Ok I've been reading about stock block limits on d,b,k, and h motors.. for example, people say stock d16 blocks are only good to 220whp until they blow.. then I see where people say they've been running their cars over the limit for a while because they had a good tune.. my question is, if a b18b is only good to 300whp, then no matter how good the tune is, at 350whp, is it gonna pop?? Someone I seen on youtube is using a bone stock b20 block with vtec head and says he runs over 372whp turbo 100% stock.. but just because the tune is great.. is that possible?? Is it really all in the tune that determines if the car will last or hp

 

Yes its possible but even with a great tune you can blow your motor, just depends on how high of hp your sleeves end up holding up

 

so ur saying that if I made 240whp bone stock d16 vtec turbo, and if I had the most tuning time put into it that was possible, I could get it to last a while?

 

http://www.clubcivic.com/board/showthread.php?t=96562
In this thread, if u read it, it says people have ran their d16 100% stock to 250whp no problems.. that's wat I dnt get about the whole stock block hp limit.. are they guesses or proven? Cuz if I can tune a d16 to 240whp, then im doing it and putting as much tuning time into it as possible.

 

When you're on the edge, it's not always black and white. Each engine setup may react a little differently. What you are really concerned about is detonation. A little bit of detonation on a sleeved block doesn't cause a lot of damage. But if you have a little detonation near maximum cylinder pressures on stock sleeves you could have disaster.

Your tuner may be tuning in the winter around 40 degrees and when the temp comes up in the summer to around 95 degrees the tune may be a little out of whack and cause detonation. The point is that tunes are conservative because you can control conditions on a dyno but you never know what conditions a motor will see on the road.

 

I think you FAIL to understand what tuning actual does/is. When you tune you add as much timing and fuel as you can to make power. There are obviously things to consider like knock/detonation and AFRs. Once they are at an acceptable level you have your maximum power.

The "rule of thumb" of maximum horsepower an engine can take is just peoples past experiences of the horsepower their engine failed at. You can take "X" motor and make a million different horsepower and end up with a million different results. The problem stems from the fact that these engines were mass produced. Let's face it, most mass production isn't as high of quality as something in a controlled low production.

With that in mind we can build a scenario: Say we have two IDENTICAL engines side by side. Their timing and fuel maps end up being IDENTICAL after tuning. The first engine lasts a week and the second one lasts 5 years. Why did this happen? Well variances are allowed in production for the metallurgy quotas. There is always a range they must meet and sometimes you get the shaft, other times you get a golden block.

So in all truth, there is no telling how much horsepower ANY engine can handle or for how long. The best you can do is go with a general blanket "safe" horsepower and go from there. There is no telling if your engine will fail even at a lower "safe" number. All you can do is perfect the tune and hope she holds.

(This is a very -very- basic explaination. Any time you go over the stock setup you shorten the life of the engine.)

 

These are ignorant statements to make. While detonation there are other things to be concerned with like washing the rings. To sit there and say that because you have detonation in a sleeved block it doesn't do a lot of damage is absurd. Detonation weakens anything, including a forged/sleeved bottom end. Maybe in a all out race engine that lasts a few pulls detonation may be acceptable - but it is HIGHLY discouraged. So please don't inform people that it isn't a big deal. Detonation is bad no matter when it happens on a completely stock engine with cast pistons. Screw the sleeves - you can shatter a piston even easier.

 

I apologize. I did not mean to make it sound like it was "OK" to have detonation. Detonation is *never* OK. Reading it back now my statements sound pretty bad. What I mean to convey was that on every setup sometimes things will go wrong on the street and you have a better margin of error on a sleeved block than you do on stock sleeves. But yes, detonation always causes damage.

 

This

 

No I get exactly wat tuning is. Air fuel ratio and correct timing is basically what they work on to prevent detonation and get the best mixture for hp. I was just trying to find out if tuning is what actually allows these people to have over the hp limit recommended for stock block for long periods of time with no issues. Now what I got out of ur post mostly was that, you never know exactly what hp level the engine will fail, but it usually is stated that the highest (safe) hp is blah blah only because of where most people usually start having problems with d motors. Also that there are poorly constructed engines that are mass produced and some that are (golden) might be the ones that last. Would a japanese spec engine be an exception to this? So I guess the answer im receiving is tuning helps, but doesn't always determine the longevity nor reliability of a motor if it is modded. Guess these people are just lucky

 

Thanks