Entries by Dr. Jeff Harper (34)
Plan B
Thursday, November 11, 2010 at 10:30AM Plan B: Since it is going to take some time to get all the pieces together for my race-prepped 2UZ short block (rods and pistons and boring/honing, ++), I have decided to put my racer back together with another standard 1UZ bottom end I already have so I can go racing. Everybody who has looked at the motor with the broken rod can confirm that there was no evidence of overheating or detonation or leaning out or hydrolicing on that or any other cylinder. All the saved data confirm this as well. There is a race on December 4th I will try to make. Wish me luck.
Dr. Jeff Harper
So, I have re-computed the dyno horsepower based on the concept that my racver was not wired correctly and was, in fact, in Overdrive (0.76 ratio trans + 4:11 rear end) during the dyno pull. The new numbers are = 367 RWHP w/o NOS . . . + the 40hp of NOS = 407 RWHP. Assuming a 20% loss through the auto trans = 440 flywheel HP w/o NOS and 488 flywheel HP with NOS. Hmmm . . . . maybe that 40hp of NOS while the motor was making 440HP was enough to break the standard rod under the load of the overdrive gearing and the extreme dyno resistance? These numbers seem more realistic when compared to the injector size (565cc) and duty cycle(75%/85% with NOS).
Dr. Jeff Harper
Son of Dyno Day
Saturday, October 16, 2010 at 8:05PM Got on the dyno again today. Of course it rained . . . and I have an open trailer. Oh well.
Everything was "fixed" on the supercharged 1UZ . . . We put it back on the AVO dyno . . . . It ran great right up to 7000rpm. We registered 955 ft. lbs. of torque at 5500rpm without NOS. We got 1093 ft.lbs with the NOS turned on. Still have to do the HP calculation.
That it Terry Wilson, Managing Director of AVO Turbo behind the wheel. This is from one of the dyno pulls:
That is some crazy torque . . . it is the actual "delivered" torque as read at the rollers (?). That HP (280) does not seem right . . . given the perfect AFR and 72% duty cycle on the 565cc injectors. But our best boost was "only" 5.5 psi. That little Vortech V9 was just keeping up with the air demands of this 242 cubic inch engine.
It was a good day. I think I have run up against those very restrictive lower intake manifold runners . . . . . there was no real increase of torque or HP above 5500.
Dr. Jeff Harper
My Friend John wrote:
Hi Jeff,
As promised: on your new dyno numbers, so 955 FtLbs and you say it was at 5500rpm. What’s your diff ratio and Nos shot?? What is the torque down too at 7500 RPM? Anyway lets say your diff is a 3.7:1 and we have 20% drive train loss then (955/3.7)/0.8 = 322 Ftlbs at the flywheel so (322x5500)/5252 = 337 Flywheel HP or 270 Wheel HP. So the dyno numbers (280WHP) are about right, or in the right ballpark. Or your SMS figures with no nos 883ftlbs @5000 so (((883/3.7)/0.8)*5000)/5252 = 283/225 FHP/WHP. Sounds like you using a 50 shot? Your numbers do seem down a tad for having cams in, it but I notice you are only at 4.6PSI. Is that 4.6psi correct? Assuming it is then keep in mind a bone stock N/A 1uz auto has 240HP or 190 WHP, and in your case you are running 0.31Bar so you should expect around 315 FHP at this boost less supercharger drive loss so the no Nos 280 FHP mark is reasonable to expect. I need to see more data and that dyno graph is vague but it sounds like torque might be dropping a little too much at the post peak torque rpm’s, you might be able to get that back through cam setting and a bit more tweaking. How does it respond to ignition timing advance increase steps? Also when you run the car on the track, the trap speed will tell us HP quite accurately, so I wouldn’t be overly concerned about dyno numbers.
John
Dr. Jeff Harper
OOPS!
Cylinder #7 shows zero compression. Something went away.
Dr. Jeff Harper
OOPS! Indeed
During the last dyno pull the engine would not rev to 5000 and there were strange noises. Upon returning to the shop the number 7 cylinder was found to have zero compression. Removing the head revealed the number 7 piston could be pushed down with one finger. A broken rod! Rats!
Dr. Jeff Harper
This is what the broken looks like:
The bottom of the piston is also broken. Hmmmmm . . . what happened?
I finally got around to getting a look at the busted rod. Here are some better photos for the amateur metallurgists to sink their teeth into!
Yep, there's your problem!
Dr. Jeff Harper
There appears to be quite a variance in opinion, and experience, as to the strength, and horsepower limits, of the standard (large rod) 1UZ bottom end. Some compliment their own good tuning for the reliability of their high boost standard short block motors, while others claim bad luck for broken parts on well tuned standard 1UZs. And there have been some broken parts because of mistakes. I believe all groups. So, now I have to make a decision. I do not have unlimited funds for an 'ultimate strength' combination (Carrillo rods), but I have some petty cash. Here is what I am going to do now: I have found a good rebuild-able 2UZ (4.7L) bottom end (in "up country" Thailand). I will use my current intake, supercharger, heads (it is good, but needs two new valves, which I have), deep oil pan, camshafts/springs, and head studs with this 2UZ short block. Amazingly, I found and purchased a set of Lextreme steel rods and Calico bearings here in Bangkok. I will check (and correct, if needed) the 2UZ crankshaft and bore/hone the block .030 over (292cu.in), get ARP main studs, and order the appropriate forged pistons in a 10.5 or 11.0 compression - because I have taken the humps out of the combustion chambers and have only 5-8 pounds of boost on race gas. I will order another set of 1.3 Cometic steel head gaskets (I have sold the 1UZ set already). I was already at 85% duty cycle on my 565cc injectors with the dry NOS, so I will also get new 1000cc injectors (for MORE NOS!). For future use, I am also negotiating for one of those high flowing New Zealand single plane high rise manifolds converted to EFI . . . . . SO LOOK OUT! Wish me luck! I hope you haven't run out of it yet!
Dyno Day (Dyno Debacle?) (Dyno Delay!)!
Sunday, October 3, 2010 at 9:29AM Well . . . the new motor combination finally got to see its day on the dyno . . . actually two days. There were a couple of issues that first delayed the dyno pull, and another that stopped it. of course the water pump chose this moment to start leaking. A runner was sent to fetch a new one . . . and it was installed four hours later. I had the opportunity to use the AVO Turbo development dyno for the day:
Then, when we got it up and running and a map was gradually being put into the ECU, the dyno computer would shut down for no reason as soon as we started to make real noise. It was determined that the combination of RF interference and too much noise from the open headers was playing hell with the computer. We devised some shields and, because we were at the AVO Turbo (Yeah Subaru!) manufacturing facility, they made up some large 3" pipes with nice stainless steel mufflers for the dyno. This worked up to a point, but the dyno computer still died. More shielding was added around the dyno computer, and a human shield was added (me!). This worked . . . . but then the car would not, absolutely not, run up above 4800rpm. All the usual suspects were checked (fuel pressure, spark, etc., etc.). It was like the throttle was being held at that rpm (it wasn't). The fuel pressure and AFR were right, and it was not missing, popping or banging. We were all mystified. Then we tested a "free rev" with the trans in Park . . it sounded like it was up against a soft rev limiter. Oh well. Time to go back to the shop and move the CDI the hell away from everything else, shield it, and separate all high RF wires from anything. Theory number two was that perhaps one, or both, of the intake cams were put in too far in advance . . . a telltale sign being the 663 ft. lbs. of (delivered) torque it generated at 4200rpm. Not too bad, really, from a 242 cu.in. (4.0L) motor on race gas. We'll sort it out and be back on the dyno in a couple of weeks. I am disappointed . . . but we learned a thing or two.
The Dyno Day Debacle started with a water pump replacement.
The AVO guys made a nice pipe and muffler set-up to keep the open headers from vibrating the dyno computer into the "OFF" position.
I complained to the AVO Turbo Mangaing Director, Terry Wilson, that this exhaust system would make my car very difficult to park at the shopping mall.
El race truck con twice pipes.
Dr. Jeff Harper
IT'S FIXED!
OK, after tracing all ignition-related wires, separating a few, and shielding a few others . . . . it still "hit the RPM limiter" of an unknown source. A quick-witted shop hand noticed some sparking at the coils . . . sure enough . . . . the car had been wired before I knew I would use a CDI, so the wiring was not insulated as it should have been at the coils: there was arcing between the terminals on the coils. Apparently, as the CDI made more and more power, it reached a level where it would cross-spark . . . and then bounce at that RPM level. We covered it all up with shrink-sleeve . . . Voila! RPM to the ceiling! Now, to rebook a dyno session for this week-end . . . . . .
Dr. Jeff Harper
Dyno Session #2 Booked
I'll be back at it early Saturday morning.
The 1UZ V-8 Runs At Last!
Saturday, September 25, 2010 at 6:25PM Next step is to put it on the dyno later this week!
It Started (I think)!
Sunday, September 12, 2010 at 11:16AM I received this e-mail from my shop guy, Art, in Pattaya:
"I started your truck today. No leaks any where. I mean not air leak, and no fluids leaks. Started right up on the first try. Starts very easy. Idle nice, and respond nice. More later...."
I wonder what this means?
Dr. Jeff Harper
Called up my engine guy last night and he started the beast so I could listen over the phone: TOTAL AUDIO DISTORTION. After the call, I had him let it idle for 10 minutes (jacked up and in gear) to get the motor and running gear up to temperature and to check to see if the fans all worked and nothing got too hot. Check. Still waiting on the dyno appointment confirmation.