#21  
Old 02-25-2020, 11:44 AM
avman avman is offline
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Rained most of the night/early morning so Tuesday's "Mardi Gras" racing was canceled, but Test and Tune followed by bracket racing is ON for Wednesday night, and I "have permission" to take the GTO since my wife is working.
I'm going for the 12.8 or better time. If I don't make that time, and it's not traction problems, I hope to come close! Other than any minor tweaks to the carbs, and playing with the timing, nothing else to do to make more power, and I'm certain that the 421 is putting out more HP and torque than the 389 my dad ran his 12.8 with.
If the reason for not making it is traction problems, the new replacement rear axle housing is going to have some adjustments available to address that.
I'll let you know Wednesday night or Thursday morning.

  #22  
Old 02-25-2020, 06:14 PM
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Dick Boneske Dick Boneske is offline
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Wish I could be there. Brings back memories. If your harmonic balancer is calibrated, I would set initial timing without vacuum advance. You want no more than 34-36 degrees total advance, depending on what fuel you use.

Regarding vacuum advance, the stock units can add 15-20 degrees at light throttle, high vacuum, which is way too much total at 49-56 degrees.

For your drag strip trial, I'd eliminate the vacuum advance. Set the initial advance at about 12 degrees, and check to see that the total advance is less than 34 at about 2500 rpm. Your total advance should be all in by 2500 rpm.

After your drag strip trip, you may want to retard the timing a little, reconnect the vacuum, and make sure you're not running in the 49-56 degree range.

Others feel free to chime in, but that's my recommendation.

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  #23  
Old 02-25-2020, 09:54 PM
avman avman is offline
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Thanks Dick...
I run 92 octane 100% petroleum gasoline. It's available by my house and at the exit off the highway of the Dragway.
I want to emphasize that I have a PERTRONIX billet aluminum distributor and the Ignitor III Module, it comes with a variety of timing tuning capabilities and pieces parts to achieve that (springs, limiters, weights, etc). I am going to use my dial back timing light to check current status. If anything it's set to the "safe side" of the curve, as the 2 test drives I took included less than ideal engine loading tests, in other words a heavier throttle than the relatively low RPMs would call for, and I got ZERO pinging. I didn't lug the motor, but I did "test" it for susceptibility to pinging, and it didn't knock at all, so it's likely that I can dial in some additional advance.
I'll bring my timing light and distributor hold down clamp bolt wrench with me, along with my Ryobi air compressor, so I can play with tire pressure too.
I'll post results tomorrow night or Thursday.
Thanks!

  #24  
Old 02-27-2020, 02:07 AM
avman avman is offline
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Ok, so I have to study the instructions that came with my Pertronix billet aluminum distributor. It has a fantastic "module" built in, the Ignitor III, which provides TRUE multiple spark output, a rev limiter, and high voltage spark capability when paired with the Flamethrower ignition coil.
The unit came with springs and weights, and some other parts to tune the timing curve and advance to be of greatest synergy with the engine it's installed in. I haven't done anything with it since it was installed. The shop that installed the 421 after the rebuild had "issues" with the vacuum advance, which I have hooked up now because most of the time the GTO is cruising around, going to local car events, and I'm all in on the benefits in efficiency that a vacuum advance can bring.
To his credit, Mr Boneske recommended that I disconnect the vacuum advance at the race track and set the total timing to about 33° I chose to disconnect it to do the total advance, but reconnected it for the trip and left it connected when I made my runs, because at WOT there is very little to no vacuum. What I did notice is the "sputtering" and "surging" sensation in the background of the main feel coming from the engine that I thought was carburetor related because it was gone when I installed the modded carbs I got back from Boneske, well that stuttering was back on the road and highway there and back.
So I think there is a lot of room for improvement in the overall performance and race track performance of the 421.
So now that I've prefaced my "track night report" I will say that the GTO is running better than ever, and the 4/10ths better than ever times reflect that. I also used the line lock for the first time, cleaning and heating the Toyo Proxes TQ drag radials in 2nd gear which seemed to give me enough torque and wheel speed to get the job done. I also did "no lift shifts" tonight, relying on my rev limiter should I miss a shift. I ran 13.6 @ 103 and 13.58 @ 102 No wheel spin on the first run, and a little on the 2nd. I don't have a tachometer, but the soon to be installed Dakota Digital gauges will remedy that, and the control box will allow for a shift light too. On each run I found the rev limiter in 2and or 3rd. Also, the combination of tire diameter on the 17" wheels and the 3.80 ring and pinion gearset make for a very high revving combo. I was concerned about hitting the 5,800 RPM limit in 4th, and I'm sure I was close, but I didn't hit the limiter on any run in 4th gear. The TKO600 5 speed is a MUST with my current combination on the highway, but certainly not at the track. If I find that as we get quicker off the line and down the track that the limiter in 4th is an issue, I may bump the limit a bit or find a taller tire.
Overall I'm very pleased with the performance of the GTO, and very pleased with the work and modifications Mr Boneske did, and the car is running better. I have jets for all 3 Rochesters in the next size up and down from what Boneske installed, so I have some tuning available there. Before I consider rejetting though, I need to get the distributor squared away.
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  #25  
Old 02-27-2020, 03:58 PM
avman avman is offline
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Here's a video of my 2nd run. I lifted a bit for a fraction of a second in 1st gear at the launch when I started spinning. In retrospect, if I could have a re-do, I'd probably just keep it planted and see what happens.
I think that for my first time power shifting I did pretty well. I never hit the rev limiter on a "no lift shift".
https://youtu.be/njG1-oLEboA

  #26  
Old 03-02-2020, 06:38 PM
Doug Doug is offline
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Avman,
I assume your tires are about 25.6 or 25.8 inches in diameter and you made a typo when you said the rear axle ratio was 3.80 when it is actually a 3.08 ratio. (A 3.80 ratio seems strange for a GTO).
If you are running a 3.08 with “short” tires you are going to lose acceleration time by going to a “taller” tire.
Of course, every little bit of “tuning” helps but I don’ think you will appreciably improve acceleration without a “stiffer” rear ratio. (The drop off between the first and second gear ratio in your tranny hurts a lot with a “cruising” rear ratio.)
Nice looking car!

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  #27  
Old 03-03-2020, 12:12 AM
avman avman is offline
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Quote:
Originally Posted by Doug View Post
Avman,
I assume your tires are about 25.6 or 25.8 inches in diameter and you made a typo when you said the rear axle ratio was 3.80 when it is actually a 3.08 ratio. (A 3.80 ratio seems strange for a GTO).
The Toyo Proxes TQ drag radials are 275/40/17s and 25.8" inflated diameter. Tread width is about 10-11".
The ring and pinion gearset in the Quick Performance Ford 9" based rear axle assembly is, in fact, a 3.80 ratio. I chose that not being certain if my wife would want a 5 speed, thinking that it would be marginal but ok on the highway with a 1:1 final gear in the Muncie. I'll tell ya though, driving about an hour each way to and from the drag strip was bad, in that while I'm not sure how fast the 421 was spinning, it was close to 3,500 but sure sounded faster than my 440 did with my old 3.54 and 4 speed that turned 3,500 at 70 mph. Anyway, we have a TKO600 in the box in the garage and the 0.63 5th gear will have the 3.80 in 5th making the 421 purr like a tiger again. Also I posted the question "What are your 60ft times for those running 12.5 to 13.5 second quarter mile times?" and the range was 2.2 down to 1.7
I believe there's lots of potential for improvement in the timing and tweaking the Pertronix distributor to the best parameters for the advance curve. Also once I find the range where I can get the RPMs up at the launch and slip the clutch for maximum forward velocity without excessive tire spin THAT is going to definitely be worth a few 10ths.
I bought a hydraulic throwout bearing for my Roadrunner, and I'm getting the HitMaster launch control system tomorrow. I'm going to suggest that my wife let me get a hydraulic throwout bearing for her car now, since we're going to be working with the new transmission, and if the HitMaster works as well as I expect it to, and I expect a lot, we can add a HitMaster to her car, and by then I'll know how to adjust it, and I can set it up on her car. That way I can tell her the couple of hundred RPM range she needs to launch at, say 2600 to 2800 RPMs and all she has to do to launch is dump the clutch and mash the gas.
Thank you very much for the reply!
Edit: We are also about to install a replacement rear axle housing because QP put the wrong LCA lift bar brackets on the rear axle housing that's in the GTO now. The brackets with the "QP" in the picture have multiple holes for that end of the UMI lift bar to go in, making adjusting instant center easier. The new housing is set up strictly for coilovers as well.
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