Club G40 Forum
Technical => Engine and Transmission => Topic started by: jez1272gt on April 12, 2010, 01:17:57 pm
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Does anyone know what the expected power gain would be when converting from 1272 to 1341cc without factoring in any other modifications?
I assume no-one has ever tested this properly?
Thanks
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I though it was about 10-15max bhp, same torque?
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about 140bhp when psd tried it back in the day. prob a 20bhp increase but it needs a remap to suit.
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Really as much as that - i was expecting it to be less..!?
Was that 140bhp with a remap then do you know hayesey??
Cheers guys
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Dont think that engine had a stock head when it was tested, but was with stock charger and pulley if i remember. Barney's wasn't it?
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I was thinking of the grey one that was Rob Chaplain's that beavis brought to an RR day years ago. was supposed to be basically standard other than 1341 and a chip to suit, I think it was the first ever 1341 done.
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as seen second from the left with plate ending 'jca' in this pic from said RR day (this was when we went to mcdonalds for a hangover cure on sunday morning after a night in wolverhampton civic hall):
(http://derby.polog40.co.uk/photos/G-unit..jpg)
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sad thing is, I think the only cars out of all that lot still on the road are Marshall's and mine.
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Ah of course, forgot about Rob's 'test mule'. ;D
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Yeah I remember Beavis telling me it was pretty much stock bar the 1341 and it got 140. Didnt it have gaffer tape covering a hole under the rear passenger side window? Looked a nice car from a distance and ran 14 inch classics?
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But then a fresh stock G40 would put out around 130bhp - so I'd say about 10 brake and probably around 10lb/ft too. The higher CR helps as well as the extra capacity, but a chip to suit is key.
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But then a fresh stock G40 would put out around 130bhp - so I'd say about 10 brake and probably around 10lb/ft too. The higher CR helps as well as the extra capacity, but a chip to suit is key.
130bhp stock - ??? am i missing something.. what happened to the 113bhp figure, did fresh G's back in the day always pull more on the rollers then?? I cant say ive ever heard of this..
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i've had 121 and 123 out of totally stock g40s on decent rollers.
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yeah healthy standard ones often do more than the book figure of 113bhp.
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I see a few aircooled high power motors being imported from California and they claim to be always more bhp than what they read over hear, running same octane and yes i know the atmospheric pressure is different but still claim more power and quite allot more, w :Pe like to call this the CCF meaning Californian Correction Factor :D
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seems to be the done thing in the US isn't it? Err on the high side rather than the low side. Don't quite a lot of brand new US performance cars make less on a dyno than the company's book figures? I always got that impression anyway.
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i've had 121 and 123 out of totally stock g40s on decent rollers.
Thats pretty interesting, cant say i had ever heard of this for the G40..
you learn something new every day on here..
Cheers
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130bhp for a stock G40 at Aldon might be a bit excessive (though didn't Nick's old one put that out?), but we're not comparing apples with apples here...
140bhp for 9:1 CR 1341cc with a custom chip, and 123bhp for an 8:1 CR 1272cc with VW's original chip. If you tweaked the map in the stock car to make it a fairer comparison you'd probably get a few more bhp out of it.
Dependant on spec and tune it's probably something like a 5-8% increase in power for 1341cc, but that's educated guesswork rather than actual testing. Are you still going to do a back to back test for your uni project?
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Yeah its all done, ive run up a standard G engine with turbo and then run up a 1341 with my flowed head etc etc.. Ill stick the results up in June'ish once ive handed in my paper, and had feed back. Ive already been warned by the tutor about posting information on the flow bench results ;D so i had better wait to be on the safe side!
Thanks for the input guys - i am just in the process of writing up the main write up and was interested in the rough figures expected for the bottom end only - i would like to have done bottom end only, cylinder head only and then both block and head comparison tests but time was not on my side with the car so over dude and other work to be getting on with..
Thanks again
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i've had 121 and 123 out of totally stock g40s on decent rollers.
Even with restrictor in the airbox outlet?
Can't seem to find a stock RR graph from my old blue G40, but my first black G (K155 EUL) put out 131 bhp at Stealth with de-restricted airbox/panel filter and Jetex backbox.
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i've had 121 and 123 out of totally stock g40s on decent rollers.
Even with restrictor in the airbox outlet?
Can't seem to find a stock RR graph from my old blue G40, but my first black G (K155 EUL) put out 131 bhp at Stealth with de-restricted airbox/panel filter and Jetex backbox.
thats stealth though!!!!
yeah 123 on my last g40 with stock charger (serviced mind) and cat and restricted airbox.
At john sleaths my g did 95.6 at the fly fully stock - which he said was about 118bhp
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you mean at the wheels pete! You keep making that mistake, have you gone senile?
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er yeah 95.6 at the wheels - approx 118bhp at the fly on sleaths rollers
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Yeah its all done, ive run up a standard G engine with turbo and then run up a 1341 with my flowed head etc etc.. Ill stick the results up in June'ish once ive handed in my paper, and had feed back. Ive already been warned by the tutor about posting information on the flow bench results ;D so i had better wait to be on the safe side!
Thanks for the input guys - i am just in the process of writing up the main write up and was interested in the rough figures expected for the bottom end only - i would like to have done bottom end only, cylinder head only and then both block and head comparison tests but time was not on my side with the car so over dude and other work to be getting on with..
Thanks again
Will be interesting to see what your results are - though without custom mapping each setup it's not a 100% fair test.
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Understandably a full custom map would have been the fairest way (£££) but the experiment showed the gains to be had from the cylinder block and head and allowed me to show the potential to be had without using external power factors...