Project Thread Supercharged 1UZ Bangkok Drag Truck

The 1UZFE EGR Delete Kit is available for sale here.
I have an appointment at noon this Friday (Oct. 1) at the dyno shop. I am not expecting big numbers. 450rwhp would be satisfactory without the NOS . . . which would be low 10 second ETs in my light weight racer. I will take what I can get . . . and then make bigger numbers with the NOS when I need it to qualify.
 
Dyno Day . . . Oh Well . . .

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. 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 were playing hell with the computer. We devised some shields and, because we were at the AVO (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 at 5100rpm. 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 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 YouTube clip is here: http://www.youtube.com/watch?v=88x8r2a2R5s


WaterPumpFix850.jpgThe Dyno Day Debacle started with a water pump replacement.
OnDyno6286850.jpgThe AVO guys made a nice pipe and muffler set-up to keep the race from vibrating the dyno computer into the "OFF" position.
DynoPIPES6284850.jpgI complained to the AVO Mangaing Director that this exhaust system would make my car very difficcult to park at the shopping mall.
OnDyno6278850.jpgEl race truck con twice pipes.
 
The torque number I quoted in my entry (663 ft.lbs. - above) was the uncorrected "delivered torque" reading from the rollers. We had not calibrated the dyno software before we quit the session. We had only begun to make the AFR-to-boost/vacuum map.
 
Found the problem!

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 . . . . . .:D
 
I wonder if cross arching has anything to do with why the A341 trans always bounces off the limiter? Iv seen people shimming accumulators w/ maxed out line pressure and still dealing with the bounce.
 
SPF_Lexus -- Sorry, I should have been clearer with my terminology: My car had been revving up and down at around 5000rpm, as if it is "bouncing" off a rev limiter". It would generate high voltage at around that RPM which was the level at which it would arc . . . then, the arcing would drop the rpm which also lowered the spark, which would then stop the arcing, which would raise the rpm, and over and over -- "bouncing," as it were, the rpm up and down. I do use a modified A340-series Toyota auto trans with a MV Automatics Level 2.5 valve body and 3800-4200 stall converter. I didn't shim the accumulators, I actually replaced the springs with a section of thick-walled brass tube to make them solid . . . . makes for some very nice wheels up 1-2 shifts! And NO BOUNCE!
dayrace04sm.jpg
moz-screenshot-1.png
moz-screenshot-2.png
 
Zuffen. I was just wondering . . . there is a lot of talk on this site about the standard lower manifold runners restricting airflow above 5000rpm . . . . and thought these might flow more. Thanks for the link. Very interesting. It looks like a couple of members purchased this set-up, but no accounts of the quality or performance. There are a couple of YouTube clips of these in anger . . . but no detail.
 
Yes I wander if a BOXED supercharger manifold would work with big single or twin throttle body ?? Could run an intercooler in manifold ???
Should be WAY better than closed down std inlet ???
 


Back
Top