Do you have to run premium fuel in a TR?

[Keller]

There is the old famous adage: "Speed costs money..."

If you don't like it, you can always buy a Prius instead...

[PaCemkr86]

also..

i wanna go fast and cheap, don't go together

[Carnag3]

What's actually funny, is that in a car hating country like Norway, we actually have 95 and 98 octane pump gas. the downside of it is that the price is overkill. We actually pay 8,76$ per gallon. It's a ridiculous amount of money, but despite this we have some of the fastest street cars, if not in the world, definetly in Europe.

How much boost can you safely go with on 98 fuel?

[PaCemkr86]

pretty dam fast ! lucky you !!

[Keller]

Originally Posted by Carnag3

How much boost can you safely go with on 98 fuel?

It depends on timing, etc. You could likely safely get perhaps 18 PSI. (vs. stock 15)

You could set a car up to run lower timing on the street and get by with lesser octane for general driving. Mr. "Turbo Malibu" who is on other sites has his car set up to run 87 octane for general use and 116 octane under boost.

If your fuel and timing are set up to work with less octane at lower speeds and less aggressive driving, you could manage 87 on the street...but not under boost. If you want one profile for cruising, and another for real driving, and want to switch fuels or have switchable cells/tanks you could set up tank switching, a thumbwheel switch chip, etc.

(*whew*)

[Carnag3]

Maybe a bit off subject here, but while you mention it: I've read a lot people pushing their stock turbo to 20psi and above. I've also read you can gain boost by adding cold air intake, bigger exhaust, power plate, chip etc. is it possible to gain boost without an adjustable wastegate or boost controller?
It seems pretty strange to me.

newbie question maybe, but at the moment I'm very busy at officers training school, and don't have any spare time to spend with my beloved GN. So I don't have the opportunity for some hands-on-education on it yet.

[kenmosher]

Originally Posted by Carnag3

What's actually funny, is that in a car hating country like Norway, we actually have 95 and 98 octane pump gas. the downside of it is that the price is overkill. We actually pay 8,76$ per gallon. It's a ridiculous amount of money, but despite this we have some of the fastest street cars, if not in the world, definetly in Europe.

How much boost can you safely go with on 98 fuel?

First, we have to talk "apples to apples" ...

Japan, Europe and the Middle East use a system called RON (or Research Octane Number) to determine the octane rating of their gasoline, whereas in the US we use a system called AKI (or Anti-Knock Index) to determine gasoline's octane rating.

This corresponds to basically research octane (RON) + motor octane (MON)/2 ... which is the average between RON and MON. Often you'll see on a US/Canadian pump something like:

91 Octane
R + M/2

which is the RON + MON average.

SO, saying that, 98 octane in Europe is equivalent to the 92-93 R+M/2 octane number that folks in North America would recognize. Fuel composition, vapor pressure, etc. may slightly affect this R+M/2 number (fuels higher in lead, for example may have a relatively low RON, but have an excellent MON).

A rule of thumb though is RON * 0.95 = ~ R+M/2.

Also, isn't your 98 octane leaded (which will kill the catalytic converter and O2 sensor eventually)?

[kenmosher]

Originally Posted by Carnag3

Maybe a bit off subject here, but while you mention it: I've read a lot people pushing their stock turbo to 20psi and above. I've also read you can gain boost by adding cold air intake, bigger exhaust, power plate, chip etc. is it possible to gain boost without an adjustable wastegate or boost controller?
It seems pretty strange to me.

There's more involved than boost ... you have to have enough fuel and octane to support that kind of cylinder pressure. Too lean or detonation and eventually you'll be walking behind the car picking up all the shiny internal engine parts!


An adjustable wastegate is a very cheap ($1.50 if you make it yourself) and easy way to gain control of boost and allow for measured and predictable changes to boost levels. It's like a cake recipe (have you read the Hot 'n Spicy Turbo Regal Recipe on the site?) ... you have to have fuel, air, pressure and flow in the proper proportions or you won't have a successful cake. You do this by making sure that the COMBINATION of parts (turbo, injectors, chip, intake, exhaust, heads, etc.) all work together effectively.

[Carnag3]

Originally Posted by kenmosher

Also, isn't your 98 octane leaded (which will kill the catalytic converter and O2 sensor eventually)?

Why should we have leaded gas when you have to go to a museum to find a car that runs on it? I have never in my life seen a pump with leaded gas here in Norway. We don't ride a horse and carriage, or wear viking helmets either



But you're maybe right on the definition of European octane and US octane. I haven't heard of that before.

And I know all about detonation, knock, recipees, that you can't add air without adding fuel to go along, and that you need a good combo. I have upgraded the fuel system on my gn. Cars have been a hobby for a long time. Turbo cars I still have some learning to do. I was just wondering if it is true what some people say, that you can gain a pound or two, in boost, with simple mods like power plate, cold air, exhaust etc. without touching the wastegate or the use of B.C.

[kenmosher]

Originally Posted by Carnag3

Why should we have leaded gas when you have to go to a museum to find a car that runs on it? I have never in my life seen a pump with leaded gas here in Norway. We don't ride a horse and carriage, or where viking helmets either

Whoa ... no worries and certainly no insult intended! Just trying to share some info (I've owned my GN since I ordered it from the factory in 1986!)

Maybe your horns are too tight on your Viking helmet?

Anyway, according to some sources, leaded gasoline is still in use in some parts of the world, which is why I asked the question.

In some parts of South America, Asia, Eastern Europe and the Middle East, leaded gasoline is still in use. Leaded gasoline was phased out in sub-Saharan Africa effective 1 January 2006. A growing number of countries have drawn up plans to ban leaded gasoline in the near future.

But you're maybe right on the definition of European octane and US octane. I haven't heard of that before.

Yes, it is different ... and it seems there's even some slight variations between European countries in how they define RON.

Different countries have some variation in what RON (Research Octane Number) is standard for gasoline, or petrol. In the UK, ordinary regular unleaded petrol is 91 RON (not commonly available), premium unleaded petrol is always 95 RON, and super unleaded is usually 97-98 RON. However both Shell and BP produce fuel at 102 RON for cars with hi-performance engines, and the supermarket chain Tesco began in 2006 to sell super unleaded petrol rated at 99 RON.

In the US, octane ratings in fuels can vary between 86-87 AKI (91-92 RON) for regular, through 89-90 (94-95) for mid-grade (European Premium), up to 90-94 (RON 95-99) for premium unleaded or E10 (Super in Europe)

As far as gaining boost ... the main reason you gain boost is because you've freed up a restriction in the airflow. The TR wastegate system has no feedback or "closed" loop control. The ECU is basically "guessing" based on what the factory components were known to flow.

Therefore, if you open up the exhaust or intake (for example), the stock calibration doesn't have anyway to know boost levels, so it commands the precalibrated wastegate duty cycle ... This results in the boost being higher than stock because you are flowing more air.

This works to a point (the stock chips have some limitations with correctly predicting fueling when the airflow really grows).

So, yes ... if you replace the stock restrictive exhaust system with a very free flowing one, you'll gain 1 to 2 psi boost. If you put a cold air system on it (depending on how well it is routed and flows), you'll generally gain about 1 psi.

The PowerPlate doesn't raise boost (in fact, it may lower it a little), but it will balance airflow so that you can manually raise the boost (usually via an adjustable wastegate) and "get away" with it, since you won't have a cylinder or cylinders that have too much/little airflow compared to the other cylinders.