[EA S]

I'm trying to find a reliable way of calculating performance improvements, or maybe even just changing plugs & HT leads, that is cheap and that I can do myself.

I started with post on Home Dyno and after reading links in White Knight's reply on that wondered if there was a simpler method that doesn't require anything more than stopwatch and basic arithmetic.

The dyno figures aren't really that important. I just want to be able to measure changes to see what does and doesn't work and how it compares with base and other improvements.

Would this work?

Get my 5sp manual 3.9mpi rolling and stabilise at, say, 20kmh and check rpm, then accelerate on WOT to, say, 100kmh and check rpm and elapsed time from 20 to 100? Or maybe do it on rpm from around 20mph rolling start to about 4,500 - 5000 and check elapsed time? Do say three runs and take average. Do all future runs on exactly same bit of road in similar weather conditions. Then compare times over base and improvement and calculate percentage difference?

I'm suggesting rolling start and staying in one gear because it doesn't involve any gear changes and eliminates driver variables and gives constant test process.

I realise it's nowhere as precise as a dyno, but it seems like it should give fairly reliable comparisons for my car.

 

[IIV8II]

There's a bloke in Sydney that makes up a performance meter wjich use magnets on your front wheel to measure speed and aceleration etc and a movement sensor to sense when the car starts moving. It caluculates 0-60ft, 0-60, 80, 100 km/h, 400m and terminal speed all in one run. Also is a digital speedo and odometer. I have one and its ace - blows Gtech away for accuracy. I used it to check out diff ratio and exhaust changes. Trouble is the bloke doesn't make em any more because he doesn't have the bux to market them properly (pre Net days!) Unless we all gang up on him. Maybe we could talk him into building a run of 10 or something.. anyone interested? Mine cost around $400

 

[EA S]

I like the idea but not the price, because I can't justify it for the amount of use it will get. But I'm still interested in knowing more about it.

Could you sound him out on his best price for an order for 10 or maybe even 20?

 

[Martin]

Have a look at this

http://www.autospeed.com/A_0703/P_1/article.html

 

[IIV8II]

I'll see what I can do - maybe the LS1 boys would be intersted, too.

 

[EA S]

Martin

Thanks. It does everything you need.

The price is still the problem. The way to go would be to be in a club that bought one, unless you can rent them somewhere. I'd happily pay $20 a couple of times a year to use it for a few hours.