converting to 1341?

Started by sinister polo, April 27, 2009, 05:32:39 PM

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sinister polo

what are the main advantages of doing this?
obviously you must gain power, but how much!

and also what parts and machining would need to be done?

cheers

daryl

breadman

The main advantage of a 1341cc conversion is reliability.
Forged pistons are used to replace the O.E. cast ones which are prone to melting.

You actually don't gain much power at all just by going to 1341cc, it's only just over a 6% increase in capacity. However, increasing the bore to stroke ratio is worthwhile anyway.

Machining is limited to a simple 77mm rebore and honing of the block.

scotsjohn

What sort of money for forged pistons Breadman?

breadman

Quote from: scotsjohn on April 27, 2009, 07:54:14 PM
What sort of money for forged pistons Breadman?

Dunno if Phil still has them, but he had a brand new set of Accralite pistons for sale at £550 delivered. (See for classifieds/parts)
Forged pistons for this conversion are typically circa £150 each.

jez1272gt

Quote from: scotsjohn on April 27, 2009, 07:54:14 PM
What sort of money for forged pistons Breadman?

As Breadman has said Phil is selling a set of Accralites for £550. This is a good price if you dont want to put much boost through your engine as they raise the standard comp ratio from 8:0 up to 9:0, this is good for driveability on/off boost at low charger pressures. If you do plan to run more boost then its probably better to go with some wossner pistons. These are approximately £400 for the set and retain the 8:0 CR for more boostie fun..

vwmk3jon

which screws up my fun! accralite pistons + eaton charger = ??????????????

jez1272gt

Quote from: vwmk3jon on April 28, 2009, 06:07:33 PM
which screws up my fun! accralite pistons + eaton charger = ??????????????

This is the same problem for me, accralites + K03 = hmm. There was about this exact subject awhile back which andy and yoof had input into iirc. It seems the best way to get the most from the 9:1 ratio is to run aquamist and also retard the timing slightly. Although advised not to im still tempted to try running a de-comp plate if they dont cost a fortune just to see the results?

The best option for me seeing that my bottom end is still on a stand is to strip it back, put wossners in and try and sell the accralites but thats gonnas cost me either way... I was sold the accralites by a mis-informing conman who clearly had a few sets he wanted rid of!!

Andy

High boost on 9:1 is attainable, but Aquamist and BV head are pretty much essential. The critical part is getting a decent chip.

PeteG40

Quote from: Andy on April 29, 2009, 12:30:28 PM
High boost on 9:1 is attainable, but Aquamist and BV head are pretty much essential. The critical part is getting a decent chip.

smooooooth - no link to the chips you're selling ;-)

Robin


lance

standalone will manage it all better.

jez1272gt

Quote from: PeteG40 on April 29, 2009, 12:31:19 PM
Quote from: Andy on April 29, 2009, 12:30:28 PM
High boost on 9:1 is attainable, but Aquamist and BV head are pretty much essential. The critical part is getting a decent chip.

smooooooth - no link to the chips you're selling ;-)

;D

Yoof


Andy

Quote from: PeteG40 on April 29, 2009, 12:31:19 PM
Quote from: Andy on April 29, 2009, 12:30:28 PM
High boost on 9:1 is attainable, but Aquamist and BV head are pretty much essential. The critical part is getting a decent chip.

smooooooth - no link to the chips you're selling ;-)
It's true though, the map is the critical part in any highly modified G40 motor - otherwise you may as well stick on an R5 carb and drill random holes in the jets. Steve always used to say the same, and it still surprises me how many people will spend thousands on an engine and bolt-on bits, and then run it on a generic chip that has fuelling and ignition timing miles off what it needs to be. Robin's det-prone 1341cc (stock head, non-1341cc cam) made an extra 10bhp or so on the dyno with a few minor map tweaks - still needs more, but it proved the theory.

You run massive boost, you need the ignition timing and fuelling setup accordingly. That's the main reason I bought Emerald - so I could tweak the mapping easily myself. In the meantime I carried on messing about with Digifant and got my head round the map structure.

lance

standalone can manage the timing and fueling better than stock ecu.