pharmd

iTrader: (4)

Contemplating 2 engine combo's ( 1 lower cost, 1 higher cost). I don't plan to run in a "class" so Im not capped with cubes or power limits. I have access to an LS1 block or LS2 block from which to start (unless I purchase something different which may or may not be cost effective). The motor needs to be rock solid durable. I plan to run an accusump and road race oil pan. The guys Im gonna be running with/against, have some crazy setups, I realize it will take cubic dollars to be competitive...but if I can just get in the mix, with a decent power plant I'll be happy.


Option 1: Rebuilt LS1 with stock crank, rods (arp bolts), forged pistons, AI TFS heads, 231/239 112 cam, FAST 102 Intake/TB, ARH 1 7/8" headers, accusump, RR oil pan with filter relocation. ~ cost $3500 (i already have several of the above parts from my previous build).

OPtion 2: Stroked LS2 (408), K1 crank, Scat Ultralight rods, JE pistons, Morel lifters, YT rockers, custom cam, AI TFS 230cc heads, Fast 102 intake/TB, ARH 1 7/8" headers, accusump, RR oil pan with filter relocation. ~$10,000

I have several other ancillary parts to buy, like brakes, sways, springs, wheels/tires...so I'm leaning towards the option 1....The previous setup made 456/415 on a conservative dyno, I figure with forged piston choice and the AI TFS heads, I could pick up a few more hp, and maintain good AUC TQ. It would put me real close to 475-480rwhp, and IMHO that would be fairly competitive with the guys I'm running with.

Thoughts?

got milk??

iTrader: (18)

Both of those setups are stout, but autoX is more about the total package than raw power. Your suspension/ wheel, tire combo is equally if not more important than a 480hp motor. You should send Sam Strano a PM or email and get his input/advice. The guy has decades of autoX time under his belt.

3.4camaro

iTrader: (1)

If I were building a road race motor, I'd be looking to spin high rpms.

I'd bore out the motor to the largest bore possible, with a short stroke crank(stock LS1 or maybe 4.8L). This way, you're getting maximum cubes and not over doing it on the piston speed. Piston speed is what melts rings and causes damage and undue wear.

This setup also allows for the largest valve size among your options, so you'll be achieving the highest airflow.

Since you're posting this in the Gen4 section, I'd recommend you get an LS3 block so you can get them fancy piston oil squirters installed. Put that dry sump to good use, and keep those fancy pistons of your VERY cool.

Che70velle

iTrader: (6)

Road course and auto cross is two entirely different animals. Road course racing is very fast paced, high rpm racing with crazy top speeds. It is endurance racing at its finest. Auto cross on the other hand, is all about suspension set up with an occasional full throttle stab. Tire choice and brakes are huge benefactors, with throttle control being king. Both of these styles of racing have some similarities, but are also very different engine wise. You won't win an autocross with the most power. I watched Kyle Tucker just this past weekend at the LSX shootout autocross, and many others, and it's finess racing. I raced NASCAR late models for many years across the street from Road Atlanta, and I can tell you road racing is very extreme. I'm building my chevelle for autocross, and street use.

pharmd

iTrader: (4)

I have an LS1 block AND LS2 block...We are leaning towards building the LS2 with stock crank, forged rods/pistons, AI TFS heads, COMP rockers, Morel lifters, FAST 102 intake/TB. We think that we will be between 480-500rwhp and 430-450rwtq. I may use my current cam 231/239 113 and advance it some (its retarted 5 deg now), or go with a custom grind...just depends on what Phil thinks are the trade offs.

My LS1 made good power, but I think I had oil control issues...I will be resolving with an accusump, and road race oil pan.

Any arguments for the stock cube LS2 build vs the 408 LS2 build? Does the power difference justify the cost?

Tainted

iTrader: (9)

Theres no replacement for displacement and bigger bore, with a better platform, and more hp and tq to start with. Ls2 all the way

crainholio

iTrader: (2)

Not so much, if you want the engine to last. Or to make power on corner exit where you need it.

pharmd

iTrader: (4)

agreed...awesome TQ from 3K on, with good HP from 3000-6000 would be very adequate. I think with how much of a focus AI keeps on port velocity and chamber efficiency, with the right CR, it will meet those goals.

garcr4

iTrader: (1)

We have been racing LS motors in stock cars our Corvette and tube frame Camaro for years.

A few observations:

Torque seems to be king in most road race applications as long as you can hook it up.
Our torquey 5.7 LS1 motors have won races and set track records at times utilizing very mild set ups: stock compression LS1's with headers, ASA hot cam, ECU tuned by Schwanke or Carb version with MSD 6LS. These motors made between 450-480 flywheel HP and turn about 6500-6800 rpm. Our 2800 pound with driver tube frame Camaro with a 480 HP LS1 turned a 1:56.9 at Daytona with a top speed of 182 mph in the trioval and beat a lot of higher HP GT-1 cars.

We have used the single stage scavenge dry sump system with success. It uses the stock pressure pump, has a three gallon dry sump tank and a Moroso ASA dry sump oil pan. This system worked well in the old ASA AC Delco series. Some used their motors for several years, sold the cars to road racers, where the motors lasted several more years.

that said, a full dry sump system is preferrable!

Anything less than this is asking for trouble if you are running sticky road race tires with high corner G's. The accusump deal is a bandaid.

3.4camaro

iTrader: (1)

A properly built, dry sump engine would have no problem spinning to 8000rpm. If the valvetrain is lightweight and properly set up, you'll be just fine.

You'd need driving lessons if you don't know how to be in the right gear when leaving a corner.

Why are you against high rpms?

crainholio

iTrader: (2)

Over 7 years experience between offshore and ARCA here. What is the source of your expertise?

Post the Grand Am, ALMS, or other endurance racing team doing what you're describing with LS engines...or are you just reading magazines and barfing up assumptions?

3.4camaro

iTrader: (1)

http://speedtalk.com/forum/viewtopic.php?p=150911

"The CTSV dominated the first races, not only did the sanctioning body enforce an RPM limit on the short stoke Caddies but they eventually implemented more restrictions to limit the horsepower on these LS7 equipped 346ci engines. "

It's clear that high rpms with short strokes win races. Look at F1 as another example. Now, what exactly are you talking down to me for?

Go ahead and answer my first question: What do you have against high rpm motors?

garcr4

iTrader: (1)

You can win races with torque or with rpm hp, but certainly twisting LS motors in the 8000 rpm range is gonna require expensive rebuilds much sooner. SCCA GT-1/Trans Am motors make over 800 hp and twist in the 9000 rpm range. But they are used up in 600 miles, requiring many new and expensive parts for the rebuild.

If you are on a club racers budget the wiser move would be to use the inherent torque of the LS design and cam for 7000 rpm or less.

The AlMS Corvettes turn less than 7000 rpm but make incredible torque and their lap times don't suffer.

I watched at Daytona last year at the HSR race and saw a front running Trans Am car with SB2 twisting around 9000 rpm (840 hp) with a race weight of 2780 with driver turn a 1:47 lap. During the same race a World Challenge Corvette at about 3150 running a torquey LS2 6.0 (maybe 600 hp) liter cut a 1:48

JD_AMG

I have to lol at this...
The only reason you are seeing high RPMs is because those classes have displacement limitations. So they HAVE TO rev higher if they want to make more power.
There is absolutely no reason to spend all the extra money on building the engine to turn 8000RPMs, that money could be spent making more power with less RPMs...

Bink

Yep.

Also, follow garcr4 advice - he's a builder and a road racer.

crainholio

iTrader: (2)

I suppose I missed the OP's stated intent to compete in F-1 or build a short-stroke engine...go back and re-read the two options he was considering.

And your quote of the current CTS-V program overlooks quite a bit of background. When they fielded that car in the mid-2000's it was running a 7.0L stroker, same displacement as the C5.R program. On most tracks they weren't even breaking 6K RPMs, and were winning races. Then came homologation rule changes and less displacement...


How many endurance racing engines have you built and put on a track? You're giving advice, so you must have experience from which you're drawing...or are you another Intarwebz Expert regurgitating magazine articles?

I already did. Go ahead and re-read my first response to your post, in the context of the options the OP was considering. High-revving engine setup does not fit his requirement for durability.

And the kind of induction setup and cam that would make power at high revs takes away from midrange torque.

If he's not running a $20K sequential trans, the extra downshift(s) to keep the peaky high-rev engine making power out of the corners will cost him plenty versus the guy who can run the same course using only gears 3 & 4.

pharmd

iTrader: (4)

Do you have a product recommendation on this? I was under the impression by adding a road race oil pan, along with oil cooler, remote mount filter, and Canton accusump I would pretty much be covered for oil control...but if Im not covered, I need to know how to cover myself. If I build the LS1 or use the LS2 block and build that motor, what options do I have (affordable options preferred).

gnx7

iTrader: (28)

3.4 Camaro must have more money than brains....

RPMs kill motors. The brighter it burns.... the less amount of time it lasts. No need to rev past 7K on a road race setup for longevity unless you have GM's bank account for frequent rebuilds.

I have an SCCA ITE car (unlimited) that runs a 438ci stroker (LS7 with 4.1" crank) and it sees a 6600rpm redline. Could it rev to 7Krpm+..... yes.... but the wide torque band is used to run a GForce GSR 4spd dogbox and 3.27 rear gear with 13" rear wide slicks. It is actually driven as a 3speed as 1st is only used to get moving. The car puts the power down everywhere and simply keeps pulling. Mine is only 2470lbs with 7 gallons of fuel... but it gets around the track in a hurry. My complete clutch/flywheel combo is only 13lbs. Triple disc Quartermaster setup. Revs instantly.

Build the largest displacement engine you can with the most compression possible and then gear it appropriately and put massive tires on the car or at least the stickiest tire you are allowed to run. Dry sump if you can afford it or an Accusump and overfill with 1 quart plus trap door/pan baffle setup minimum. I run an ARE multi stage dry sump pan with Aviad pump and 3 gallon sump behind a firewall in the passenger side area.

IMO if you are limited to an LS2 block than run some TFS 225cc as cast heads with Brian Tooley touch up work (ex-TEA porting guru) and FAST 102mm intake. If you need his contact info LMK. Consider a 4.1" crank also. No need for Morels... I'm running $100 CTS-V GM lifters and stock rebuilt Comp Cams trunion rocker arms. If you are on a budget skip the FAST and run an LS6 intake as you don't need to wind out this motor. A straight shot intake with no bends will add 10-15rwhp.

Next will be track time to learn the car and punish what you have to work with.

garcr4

iTrader: (1)

ARE, AVIAD, and DAILY all make nice dry sump systems for LS Motors.

My Corvette uses an ARE pan, with a Barnes single stage pump set up from Schwanke.

Our Camaro uses the ASA Moroso pan that was on the Lingenfelter LS1's run in ASA AC Delco stock car series. I have one of those set ups for sale if you are interested. They used a RAZOR single stage pump.

LSfan70s

Awesome post. Thanks for sharing all the good info.

Is there any recipe for the LS's engines scavenge only dry sump pulley sizes? This is for budget/get all parts one by one project. I read somewhere that a 50% relation would be fine, but I can't confirm. Any guidance is highly appreciated.