70 replies to this topic

[CYBORG-X]

In reading all of this i am building a new motor for my awd satria, i'm going far out and using a bit of old school tuning as an experiment.. the car will be a daily so it needs to be drivable.. im going 11:1 pistons, polished and peened rods, stock boltons with a 93t head with very minor cleaning up to reduce detonation. A garrett 2869 bb turbo will be used.
The idea behind this is to make torque and mid power with light free reving internals. Remember heavy pistons dont like to stop and go the other way..lol.
All i'm saying is some times less is more and there are alot more factors to consider

[BMGTZ]

Stock rods polished and peened? Or forged?

[VIN18M]

That will be an animal with 11:1.

You'd want to get it on e85 for safe tuning though.

[CYBORG-X]

Stock rods, polished and peened. Im going to get a nice safe tune on 98 and just use the torque of the motor..

[BMGTZ]

mmm...risky on stock rods

 

by the time you get someone to polish, resize and shot peen aren't you at least half way in cost of a set of forged rods?

[leadfoot]

I wouldnt do it with stock rods piston sure but rod no way. Spector from evo coupe bent stock 4g93 rods na with 11:1 and mivec. About 123kw. 4g93 rids realy are their achillies heel. Invest in forged rods and machine pin locks into your pistons

[CYBORG-X]

I do the rods myself, so minimal cost. And i have a full set of forged rods and pistons already
The whole idea behind the high comp is to keep the engine torquie, use the 2k-5k rpm band. The motor will be in a daily drive doing 120kms a day.
As for the rod, i've seen bigger rods on dirtbikes, they are very average, but if treated well i do believe they will be fine.
The stresses on a rod is the same whether 17psi with 8.5:1 pistons in a gsr
11psi with 10.5 pistons in a bolt on gti
8psi with 11:1 pistons.

[BYBY5L]

Fuckin hell! Your a mad man! Lighter rotating mass is all good but... 11.1 on 98 with factory "treated rods"- your either Einstein crazy or just bat shit crazy, lol
Ya got me watching with alot of interest!

[leadfoot]

and spektor bent hist 4g93 rods at 11:1 on 0 psi at 7000rpm the 4g93 has a terible bore to stroke ratio an realy real shit angles on the rods on the power stroke this combined with being H beam toothpick dosn't help them stay straight. if they were I beam i'd be inclined to agree with you but you've been warned that an engine has been know to fail at the CR your intending

[CYBORG-X]

The opposite side to the coin is, alot of people have run gsr's with 17psi. Also the proton gti is a 10.5:1 and mine ran a big 16g for a few years completely untouched.
I'm not saying either way is right or wrong, just different ways of approaching it. You do make a valid point about the rod ratio, but i think forged H beams (spool rods) are a bit too heavy for daily use..
If it ejects a rod, i have 2 spare gsr engines and forgies ready to go and i'll be wiser for it.

[leadfoot]

Ive been daily running spool rods for about a year and abit now and must say its running mint.

Just dont rev its tits off or get to agressive with the timing and you should be fine your biggest risk will be tuning as even a touch of detonation can likely kill this build.