how much boost can a 4g63t 6bolt handle safely?

[TERBOLASER]

okay here it is I want to know how much boost can a 6 bolt 4g63t safley handle on stock internals provided that there is minimal knock(talking no more than 10 count on the logger) and its fuel tuned with a Safc and datalogger. no fuel cut is hitting or anything what is the highest it can be safely set at with out blowing nething. because i am having boost creep problems from 15lbs that I set it at at around 5000 little before then it spool its self to 20lbs solid. so I have tuned for it to keep it from reaching hardly any knock around 5 or 6 knock. it runs fine in my opininion with respect to the logger.is this safe cause I want to know. I dont plan on racing it like this I just want to know for my own piece of mind. only od thing about it is I get this weird buck between gears like it isnt a smoot transition boost wise. after shifting to 2nd it feels like 20lbs of boost hits all at once. feels cool but also dangerous. Im stillsorta a newbie its only been a year Ive learned alot but im still learning . any help would be greatly appreciated.o yea we are talking a motor with like 40 or 50k on it.

thanx Jacques

 

[RipperXX]

boost pressure dont mean shit.. but when you mention air flow and HP.. thats deferent.

for instance, on stock pipes 20psi vs 20psi on full hard piped intake... yea there will be a giant deference in flow but the same pressure per squar inch.


Soo if you just mean my HP.. at the crank realisticly 380.. any more than that with out it tuned to a perfection and its really get risky past that.

 

[TERBOLASER]

okay so what your saying is that since i know im not any where near 380 that if im pushing 20lbs stokc piping and intercooler but im fuel tuned so that i dont knock and that im not lean at 20lbs ona 16g small its okay right.as long as its tuned right

 

[MNGSX]

It's tough to say.

Are they stock head bolts?

If so you will likely lift the head before you break a rod just from power output... as in no detonation just too much hp..

Also has it been rebuilt or how many miles etc..etc..

I think the stock CAS and the ECU with its time based spark advance calculations breaks more rods than anything... Which is why when I go to a standalone I will run a aftermarket crank trigger... What the ecu thinks is a given advance wanders with RPM due to sensor error and limitations of the sensors accuracy.

 

[kpt4321]

This is from a reply I posted on Honda-Tech a few days ago:

Engine Limits - Psi, CFM, or horsepower?

A lot of people like to define an engine's limitations in terms of the maximum boost pressure it can sustain, but that's really not the right way to do it.

What happens in most of the cases when these limits are exceeded, is you either blow up bottom end stuff (ringlangs, for example) or you lift the head and/or blow up the head gasket. All of these problems are directly caused by too much pressure during combustion. However, maximum cylinder pressure is NOT determined solely by boost pressure, so we shouldn't use boost pressure to define the limits of a motor.

Another popular way to define the limits of a motor, are with a horsepower limit. While this is closer to being related to the true cause of motor problem, cylinder pressure, it still is not perfect. Horsepower is the net result of cylinder pressure over time, meaning that 300 horsepower at 5000 rpm is NOT the same peak cylinder pressure as 300 horsepower at 9000 rpm. Because of this, you can increase power by increasing top-end breathing capacity, without getting any closer to the limitations of the bottom end.

Cylinder pressure is actually most directly related to torque, because torque comes from the push on the top of the piston. In terms of what we can measure, torque is the most representative of cylinder pressure. Also, rpm is not an influence in the relation between torque and cylinder pressure. In general, if torque goes up, cylinder pressure goes up. (Interesting tidbit: thus, cylinder pressure, motor stress and load, and knock propensity are highest at the torque peak, which is also the VE peak).

In the end, I think that defining a motor's limits in general terms of horsepower, or maximum MASS flow, is the way to go. Torque is a better measurement, but nobody ever has payed much attention to it so switching over would be difficult.

Also, everyone knows that tuning plays a big part in all of this, because the quality of the tune plays a VERY big role in determining not only the maximum cylinder pressure, and also how it happens. Very sharp spikes in pressure can be more harmful to the motor than a nice smooth curve up to the same pressure. Also, knock/detonation is one of the primary killers of motors, because it causes excessive cylinder pressure oscillations.

You can read the thread here:

http://www.honda-tech.com/zerothread?id=728240

 

[TERBOLASER]

well that is an interesting tid bit fact thank you. I am now very enlightened on how that works.so If im not knocking and its not a boost spike but a creep from 5000 to 6500 maybe 6700 from 15lb to 20 not instant but curves to it. is that okay. its a realativly new motor its has about 40 k on it. jdm motor not that it makes a difference wheree its from. stock studs. I guess yall are suggesting thatI get ARP studs sounds like a good idea. but I have reduced detonation completely I highly doubt that im breaking 300 on stock piping so is it healthy im thinking about posting my datalogger read out of 1rst thru 3rd gears to see what yall think. cause it looks good to me but I dont wanna chance it too much.