[GM Racing Hosts ECOtec Race Engine Class
Written by Andy Williamson Friday, 22 June 2007
Garage
Recently, GM Racing hosted a class for engine builders, where we showed off our GM Racing Powertrain facility and all the cool things going on in the world of pro-level, turbo-charged ECOtec race engines.
We picked a few experienced engine builders to come out for the one-day class and passed along what we'€™ve learned from our more than five years of ECOtec engine development.
Our "students" got an in-depth look at the ECOtec drag race engine that is now producing 1450hp for racers like Marty Ladwig, Gary Gardella and Jason Hunt.
Possibly the most interesting part of the class was discussing some of the parts we’ve broken over the years, and what we did to fix them. We handed out The GM Sport Compact Build Book, but also covered some things we’ve changed since that book was written (we hope to have an updated book by the end of this year).
Here are a few highlights:
1. The 3.500"€� 5-unibolt ECOtec race block:
We began the race program using a 3.400"€� bore, steel-sleeved L61 block. As we advanced in horsepower above 1000 horsepower, we increased our bore to 3.500â€� (we use a 3.505"€� billet crank from Bryant and get an overall displacement of about 2.16L). As horsepower and boost pressure continued to rise, we started splitting blocks completely into two pieces. Drawing on broad engine experience, our partner, Roush Industries, developed the "uni-bolt,€�" which is a long bolt from the bottom of the girdle, through the block, and through the head. We use them in pairs, with a strap connecting a uni-bolt on one side to the other. Over time, we've gone from using 3 pairs, to 4 pairs, and, just recently, to 5 pairs. The 5th location requires some welding expertise because it breaks through the oil galley at the back of the block. These uni-bolts carry the load that was causing our production blocks to split in half.
2. The LSJ sand cast head:
ECOtec engines can have either lost-foam or sand-cast heads, depending on the engine variant. Sand cast heads are found on turbocharged and supercharged ECOtec applications. These heads are cast in Germany and the sand-cast process results in improved material properties including reduced porosity. While the lost-foam heads are fine for applications under 1000 horsepower, we get better life from the sand-cast heads at higher horsepower levels. We do race-porting of heads internally or at Chapman Racing Heads.
3. 300M rods
At power-levels approaching 1400 horsepower, we began to see buckling of the 4340 steel "H"€� beam rods we were using. The rods were collapsing under the load of extremely high cylinder pressure. Our first step was to develop a tool, the TDC gauge (a dial indicator mounted on an extended rod that screws into the spark plug hole), to measure the location of each piston at top-dead-center. A change in the piston location indicates rod buckling (or damage to the piston). To improve the rod, we upgraded to a 300M material, large "œI"€� beam rod from Manley. This new rod has withstood our fierce cylinder pressures at more than 1450 horsepower and over 60psi of boost.
See photos of the class and some of our race parts in our photo gallery on flickr.
Our Sport Compact Build Book is available for download on this site, or you can purchase one from your local GM dealer'€™s parts department (part number 88958565). Each ECOtec Class participant also walked away with a set of written engine and head assembly instructions, which are available, upon request, to professional engine builders. On our ECOtec Tech page, you can find ECOtec packaging drawings and other technical information. Remember, though, this information is for use by experienced, professional engine builders. For the rest of us ECOtec enthusiasts, it’s just cool stuff to dream about
Written by Andy Williamson Friday, 22 June 2007
Garage
Recently, GM Racing hosted a class for engine builders, where we showed off our GM Racing Powertrain facility and all the cool things going on in the world of pro-level, turbo-charged ECOtec race engines.
We picked a few experienced engine builders to come out for the one-day class and passed along what we'€™ve learned from our more than five years of ECOtec engine development.
Our "students" got an in-depth look at the ECOtec drag race engine that is now producing 1450hp for racers like Marty Ladwig, Gary Gardella and Jason Hunt.
Possibly the most interesting part of the class was discussing some of the parts we’ve broken over the years, and what we did to fix them. We handed out The GM Sport Compact Build Book, but also covered some things we’ve changed since that book was written (we hope to have an updated book by the end of this year).
Here are a few highlights:
1. The 3.500"€� 5-unibolt ECOtec race block:
We began the race program using a 3.400"€� bore, steel-sleeved L61 block. As we advanced in horsepower above 1000 horsepower, we increased our bore to 3.500â€� (we use a 3.505"€� billet crank from Bryant and get an overall displacement of about 2.16L). As horsepower and boost pressure continued to rise, we started splitting blocks completely into two pieces. Drawing on broad engine experience, our partner, Roush Industries, developed the "uni-bolt,€�" which is a long bolt from the bottom of the girdle, through the block, and through the head. We use them in pairs, with a strap connecting a uni-bolt on one side to the other. Over time, we've gone from using 3 pairs, to 4 pairs, and, just recently, to 5 pairs. The 5th location requires some welding expertise because it breaks through the oil galley at the back of the block. These uni-bolts carry the load that was causing our production blocks to split in half.
2. The LSJ sand cast head:
ECOtec engines can have either lost-foam or sand-cast heads, depending on the engine variant. Sand cast heads are found on turbocharged and supercharged ECOtec applications. These heads are cast in Germany and the sand-cast process results in improved material properties including reduced porosity. While the lost-foam heads are fine for applications under 1000 horsepower, we get better life from the sand-cast heads at higher horsepower levels. We do race-porting of heads internally or at Chapman Racing Heads.
3. 300M rods
At power-levels approaching 1400 horsepower, we began to see buckling of the 4340 steel "H"€� beam rods we were using. The rods were collapsing under the load of extremely high cylinder pressure. Our first step was to develop a tool, the TDC gauge (a dial indicator mounted on an extended rod that screws into the spark plug hole), to measure the location of each piston at top-dead-center. A change in the piston location indicates rod buckling (or damage to the piston). To improve the rod, we upgraded to a 300M material, large "œI"€� beam rod from Manley. This new rod has withstood our fierce cylinder pressures at more than 1450 horsepower and over 60psi of boost.
See photos of the class and some of our race parts in our photo gallery on flickr.
Our Sport Compact Build Book is available for download on this site, or you can purchase one from your local GM dealer'€™s parts department (part number 88958565). Each ECOtec Class participant also walked away with a set of written engine and head assembly instructions, which are available, upon request, to professional engine builders. On our ECOtec Tech page, you can find ECOtec packaging drawings and other technical information. Remember, though, this information is for use by experienced, professional engine builders. For the rest of us ECOtec enthusiasts, it’s just cool stuff to dream about
