Sunday, December 22, 2013
Here we show what the twin turbo LSX engine can do on our Superflow Powermark engine dyno! In the famous words of Tim Allen "moreeee powerrr!"
Tuesday, December 17, 2013
So here we are with the last installment of the LSX project. (There may be a brief installment when the car is done, just to say how it runs.)
I’ve changed a few things from the original design (but not much) in order to better handle the turbo platform. Here are the changes.
- Bored out the block to a final size of 4.200. I would have rather kept it at 4.185 per the original bore but one of the cylinders was screwed up from our – mishap we’ll call it, and it had to be stretched to 4.200
- Sold the crank. Not because there was anything wrong with it, but because I decided to keep the RPMs a little lower and opted for a few more cubes to get some more bottom end power. I ended up with a 4.000” stroke yielding a total CID of 444. This time we used a 2.100 pin Callies Dragon Slayer model.
- Changed the rods to match the crank. Even though I have used the Callies Compstar stuff after the failure, with success and I magnafluxed the remaining seven rods with no problems, I wasn’t about to reuse the remaining seven good rods in this motor making this kind of HP. I believe they would’ve worked fine but instead I opted to go with some Olivers this go round. I have used Olivers before in my 9000 rpm circle track stuff and never had a problem so I felt a little more warm and fuzzy with them, at this time.
- Changed the lifters. This engine originally had Comp roller lifters in it. Upon reassembly I used Isky Red Zone lifters. The reason for this is I ran into a failure with the Comp roller lifters with needle bearings in a big block Chevy about a year ago. It wasn’t the fault of the lifter as much as it was the combination. You see I had purchased a set of assembled Dart Pro 1 heads with the stiffer spring set up to go with the solid roller cam that was being put in. I didn’t double check the spring pressure and assumed it was what Dart advertises. Shame on me! Turns out they had way more pressure they advertised due to the installed spring height being too short. This, in conjunction with a very aggressive ramp profile on the cam and the low rpm’s of street driving wiped out the lifter’s needle bearings. When I reassembled it, I changed the ramp profile, spring pressure and went to the Red Zone lifters. Never had a problem again. Since then I’ve been using the Isky lifters a lot. So far they’ve been great in everything and I really like the concept of no needle bearings. Isky uses a bushing with no needles. This is a more efficient design, in theory at least, and seems to work well.
- Changed the cam (which we were going to have to do anyway) to a more turbo friendly 242/242 @ .050 .690/.690 on a 114 LSA, still a solid lifter version.
- Added piston squirters in an attempt to keep the piston cool under high boost.
- Ordered Diamond pistons with the hard anodized coating on top and friction coating on the skirts. I’ve started using Diamond pistons because I got sick of the California companies making me wait eight weeks for custom pistons to be made and then waiting another two weeks for them in the shipping process. Even with custom stuff, Diamond usually gets them done for me in about six weeks, then it’s only one day shipping to where I’m at. Their product is just as good if not better than the other major brands. After all, they’re all using the same alloys. Another advantage to Diamond that the other companies haven’t caught up to yet is, they keep an unbelievable amount of pistons in semi-finished form. So if you want to make a few minor changes to their shelf pistons – no big deal. I was even told by an old friend that works for a competitor of Diamond, “Diamond’s got it figured out. I’m trying to get our company to structure itself more like them.” (meaning Diamond)
- Enlarged the throttle body to a massive 102 mm by FAST to go with the new intake. We used a MAST Motorsports 2 piece intake with an elbow on top to feed the beast. The design of the MAST intake allows for better air distribution. The only reason stock intakes feed from the front is to obtain a lower profile for hood clearance. More hood clearance means the manufactures can lower the hood making your car more aerodynamic and therefore increase fuel mileage. Since we are now putting the engine into a 69 Camaro, we have enough hood clearance to use a better intake. The testing we’ve done on this intake showed us an increase of 30 to 40 HP over the stock design. This was on a N/A engine.
- Turbos. We used Precision PT6768 turbos. These turbos are capable of 935 HP each. They have a 67mm inducer and a 68 mm turbine with an A/R of .81. We also upgraded to the ceramic ball bearings for faster spool up time.
- Intercooler. We had the boys at Precision build us the air to air intercooler. I can’t remember the dimensions off the top of my head but this thing is massive. It’s the biggest we could fit in front of the radiator and behind the grill. It has single 4” inlet and single 4” outlet. When building a turbo system for the street, HP is limited to how cool you can keep the intake charge. Some of you may be thinking just add more boost right? Here’s the thing, more boost does make more power by forcing more air into your engine but it does this by compressing the air. Any time you compress air, it heats up. 5 to 7 psi is nothing in the turbo world and doesn’t heat the air up much either. But when you start talking about 30 to 40 psi, the air intake charge temp can go up over 200 F. When air enters the combustion chamber at these kinds of temps, you’ve just created your very own diesel engine with your very own detonation and mama says “Detonation is the double!” This is why, especially with a street driven, pump gas car, you can never get too big with an intercooler.
- We use 2000cc injectors from Fuel Injector Connection in Georgia. Call John for any of your injector needs. He’s one of the nicest most helpful guys your ever gonna meet on the hot rod scene.
- We used a FAST ECU with build in traction control. Just about every sub seven second EFI car in the world uses either Big Stuff 3 or FAST controllers. We chose FAST because we are able to use the incorporated CAN data line to tie into the TCI TCU for the trans we are using.
Well that’s about all the changes I can think of. So I guess it’s time to put it on the dyno, which we did.
I started out very conservatively as I always do. No need to get in a rush just so you can see the huge number that you’ve been waiting for. We need to be careful or instead of seeing that huge number you might see a huge fireball and a hear a huge boom. First I tuned it with no boost. I like to get a good N/A baseline before adding boost. It’s a lot harder to melt down a low compression N/A engine than it is a boosted one. I think we ended up with something like 439 HP through the turbos with no boost. Not very impressive at first glance but remember this engine wasn’t designed to be ran with no boost. Remember it’s making no boost but still trying to push the exhaust through the turbos, simulating a plugged exhaust system. Now that we got a nice safe fuel and spark curve for N/A we can add a little boost. Easy now I said A LITTLE BOOST! Let’s start out with about 5 psi. Now that that’s dialed in we can go to 10, then 15 and finally 20 psi. We ended up with about 1269 HP @ 6250 RPM and 1134 Torque @ 3900 @ 20 psi with a very, very conservative tune. I mean the AFR is like 11:1 and the timing is set at about 12 degrees BTDC. I was shooting for about 1100 HP on pump gas. So when I saw 1269 HP on the dyno, there was no need to get any more aggressive with the tune. I was running 11 degrees BTDC and creeping up on it slowly. It was making like 1209 HP. Going from 11 to 12 degrees timing picked up like 60 HP which is typical of a boosted engine. More timing usually means more power until detonation begins. From there it doesn’t take long before you have that very expensive piston blender that I’ve talked about.
This engine is going in a 69 Pro Touring Camaro and will probably never see the track. So let’s be honest, do we really need any more power for the street? I mean really. If you need 1300 HP for your daily driver or your show car you might wanna think about getting up for work a little earlier or leaving for the show a little sooner. So why put 1300 HP in a car like this? Let just say, Just in case. I’m sure on race gas and something like 28 psi we could see the 1700 HP mark, but for now this is where we’re going to leave it.
Now I can’t remember all the HP number at all the different levels of boost but if you go to engineeredvictories.com or our youtube channel, you’ll be able to see the full pull @ 20 psi of boost.
Thanks for keep up with all the projects at Engineered Victories and check back often to see what’s new.
If there is any way we can help with one of your projects give us a call and will be happy to help.
OK, a lot of time has passed since our last update on the LSX project and I apologize for that. Please let me explain.
To make a long story short and get to the good stuff I will tell you what happened as briefly as I can. We finished the naturally aspirated version of the engine and it ran good. But truthfully not as good as I had hoped. It made about 500 RWHP and I expected more. I did the math on HP per CID and it was about the same as a cammed LS7. I said to myself, "self, with all of your engine building knowledge and experience, how can this be." (Remember, it’s been more than a few years since our last update and everyone’s knowledge of all types of LS engines wasn’t as great as it is now.) Well, I’ll tell ya.
It was only a few months after this that a customer wanted us to build him a twin turbo LS7 for his Z06. (Which we did and it turned out awesome. But that’s another story for another time.) It was only when I disassembled the LS7 that I realized why the LSX made only about the same HP per CI as the LS7.
I was amazed at what I saw. The LS7 had coated, short skirt pistons, a tiny ring package, CNC ported heads, dry sump oiling, titanium intake valves, 1.8:1 rocker ratio, titanium connecting rods, forged crank and lots more. GM had built a race engine for the street, with all of the HP tricks I used (and even some more) on the LSX!!! Bravo GM!!! Now most of the things that were incorporated into the LS7 I had known about, but I guess I had to see it laid out in front of me to really appreciate it.
Anyway, I drove around the WS6 for a couple of weeks and it ran pretty good. I’m sure it would have been more than enough HP for 99% of the people with a license, but remember, I drove 200 MPH NASCAR stock cars for 10 years of my life and 500 RWHP believe it or not can get a little boring after a while. I’m sure anyone who has ran faster than 11’s at the track would agree. (Right guys) So, I decided to hit it with a little go juice until I could finish the project with the twin turbos it was designed for.
I installed a 200 HP wet plate kit and it really woke it up. I’m sure it would have taken me more than a few days to get bored, but we never made it that long. Here’s where the story starts to come together and you’ll understand why it’s been many years since an update.
One night we were all out having fun and beating on our toys when the engine started knocking. We towed it home and did the post mortem tear down. What I found was a broken rod. It was broke right in half about half an inch above the big end. Naturally I needed to find out what exactly happened so every part was scrutinized very carefully. Bearings and caps all looked good. The bearings showed a perfect wear pattern. Combustion and headers showed good color meaning the air fuel mixture was right. There were no signs of detonation so what happened? After examining the breakage area of the rod under a microscope, it was apparent what caused the failure. There was porosity in the rod that could not be seen on the outer service. The porosity was on the inside of the rod as if the forging was a blem. You would never see this with a visual inspection. This is the kind of thing that takes x-ray or ultrasound to detect. You’re not going to get this type of quality control from a set of $600.00 rods. It goes back to, you get what you pay for and that’s why the best rods are in the $2000.00 range.
So there you have it. The engine sat disassembled for about five years and the WS6 got put back to it’s original state. Not to worry though. We started another project for the LSX to go into and this time we finished it the way we originally planned. That’s right, with twins.