Tachometer question

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jphoenix
Posts: 105
Joined: July 12th, 2013, 7:41 pm

Tachometer question

Post by jphoenix »

I want to install a smaller tach, I see 2" units available that will work, how does one go about insuring the tach is reading correctly , within 100 rpm? Are they all just perfectly accurate, or does accuracy depend directly on price paid? Any specific brand better than others? Is it reasonable to get one from the local parts store and get the accuracy needed?
Jim Phoenix
2016 Red Mercury FV 44
FV80
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Joined: June 27th, 2006, 9:07 am

Re: Tachometer question

Post by FV80 »

Jim,
From my experience *ALL* relatively inexpensive tachs are pitiful for getting you what you need in a race car. You'll be lucky to get 300 RPM accuracy from the autoparts store and it will probably swing and sway in the race car so much as to be 'not very useful'. Pretty sure that's the majority reason why people are mostly going to data acquisition systems. There are small systems out there for about $300 that will give you a reasonable representation of RPM as well as some other info and log it for you.

I guess it depends on what you think you NEED from a tach. What do you expect to use it for and how much (or little) do you hope to spend on one?

Steve, FV80
The Racer's Wedge and now a Vortech, FV80
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brian
Posts: 1348
Joined: June 26th, 2006, 12:31 pm

Re: Tachometer question

Post by brian »

If memory serves me right, the tack in your car is a high quality VDO unit. I agee with Steve about cheap tachs. If shift points are your concern, a shift light is better. They're accurate and easy to see when you're racing.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
jphoenix
Posts: 105
Joined: July 12th, 2013, 7:41 pm

Re: Tachometer question

Post by jphoenix »

Brian,

It is the high quality VDO, but I'm moving the wheel up an inch (new panel) and real estate is limited (to see through the steering wheel. I may simply relocate the tach to ensure I can see the important part of it (4 to 7k rpm) most of the time. I'm also considering using a different wheel - my problem is wide shoulders and long legs that have all of their length between knee and hip causing the legs to hit the wheel. Another option is to move the wheel aft (towards the driver) 2 inches and then the wheel fits perfect in the original vertical position.

In any case, you've answered my question about tachs and I see SR race supply has a couple that are 2" if I need go that route. Perhaps someday I'll go with data acquisition, after I learn to drive!
Jim Phoenix
2016 Red Mercury FV 44
jphoenix
Posts: 105
Joined: July 12th, 2013, 7:41 pm

Re: Tachometer question

Post by jphoenix »

brian wrote:If shift points are your concern, a shift light is better. They're accurate and easy to see when you're racing.
I like the idea of a shift light, something like this?

http://www.summitracing.com/parts/sum-g2945/overview/
Jim Phoenix
2016 Red Mercury FV 44
Dave
Posts: 187
Joined: June 24th, 2006, 2:40 pm

Re: Tachometer question

Post by Dave »

Buy what you want and use your tack checker to test the accuracy.

Dave
brian
Posts: 1348
Joined: June 26th, 2006, 12:31 pm

Re: Tachometer question

Post by brian »

Yes JIm, that's perfect and reasonably priced. A data system is a good learning tool but I always suggest investing in seat time. The rather subtle things you learn with data come later.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
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