Forged or Cast

[Shannon]

Whats the go with pistons, is it worth going forged??
Just thinking that with the restrictors that we have to run, is it worth it or is cast good enough ??

Sorry Car is a Mazda 1.6 turbo for those that don't know (B6T).

As for rods should I throw some after market rods in there or would the standard do (I suppose this would depend on the amount of boost?).
In the long run I would like to run a bit of anti lag as much as the box is going to let me

Whats peoples thoughts, would the extra cost be worth it or am I just wasting my money.
Or have I just had to much Rum

Cheers
Ian

[col]

If you want info on the b6t go to some mx5 forums.
Turbo miata is a good one.
These motors are good for a heap of reliable hp, anything up to 10-12 lbfor road . But if rally is intended maby keep it down a bit lower.
The big thing with pistons breaking on these engines is bad tune and over reving.

[Rhys Llewellyn]

Originally Posted by Shannon

Or have I just had to much Rum

Cheers
Ian

No Such Thing.
Have another one and then have one for me.

[Mx5 nut]

Stock Rods will be fine up to 14 PSI
after that this happen
the last picture is what I replaced them with Good for 30 PSI

[Spac]

Forged are worth it.

Forgies are 'stronger', won't fail catastrophically if you overheat them and can be made to exactly the specs you want.
The downsides are that they need more clearance when cold (making the engine clattery until it warms up), and are more expensive.

Having a turbo restrictor typically means that you'll run more boost lower in the rev range (ie: Trying to get as much area under the power curve before the restrictor kills the fun), which is where detonation is most likely (and therefore where forgies are most likely to save your asre).

And Remember: More power = more gearbox dramas.... They're great little engines, with the potential to make a lot more power than the gearbox can dream of handling.

[buzzard]

Here is a simple equation. Detonation = broken parts.

Chris

[Spac]

Never a truer word typed.
But the reality is that rally cars are amlost inevitably going to be subjected to huge variations in fuel quality and air temperature, and that a bit of a 'buffer' is a good idea.
Either that, or tune is so fat that standard 120Ys blow your doors off.
Or spend so much time on the dyno that you could have bought an Evo10...

[Swill]

Buy some forgies and whack some ARP rod bolts in some proper prepared standard rods and she'll be apples

[RS1800]

Forced induction of any kind/size/force dictates the use of forged internals for all of the above mentioned reasons. Don't bother with the "tricked up" standard rods, a complete waste of time and money. By the time you have had them shot peened, new rod bolts, closed and honed etc etc you are nearly at the cost of a set of forged rods and you are still stuck with the standard ****e!! Put forged stuff in it and forget about it.

[Mx5 nut]

Originally Posted by buzzard

Here is a simple equation. Detonation = broken parts.

Chris

R U refering To ME ??

[Matthew Ferguson]

If you can not afford it you'll live with out it.

If you can afford it you'd be stupid to be with out it.

[buzzard]

Originally Posted by Mx5 nut

R U refering To ME ??

Not really, I was merely pointing out that det=broken.

I have tuned engines with cast components that made more power than I thought they should and ran for a long time.

If you get severe detonation forged components will not help you.

Chris

[buzzard]

Broken conrods such as the one shown in the pic are generally caused by running bent.

Bent conrods generally have two causes.

1. Hydraulic lock
2.Ignition is randomly firing some/many degrees before the ideal ignition point.

MX5, might I enquire what ecu are you using ?

Chris

[Mx5 nut]

Originally Posted by buzzard

Broken conrods such as the one shown in the pic are generally caused by running bent.

Bent conrods generally have two causes.

1. Hydraulic lock
2.Ignition is randomly firing some/many degrees before the ideal ignition point.

MX5, might I enquire what ecu are you using ?

Chris

I run an Autronic SM4 and I do the Tunning
Bending rods is Common in an MX5 (BP/B6)engine the stock rods hold 14PSI all
day. But when your 1/2 a sec off 1st place and turn the BOOST up to 18PSI
then the bending and the braking happen very Quickly.
ON 14PSI was make just under 200KW

[col]

Bent rods are commonly from the peak cylinder pressure being too high, and that is mostly a timing problem.
If you have tuned for 12lb then leave it at 12 lb and you probably won't have trouble.
People tend to tune for 12lb and expect to wind the wick up further without tuning, then bang, broken rod ,and blame that on weak parts.
"It's all in the tuning"
There are limits to the standard b6 parts , but there is no reason to exceed them on a rally car. Simply not enough traction on a light two wheel drive.
If you intend to race on bitumen that is a diferent story and the money on forged internals is warented.
In my opinion , on dirt the extra money would be better spent on suspension.