Author Topic: *edit* how to get more power off boost?  (Read 4270 times)

Offline Justin14100

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*edit* how to get more power off boost?
« on: October 02, 2010, 10:43:25 am »
While searching for more off boost power I think increacing CC's is te best way to go (any suggestion??) but as a student living off Asda pasta it's pretty hard to come up with the funds to get some forged pistons and a re-bore. If I locate a 1W crank (anyone got one?) is it just use it with G40 con rods? As it's going in for a rebuild I could swap the crank then. Would it change the compression ratio or just give more stroke / cc's??
Thanks!
« Last Edit: October 03, 2010, 08:39:43 pm by Justin14100 »

Offline Nick_S

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Re: 1W crank on standard pistons? cc?
« Reply #1 on: October 02, 2010, 11:54:23 am »
Compression ratio will be out as well as the pistons from the block. New set of pistons needed really.

If you want extra cylinder capacity on a budget, then have a look out for Tom's thread on here. He has used a 1391cc ABD engine with a little boost :)
« Last Edit: October 02, 2010, 12:34:29 pm by Nick_S »

Offline Justin14100

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Re: *edit* how to get more power off boost?
« Reply #2 on: October 03, 2010, 08:42:44 pm »
Ok so that won't work - anyone got any tips for getting more power off boost?
Working on getting a metal head gasket on the car during a rebuild and I'm half way through a batch of 51mm throttle bodys with porter t-prices. Just wanna know, does it turn into a n/a engine off boost - so port matching and 4-branches make a big difference off boost?
Thanks!

Offline dazzle53

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Re: *edit* how to get more power off boost?
« Reply #3 on: October 03, 2010, 10:46:29 pm »
hi mate ive got a 1308cc bottom end which has been lightern and balanced. the engine does need honing tho. pm me if you intrested..

thanks
darren

Offline s.e-power g40

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Re: *edit* how to get more power off boost?
« Reply #4 on: October 04, 2010, 01:48:59 am »
 ;)  Good ideas from Portugal !!  ;)

I have done several projects with 1w crankshaft, using 75mm stock pistons worked in CNC Machine to stay with the same compression ratio of 8:1 up with 1398cc-
I'm currently working on a project with same 1w crankshaft, JE pistons 77mm with compression ratio of 9:1 making 1472cc. have oil injectors and calibrated flywheel. but unfortunately this is an expensive project, the first assembly may be a good option for those with less money offering a good quality product with the 75mm stock pistons..

See you   ::)

Offline Justin14100

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Re: *edit* how to get more power off boost?
« Reply #5 on: October 04, 2010, 08:19:16 am »
I have done several projects with 1w crankshaft, using 75mm stock pistons worked in CNC Machine to stay with the same compression ratio of 8:1 up with 1398cc-

Do you know the exact amount you had to machine off to get this? What were the results like? Do you know how much you would need to remove for a higher compression like 8.5:1 or 9:1?
Thanks!

Offline Andy

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Re: *edit* how to get more power off boost?
« Reply #6 on: October 04, 2010, 06:49:15 pm »
If you're willing to machine pistons, why not get an ABD like Tommo did and machine the pistons down in that? The engines are cheap as chips, and all you'd need to do was sort the pistons out.

There's no rare/pricey 1W crank to mess about sorting this way, and if/when it dies you've still got your original G40 motor to throw back in (or build up as a 1.5 1W long-term project).

To get sprightly performance off-boost you need to raise the compression ratio. The 9.3:1 CR you can get with metal HG and 77mm Accralite pistons is very nice off boost compared to a stock G40 - though does need careful mapping as it's very sensitive to ignition timing on boost.

Offline Justin14100

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Re: *edit* how to get more power off boost?
« Reply #7 on: October 05, 2010, 12:18:25 am »
If you're willing to machine pistons, why not get an ABD like Tommo did and machine the pistons down in that? The engines are cheap as chips, and all you'd need to do was sort the pistons out.

There's no rare/pricey 1W crank to mess about sorting this way, and if/when it dies you've still got your original G40 motor to throw back in (or build up as a 1.5 1W long-term project).

To get sprightly performance off-boost you need to raise the compression ratio. The 9.3:1 CR you can get with metal HG and 77mm Accralite pistons is very nice off boost compared to a stock G40 - though does need careful mapping as it's very sensitive to ignition timing on boost.
So without slashing half my student loan on some new pistons and a rebore the best thing I could really do is the metal HG when a rebuild and just get a good n/a tune on it?
Will bare the ABD block in mind for long term future though. Other than compression ratio any other tips?

Offline s.e-power g40

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Re: *edit* how to get more power off boost?
« Reply #8 on: October 05, 2010, 12:35:48 am »

the crankshaft of the ABD and 78.7 is the same thing to the first piston engines diesel.E with only 75 of the 1391 and 1W is 79.1 and the piston 75 1398.Ficam give here some pics of some machined pistons CNC.

[URL = http://img714.imageshack.us/i/dsc00230gc.jpg/ ] [/URL]

Offline s.e-power g40

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Re: *edit* how to get more power off boost?
« Reply #9 on: October 05, 2010, 02:30:06 am »

With the block ABD'll always have a high compression rate, I think to get a good mount you'll ever spend money on a custom chip, otherwise the power to melt a piston.


[img=http://img714.imageshack.us/img714/4020/dsc00231qg.th.jpg]

Offline G40supercharged

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Re: *edit* how to get more power off boost?
« Reply #10 on: October 06, 2010, 05:39:19 pm »
What is the point of more power off boost?

Offline Justin14100

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Re: *edit* how to get more power off boost?
« Reply #11 on: October 06, 2010, 05:45:26 pm »
What is the point of more power off boost?
i spend a lot of time off boost as i commute to uni in it (70 miles 3 times a week) so need as much power off boost as i can get for economies! just got 38mpg but want more! 40 is my best!

Offline s.e-power g40

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Re: *edit* how to get more power off boost?
« Reply #12 on: October 07, 2010, 02:07:07 am »

sorry .. liked to tell me what are 38mpg or 40 mpg ..?

Offline Justin14100

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Re: *edit* how to get more power off boost?
« Reply #13 on: October 07, 2010, 02:28:58 am »

sorry .. liked to tell me what are 38mpg or 40 mpg ..?

mpg is fuel economy, in european terms:

38mpg = 6.2L/100km (16km/L)
40mpg = 5.9L/100km (17km/L)

Offline s.e-power g40

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Re: *edit* how to get more power off boost?
« Reply #14 on: October 07, 2010, 03:19:08 am »

whenever I make changes to the G40's engine capacity, these are meant to think of driving pleasure in many horses on the road, doing usually about 9 or 10 litres/100km .. consumption of six litres/100km here we do with stock G40 with only one compressor preparation ..