Discussion
DHGTR said:
guys do any of you know the gear ratios for the getrag box. and secondly do any of you have the gearbox speed calculator program that you can send me. i have tried to access the locost website that we used to get links for on here but it seems to have died. cheers dave.
Check here for lots of trans links.
-- Scott
>> Edited by builder on Thursday 4th August 01:46
B1 ECC said:All depends on what the top revs are.
Factory sheet for the records states 231mph.
Steve[/quote]
For that, with standard gearing you need 8700 rpm, which is fine if you installed a DFL![/quote]
Gareth's motor will pull 8000 at a pinch. Don't know what the factory 640 pulls.
Steve
DHGTR said:Oops! Yes, that is correct Michael. Here's the link.
Hi Scott, dead link i'm afraid.
Andy, using ratios posted here the top speed is 176mph.
andygtt said:
I was told the factory 640 isn't the same engine as gareths and is actually a larger displacment (ie not a 377)... if so it suggests to me its unlikely to rev as high as gareths.
Also I don't think gareth used a getrag did he?
Gareth does not have a Getrag but a factory owned box was fitted for the tests. What type it was I don't know but as you say it was unlikely to be Getrag.
I think it went somewhere along the lines of 'If there's a possiblity of the box going bang it's not going to be mine'.
Steve
ultimad said:
Thanks for the replies. How straightforward is it to change the gearing in the GETRAG, should I want to change the suggested 176 mph top speed.
I would imagine it is possible at a price, the ratio's in a G50 are much easier, " should you want to change the 176mph top speed"--No, your going to blitz most things to 120-130mph anyway, if you want to continually drive at greater speeds on public roads then "plod " will have your licence. On Uk Tracks you wont see any more than 155mph, if you go to europe then you will see higher speeds, but, IMHO thay extra 20mph takes a lot of dealing with!
Folks, I've been talking to Roger Brown from PowerHaus II about a possible change to my Getrag 6 speed ratios. We have only talked so far about a change he has currently available to make 1st gear taller (ratio 2.75). He says he can do a run of taller 6th gears if the demand is there. Quote :
"Fitment involves the gearbox to be fully stripped with all gears on the input shaft removed. The custom tall 1st gear that we have had produced is a weld on type and includes a new reverse as well (they had to be made that way). The original first and reverse would then be machined off the input shaft and re-fitted with the new gears. I can provide you with an input shaft already prepared, so to speak, and ready to install. Your price for a ready to install input shaft with new gears is $1350.00 plus shipping. Currently I don't have an optional taller 6th gear but would not be opposed to having a small run made if the market is there."
Now before I even consider taking this further I would be interested in your views on this. I have also asked him about a change to make all the gears taller (say similar to the turbo 6 speed Getrag ??).
What would be great is if anybody has had experience of doing similar or have taller gear ratios on their boxes than mine and what they feel about drivability, impact on acceleration, etc. ? I have an engine that can rev to 7500, I do find 1st not very unusable and to be honest I reckon all gears could do with being a little taller (definitely 6th). I'm not an 'engineer' but I know there's a few of you here so I would value your input.
"Fitment involves the gearbox to be fully stripped with all gears on the input shaft removed. The custom tall 1st gear that we have had produced is a weld on type and includes a new reverse as well (they had to be made that way). The original first and reverse would then be machined off the input shaft and re-fitted with the new gears. I can provide you with an input shaft already prepared, so to speak, and ready to install. Your price for a ready to install input shaft with new gears is $1350.00 plus shipping. Currently I don't have an optional taller 6th gear but would not be opposed to having a small run made if the market is there."
Now before I even consider taking this further I would be interested in your views on this. I have also asked him about a change to make all the gears taller (say similar to the turbo 6 speed Getrag ??).
What would be great is if anybody has had experience of doing similar or have taller gear ratios on their boxes than mine and what they feel about drivability, impact on acceleration, etc. ? I have an engine that can rev to 7500, I do find 1st not very unusable and to be honest I reckon all gears could do with being a little taller (definitely 6th). I'm not an 'engineer' but I know there's a few of you here so I would value your input.
Can't tell you about the drive, yet.
But Roger has suggested and supplied the following for my G50 03:
ring and pinion 3.444
At 7000rpm
1st 3.5 44.781mph (std)
2nd 2.059 76.124mph (std)
3rd 1.407 111.364mph (std)
4th 0.967 162.139mph (OE Porsche)
5th 0.688 227.977mph (Custom PHII)
All the rev drops fall from 7000 rpm to around the 4,800 mark. I have seen from the vid of honigton that the 4th and 5th gears had drops to around 5,000 + and very soor ran outta legs.
We'll see.
Lucky
But Roger has suggested and supplied the following for my G50 03:
ring and pinion 3.444
At 7000rpm
1st 3.5 44.781mph (std)
2nd 2.059 76.124mph (std)
3rd 1.407 111.364mph (std)
4th 0.967 162.139mph (OE Porsche)
5th 0.688 227.977mph (Custom PHII)
All the rev drops fall from 7000 rpm to around the 4,800 mark. I have seen from the vid of honigton that the 4th and 5th gears had drops to around 5,000 + and very soor ran outta legs.
We'll see.
Lucky
Edited by LuckyP on Thursday 16th November 11:40
Edited by LuckyP on Thursday 16th November 11:48
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