How much WHP can the stock pistons hold????
I hear from numerous people that the stock rods are weak but how about the pistons?
A lower comression would be ideal, but are they necessary to replace?

 

hey john, may i ask what exactly happend to your motor? i know u were boosting 6psi untunned but was that the cause of blown or was it a miss shift? id like to know before i boost again

 

hey man - lol - motor not blown jsut beat spark plugs and loose coil pack---must have been from the hi rev---but I did order an 05 block from dezodwest that ship tomorrow....im scared now that I will blow my motor so im building one to swap in april---i dont plan on running rediculous boost but prob like 13-15 with a small turbo......nothing voer 400whp...on the other thread(forgot which on and who) some one stated that the pistons are good for about 400whp....so i was goin to see if it was worth the money to even get upgraded pistons if im not going to surpass te 400whp mark

 

just buy the pistons and rods, its like using a condom

 

 

Get pistons and rods fo sho! With the compression on the tC, the safest maximum boost pressure is only 10 or 11psi with 93 octane without having to worry about blowing your motor.

 

dont people run 12psi daily?

 

That maybe true but you would have to retard the ignition timing a lot to run 12 pounds on 93 not to mention its not efficient. Boosted car will run retarded ignition timing to start with and still be efficient but there is a threshold on maximum boost with engines compresson on pump gas and anything more than 10-11lbs on 9.6:1 is pushing the limit. I will find the calculation and post it just give some time to.

I am still searching but this is from Procharger.com

"Compression ratio:
For pump gas (91-93 octane) applications, a compression ratio of 8.5:1 to 9:1 is recommended for boost levels of 8-10 psi. Higher octane fuel will allow you to run higher boost levels, approximately 1 psi for every 2 points of octane. To determine the maximum boost level for your compression ratio (using pump gas), refer to the enclosed compression ratio chart."

 

This applies to turbochargers as well


http://www.pawinc.com/charts/Superch...mpression.html

Another link that explains it as well but a lot of reading is required.

http://www.faqs.org/faqs/autos/gasol...section-1.html

 

I put down 295 on stock internals on a DynoDynamics on 93 octane and a self tune. A DynoJet would have read around 330 and DynaPack around 340whp (high readings, DD is much more accurate), so I'd say 350 is the limit.

 

Yea. I wouldn't push it past 12psi on stock internals and pump gas.

 

Seriously, if you're opening the block, why not swap pistons? They're probably the cheapest internal part after bearings, and only add to the safety margin. Plus, since the replacement pistons will be new, you can get them coated without much hastle, both with a thermal barrier topcoat to brevent burn-through if detonation occurs and a dry lube sideskirt to reduce cylinder wall wear and compression reduction over time.

 

Where can you get that stuff done?

^^

For future reference, lol.

 

Isn't that called sleeving the block or am I getting this confused with sleeving?

 

A stock pistons threshold will depend heavily on the tune. EOS

 

Sleeving the block is quite different. That involves either milling off material from the stock block and inserting a hollow "sleeve" or replacing a stock one if it was present in the initial design.

Piston coating is done several places. Swaintech uses the thickest coatings, but are also the most expensive. It's a process similar to ceramic coating headers, though the coating material is different.

please note: I have not used any of these companies and am not endorsing one or another, these links are provided for reference.

http://www.swaintech.com/

http://www.hpcoatings.com

http://www.calicocoatings.com/

http://www.performancecoatings.com/

http://www.engineceramics.com/index.html

http://www.thermaltechcoatings.com/

http://www.bcdcoatings.com/

 

If the piston is coated, shouldn't the rest of the cylinder wall, and cylinder head (cylinder portion), be coated as well???

Sorry for the n00b question >.<

 

You got the answer you need right there

its all about cylinder pressure ie heat........ignition and intake temperature.



PSI is irrelevant....as again x turbo flows x cfm at 10psi

while y turbo flows y cfm at 10psi.


highest so far on my end....406 at 15psi and water/meth on a 3071R. (stock motor)

Regards-

Todd

 

Yep! Highest with our kit was about the same 401 on 14 PSI with an E54

 

as long the car doesnt see knock/detonation the stock internals would hold like 400s as mentioned.. of course repeated or prolonged use on that hp will weaken the stock motor faster..

on the other hand a bad tune will kill the motor on less than 7 psi