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Chassis dyno, anything to know before hand?
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DRR Trophy
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Hey guys, I will be sending my carb for a rebuild next weekend and the carb builder will be doing the chassis dyno on my car. This will be the first time I have had my car or motor on Amy form of dyno. Is there anything I should know going into this or look for during the process? This is a alcohol bbc small tire car, I want to tune for consistency obviously as power is no concern to me. Thanks for any advice you guys have to offer
 
Posts: 183 | Location: NJ | Registered: January 29, 2003Reply With QuoteReport This Post
DRR S/Pro
Picture of Curly1
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One common mistake I see many doing is running too much timing. Be sure to pull some timing out and see what it does for you.

As for tuning for consistency? Well if you tune for peak torque and HP then that is where it is most efficient and I would think would be most consistent.

What size is your carb?

Also when I dyno my motor I use 8 O2 then what ever I get for peak performance on the dyno I shoot for that number on the track. Mine is mechanical injection so I have to change my tune up some with weather changes. An O2 system on your car can be a big help.


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Posts: 1145 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post
DRR Trophy
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I will have one o2 sensor to judge from on the dyno, the dyno guy said 12” from flange but in my car it will realistically be where the primary comes into the collector. I will not be running data logging after the dyno. Carb is a 4150, 1000 cfm
 
Posts: 183 | Location: NJ | Registered: January 29, 2003Reply With QuoteReport This Post
DRR Sportsman
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Who's shop?
 
Posts: 632 | Location: Bucks Co Pa | Registered: January 23, 2003Reply With QuoteReport This Post
DRR Trophy
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Posts: 183 | Location: NJ | Registered: January 29, 2003Reply With QuoteReport This Post
DRR Sportsman
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Don't hit the brakes. 2 of my friends put their dragsters on Chuck Seitsingers chassis dyno and Comstock was there and said unless you want to see it fly through the air don't touch the brakes
 
Posts: 1100 | Location: OklahomaCity,OK | Registered: December 01, 1999Reply With QuoteReport This Post
DRR Pro
Picture of 68TSCAMARO
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What are the actual results on chassis dyno tuned and track tuned ? Sounds good in theory but it would be interesting to see a/b/a results .....
 
Posts: 858 | Location: middle georgia | Registered: July 20, 2003Reply With QuoteReport This Post
DRR Pro
Picture of Brktracer
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Make sure to document any and all changes you make on the chassis dyno just in case you need to get back to your baseline.


Matt



 
Posts: 1195 | Location: South Carolina | Registered: March 20, 2004Reply With QuoteReport This Post
DRR Pro
Picture of Mike Beck
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Tune for best power on the chassis dyno then pull 2 degrees of timing before you hit the track and finish fine-tuning from there.

If you plan on making changes and going back at a future date to test the changes, then make sure you run the engine oil and coolant at the same temp, same goes for the trans and rear. Keep the rear tire pressure the same as well as the size.

If you don't plan on going back in the future then it won't matter.

I have been running cars on Bob Ida's chassis dyno for 15 years. I can go back with my car at anytime after making changes (cam/heads/exhuast....) and see the results there and actually see the change on the track.

PS: Doing a NA run then hitting it with 300+ on nitrous really gets people in the shop to stop and go see what the f....... Smile
 
Posts: 1678 | Location: South River, NJ | Registered: June 19, 2007Reply With QuoteReport This Post
DRR Trophy
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Thanks mike, for the most part this will be a one time thing to see what it will do for me. My combo works well and there is really nothing I’m specifically there to look for or change, I have heard of guys having good results tuning alcohol on the dyno so I want to try it out, my car is consistent but has not been type of alcohol car that I can leave the same number on all day. I don’t know if this will change that but it would be great. I have never played with jets or different timing on the motor as it has always served me well the way it is set up now but if there is room for improvement I will gladly take it. I am not looking for et as I already have a throttle ruducer to slow the car down now, but naturally if the car is running better it will pick up but that will not be the goal
 
Posts: 183 | Location: NJ | Registered: January 29, 2003Reply With QuoteReport This Post



DRR Sportsman
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I would not think that your tuning is over when you get things back. In fact, I've found that dyno tuning is just relative. Ive spent time years ago playing on them only to find on the track, were you plan to race, is the best to get the car dialed in.

For instance if you run a scoop - there is a difference that is tough to simulate on a dyno.

I personally would save the money and do it in person at the track. All you need is logic, time slip and 02 readings or plug readings to get you dialed in.

With EFI cars, I could get mine dialed in within 5 runs and never touch it again. If you invested the money on racepak you too should be able to do it vs just a sheet of paper. I compare it to running on a treadmill and thinking real life running off one is the same.



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Posts: 1198 | Location: St Marys | Registered: January 12, 2004Reply With QuoteReport This Post
DRR S/Pro
Picture of wideopen231
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Agree^^^. While dyno should get you close,you will more than likely need a few runs to tweak those results. IMO a day of flogging motor on dyno or flogging on track,track wins hands down. But thats just that my opion.


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Posts: 1458 | Location: Greensboro NC | Registered: May 24, 2011Reply With QuoteReport This Post
DRR Pro
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Posts: 1545 | Location: UsA | Registered: October 30, 2004Reply With QuoteReport This Post
DRR Sportsman
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You won't have any problem.
Deans'been tuning cars for Atco for a while now. What's your car weigh race ready.
 
Posts: 632 | Location: Bucks Co Pa | Registered: January 23, 2003Reply With QuoteReport This Post
DRR Sportsman
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Just curious,

Do tires/slicks spin on a chassis dyno? I have never used one so I don't know. What are the rollers on the dyno?


Cool
 
Posts: 145 | Location: Atco NJ | Registered: March 14, 2002Reply With QuoteReport This Post
DRR Sportsman
Picture of Tom Reyer
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I ruined a set of drag radials on my turbo Camaro spinning them.

I've also read and been warned not to run Mickeys on the dyno. Seen pictures of them blown out after dyno tuning. (lots of hits if you google it)

Mar 23, 2015 - Use of Mickey Thompson tires on a Dyno will invalidate the tire warranty. At no time should the following Mickey Thompson tires be used on a Dyno: ET Drag ET Motorcycle Pro Drag Radials ET Street ET Street Radial ET Street Radial II This is Mickey Thompson DRAG / STREET Technical Bulletin #8.


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Posts: 516 | Location: Hanover, MD | Registered: June 20, 2016Reply With QuoteReport This Post
DRR Trophy
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Leave it up to Lou to find that video lol!!

Car is 3500 with me in it
 
Posts: 183 | Location: NJ | Registered: January 29, 2003Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by M120:
Just curious,

Do tires/slicks spin on a chassis dyno? I have never used one so I don't know. What are the rollers on the dyno?


Absolutely. We ruined a set, despite several attempts to strap it down better. Very reputable shop but after 4 pulls it cost us 500 in tires. And data was flawed obviously.

Like i said with today's technology of racepak, 02s, one could be much further ahead top just invest in those items and do it themselves.
 
Posts: 1198 | Location: St Marys | Registered: January 12, 2004Reply With QuoteReport This Post
DRR S/Pro
Picture of wideopen231
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Never thought it that way. Don't know what 3 or 4 pulls cost but it puts good dent in cost of racepac.


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Chris McBride

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Posts: 1458 | Location: Greensboro NC | Registered: May 24, 2011Reply With QuoteReport This Post
DRR Pro
Picture of Mike Beck
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quote:
Originally posted by M120:
Just curious,

Do tires/slicks spin on a chassis dyno? I have never used one so I don't know. What are the rollers on the dyno?


Up to 1200hp or so to the rear tires we never had an issue. Above that yes, it becomes a problem.

East Coast Supercharging has a neat chassis dyno. Take the rear wheels off, an adapter gets bolted on which goes between the dyno and the hub. No traction issues! Just takes a little bit longer to setup, but will never hurt a tire.
 
Posts: 1678 | Location: South River, NJ | Registered: June 19, 2007Reply With QuoteReport This Post



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