slatermvp

iTrader: (13)

I think he means like making all bolts from ARP...we already use the head bolts but he means replacing most of the bolts with the ARP ones.

RoadSpike

iTrader: (5)

I'm also wondering if the factory 4g94 oil pump isn't as high flowing as the 4g63 and 4g64 oil pumps. Been checking out the clearances that come stock no the 4g94 and it doesn't look that bad for a higher rpm setup but if the oil pump isn't high flow and low pressure that would obviously be an issue.

HornstarBU

iTrader: (7)

http://en.wikipedia.org/wiki/Mitsubishi_4G9_engine#4G94

This says that the stock rods are forged, is that true? Maybe that's why Steven was able to run 17lbs and didn't break something. I kept hearing "weak rods, weak pistons, etc etc" but never really looked into it much. The rods look very similar size to the 4g6x ones.

Demon_ni2

iTrader: (15)

oem vs 16psi

oem vs pautar

HornstarBU

iTrader: (7)

those K1 rods are a lot thinner, wonder how they compare side by side

Demon_ni2

iTrader: (15)

I have a side by side shot somewhere... I cant find it, my buddies lancer setup was with k1 rods, and they were Much smaller and almost identical weight as oem

steven121

iTrader: (27)

The rods are only affected at a certain point, i spoke to a guy from k1 who has 17+ years in developing rods for racecars. he said its not the rod itself but how much fuel your car delivers to keep itself cool. heat plays a big part, the leaner you are the more heat = rod failure. I was able to run 17 pounds because my tune was safe and i kept it at 11.5 around 4k and up to 6k 11.3.

Im pretty sure I could have ran 20 pounds and set a record for the car. the only issue is since we don't have alot of cooling on the motors the heat potential raises. if you can get an oil cooler, a body kit that helps reflect air in the motor etc 'my evo bumper was designed for that = all evos" So my temps inside were nice and cool. When I get my new lancer I will be building it slow and I think I might push it 20 pounds and prove a point, unless someone else wants to beat my record of 17 pounds...

Demon_ni2

iTrader: (15)

Rods are broken and damged normally by torque. thats why tuning on dyno is important to remove and trq spikes and make a more smooth linear increase without major fuel or timing changes. . fuel trims and timing are the key to any properly running car. At 20psi with a real tune for proper power for that boost level, u will lose ur rods garenteed. jump on dyno and aim for 300-320hpcuz thats realistically what u should be making with a proper tune, they will go. and fuel is related to heat in 2 ways, to lean is to hot,and to rich is also to hot.

at 12-13psi with the car tuned pushin the motor to the limit, they should bend/break eventually..
u could run 30psi, with tons of timing pulled and make no real power, and ur rods shouldnt break.

Boost means nothing. its all about power. and at 17psi, with ur rods holding up, ur probably on a very safe tune and missing out on alot of power because of that. normally lowering the boost and fine tuning is ur best bet, its less abuse of other aspects of the motor and u should make similiar if not more power. abuse on our motors suck, exspecially our crappy piston rings pistons and headstuds.
but fine tuning involves more dyno time.

HornstarBU

iTrader: (7)

I like everything you're saying. One thing I've heard that halfway contradicts what your point on power vs boost being what breaks/bends rods is that some say "more boost is safer than more timing, at equal power levels". Do you think that there is anything to be said for that, or is it bogus?

Demon_ni2

iTrader: (15)

Boost doesnt break/bend rods, but can be directly related based on power, i said power breaks/bends rods. specifically torque. so...

i agree with that statement.. Boost is safer then adding timing, because ur suppose to pull timing with more forced induction, yielding a nonlinear power increase thats related to boost, if u have a linear power increase(say 20hp per psi) and u maintain it u actually pushing the motor loads harder. but at equal power levels,(at lower boost) ur probably risking things other then just rods. ur talkin the difference of a Safe tune at more boost, and a tune thats at the limits of what the motor can handle at lower boost. staying in a safe range is always convinent for street cars. but with that in mind, u have to remember, our cars arent built for boost, and Other things will start to fail from the stresses of boost n power, specifically piston rings going out. also things like rear mains failing because of to much crankcase pressure, which is directly related to boost(its a bigger issue with v8 guys then us though) sadly, on a safe setup the more boost your pushing the more power u missing, so u ideally do still wanna stay near the realistic max for that motor.

Ideally.. which seems to be about the same for every OEM nonturbo car, 9psi is realistically the most power u can make with a good tune without risking to much, and thats with a tune pullin every ounce of power out of it... yes, its a low amount of boost, but ur still pushing the motor to its realistic limits without playing Chicken with a piston detonating or a rod bending like a twig.
and sadly, with a good tune at 9psi ur probably making more power then most of our street tuned cars that seem to be running in a safe range.

down side about most of our street tuned setups, most of u dont dyno at all, and most dont egts either, so u donno how much timing u can really add, and if u have any timing spots that are makin to much or to little power other then just feel and afr. so not many of us are really pushing at setups to the limits or properly.

RoadSpike

iTrader: (5)

Demon on a street setup running pump fuel your going to hit knock and det way before you reach mbt its why people end up running more boost and pushing lower safer timing levels with moderately rich afr's to achieve bigger power on pump. I wouldn't rely on egt as the benchmark to achieving good timing it has its own pitfalls for example pre det and det would make the egt's look colder making it seem as if your on the right track when its just a road to failure. We have knock sensors using them is a safe way to find out what works and what doesn't.

There is one other factor your not considering which is the efficiency of the motor. The 4g94 seems to be geared toward low end rpm torque so i'm expecting VE falls off like a rock as the rpm's climb.

Demon_ni2

iTrader: (15)

Well ya, RoadSpike thats all good and true for pump street setups, but dont u agree that fine tuning a lower safe boost range (say 10psi) should yield similiar power,compared to say 16psi w/ a bunch of timing pulled to keep it safe, being that we know that around 220-240hp/trq rods give out regaurdless and people normally make that around 10-12psi

HornstarBU

iTrader: (7)

Everything I read about last night said these 3 things consistently.

1. More power (torque) breaks rods
2. Increased cylinder pressure (detonation) breaks rods
3. Lack of Oil ruins engines

So, I think everyone is saying the same things then, a safe tune will minimize wear from knock. Rods can only take so much, before they just physically can't hold up. And you've got to have oil there at all times, or the parts weaken from extreme heat.

I turned my boost WAAAY up last night, from 6psi, to almost 6.5 psi!!!!! /sarcasm I am excited to see what happens when I turn it up to 9-10psi...slowly. I think the whole topic though...boils down to this:

4g94 engine > 4g64 engine, regardless of power and mods. Whichever you have, if you can make it "stick" to the ground, you're gonna be fine. The 4g94 just weighs less, so it wins...

RoadSpike

iTrader: (5)

Safer for sure but not faster.

The car with the higher boost could keep a flatter torque line achieving greater overall power and faster 1/4 times while still being in the safe torque range at the cost of a hotter egt.

steven121

iTrader: (27)

see this is where im confused at I built full boost around 4-5k at 17 pounds and my timing was set to I think 4-5 degrees.

Hornstar says lower timing to build quicker boost, demon says raise the timing to increase power with boost... can somone clarify if I did something wrong?