Increasing Bore Size

[EP91_Chris]

Hi guys,

I have a 5e-fhe lump in my Sportif, unfortunately the piston rings have given up.

While I have the engine apart again, I have been pondering at the idea of increasing the bore size.

Question time

1) Has anyone done this before?

2) What is a safe increase in mm?

3) What pistons were used?

4) Any further cooling upgrades required?

Thanks in advance

 

[Phil]

you can go 75mm without having to spec one off pistons.

aside from that ive heard of Suzuki vitari pistons being used they are 75.5mm dia!

id stick to 74.5 and go low comp and turbo while your at it chris.

Phil

 

[EP91_Chris]

Cheers Phil.

As much as I would love to go turbo I just don't have the cash at the moment, it is on the cards eventually though.

 

[Phil]

Cheers Phil.

As much as I would love to go turbo I just don't have the cash at the moment, it is on the cards eventually though.

Start gathering parts then and enjoy the car as is for the meantime

Ive got a stock ct9a turbo/ported mani/gutted cat that you can have for not a lot if you do decide to go down the turbo route

Phil

 

[Mikey4410]

I have seen people only go one oversize,as it allows for another oversize after that if ever needed.once u have done 2 oversizing thats it.if theres a problem and u need a rrebore ure out of luck....

 

[EP91_Chris]

Start gathering parts then and enjoy the car as is for the meantime

Ive got a stock ct9a turbo/ported mani/gutted cat that you can have for not a lot if you do decide to go down the turbo route

Phil

I quite like the idea of staying n/a and seeing what power can be squeezed out of her.

I have seen people only go one oversize,as it allows for another oversize after that if ever needed.once u have done 2 oversizing thats it.if theres a problem and u need a rrebore ure out of luck....

Thanks Mikey, I will prob just go one oversize to keep things simple.

 

[weeJohn]

Speak to Joel @ ECC, pretty sure he was going this way but changed his mind so there could be a few parts you may be interested in that he wants rid off.

 

[EP91_Chris]

Thanks John, I will drop him a message.

 

[HYBRID]

well in my opinion u dont need to go over 74mm unless the bore is scratched from the ring failure u suffered.... power wise ur not going to notice any difference especially on an n/a .. unless of course u increase the cr by a fair amount...

kon

 

[dark_knight]

NA gives nice linear power so maybe you won't mind it too much..

 

[Tim@TBDevelopments]

the way to get power out of an n/a is to increase the rev limit. with supporting modifications of course. spec the head and cams for that higher RPM.

prime example the 3sge pushes out 170bhp (ish) the best i've ever seen was a TRD unit making 260bhp still in completely N/A form. This had a 11,000RPM redline. and then flow modifications to suit. But remember with the n/a it really is a comprimise you'll gain power up top but then loose it lower down

Tim
TB Developments

 

[AdamB]

Agree with Tim, if you take a look at any dyno graph of the 4EFE engine, you can see that its still making power at the rev limit. The problem lies with that the FTE and FE head are exactly the same spec (except valve springs). I've seen a stock cylinder head make 350bhp, which no way is a 1.3 N/A going to make. The port sizes are really too large for the N/A engine, losing velocity and pressure.