Author Topic: Performance engines  (Read 9377 times)

Offline Lazy Dog

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Re: Performance engines
« Reply #15 on: July 28, 2008, 09:36:14 AM »
Yep, agree with everything you say regarding estimating mpg, my problem is it's not my daily driver and there is a leak somewhere around the 3/4 full mark , hence having to drop the engine .
Never meant to infer mine was a performance engine, I'm fully aware some shiny tin-ware, a pair of ICT's and a Monza 4-tip are not the things of legend! I meant "here is a picture of mine", that's all :)
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Offline rony

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Re: Performance engines
« Reply #16 on: July 28, 2008, 09:50:57 AM »
Bit difficult to estimate MPG, so many variables... hills, whether you're happy cruising at 60 or are in a bit of a hurry and pushing 70/75, wind direction, broken fuel gauge, load, the condition of your engine in general, the list could go on and on, but they are supposed to improve fuel economy (dunno tho') and definately improve performance!

Despite all the factors you've mentioned, it's really easy to calculate your fuel economy. For example, starting tomorrow, fill up the tank of your van and record the starting mileage on the odometer (ignore how many litres it took on the initial fill, just be sure to fill it). Drive the van for a month, you're sure to encounter all types of driving conditions from slow city traffic to open roads, to hills, to motorways to traffic-light-grand-prix. Keep filling up the van each time you refuel and record how many litres it took each time. After the month fill up the tank one last time and record how many litres it took and record the final mileage before leaving the petrol station. Add up all the litres of fuel you put into it (remember, ignore the initial fill, you just want to add up the fuel you had to replace to return it to a full tank), subtract the starting mileage from the final one to determine the total mileage covered, do some sums and work out your miles per gallon. Once you know this (and it'll be a good average of your month's driving) you'll know how far you can drive before refuelling, even if your fuel tank sender is broken, it's called your "range".

Both the fuel economy and your range are useful to know as you don't want to venture out into the wilds if you've only got a quarter tank left and you don't know where the next station will be.

oh, add-ons like carbs don't necessarily make your motor a "performance" engine. My bug's engine is stock except for the 4-1 header and stainless "turbo" style muffler, my van's engine is stock except for the twin 34ICT webers. I wouldn't consider either of them "performance engines. To me, a performance engine is one which has had major surgery to squeeze out a lot more horsepower than the factory intended. To me, "performance" modifications include stroker cranks, counterweighted cranks, balanced rods and pistons, larger pistons and cylinders, increased compression ratio, different cams, ratio rockers, bigger valves, matched ports, etc etc etc. The list is almost endless and usually ENDS with carbs and exhaust after all the other stuff has been done. To that end, the motor in Roger's samba is probably one of the few true "performance" engines in the country. I wish I had the money and know-how to build myself a performance engine. Maybe one day ::) ;)

another thing, the old "buttcheek dyno" is notoriously inaccurate when determining the benefits of engine modifications ;D

just bet me to it trev :P

Offline trev

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Re: Performance engines
« Reply #17 on: July 28, 2008, 12:10:19 PM »
I meant "here is a picture of mine", that's all :)

fair enough!!! it looks like a well kept engine bay, do you clean it often?

Offline Lazy Dog

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Re: Performance engines
« Reply #18 on: July 28, 2008, 04:37:22 PM »
I meant "here is a picture of mine", that's all :)

fair enough!!! it looks like a well kept engine bay, do you clean it often?
Nope, just doesn't get used due to a fuel leak issue that needs addressing, I also have a 2 litre Westy that does get used quite a lot tho', and is a real hoot to drive!
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Offline airhead

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Re: Performance engines
« Reply #19 on: July 30, 2008, 10:06:51 AM »
The quicker way of finding out fuel economy is to fill the tank (let the pump click off twice) then reset the trip counter and drive 62 miles, or 100km's. After that time, fill the tank again and measure how much it takes to get the pump to click twice again. So if it took for example 6 litres, use this calculator to calculate miles per gallon... http://www.convertworld.com/en/fuel_consumption/Liters+per+100+km.html
And you'll see that 6l/100km is 47.08MPG.

You can do it maybe 4 or 5 times and take an average and it should prove to be quite accurate.
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Offline Manana

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Re: Performance engines
« Reply #20 on: July 30, 2008, 12:35:34 PM »
just make sure that you don't have a leaky fuel guage....

Click - click splash splash.

took engine out last night, replaced seal with proper one.... i had used incorrect one.

Engine is almost in sitting on trolley jack outside my house..... something in the way that i cant figure out..... even took off the reat engine mountings ot help. It's the sort of thing that walkiing away for a few hours and coming back to will sort!

Offline Lazy Dog

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Re: Performance engines
« Reply #21 on: July 30, 2008, 01:01:21 PM »
It's the sort of thing that walkiing away for a few hours and coming back to will sort!
Wise words! Taking a step  back and thinking about something is far superior to the "Gunther Method" which usually complicates things worse.... it took me a while to learn.... but I finally have...... I think....... where's me hammer?
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Offline rony

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Re: Performance engines
« Reply #22 on: July 31, 2008, 09:31:17 AM »
The quicker way of finding out fuel economy is to fill the tank (let the pump click off twice) then reset the trip counter and drive 62 miles, or 100km's. After that time, fill the tank again and measure how much it takes to get the pump to click twice again. So if it took for example 6 litres, use this calculator to calculate miles per gallon... http://www.convertworld.com/en/fuel_consumption/Liters+per+100+km.html
And you'll see that 6l/100km is 47.08MPG.

You can do it maybe 4 or 5 times and take an average and it should prove to be quite accurate.

did your bay have a resetable trip counter/odometer???????

their rare enough i'm told

Offline GaryC

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Re: Performance engines
« Reply #23 on: July 31, 2008, 12:54:42 PM »
The quicker way of finding out fuel economy is to fill the tank (let the pump click off twice) then reset the trip counter and drive 62 miles, or 100km's. After that time, fill the tank again and measure how much it takes to get the pump to click twice again. So if it took for example 6 litres, use this calculator to calculate miles per gallon... http://www.convertworld.com/en/fuel_consumption/Liters+per+100+km.html
And you'll see that 6l/100km is 47.08MPG.

You can do it maybe 4 or 5 times and take an average and it should prove to be quite accurate.

did your bay have a resetable trip counter/odometer???????

their rare enough i'm told


Mine and Matts both have them...

Hit reset every time i fill up as the fuel gauge does'nt work  ::)

Offline Bdub

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Re: Performance engines
« Reply #24 on: July 31, 2008, 03:13:20 PM »
I'm gathering those monza exhausts are a load of crap? I have one on mine since I got it first, its got alot of surface rust and all the chrome has flaked off. Im debating if I should buy the same one again/ re-paint it or buy something else, they are going for around 90 euros these days after VAT, any suggestions? a thread on exhausts would be very beneficial I think!

Offline Manana

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Re: Performance engines
« Reply #25 on: July 31, 2008, 03:33:22 PM »
I put a note on my phone for the mileage i will run out of fuel at.

Now i can fill my tanks , so it will be a little easier.

Question on the guage:
1. The little tip was not hitting the potentiometer, now it is and i was able to prove it was working well using my trusted multimeter. 77ohms at Empty 15 ohms at full.
2. when i connected the sender wire to earth, the dial went to full, in a rush too... from someone's advice.
3. It didn't after a while and sits at 1/4 all the time, regardless of the guage position.

Have i blown it, or did i pull a wire to hard or what?

p