posted on September 24, 2015 14:01
Building the Ultimate Turbo Small Block Chevy-Part 1
The Small Block Chevy is a dead outdated hunk of iron that is best left to old guys puttering around restoring muscle cars in their garages, or is it?
The venerable Small Block Chevy was first introduced to the motoring public in 1954 and was installed on the assembly line until 2003 and is still in production as a replacement motor. This means that the good old small block has been around for 60 years, making it one of the longest lived and most produced engines of all time with over 100,000,000 units having been built to date.
The longevity of the Small Block speaks volumes to the genius of the original design. With a lightweight for the time 90 degree, thin walled, short skirt block and overhead valves, the Small Block was exceedingly compact and could pack a lot of displacement and power into a compact lightweight package. By being produced in such huge numbers for such a long time the Small Block also enjoyed what is perhaps the largest aftermarket following of any engine ever made by several orders of magnitude.
The Small Block Chevy was updated and modernized many times during its long life cycle but by the new millennium it had become painfully apparent the the old war horse was getting long in the tooth. Its single cam in block overhead valvetrain and iron construction became a symbol of how out of touch the domestic carmakers were with modern technology as the Japanese then European manufacturers pumped out lightweight alloy DOHC multivalve motors by the bushel.
GM responded with the all alloy world class LS series of V8 engines and those of us on the cutting edge forgot all about the Small Block. Until recently.
When looking to do an engine for Darren McNamara's Formula D S14, Team Falken was looking to do something new. As the professional drift world has become more competitive, more and more power has been needed to keep up with the pace of competition. Long gone are the days when a 200 hp AE86 Corolla could win a drift event.
At first a 450 hp Nissan SR20DE was considered to be a big power motor, then as suspension and tire technology evolved, 550 hp then 650 became necessary. At this point the Chevy LS motor in naturally aspirated form started to become the dominant engine. With little stress, a big LS could reliably last an entire season and engine problems disappeared.
All looked relatively stable in the engine world until a Japanese guy by the name of Daigo Saito came on the scene. With a turbocharged and nitrous injected 2JZ engine packing an unheard of maximum of 1300 hp, Daigo shredded the FD field in his rookie year. Thus the power wars were triggered with 850 to 1000 hp becoming the new norm.
When looking for a way to develop 1000 hp reliably, the Falken team looked towards turbocharging a V8 engine. It would potentially be less stressful to run low boost through a big V8 instead of trying to develop super high compression and high revving motors to respond to Formula D's current power demands. In addition, turbocharging made it easy to get more power in case future developments in tire and suspension technology dictated the need for more power.
When looking for a base engine to turbocharge, at first the Chevy LS engine was considered with its modern all alloy construction but with its 4 bolt per cylinder design, cylinder head sealing at more than 10 psi of boost was an issue, Racing versions of the LS can be had with 5 bolts per cylinder for better seal but those engines were prohibitively expensive. That being said, attention was focused on the latest developments in the Small Block Chevy racing world and after looking at stuff developed for Sprint Car and NASCAR racing, it was discovered that the Small Block could potentially be smaller, lighter and just as powerful as the LS.
Falken had lots of Small Block Sprint Car engine parts in inventory from older cars so the decision was made to build a turbo motor from some of these parts. Is the Small Block old and outdated? Not at all, let us show you how the modern Small Block racing engine is not what it was in 1954!
Team Falken's turbo wonder engine starts with not your junkyard old Small Block pulled from a wrecked Camaro, but this totally modern racing block constructed from Aluminum by Dart Manufacturing. Even though it was made of cast iron and had 5 bolts per cylinder, the old Small Block would flex and be stressed out with the power levels a modern drift car needs. The Dart block has a thick deck for good head gasket sealing and a lot of beef around the main webs to help support the crank. Thin iron liners can be bored, in this case to a larger 4.166" which is a little marginal for a turbo engine due to gasket sealing in between cylinders but use of existing parts in the Team Falken inventory was a priority and low boost was anticipated. An interesting feature is the thick plate bridging the lifter valley. This bolts to thick buttresses and serves to stiffen the block. In Sprint Cars and in the Falken S14 the engine is a stressed member of the chassis so block stiffness is important. Stiff blocks also distort less in the cylinders and crack bores while making more power. The Dart block is lightweight and strong.
Flipping the block over reveals the thick and strong pan rails and main caps. The Dart block uses stiff billet steel main caps bolted in 4 places to the block vs the stock cast iron caps attached which are only attached with 2 bolts. The stiff pan rails are due to the oil pan being part of the block structure for additional strength, more on that later. If the background looks familiar, it's because we're in the MotoIQ HQ building and Technosquare's Howard Watanabe is serving the engine's builder.
The Dart block has some more modern features when seen from the front. The cam spins in roller bearings on non standard 50mm journals. The roller bearings need less oil and have much lower friction. This is important due to the loads that a modern aggressive high lift roller cam can place on the bearings due to the high seat pressures required. The cam is also higher in the block than your old Chevy to accommodate stroke lengths up to 4 inches. In our case we are running a 3.8 inch stroke for a total displacement of 413 cubic inches or 6.77 liters. In older motors, the crank would hit the cam or a special reduced base circle cam could be ground for more clearance. Of course this would be less than desirable for valvetrain stability. Raising the cam higher in the block fixes the issue of cam/crank interference.
Since racing engines actually "breathe", they tend to flex and distort under high stress and in race engines it is not uncommon to run really high coolant pressures of over 25 psi. As a result our block uses super heavy duty screw in freeze plugs. Your traditional stamped steel press in plugs tend to fall out under racing conditions which is no bueno but they sure won't on this engine!
Monday, June 16, 2014 9:43 AM
Talking about small blocks in general. The dart block is a far cry from a junkyard find that most garage tuners would use. It seems that in that case the LT/LS might still be a better choice to get an aluminum block and better power delivery.
Monday, June 16, 2014 10:45 AM
It's actually a single cam-in-block ohv design, not a single overhead cam, but I'm sure you knew that. You just testing to see who's paying attention?
Monday, June 16, 2014 11:17 AM
@ sethulrich: Of course Mike did, I inadvertently modified that part when I was going over things previously. Guess I had SOHC on the brain :)
Monday, June 16, 2014 12:02 PM
It originally said overhead valve.
Monday, June 16, 2014 12:56 PM
Don't screw-in freeze plugs defeat the purpose? I can't see one of those rotating out, should the coolant freeze. Why not just eliminate the plugs altogether?
How come the crankshaft is only knife-edged/tapered on the rod journal side? I can see why knife-edging wouldn't be as important in a dry sump engine, but why the journal side, then? What is the reason for the huge counterweights, as opposed to say, "pendulum-cut" ones, that are supposedly common in modern racing engines?
Monday, June 16, 2014 12:59 PM
Worth mentioning (meh, some people probably know this anyway but I'm on my lunch break) is that sandcasting isn't necessarily lower tech or less desirable, just that it's not as cheap to mass produce. There's some shapes that you can't make with die casting, you can do various things to have a better pour with sand casting that result in denser, stronger structure even with the same alloy, and there's various alloys that you can use with sand casting that don't work very well die cast. It just takes longer to do each individual part.
An import example that always comes to mind is the Subaru EJ blocks - the closed deck block homologated for WRC was sand cast, while the open and semi-closed blocks they used for everything else were die cast. Hell, F-1 stuff is mostly sandcast (heads at the very least) and it's not like they're under much cost restriction.
Also, "freeze plugs" are also holes that are required by the casting process to align the core - the hollow bits where water is going to be, in this instance. So you can't really just eliminate them.
Monday, June 16, 2014 1:15 PM
Jeeeeeze, the comment section doesn't like to work often.
Is there going to be any updates on the TA r32??? Last we heard, in 2012, we had more frequent updates heading our way for 2013. Have only seen hints that is still an actual project from the wtac website, nothing here.
Is that not a project associated with motoiq anymore?
Monday, June 16, 2014 1:23 PM
The crank is not knife edged at all. Some Calles cranks are but not this one. I am not to thrilled with this crank for this application but this is what we had in inventory. Screw in freeze plugs or plugs with set screws are SOP for race engines. They tend to blow out under race conditions.
Monday, June 16, 2014 1:24 PM
The Team America car is being worked on but we hardly have time to write about it.
Monday, June 16, 2014 2:28 PM
Love this article!
Mike - I had imagined going for this much horsepower, I'd be using H-beams; Why the decision to stick with I-beams?
That's true Team America COULD make this year's WTAC!
Monday, June 16, 2014 3:01 PM
Because Brian Crower sponsors the car and they are damn good rods!
Monday, June 16, 2014 3:44 PM
page 2 pic 2
how exactly do those standoff's control the amount of oil and overall vacuum? can you dumb it down a bit so someone like me could understand? or would that require writing a book?
Tuesday, June 17, 2014 1:10 PM
So it IS being worked on, very cool. That is great news, makes me excited to see the final product.
I would be happy with a 1-page update that had nothing but bullet points summarizing the progress. Lots of pics and elaborate descriptions/explanations are great, but at this point I am looking for very little. Mike's response just about counted as an update for me.
Tuesday, June 17, 2014 11:52 PM
The standoffs have drilled orfaces in them at a given height.
Wednesday, June 18, 2014 3:29 AM
You said BC Provided the roller lifters but that looks like a Crower Cams & Equipment logo. I know the smallest most pointless comment ever.
Wednesday, June 18, 2014 11:43 PM
@EvanFitch - Anyone is welcome to correct me, but unless I'm highly mistaken, BC is owned and partially operated by Crower Cams & Equipment. As you may be well aware, BC stands for "Brian Crower", so it's not terribly far out of the box to imagine that Brian Crower may be part of the Crower family, of Crower Cams & Equipment fame. I can easily see why one might be confused, though, since they share no parts on each other's websites, that I know of at least.
Tuesday, June 24, 2014 8:23 PM
Looking forward to part 2 with the details on the head and valvetrain. The small block IS old and dated...but that doesn't mean they haven't come up with some clever tricks in the last 60 years to make them monsters.
Unfortunately though, those DART blocks alone are about as much as you can pick up an LS/T56 donor car for.
Wednesday, June 25, 2014 4:45 PM
All of the parts shown here for the Chevy can be ordered through BC. It is all in the Crower family!
Friday, September 25, 2015 11:38 AM
There are a lot of circle track tricks in this engine! Also thanks for commenting on the turbo cam - low duration high lift. If these were a vvt setup would you also want the exhaust cam to be parked much more to build boost.. vs. the NA tune where you retard the exhaust a lot at low rpm and then bring it back to about 110-112 at high rpm. where would you want the vvt settings on a turbo?
Back to topic, I love these coatings they make such a huge difference to rpm and heat build up.
I would love to see the final engine on the dyno. since I see some dates from 2014 its been going a while, when is the start up?
Friday, September 25, 2015 1:31 PM
Concerning the number of main bolts on a small block, Chevy had both 2 bolt and 4 bolt versions in production. Generally the 4 bolts were limited to pickup trucks. I can't tell if the Dart block is using Chevy's 4 bolt pattern or something specific to them.
Friday, September 25, 2015 1:34 PM
Edit to my prior comment:
Definitely not a Chevy pattern for the main bolts. Production blocks spaced the bolts much closer together and the 4 bolt mains were limited to the center 3, the outer pair only had 2 bolts unlike this Dart block.
Saturday, September 26, 2015 2:14 AM
The engine made about 1100 hp and then spun the wheels on the dyno.
Monday, September 28, 2015 2:06 AM
Corvette LT1s were the only LT1s to be 4 bolt mains as well, generally it was the 8 lug trucks to get the 4 bolt mains for the GenI small block.
I see no radiator shroud, is this because the car is mostly sideways and relies more on fan flow to cool the engine?
Monday, September 28, 2015 2:42 AM
All fan flow.
Thursday, November 19, 2015 10:56 PM
The rods, camshaft, springs and lifters are CROWER not Brian Crower. Two different companies. Just thought you should know
Thursday, November 19, 2015 11:18 PM
They come from Brian Crower himself who is one of our teams sponsors.