Question I've been wondering about...
 

I have a huge noob question. What exactly blows motors with stock internals? Is it the HP or the amount of boost? For example, I have heard about guys blowing their stock internal motor at 450 HP, yet the Momentum kits are making 525 at the same or a little higher boost level. Sorry if this doesn't make sense, it's kind of hard to say what I'm asking..

Basically, are you safe making more horsepower at the same level of boost, say by adding supporting mods like headers, test pipes, tuning, fuel system ect. :dunno:

In my opinion its the torque that blows motors ...

I actually think that is what helps the hr produce the higher HP along with beefed up internals...

That momentum car is a built block, i assume you are referring to the one S&R installed?

There are only a few of us making over that 450rwhp on stock block, and actually drive the car (to my knowledge just me and Sylvan)

The TQ is what kills the internals, HP is imaginary. But even then very few make the TQ i do on stock block, and thats because its extremely risky.

The biggest part of a car holding up is the tune. Most cases of blown stock blocks are people with either an inexperienced tuner or EMS problems, Like the UTEC, the way the stock ECU will lean the car out over time due to the UTEC being a piggyback.

#1 rule if you want to push the limits of stock block, Don't do it unless you have the $ for a built block and you don't have to rely on the car as your only transportation

the tune blows it.

You can take a stock engine, no mods at all with no boost and tune it wrong and blow it up.

For boosted applications tuned properly it appears that mid 400's for torque are the limit of stock rods though. It varies from engine to engine because there could be a bad piece of metal in one of the castings of your rod verses someone elses rods.

I see, thanks a lot... So it may or may not be safe to squeeze out more horsepower at a consistent boost level? I know it sounds dumb, but the added HP, say from a header back exhaust won't put more strain on the motor right? Is it more related to effective and efficient use of the current amount of boost?

Any additional TQ will add strain on the engine, so if that header back exhaust makes more TQ then yes, but if it just adds HP then no. HP is just a calculation based on sustained TQ.

typically, it's one of 3 things

1. the tune
2. the installer
3. the owner (poor maintenance, etc)

it's impossible to say "x" engine made 400whp and blew apart and "Y" motor made 520whp and stayed together, because 1. you don't know if either dyno figure are truly accurate relative to one another (unless on the same dyno) and 2. how long has each setup been running? How many miles? What was maintenance like? What was the tune like and what was the method of tuning? Without all these factors being known, it's at best, a guess based on opinion

Plan for the worst, hope for the best. IMO, if you can't afford, or aren't willing to go through the process, to build the motor when it blows, you probably shouldn't be considering forced induction in the first place.

:werd:

UTEC has complete fuel and timing control in boost, it makes no diff what the stock ECU does. UTEC is by far the safest piggy as long as a competent UTEC tuner sets it all up right. It's just too bad that the UTEC has some quirks like open/closed loop transition that make it sucky for a DD but great for a track only car.

It's the other piggy backs add/subtract from stock signals and are susceptible to the stock ECU 'learning curve'.

Boost doesn't matter (given it's limitations.. octane, knock etc). Tq is the killer, and rods are the limitation.

Sam@GTM said otherwise:confused:

If thats the case i may go with Utec

Well he's wrong :P, I'll say it with a straight face as someone who has had and tuned a UTEC. In boost it works just like a standalone. But I still won't recommend it for a DD or for >500WHP due to it's various quirks.

Hey Phreaktor,
I agree with the folks like rh_334 that blame torque here’s why.
It’s really common to assume that power wrecks things but power is a rate at which energy is applied and that energy stems from a force. The torque generated results from a compressive load applied to the connecting rods and that force causes a stress and strain in the connecting rods. Once that stress is too high, the rod will bend beyond its elastic limit and experience plastic deformation. (Man, this is getting nerdy in a hurry…:confused:) All that means is that it has bent far enough that it won’t “spring back” to its initial shape.
Think about bending a butter knife. You can bend it a little and it will return to its initial shape without a problem; but, it you bend it too far, one time and one time only, it will spring back a little, but not to the same shape it was before. That “one time” is represented by the torque. The horsepower represents you bending it a whole bunch of times but it doesn’t matter anymore if you already screwed it the first time you exceeded its bending stress.
Lost all your butter knives in some sort of “heat related” activity? How about we use a McD’s straw, then? Stand your straw on the table holding the bottom and push a bit on the top. It can support a reasonable load but if you push too hard it buckles* and it’ll never hold the same load it did before again. You can put a light load on it thousands of times and it doesn’t care, but the first time you exceed the limit, it’s pooched and the next thousand times you apply that load don’t matter anymore. *(Strictly speaking, column buckling isn’t the same but in a crude demo, this gets the point across…)
Of course, maintenance and manufacturing tolerances and whether the assembler tightened both of your con rod bolts before his coffee break all play a role in the variability of the final product and that is why there’s no magic torque number that bends rods and why binder gave a torque range based on his experience. The overly aggressive or inaccurate tune can also generate a force too high for the rods.
As for other modifications, I think it depends on what it does to your torque curve (but I’m open to others’ suggestions as I’m more thinking out loud now). If it increases your peak torque number beyond what your internals (most say the rods are the limiting factor) can handle, then you’re in trouble but often the supporting modification changes your torque curve in other ways. It can broaden it in such a way that gives you a higher maximum power, or it can add a bunch of torque in an area that was nowhere near the max torque before, so you’re seeing and feeling a benefit without exceeding the maximum stress that your rods can take.
Hope this helps.

utec
 

I experience this when going from boost to no boost...Is this going form closed to open loop?

Agreed! Getting tired of all the UTEC bashing. Lets face it, the utec was phased out because of the Performance shops that threw it under the bus in order to sell other brands.

Also my issue was not close vs open but the transition from ecu to utec.

*Tune

*Power level, specifically torque

*Driver

If one of those is bad, too high (stock block) or crazy, the chances of a failure, even when setup "corrrectly" and its game over. That goes for built motors as well.

I set my stock block up with top tier parts, it had a smooth conservative tune, no big numbers, but I drive my car, HARD. It blew up only 3000 miles later.

370's can hold more power so dont look at what they are doing as to what your DE can do safely.

:+1: You a Materials Engineer?

The only thing i don't agree with 100% is the HP comment, it does someone simulate how many times the rod is stressed to an extent, but in HRs and VQ37s they make drastically less TQ but sustain it longer, that is one of the reasons they can make so much more rwhp than a DE. If you look at the TQ they make its usually >400ft-lb but they maintain it better past the magic #5252rpm.

define "other piggybacks"

Unichip?:dunno:
Like included in the APS kit, would that be considered a piggyback?