# Fray car MPH ?



## Dyno (Jan 26, 2009)

I have a question that maybe someone on this forum can answer. Last falls Bob Beers show was the first time I saw Fray/ Echorr type cars in action, and I loved the way they drove and handled. It reminded me of the 1/24th cars I used to dabble with 15 years ago. I bought a bunch of parts and built myself two cars. Before I enter a race, ( not much going on in this neck of the woods) I kinda want to know if Im in the ballpark with the speed of the car. My friend has an HO chassis dyno that gives a readout in KPH thats easily converted to MPH, but I have no reference to shoot for. So my question is does anyone know the top speed of an average 16 ohm 14 tooth pinion car? I know the handling is just as important, but I want to know Im not gonna get slaughtered on the straights. Any feedback would be greatly appreciated.


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## tjetsgrig (Nov 1, 2009)

Around 12 to 16 mph. The lower end with 9 tooth, the higher end with 14 tooth. That is with 25.3 volts ( car batts. ). It's all subjective due to different power supplies.


JS


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## Boosted-Z71 (Nov 26, 2007)

I have several Fray style cars that are turning just over 13 mph (converted from KPH) on the 9 tooth gear on my dyno, Powered by a 22 volt wall wart, again, power supply differences & dyno differences would make it almost impossible to compare numbers from different setups. I will tell you that the car that put the best numbers up on the dyno is not the fastest on the track. Not sure why, but one of the cars that put a lesser MPH number on the dyno is my fastest straightaway car on the track, I even check rpm with a laser tach while there on the dyno & this car is a dog on the dyno, the track is another story. Funny thing is it has similar current draw & voltages as the hot car on the dyno, it just wont spin the roller as fast. 


Boosted


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## Dyno (Jan 26, 2009)

tjetsgrig said:


> Around 12 to 16 mph. The lower end with 9 tooth, the higher end with 14 tooth. That is with 25.3 volts ( car batts. ). It's all subjective due to different power supplies.
> 
> 
> JS



Thank you, I tested it at 18 volts so Im off on the mph. I will re test it at 25. I have a 25 volt 20 amp supply to hook up. I guess its all subjective to how accurate the dynos numbers are also. Im assuming your numbers were achieved on your dragstrip? I guess it will pick up a few more mph at 25. Any guestimates at how much it could possibly pick up going from 18 volts to 25?


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## Dyno (Jan 26, 2009)

Boosted-Z71 said:


> I have several Fray style cars that are turning just over 13 mph (converted from KPH) on the 9 tooth gear on my dyno, Powered by a 22 volt wall wart, again, power supply differences & dyno differences would make it almost impossible to compare numbers from different setups. I will tell you that the car that put the best numbers up on the dyno is not the fastest on the track. Not sure why, but one of the cars that put a lesser MPH number on the dyno is my fastest straightaway car on the track, I even check rpm with a laser tach while there on the dyno & this car is a dog on the dyno, the track is another story. Funny thing is it has similar current draw & voltages as the hot car on the dyno, it just wont spin the roller as fast.
> 
> 
> Boosted


13 mph with a 9 tooth is hauling, at least with the dyno and voltage we were using. Our good running JL/ AWs were turning about 22 to 24 KPH and the Tyco 440x2s were all about 30 kph at 18 volts. I also have a car that was a few KPH down on the dyno but cleans up on the track. Its probably the torque profile or something. I need to re test at a higher voltage and see if my numbers are in line. I need to get my hands on a pro level car and compare the numbers on the same machine.


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## martybauer31 (Jan 27, 2004)

The dyno's are cool, but I have always found that the sound the car makes is a better sign of things to come. Go through a few arms and you will see what I mean.

And just an FYI, you will get slaughtered in the straights, the curves, everywhere on the track. You won't be in the ballpark, it's just the way it is when you first start racing them...  

Just go out and expect to get your butt kicked, learn as much as you can from the seasoned racers and then you can expect to be in the ballpark down the road. Most of all though, enjoy them, they are a blast! I wished my group raced them more, but that's life I guess.


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## Joe65SkylarkGS (Feb 15, 2010)

martybauer31 said:


> The dyno's are cool, but I have always found that the sound the car makes is a better sign of things to come. Go through a few arms and you will see what I mean.
> 
> And just an FYI, you will get slaughtered in the straights, the curves, everywhere on the track. You won't be in the ballpark, it's just the way it is when you first start racing them...
> 
> Just go out and expect to get your butt kicked, learn as much as you can from the seasoned racers and then you can expect to be in the ballpark down the road. Most of all though, enjoy them, they are a blast! I wished my group raced them more, but that's life I guess.


Every word here is the truth!!!!!!

And my Dyno gives output voltage that the internal motor is generating? No mph here


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## Boosted-Z71 (Nov 26, 2007)

I have the dyno setup to read out kmh, wheel RPM & internal motor voltage & amperage draw, Then my comparison car is a KC-jet I bought strictly as a baseline car & then try to tweak all my builds to match or out perform the KC-Jet.

Boosted


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## Dyno (Jan 26, 2009)

martybauer31 said:


> The dyno's are cool, but I have always found that the sound the car makes is a better sign of things to come. Go through a few arms and you will see what I mean.
> 
> And just an FYI, you will get slaughtered in the straights, the curves, everywhere on the track. You wont be in the ballpark



I dont expect to win, I just want to be able to have a car that can win in the right hands. The bad thing is that there is nowhere near me that is involved in HO racing. If they have the track at the April Bob Beers show, I will enter that race.


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## tjetsgrig (Nov 1, 2009)

Dyno said:


> Thank you, I tested it at 18 volts so Im off on the mph. I will re test it at 25. I have a 25 volt 20 amp supply to hook up. I guess its all subjective to how accurate the dynos numbers are also. Im assuming your numbers were achieved on your dragstrip? I guess it will pick up a few more mph at 25. Any guestimates at how much it could possibly pick up going from 18 volts to 25?


Yes Dyno, numbers are from my strip. 7 volts is gonna make a big difference!

JS


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## RT-HO (May 27, 2009)

Hello,

I hate to break the news to you but a 14 tooth pinion car is not Fray legal.


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## Dyno (Jan 26, 2009)

RT-HO said:


> Hello,
> 
> I hate to break the news to you but a 14 tooth pinion car is not Fray legal.


The rules I'm following are the ECHORR SS. That is the class they ran at the last show/race. 14 tooth pinions are allowed.


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## martybauer31 (Jan 27, 2004)

Dyno said:


> I dont expect to win, I just want to be able to have a car that can win in the right hands. The bad thing is that there is nowhere near me that is involved in HO racing. If they have the track at the April Bob Beers show, I will enter that race.


I hear you my friend, just trying to set the tone for you. Just go out and have a good time, you probably won't have anything anyone else is going to win with either. It's extremely hard to tell what you have until every else shows up.

Boosted had a great idea, and I did that as well. I bought a KC-Jet a few years back, and I tuned my own stuff until it was as good as the KC, then I knew I was getting somewhere.

The best thing you can do if you show up at Bobs race is to hand your car to a known good racer and ask them what it needs. They should be able help, if not, borrow better my man!  We've all been there!


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## Dyno (Jan 26, 2009)

Since I don't have a KC Jet right now, I've been using my next best thing. I have a few cars that I ran alongside the ECHORR cars at the show during practice, and know how they stacked up. I had an NOS Aurora Tuff ones with AJs that was neck and neck on the straights and an AW Thunderjet 500 that was WAY faster than the class legal cars. So for know I'm trying to get in the middle of those two cars hp wise.


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## slotking (May 27, 2008)

the the dyno is to test 1 car vs itself! not to compare cars!
this is from -t-jets to magnet cars.

torque vs top end can make a big difference!
I have arms that do spin up high but lack punch and you can see it on the track. and arms that are mid range that provide punch and let blast out of the hole so lap times are higher than the high top end cars!

lastly on a t-jet! shoes, shoes shoes is so key


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