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ive read that stock block d16's can handle 250whp on a good tune. ive also read that the amount of psi of boost doesnt effect engine relability? i'm confused. if a d16 makes 230whp and lets say it took 16psi of boost to get that power, wouldnt that psi level create more stress on the engine than another d16 making 230whp with diffrent turbo boosting at 10 psi?
 

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depends on the actually condition of the engine and which turbo..
a bigger turbo on 10psi is different say than a TD04 from greddy
 

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sohc-gT said:
if a d16 makes 230whp and lets say it took 16psi of boost to get that power, wouldnt that psi level create more stress on the engine than another d16 making 230whp with diffrent turbo boosting at 10 psi?
the rule of thumb is that it's hp you need to pay attention to, not psi.

but based on the way turbo's work, yes
all things being equal, identical engines putting out identical power,
only diff is the PSI, then the one running more psi should be less reliable.

And i'll tell you why,
bear in mind this is just my thinking on the subject.
To reach and equal ammount of power with more psi as another setup running less psi. You would be using a smaller turbo.
and thus chances are you would be overspinning it, or spinning it at a much greater rate. AND if it's overspinning, the turbo it'self is going to be overheating, and probably heating the charge air, so i'm guessing you would see much higher IAT's and thus a higher chance of detonation, or just more work to keep that engine running right.

Then theres also the simple fact that there is just more pressure in there,
more pounds per square inch pushing on everything.
However I haven't really read anything about the pressure itself ever causing damage to anything. Damage is almost always caused by one of three things.
Improper tuning, resulting in detonation, preignition, lean condition, etc etc.. kills motors
Too much power for the engine to withstand, it basically tears itself apart,
even if it is tuned well.
or overheating(which shouldn't be a problem if your cooling system is in good shape and up to the task).

again, just my 2cents on the subject
 

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yes, i think for z6's, it's the rods that will break near 250whp (with a perfect tune) from the sheer stress of having all that power push down on them.

I've read that the stock sleeves can be good to 400whp... again with a perfect tune (no detonation) so cylinder pressure is not a major issue.

What I'm not sure about is how much pressure the ringlands on stock pistons can take.
 
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Rotory hit the nail on the head.

if your engine is in perfect shape and have everythign proerply done including properly changed out parts like timing belt, water pump, and such, then you'll be fine. if not, then you might think twice about pushing it. you might be using your leather express if you do.
 

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makku said:
yes, i think for z6's, it's the rods that will break near 250whp (with a perfect tune) from the sheer stress of having all that power push down on them.

I've read that the stock sleeves can be good to 400whp... again with a perfect tune (no detonation) so cylinder pressure is not a major issue.

What I'm not sure about is how much pressure the ringlands on stock pistons can take.
this is true i broke 2 rods and bent another at 17psi of a 14g. on a nearlly perfect tune nothing is ever perfect. stock rods give out about 250hp. need i add my motor had 165xxx miles on it with around 15xxx on 10-15psi for over a year.
 
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hello all im running a d16z and i was think of gettin a garrett turbo kit,
i wanna be atleast 200whp on stock motor, but just on the safe side wot r da 5 most important things to upgrade b 4 installin da turbo
cheers all. :)
 

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it's all in the turbo noobs sticky at the top
 
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I just don't understand this, at, let's say, 10 PSI, the amount push in the motor would be the same wether it is from a big or small turbo no ? so the only difference would be in the reliability of the turbo not the motor ?? also, at the same PSI on the same setup, a big or small turbo ain't suppose to make the same HP ???
 
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no, psi is 1 value, but volume is another. take a straw and put 10 psi in it. it's ok but norhtng special. now take a 1" pipe and do the same. understand? volume also determins hp.
 
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now, that, I understand, but with that example, you change the dimension of the pipe... but, even if you do and at the end of the pipe you put a restriction, so you only have a hole as big as the straw, what you with get on the other side will be the same .... as long as you can keep the 10 psi constant... same thing with motor, as long as you dont change how your motor breath, like the intake manifold, port the head, etc. you wont see any change...
 

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not necessarily. size of piping can change a lot of things. for one velocity into the combustion chamber. its the same principle as exhaust. you have to balance between the right amount of volume, and the right velocity. psi is just the number assigned to how much pressure is against the charge piping/IM/valves ect.
 

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Old post however maybe someone will respond. Tune of course makes a difference. However If your pushing 250 WHP. Then how you drive the car will make a difference. If you abuse it. Something breaks. But if you love it and give it some good preventative messures then you should be ok. I would personally have a good tune done. Bigger Radiator. Transmission oil cooler and Oil cooler arp head studs and a Comtech HG.
 

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Oil, trans cooler and bigger radiator are not going to change how much force you are putting on the rods. If you had a 250 hp car and never put the hammer down, is a complete waste of time and potential. My .02
 

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Old post however maybe someone will respond. Tune of course makes a difference. However If your pushing 250 WHP. Then how you drive the car will make a difference. If you abuse it. Something breaks. But if you love it and give it some good preventative messures then you should be ok. I would personally have a good tune done. Bigger Radiator. Transmission oil cooler and Oil cooler arp head studs and a Comtech HG.
I'm sure this guy has his setup done and possibly sold by now. It was 9 years ago.
I give him props for searching, least I hope he did and not just pick a random page from all of the pages ever on DSO
 

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Discussion Starter #18
hey guys thanks for replying to my thread. after 10+ yrs of experience with the single cam this is my final conclusion.
yes its true psi does not matter.horsepower level does not matter either - to some extent. It comes down to the torque and how that amount of torque is applied. you can actually have 300whp stock internal z6 but the torque cannot exceed 210. When were talking about "threading the needle" it all comes down to tuning in which ignition ignites the a/f ratio.

When I had my 250whp stock internal z6 and d15b my 15g turbo was working hard. the turbo spools alot faster than a t3/t4 however the engine was able to take the abuse due to great tuning. that turbos efficiency range was right in the middle of the engines rev limit, which was 8k rpm. when the force was applied at full boost the piston has already began its downward stroke. compared to a bigger turbo we would have to advance the ignition timing to get it to spool, to make the engine have more "pep". Eventually you will have to bring the ignition timing down enough so that the torque does not exceed the engines limit. If you can control the torque and in some cases with a bigger turbo hp factors in, cause we all know torque makes hp, you can determine how long the engine will last.

I would just like to say im no expert im just sharing my experience with you guys because it was a wonderful journey. What had started to be fun lead me to build a 10 sec single cam. A street racing monster that took everybody (b,k,h-series) in its path down. I had fun but I had to sell it. And I dont regret it.
 
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