Stroker?

[Roadrunner]

The 2-litre Evo engine can be stroked to 2.2 litres. Can the VR-4's 2.5-litre be stroked? - to 2.7? 2.8? If so, how?

[paulmc]

Evo lads use a longer throw crank the different pistons, prob the best way as re-boring can weaken the block.

[enigma]

speak to mante, I think he is up around 3.1 litres..............................

A longer throw crank, different rods and pistons will achieve the desired effect, but it aint cheap!

You can offset grind the original crank if there is enough meat on it, you will make the journals a wee bit smaller and weaker, but it would be cheaper than the above, if you make the journals 2mm smaller you could be looking at an increase of as little as 50cc.....so you see you would need to take a lot off to make any real difference.

[Roadrunner]

Thanks guys :) Not planning on doing it, just wondered whether it was possible.

[enigma]

anything is possible if you pockets are deep enough!

[Roadrunner]

anything is possible if you pockets are deep enough!
Does anyone know if the GTO 3-litre engine is a stroked version of the 6A13, or a different beast altogether?

[Nick Mann]

Can't tell you bore and stroke, but it sits in the car the other way around. (Gearbox on the drivers side)

/edit:

google tuns up 91.1 bore and 76 stroke, so that looks like a no!

[Kieran]

Does anyone know if the GTO 3-litre engine is a stroked version of the 6A13, or a different beast altogether?

Nah. The GTO engine is the 6G72. The 6A13 i believe is a development of the 6G72, but i think they are sufficinetly different to make swapping bits impossible....

[FTOLTD]

there are several ways to do a stroker on the 6A13 depending on how much money you have

1 would be to increase the bore and stroke on the standard engine by offset grind of the crank and conrods with smaller big ends and bigger pistons. you could easily go to 83 bore and 83 stroke this would give you 2693 cc so you could say 2.7ltr, the bore and crank integrity should be OK at this size. If you want to go bigger i would recommend using cylinder liners for the engine which would give you the capacity to take it up to 86 or 87 mm bore and getting a custom crank made that would give you a stroke of 86 or 87 mm.

86 stroke and 86 bore would give you 2996.08 cc effectivly 3ltr

87 stroke and 87 bore would give you 3101.81 cc effectivly 3.1ltr

of course you have to decide how much horsepower you want .

i think putting good set of forged pistons in with a good set of forged rods and decent single or twin turbos with a bit of work to the cams and heads with afterket ECU and the other necessary goodies would easily be able to get you to 500 @ the wheels with the right combination.

If you are going to the trouble of stroking it, I am guessing you would be thinking of going for big numbers and there for wouldn't want a crank that could snap, so the custom racing crank would seem the best way to go.

[FTOLTD]

you could also keep the stroke at 81mm and just increase the bore from 81mm to 89mm using some cylinder liners and that gives you 3022.20 cc

If anyone is looking at getting a custom made 3ltr stroker crank made let me know , i could get one reground but would prefer to get a custom racing crank.

who is for a group buy

[Roadrunner]

there are several ways to do a stroker on the 6A13 depending on how much money you have
Thanks for all the info :thumbsup:

[FTOLTD]

no problem

really you wouldn't do it unless you had a lot of money

better off doing a lot of other things first. you could easy get 400hp out of the stock engine with a good turbo and aftermarket ECU and a few other bits

[FTOLTD]

i forgot to add if you go with the custom crank you would also need to do some relief work to the block so that the crank or conrods don't hit the block. it dosen't look like much would have to be removed though, with the bigger argo rods i put in my motor there was still enough clearance and only came close in a few places.

[RED]

Dave, have you still got that crank and rod? If you have and it hasn't gone in the big BDA garage clearance can you bring it to Japfest with you?

I will take it up to Farndon Engineering and /or Doug Kiddie and see what a forged set would cost.

Marcus

[FTOLTD]

would probably be a good idea to take a block with you too, then they can design a stroker kit.

I would buy one