Re: Dyno Results (Long)

Lots of good info in your post - thanks for that.

Rev-N-Nator: Good advice on jumping to the MSD. But, I'm already into the Rev-N-Nator. May still bite the bullet over the winter and go to the Digital 6-plus just because I seem to be having some misfire at the upper RPM ranges. Would the 6-AL be an accpetabl alternate? Might be able to find those used at a swap in November.

As luck (both bad and good) would have it, I ran my street tires on the dyno. I'll do that in the future. Thanks.

The day was hot - think we we're in the mid-80's and humidity was up there. The numbers were adjusted for the weather form what I can pick up on the dyno sheet and conversation. I'll try the dropping one size in the fall. Dyno guys did remark that my AED 850 was a finicky unit and didn't like big jumps in jetting. I'll stick with the size I have as the largest and go down from there as weather dictates.

I run 93 octane pump gas. I wonder if running the higher cost of 100 octane race gas would gain me much more HP. Compression ratio with my non-quench motor iron heads is right around 10.5 and that's really pushing 93 octane from all I've read.

Very true about finding someone who knows how to mount tires with tubes - it's a lost art. I've lost at least two due to inexperienced tire techs.

The wheels wobbled left and right when he spun them on the balancer. He figured they'd jump a 1/2" running down the track. There was no benefit to them telling me an untruth since he was not expecting to sell me a new rim. Maybe I'll try the local tire store here for a balance. And I'll break down the tire first and add more talcum. Tires already screwed to the rims.

that said, fixing those two weak cylinders (25% and 45% leakage) may be the big $$$ project over the winter.

Thanks for the input.

Akron Don Gallimore

From: mike creglow <mcreglow@xxxxxxxxx>
To: 1962to1965mopars@xxxxxxxxxxxxxxxx
Sent: Wednesday, September 11, 2013 8:18 AM
Subject: Re: Dyno Results (Long)

hi don,

if you plan on getting the most out of your engine for racing, consider a real ignition controller e.g. MSD digital 6-plus or equivalent. for only $100 more than the rev-n-nator (also ~$50 for a matching coil); you will have a reliable, configurable controller. that's what i have on my car and i spin my engine to 7800rpm.

what tires did you use in your dyno test? racing slicks are not good for testing (and it will also wreck your slicks). use hard street tires -- i picked up almost 40hp switching from slicks to street tires. mustang dyno is what i used also.

what were the atmospheric conditions for your test? if you are at the track on a good air day don't hesitate to fatten your secondaries.
what fuel were you using for your test? if you are running good race gas (e.g. VP c12) you can add more timing to find out what your engine likes best (all engines are different).

lastly, i would have a second opinion on your wheels. find someone who knows how to mount tubes in racing slicks. if the tubes get wadded up it will be impossible to balance your wheels. they need to use talc liberally when mounting the tubes in the slicks. i'm not sure if you are using a transbrake or not but if you hit the tires hard on launch, consider screwing wheels to the slicks - -this is for safety. if the slicks spins on the wheel it can snap off the tube's air valve.

mike

On Mon, Sep 9, 2013 at 7:34 PM, Donald Gallimore <dongallimore@xxxxxxx> wrote:

Did a 4 hour dyno session today. The car is a '65 Belvedere with a 440, TF tanny with a 3800 stall converter, 4.1 Dana and weighs about 3600 without the driver. Last runs at the strip was 12.42/107.5 best and it has done a 12.16/111 best.

The rear wheel HP hit a max of 342 at about 5200 RPM. Dyno operator says that is equivalent of 425 at the flywheel. Doing some math, he either is using a flat 20% loss through the drivetrain or maybe he knows more.

I expected more, like 375 to 400 or so. Still, not bad numbers. Given my previous dyno reading on another brand of dyno was 357, it's OK.

The motor has two weak cylinders with 25% and 45% leakage. The rest were in the 5-10% range. The worst cylinder has some finger nail catching scores in it.

What did we change during our various runs today? The focus was on the jetting. Turns out the jetting on the AED Holley was four and a half jets too rich. Took the primary down from 79 to 75 and the secondary from 88 to 83. When we went in, the AFR was running in the 10-11 range and now running right around the ideal 12.4 AFR range.

Also, we found that new $200 Rev-N-Nator ECU with four runs down the strip was defective, apparently - need to discuss this with them and I'll get back to the group. Swapped that out for a Mopar Chrome box I'd just taken off and it was bad. Threw a Blue box on and it ran till about 5000-5200 which is consistent with what I'd Heard. Borrowed another Chrome box and that fixed it. These bad ECUs could explain some of the weaker runs I've had of recent including some high speed studders.

Another thing I learned. When you change the ECU, it may affect your timing. After swapping out to the good chrome box, we found the timing had changed from 35 degrees advance to 0 degrees. We changed nothing but the ECU and that was the result. Surprised it even ran at that value but it did hit 275 HP.

Some dyno issues to discuss FYI. Today's dyno was a Mustang 4WD unit. All my previous runs were on a DynoJet brand dyno. The operator today said that the Mustang will read lower than the DynoJet. The simplest conclusion is use the same dyno for any subsequent test if you want to judge the impact of changes to your combo.

Bad news for the day is unrelated to the dyno run. I had replaced a bad tube on my slicks and needed to get the wheel balanced. They determined that the wheel was bent. This is the same wheel that I have had on back order since the end of the May. There goes this weekend's race at Monster Mopars at Norwalk/Summit Raceway Park.

Akron Don Gallimore
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Please address private email -- email of interest to only one person -- directly to that person. That is, email your parts/car transactions and negotiations, as well as other personal messages, only to the intended recipient. Do not just press "reply" and send your email to everyone using the general '62-'65 Clubhouse public email address. This practice will protect your privacy, reduce the total volume of mail and fine-tune the content signal to Mopar topic. Thanks!

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