If everybody is doing their job correctly I think the cyls should only see a 20-25 F difference between them under load. When you are checking big bore V12 and V16 turbo charged engines.50F to 75F is acceptable under high boost and that is sometimes dependant on cylinder position in the cooling system.

Just my two cents

Bluecometk

I have been using laser pyrometers for years on our team race engines. The units we have are very accurate at the high temps we use them. We also have pyrometers in the exhaust ports in each cylinder to compare the two temps. The average variation between the two test types is about 7 degrees F. This could be because they are reading two different types of temp, surface temp and gaseous temp. The only other difference is a slight delay in the timing from the two when they actually read the temp. They have saved us many times. The units we use are fairly high dollar units. We have some lower priced models that work quite well, they are a little slower and 1 or 2 degrease less accurate. They all are well worth the Expense.

Just my two cents

Some of the latest Mercedes have 7 speed AUTOS in them.

 I have a 95 Subaru auto that gets an average 27.9-mpg at an average speed of 51 mph on an average 127 mile daily drive.

 On the other hand, the Subaru STi has had a 6-speed manual in it since 2004. Sti’s have stock hp numbers of 305 hp and get a highway average 27mpg.
 
The ESX STi's I work on get slightly less mileage. The first is a street legal AWD STi with a 2.5 liter turbo charged engine that churns out 1,042 hp and runs the Quarter mile in 8.91 seconds at 154+ mph on street tires with a full interior, exhaust, power windows and a curb weight of 3,262 lbs. This vehicle is fully street legal except for catalytic converters, its fuel mileage is about 1.84 gallons of VP import gasoline (125 octane fuel) per Quarter mile. It is well known as the worlds fastest Street tired STi with 18 national NHRA championships and 2 NHRA  world championships in 2 years.


 http://www.youtube.com/watch?v=yHSyRuQxulw




The other is a Molly tube all carbon fiber bodied 2,060 lb modified STi with a 2.57 turbo charged 4 cyl on Methanol. It produces 1,400 hp on 50psi of boost. It runs 7.60 second quarter mile passes at 176 mph. Its fuel consumption is about 2.6 gallons per quarter mile pass.  This vehicle is the fastest AWD Subaru in the world. 

   Some Stats. Pro car

The engine spins at 9,300 rpm and uses 3 injectors per cylinder to supply fuel .One of the three injectors is used to spray a cooling charge into the intake to cool the intake valves. If the engine is shut down at the finish line the valves will bend from being white hot. The turbo's inlet is 101 mm in diameter. Nitrous oxide is used to spool the turbo at the line. The turbo spools to 50psi, which is full boost in just under .68 seconds. The power produced is transmitted through a slightly modified Subaru 4 speed automatic trans (AWD 4-EAT). The pro car uses 30 lbs of ice per quarter mile pass in its intercooler.

http://www.youtube.com/watch?v=ncYdlNsZyCA

Sorry to bore you with this stuff.

Bluecometk

 rcavictim, THANK YOU FOR THE HEADS UP! It took a lot of courage to talk about your accident. What is good is that you have a plan to not have it happen again. Hope your convalescence is short. Enough said.


Thanks again.
 Â               
 Â                Bluuecometk.

 I partially agree a 2.5L DOHC will for the most part bend the valves but not usually hurt the pistons or the head if it looses the belt. The issue is the valve angles of the Pent head design. If the intake is open and the exhaust opens the faces will hit. As a note the 2.0L DOHC will do the same.

If your friend’s vehicle lost a belt before the service interval it is most likely that one of the idler pulleys or water pump failed. If the coolant isn’t changed as per the book the pump bearings will fail prematurely. The other idlers will fail if the vehicle has had water invade the belt cover area. The belt will sling it around and force it into the bearing dust seals.

Under normal conditions it is very, very rare for a belt to just break.

If you PM me I can help you get your timing belt   R&R time down to about 40 minutes

 Subaru has an unbelievable gasoline engine hybrid system that can get 47+ mpg and still make 247 hp. The place that the flywheel would normaly be houses a linear power/starter/charger/braking motor. But we won't see it for a long time because Toyota temporarily purchased the rights to our battery technology (NEC). The battery tech is unbelievable.   You can charge a discharged battery (-30%) to 90+ percent in 15 minutes and 100+% in 20 minutes. Nobody else can do that yet. And now some Toyotas are being built in the (SIA) Subaru Indiana plant.

On the CVT side, Subaru had an (ECVT) Electronically Controlled Variable Transmission back in 1987 in the Justy and we used it until 1994 until we sold that technology to Nissan. Back in the day, the Justy ECVT was getting 36 to 43 actual mpg and the 4WD ECVT version about 3 mpg less. The trans was really neat in that the belt was not conventional; it was made up of 256 segments held together by 8 flat bands. What is really ingenious about it is it pushed the  drive pulley instead of pulling it. Think about the technology that it took to keep the belt tight enough to not slip but loose enough to ratio up and down the pulley. Slick as snot on a doorknob!

 The simple Japanese b--tards even put a high performance mode on it for what they called sport driving. Yeh, sport driving from a three cylinder three valve per cylinder fuel injected 77hp engine. NOT!

 In 1989, we did take one Justy and lowered it, de-stroked it to 966cc, took the balance shaft out, machined a cam that made power at 10,000 rpm and up, put three Makuuni carbs on it, and a coffee can for a fuel cooler along with a Pampers diaper box for an air intake box in the cowl and a piece of hardware store flexible dryer hose and then set the Bonneville I-production record at 124.23 mph. On the first day we set the record at 117.86, but that was before the Pampers box and dryer hose and coffee can fuel cooler. With the second day came the big numbers.  On the first out and back pass, it went 124.23 mph with the engine twisting 11,930 rpm. Then it all went south and the engine lost a cylinder or so we thought. So with a record some twelve mph faster than ever before, they went home.

Come to find out 5 years ago that the engine didn’t go away. I had to get it running for a news article and so I had to put it all back together. What we thought was a cylinder failure turned out to be that a screw had fallen out of one of the carb bell cranks. So when the engine was idling, it ran on all three cylinders but off of idle it would lose a cylinder, because that set of throttle plates wasn’t opening.

Just a note, the record is still held today by the Justy and it was all done by a bunch of DIY guys on thier own time and money after work at our R&D center. Fun stuff if that’s your cup of tea.I know it is mine

Bluecometk

Nice find, thanks for the info.

Bluecometk