Help With Understanding the ISF Engine Construction
#1
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Help With Understanding the ISF Engine Construction
Since recently purchasing an ISF and reading some publications getting very technical on how it was built and having hollow camshafts and sintered rods, titanium valves, rib this and polished that. I know there are some tech heads on here for us non tech heads that may be able to bundle all of this together and exlain what some of this means for me and maybe others. From my understanding this engine was fairly revolutionary when it came out since it was coauthored with Yamaha racings engineers. Now you read some places that it is a dated design but I'd rather refuse to believe that yet. I bet not many of you knew the first gen SHO's were capable of 9000 rpm in stock form as long as you built up 3 components and I think two were the water pump and starter or alternator and something else. Compared to other V8's of that time like GM's muscle cars, the first gen CTSV as well was a 2008 model year without SC. The V8 in the Pontiac G8. Even maybe some German cars like the Audi RS4 Mercedes AMG..... etc. How "technology" wise did they compare and what kind of effort was really put forth to produce an overbuilt engine. Sorry to get long in the tooth.
#2
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Are you asking to compare the IS-F motor to the LSx series of GM Motors?
LSx motors are the dumb simple, reliable motors, single camshaft in middle, same cam profile all the way through the RPM Band. GM had some weak spots in some of the motors. The valve springs were crap in some of them, the have oil starvation issues in some version of the LSx motors, which lead to spun bearings.
Due to the design of the LSx motor, the torque curve is more of a straight line, dropping off around ~5800 rpm if my memory serves me right.
The IS-F motor was basically built to be a racing motor. It has been designed to have less rotating mass, as well as small oil cooler, scavenger oil pumps to pull returning oil from the heads back into the oil sump. Most Toyota stuff is overengineered as they are very conservative.
Take a look at the RC-F motor to see what they improved from the IS-F motor. The RC-F motor literally was pulled from the IS-F race car and put into a street car...great motors.
LSx motors are the dumb simple, reliable motors, single camshaft in middle, same cam profile all the way through the RPM Band. GM had some weak spots in some of the motors. The valve springs were crap in some of them, the have oil starvation issues in some version of the LSx motors, which lead to spun bearings.
Due to the design of the LSx motor, the torque curve is more of a straight line, dropping off around ~5800 rpm if my memory serves me right.
The IS-F motor was basically built to be a racing motor. It has been designed to have less rotating mass, as well as small oil cooler, scavenger oil pumps to pull returning oil from the heads back into the oil sump. Most Toyota stuff is overengineered as they are very conservative.
Take a look at the RC-F motor to see what they improved from the IS-F motor. The RC-F motor literally was pulled from the IS-F race car and put into a street car...great motors.
#3
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Are you asking to compare the IS-F motor to the LSx series of GM Motors?
LSx motors are the dumb simple, reliable motors, single camshaft in middle, same cam profile all the way through the RPM Band. GM had some weak spots in some of the motors. The valve springs were crap in some of them, the have oil starvation issues in some version of the LSx motors, which lead to spun bearings.
Due to the design of the LSx motor, the torque curve is more of a straight line, dropping off around ~5800 rpm if my memory serves me right.
The IS-F motor was basically built to be a racing motor. It has been designed to have less rotating mass, as well as small oil cooler, scavenger oil pumps to pull returning oil from the heads back into the oil sump. Most Toyota stuff is overengineered as they are very conservative.
Take a look at the RC-F motor to see what they improved from the IS-F motor. The RC-F motor literally was pulled from the IS-F race car and put into a street car...great motors.
LSx motors are the dumb simple, reliable motors, single camshaft in middle, same cam profile all the way through the RPM Band. GM had some weak spots in some of the motors. The valve springs were crap in some of them, the have oil starvation issues in some version of the LSx motors, which lead to spun bearings.
Due to the design of the LSx motor, the torque curve is more of a straight line, dropping off around ~5800 rpm if my memory serves me right.
The IS-F motor was basically built to be a racing motor. It has been designed to have less rotating mass, as well as small oil cooler, scavenger oil pumps to pull returning oil from the heads back into the oil sump. Most Toyota stuff is overengineered as they are very conservative.
Take a look at the RC-F motor to see what they improved from the IS-F motor. The RC-F motor literally was pulled from the IS-F race car and put into a street car...great motors.
Yes that's what they said about the RCF motor. How about against aome of the German competitors? It's jus nice to have a simple understanding. Appreciate the response.
#4
Lexus Test Driver
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Take a look at the insides of our V8's in "Geoff's swap thread" in the "Build Threads" subforum. There's pics showing a beefy, deep-skirted block with 6-bolt main bearing journals. And notice the fully machined crank counterweights & rods. In the shots of the cyl heads, check out the phasers on both intake & exhaust cams, not to mention the scavenge pumps.
Talk about overbuilt.
Talk about overbuilt.
#7
The hollow camshafts and sodium filled exhaust valves are nothing new, they have been out there for quite sometime. The Subaru WRX STi had these features.
The titanium intake valves are surely a nice touch.
The lubrication system seems to be pretty advanced with the secondary pump.
The titanium intake valves are surely a nice touch.
The lubrication system seems to be pretty advanced with the secondary pump.
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#9
Tech Info Resource
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The hollow camshafts and sodium filled exhaust valves are nothing new, they have been out there for quite sometime. The Subaru WRX STi had these features.
The titanium intake valves are surely a nice touch.
The lubrication system seems to be pretty advanced with the secondary pump.
The titanium intake valves are surely a nice touch.
The lubrication system seems to be pretty advanced with the secondary pump.
This is not even close to a race engine. Stroke is way too long which limits safe redline pretty significantly, and at the very least the cam profiles are totally street oriented. it's why the engine can't breathe above 6800 rpm and torque drops like a rock as redline is exceeded. Without different cams, I see no advantage at all to raising the redline on this configuration. Last, but not least, while the lubrication system is better than many wet sump designs, it is still a wet sump. No proper racing engine uses a wet sump unless the rules for the class prohibit a dry sump.
I am also wondering if our engines will become the sought after design since we have bigger rod bearing journals than the RC F version which means our cranks are stronger. Yes, there is more fluid drag because the pins are larger and the linear speed (shear) of the bearing is higher which also very minorly impacts redline vs. service life, but the crank being stronger means less flex, less issues with torsional vibration, and ultimately more power before disaster strikes.
It would still be an interesting experiment to see if the top end pieces will fit our bottom end pieces and run with the RC F ECM.
#11
Tech Info Resource
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Not on a significant scale. That's a lot of the problem. More cars on track means more development. More development means better aftermarket support. If you look at the small block Chevy platform, there are so many options it is staggering, simply because that engine has been used in all kinds of competition. Parts are cheap. Good tuning advice is easy to get. Millions upon millions of man-hour have been spent on making that engine better, faster, cheaper. And it really is.
#12
Not on a significant scale. That's a lot of the problem. More cars on track means more development. More development means better aftermarket support. If you look at the small block Chevy platform, there are so many options it is staggering, simply because that engine has been used in all kinds of competition. Parts are cheap. Good tuning advice is easy to get. Millions upon millions of man-hour have been spent on making that engine better, faster, cheaper. And it really is.
I hear they make great engines, but I've never heard of a reliable GM product.
#13
Tech Info Resource
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I didn't say factory engines, I said platform. The factory still hasn't decided they want to build quality products. Once you get them, you can make them into quality products, and pretty cheaply compared to other options.
#14
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Hi. 2008 Z06 btw . When a non stock tune puts you in knock retard hell and causes the disintegration of a piston, it's hardly the manufacturers fault.
#15
Now that the ECU has been cracked time will tell how strong the IS-F engine is. We don't really need this engine to rev to the moon, 6800rpm seems acceptable to me.... We seem to forget that we have a transmission that can shift in 100ms