the trip computer (mine used to tell me I was doing nearly 40 mpg but I wasn't!) or from real world checks?

The gumming up on the 9-3 was down to two changes when Saab altered things from the 900 to the 9-3. It's the exact same engine but they changed the PCV arrangement to meet Californian emissions and moved the cat to under the sump. There was a mod that should have been done to the PCV system as long as the car was serviced by a Saab agent and the overheating of the sump from the cat was the reason they changed the recommendation from semi to fully synthetic oil.

My Engine is the B205R 2.0t I bought a HOT because 1. It looks cool and the 9-3 2 door was on my bucket list , 2. I got it for £750 with full years MOT and 3 months Tax.

As I said above I have already changed the PCV to the latest version and I have dropped the sump 4 weeks ago and changed the oil to Fully synthetic Mobil1 0-40w. Air filters changed and I added ZX1 lube to the oil and Gearbox for added slippyness. I checked the petrol MPG via filling the tank and filling it back up then doing the Math myself ( don't trust the trip comp). New NGK PFR7H-10 plugs going in next week..

[billynoband]

Your mpg seems about right for a old fashioned auto box and your being honest. There is some very strange mathematics quoted on here sometimes by owners about their mpg.

[Gilbertd]

It might be that the mixture has been set slightly rich (although the petrol ECU will compensate for it anyway) as your plugs were well worn. Even if a misfire isn't noticeable, it could still be there and causing you to use more fuel than you should. As LPG needs a better spark than petrol, the effects will be raised fuel consumption. The plugs you have ordered are Platinum and it has been found that Platinum plugs and LPG are not a good mix. I ran Iridium plugs in mine and they would last for well over 50,000 miles a set although it looks like NGK don't do an exact Iridium equivalent for your car..

[buckejit]

When he modified the LPG ECU to compensate for the misfire will that have changed the characteristic of the gearbox. As I said it holds the revs for ages going over 3000 rpm instead of the usual 2500 gear changes (when driving easy). My Saab has a normal Auto and Sport button which holds the revs for longer keeping it in the power band and a Winter button which kills all the Torque. My gears seem to be in the middle of the sport and winter setting . The car has loads of revs and no go!

[demonicwillow]

perhaps its a faulty button dunno about a Saab but my Jeep has a seperate ecu that controls the auto box, have a switch for sport or comfort, sport it holds the gears and tc lock for longer, comfort lets it change up and lock at lower revs.

[buckejit]

I just did a weekend of driving around town. I used up 29 ltrs when i filled back up and I only got 140 miles from that. again surprisingly very low for a 2.0 Car.. I really hope it gets better as the cost savings are not what I was budgeting for when i converted the car.

[Gilbertd]

140 miles from 29 litres would equate to 220 miles on 46 litres. I used to get no more than 190 miles out of 46 litres from my Saab running around town so is far better than I used to get. You've got a 2.0 litre engine in a fairly heavy car, so sub-20mpg figures in stop-start driving is about what I would expect. Mine used to show around 23mpg on the trip computer around town so I was actually quite pleased with 18-19mpg on gas. I don't know what you expected but what you are getting seems about right.

[lazydocker]

For some strange reason I always seem to get "worse" economy on short fills (i.e. Filling before empty or nearly empty) too.

I don't look at MPG when comparing costs as it's really an unfair comparison. The fuels have different calorific values as well as densities. I work on pence per mile savings and experiences of several (V6) Omega drivers is 9-10 pence per mile.

Of course, the other thing I've found is that with the reduced fuel costs I don't tend to drive like Miss Daisy very often