Loss of MPH IN 1/4 mile
Loss of MPH IN 1/4 mile I've been told that with the vigilante you tend to loss some of your mph in the 1/4 mile. I was wondering had anybody experienced this thanks. Just trying to make my final choice on convertors.
Thanks
Thanks
So if you do loose a little MPH how does it afftect your car on the freeway with a stall. If you are doing 65MPH and jump on it, will it be slower then it was with a stock converter?
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TECH Fanatic
Joined: Oct 2003
Posts: 1,132
Likes: 0
From: Grand Rapids, Michigan
Originally Posted by 68birdls1
but if you gain .3-.6 in the 1/4, does it really matter if you lose some mph?!?
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Verdad Gallardo [QUOTE] It will matter when you get raped by a 6spd from a roll. Vigs will shave some good time off your 1/4mi times, but usually are not the most efficient converter on the market< MPH gain/loss will tell you that with any converter.
your statement made no sense what so ever!
there are so many different variables that can affect your et and trap speed is what i was refering to when i made my intial statement!
but just because your speed drops one or 2 mph in different runs doesnt mean that you lossed them. you could be spinning the tires more, but still moving down the track, you are getting there quicker, but not faster. do you get what i am saying. by quicker meaning a lower et, and faster being that your mph is not where it was. and from my understanding happens on a lot of cars.
your statement made no sense what so ever!
there are so many different variables that can affect your et and trap speed is what i was refering to when i made my intial statement!
but just because your speed drops one or 2 mph in different runs doesnt mean that you lossed them. you could be spinning the tires more, but still moving down the track, you are getting there quicker, but not faster. do you get what i am saying. by quicker meaning a lower et, and faster being that your mph is not where it was. and from my understanding happens on a lot of cars.
Typically, you use a looser convertor to get the motor up into the power band faster at the launch (and on the shifts). This helps you on the start to get rolling more quickly. However, the slippage that a higher stall (looser) converter uses to get you in the powerband more quickly translates into a converter that is less effecient and "wastes" more hp than a lower stall converter. It's similar to a manual car with a clutch that's slightly slipping for the whole run. You'll get to the end, but your RPM and MPH may be different (RPM could be the same or higher, MPH could possibly be lower, even with more rpm). So, you get a better launch and get "help" at the beginning of the track (where you really need it) and lose a little on the big end of the track (due to converter slippage). It's a trade off. If you get enough extra performance on the bottom end, you may still be faster on the top end. If the converter is too loose, you may lose some on the top end, and be quicker (et) anyway.
It's always a trade off, sometimes it just works better than others.
Have fun!
It's always a trade off, sometimes it just works better than others.
Have fun!
MPH is horsepower and delivered HP is the converter
efficiency. This varies a lot from model to model and
is never well specified. The efficiency seems to come
in third, among the three main performance criteria
(stall speed, STR, efficiency) and they all are related.
You can't go by the peak efficiency numbers that the
manufactures quote (when they bother). It's delivered
efficiency across the powerband, and where in the
powerband it puts you, that matter to MPH.
I made a stab at collecting locked / unlocked dyno data
to get at broad-range efficiency profiles. I got a little
bit (and have to get back to that, one or two curves
to analyze & add in) but there is a great big hole in how
converters are advertised and efficiency vs RPM @ TQ
is it.
You can see >95% or less than 90% up top and that
is easily 15HP lost; that's at the peak efficiency and
where the converter slips more, you lose more.
efficiency. This varies a lot from model to model and
is never well specified. The efficiency seems to come
in third, among the three main performance criteria
(stall speed, STR, efficiency) and they all are related.
You can't go by the peak efficiency numbers that the
manufactures quote (when they bother). It's delivered
efficiency across the powerband, and where in the
powerband it puts you, that matter to MPH.
I made a stab at collecting locked / unlocked dyno data
to get at broad-range efficiency profiles. I got a little
bit (and have to get back to that, one or two curves
to analyze & add in) but there is a great big hole in how
converters are advertised and efficiency vs RPM @ TQ
is it.
You can see >95% or less than 90% up top and that
is easily 15HP lost; that's at the peak efficiency and
where the converter slips more, you lose more.
TECH Fanatic
Joined: Oct 2003
Posts: 1,132
Likes: 0
From: Grand Rapids, Michigan
[QUOTE=68birdls1] Basically what I was saying is with an inefficient converter you will loose MPH. Read the 2 responces above this....it makes sence..........
It will matter when you get raped by a 6spd from a roll. Vigs will shave some good time off your 1/4mi times, but usually are not the most efficient converter on the market< MPH gain/loss will tell you that with any converter.
your statement made no sense what so ever!
there are so many different variables that can affect your et and trap speed is what i was refering to when i made my intial statement!
but just because your speed drops one or 2 mph in different runs doesnt mean that you lossed them. you could be spinning the tires more, but still moving down the track, you are getting there quicker, but not faster. do you get what i am saying. by quicker meaning a lower et, and faster being that your mph is not where it was. and from my understanding happens on a lot of cars.
your statement made no sense what so ever!
there are so many different variables that can affect your et and trap speed is what i was refering to when i made my intial statement!
but just because your speed drops one or 2 mph in different runs doesnt mean that you lossed them. you could be spinning the tires more, but still moving down the track, you are getting there quicker, but not faster. do you get what i am saying. by quicker meaning a lower et, and faster being that your mph is not where it was. and from my understanding happens on a lot of cars.
