NJFBOA - Home of New Jersey's Camaros and Firebirds - View Single Post - Getting my new 406 SBC installed, running, and driving

IROCZman15 · 09-30-2023, 12:33 PM

Pull 8:

Curious to see what a 175 jetting would do, I put in the .063 nitrous and .032 fuel jet combination. We pulled out only another .5 deg, for a total of 29.5 deg timing wot. No lockup on the converter, so it flashed to 5500 when the nitrous kicked on. It ran wayyy rich again, climbed slowly, but the dyno graph really shows the big drop in power immediately after the converter gets to 5700 rpms.This now showed that I made more power with a 150 shot than I just did with a 175 shot (lost 8 hp by jetting up).

507 hp and 471 tq

https://www.youtube.com/watch?v=TVx0dQVFjFc

Pull 9:

We started wondering if my nitrous solenoid might be the culprit. These solenoids are now 9 years old and started life designed for just the 100-150 shot lifestyle on my old TPI 305 engine. I have used and abused these things for a long time, so that might be something to look into. The fuel solenoid is rated for 200 hp flow when new, and the nitrous solenoids are 175 hp when new. I knew this when putting the system together, but at the time just wanted a functioning system. If Science says the solenoids are the culprit, I will just step it up. But, to test our theory, we said, lets keep the fuel jet the same as the one of the 175 shot and put the 200 shot .067 jet in for the nitrous. If we still run rich, that will then tell us something. Well, we still ran rich, lost power starting after the converter grabbed, and the engine was telling us it wanted to pull 37% fuel out in CL comp and Learn numbers.

464 hp and 443 tq

https://www.youtube.com/watch?v=AnyNuvzOJjI

checking fuel pressure again,
but
due to this video, I noticed that my jamb-nut on the lokar throttle cable assembly likes to un-thread itself while going WOT, and then re-thread itself when the engine decelerates!!
Can see it in the other videos too. I've snugged it up now
https://www.youtube.com/watch?v=zZTTAjRen8s

Pull 10:

Put the 175 jet back in on the nitrous side and Jeff watched the AEM o2 sensor again to verify it was reading the same as what the holley would show in the log. Rich again, but losing a bunch more power than the previous 175 shot. In fact, it did almost exactly the same as the above 200 shot in numbers. ITs only getting me a good peak number just around when the converter flashes, after that its not gaining so I was less concerned with power numbers, but more as to the "why" of the graph always falling off.
466 hp and 445 tq

https://www.youtube.com/watch?v=AS4b_EXaHI4

Pull 11:

To cap off our experiment, I went back to the 150 jetting that was used on Pull 5, 6, and 7. Same tune as before with 30 deg WOT timing as the shot is activated. Please note, that we were also curious about heat soak and whatnot, but on these logs, my MAT intake temp shows/logged stable numbers around 102-108 deg mot pulls. It flashed at 5500 and then pulled down into rich fueling territory. the CL comp brought it back up to the 12's but it had to take out 30%. Soon, that 30% (my set limit for dyno not for normal use) was no longer enough, and it ran rich 5750 rpms to 6330 rpms. We also considered that I could be running out of nitrous bottle volume. I had the second full bottle with me, but I think we were all done for the day so I called it quits and we began to free the car from the straps.
456 hp and 439 tq
(I have to laugh, that the same 150 nitrous shot that had produced 149 rwhp just an hour earlier, now only produced 81 hp)
ugh, the nitrous struggle continues.

https://www.youtube.com/watch?v=hZ9h3GUPPFs

Armed with all that data, whats the next thing I went and did?!?!
Dug into the science and try to figure it all out?!
Nope, went home, swapped the wheels off, cleaned the car up, and packed because the next morning I drove down to that big FuelFest car show at New Jersey Motorsports Park. That was a long day, but the car racked up 311 miles of driving without a single issue the entire day. So despite a troublesome and confusing dyno day, I still got some dyno data, made 11 pulls, and then put 311 miles on the car the next day.

Then on Sept 22 I took it to Island Dragway; where I had the COMPLETE OPPOSITE results at the track (writeup to follow one day soon).

09-30-2023, 12:33 PM	#606
IROCZman15 10 Second Club / Meet Coordinator Join Date: Dec 2004 Location: Roxbury, NJ Posts: 2,101 iTrader: (8)	Pull 8: Curious to see what a 175 jetting would do, I put in the .063 nitrous and .032 fuel jet combination. We pulled out only another .5 deg, for a total of 29.5 deg timing wot. No lockup on the converter, so it flashed to 5500 when the nitrous kicked on. It ran wayyy rich again, climbed slowly, but the dyno graph really shows the big drop in power immediately after the converter gets to 5700 rpms.This now showed that I made more power with a 150 shot than I just did with a 175 shot (lost 8 hp by jetting up). 507 hp and 471 tq https://www.youtube.com/watch?v=TVx0dQVFjFc Pull 9: We started wondering if my nitrous solenoid might be the culprit. These solenoids are now 9 years old and started life designed for just the 100-150 shot lifestyle on my old TPI 305 engine. I have used and abused these things for a long time, so that might be something to look into. The fuel solenoid is rated for 200 hp flow when new, and the nitrous solenoids are 175 hp when new. I knew this when putting the system together, but at the time just wanted a functioning system. If Science says the solenoids are the culprit, I will just step it up. But, to test our theory, we said, lets keep the fuel jet the same as the one of the 175 shot and put the 200 shot .067 jet in for the nitrous. If we still run rich, that will then tell us something. Well, we still ran rich, lost power starting after the converter grabbed, and the engine was telling us it wanted to pull 37% fuel out in CL comp and Learn numbers. 464 hp and 443 tq https://www.youtube.com/watch?v=AnyNuvzOJjI checking fuel pressure again, but due to this video, I noticed that my jamb-nut on the lokar throttle cable assembly likes to un-thread itself while going WOT, and then re-thread itself when the engine decelerates!! Can see it in the other videos too. I've snugged it up now https://www.youtube.com/watch?v=zZTTAjRen8s Pull 10: Put the 175 jet back in on the nitrous side and Jeff watched the AEM o2 sensor again to verify it was reading the same as what the holley would show in the log. Rich again, but losing a bunch more power than the previous 175 shot. In fact, it did almost exactly the same as the above 200 shot in numbers. ITs only getting me a good peak number just around when the converter flashes, after that its not gaining so I was less concerned with power numbers, but more as to the "why" of the graph always falling off. 466 hp and 445 tq https://www.youtube.com/watch?v=AS4b_EXaHI4 Pull 11: To cap off our experiment, I went back to the 150 jetting that was used on Pull 5, 6, and 7. Same tune as before with 30 deg WOT timing as the shot is activated. Please note, that we were also curious about heat soak and whatnot, but on these logs, my MAT intake temp shows/logged stable numbers around 102-108 deg mot pulls. It flashed at 5500 and then pulled down into rich fueling territory. the CL comp brought it back up to the 12's but it had to take out 30%. Soon, that 30% (my set limit for dyno not for normal use) was no longer enough, and it ran rich 5750 rpms to 6330 rpms. We also considered that I could be running out of nitrous bottle volume. I had the second full bottle with me, but I think we were all done for the day so I called it quits and we began to free the car from the straps. 456 hp and 439 tq (I have to laugh, that the same 150 nitrous shot that had produced 149 rwhp just an hour earlier, now only produced 81 hp) ugh, the nitrous struggle continues. https://www.youtube.com/watch?v=hZ9h3GUPPFs Armed with all that data, whats the next thing I went and did?!?! Dug into the science and try to figure it all out?! Nope, went home, swapped the wheels off, cleaned the car up, and packed because the next morning I drove down to that big FuelFest car show at New Jersey Motorsports Park. That was a long day, but the car racked up 311 miles of driving without a single issue the entire day. So despite a troublesome and confusing dyno day, I still got some dyno data, made 11 pulls, and then put 311 miles on the car the next day. Then on Sept 22 I took it to Island Dragway; where I had the COMPLETE OPPOSITE results at the track (writeup to follow one day soon). __________________ 1987 IROC-Z - modified Last edited by IROCZman15; 09-30-2023 at 12:37 PM.