boosting a stock 200

[64 200 ranchero]

how much boost can be run with stock compression and cast pistons for a 200 daily driver

 

[ryan11]

boost psi is different in different turbos,,in laymans terms, a small turbo at 10 psi might = a big turbo turbo at 1psi
lame example:: small turbo at 10 psi pushes 50cfm big turbo a 1 psi pushes 50 cfm.

 

[RacinNdrummin]

Sort of....

What it comes down to is how much air your engine can flow...

With the small turbo, the 50cfm @ 10psi may work just fine, and do it lower in the RPM range. With the bigger turbo that pushes 50cfm @1psi, your engine is going to have to spin higher to take advantage of the bigger turbo, because 10psi is 10psi, no matter what, and if your engine can only flow 50cfm at 10psi, thats all your going to get.

 

[351 celi]

If you don't beat on it all the time, 7 psi is very doable. I am going to 10, though only a weekend car here. If you don't turn excessive RPM, say staying under 4500, I think you can do more as I plan to do as long as you utilize an intercooler and smog era compression ratio of 8.0:1. My 2 cents.

 

[ryan11]

Sort of....

What it comes down to is how much air your engine can flow...

With the small turbo, the 50cfm @ 10psi may work just fine, and do it lower in the RPM range. With the bigger turbo that pushes 50cfm @1psi, your engine is going to have to spin higher to take advantage of the bigger turbo, because 10psi is 10psi, no matter what, and if your engine can only flow 50cfm at 10psi, thats all your going to get.

yes, but i have seen this same ? many times with new commers to boost, and i try to tell them what i wrote 1st, so they can start searching, then after some reseach they will start asking ?'s about turbo maps.

 

[1967JMG]

Sort of....

What it comes down to is how much air your engine can flow...

With the small turbo, the 50cfm @ 10psi may work just fine, and do it lower in the RPM range. With the bigger turbo that pushes 50cfm @1psi, your engine is going to have to spin higher to take advantage of the bigger turbo, because 10psi is 10psi, no matter what, and if your engine can only flow 50cfm at 10psi, thats all your going to get.

yes, but i have seen this same ? many times with new commers to boost, and i try to tell them what i wrote 1st, so they can start searching, then after some reseach they will start asking ?'s about turbo maps.

If a man is hungry, give him a fish and he'll have food for a day. TEACH him to fish and he'll never go hungry again... unless he's lazy of course... good thinkin' there ryan

 

[wallaka]

Sort of....

What it comes down to is how much air your engine can flow...

With the small turbo, the 50cfm @ 10psi may work just fine, and do it lower in the RPM range. With the bigger turbo that pushes 50cfm @1psi, your engine is going to have to spin higher to take advantage of the bigger turbo, because 10psi is 10psi, no matter what, and if your engine can only flow 50cfm at 10psi, thats all your going to get.

yes, but i have seen this same ? many times with new commers to boost, and i try to tell them what i wrote 1st, so they can start searching, then after some reseach they will start asking ?'s about turbo maps.

Besides, 10 psi ain't always 10 psi. Depends on the temperature, and the pressure only builds if your engine restricts it...all else being equal, a fully ported head will not see 10 psi where a stock head will. It'll be at 8 or 7, but make more power and flow more air. "Boost pressure" doesn't matter, cfm, temperature, and thus efficiency does.

 

[JGTurbo]

boost psi is different in different turbos,,in laymans terms, a small turbo at 10 psi might = a big turbo turbo at 1psi
lame example:: small turbo at 10 psi pushes 50cfm big turbo a 1 psi pushes 50 cfm.

I won't say you are wrong, I'll say your wording is wrong. If you're talking about horsepower in your equation, PSI is PSI no matter your turbo size, all else being equal. A turbo with a compressor map that follows the engine's air demand throughout the rpm range is key.

 

[rbohm]

8) ok, to answer the original question, it isnt boost pressure, to a point, that kills pistons, it is detonation. as long as you stay away from detonation, the stock pistons will handle 10psi without problems. another thing that kills engines is rpm. stay under 6000 while boosting the engine, and again 10psi is not a problem.

now as for boost pressure, it in reality is a measure of back pressure. take for instance a stock small block ford with stock heads, and boost it with 10psi, and you get about 350 or so hp. now take that same engine and drop on a set of aftermarket heads using the same setup, turbo, supercharger it doesnt matter, and at the same rpms the boost pressure indicated actually drops, but hp goes up. the reason is that the engine is breathing better, thus more airflow gets through with less pressure.

so before you boost an engine, optimize the intake and exhaust tracts as best you can, then boost the engine.

 

[ryan11]

yes there are other things that do factor in,, but no matter how you cut it a
ihi vj-11 (small tubro came on mazda 2.2 sohc) at 10 psi will never make as much power as a holset hx-35 (bigger turbo came on mostly dodge desiels) at 10 psi, no matter what motor it is on, so 10 psi is not same, so you can not go around saying my straight 6 can take 20psi,, cause 20psi on this turbo is not 20 psi on that turbo.

yes a smaller exhaust housing will spools quicker, but it can also run out of steam at higher rpm,and your motor might still be able to make power at that rpm, even thou the turbo has ran out of steam. also a big turbo might make a lot more power, but not spool untill a super late rpm.
there are alot of ways to go about picking a turbo, it all depends on what your goals are with the car.

 

[ryan11]

8) ok, to answer the original question, it isnt boost pressure, to a point, that kills pistons, it is detonation. as long as you stay away from detonation, the stock pistons will handle 10psi without problems. another thing that kills engines is rpm. stay under 6000 while boosting the engine, and again 10psi is not a problem.

now as for boost pressure, it in reality is a measure of back pressure. take for instance a stock small block ford with stock heads, and boost it with 10psi, and you get about 350 or so hp. now take that same engine and drop on a set of aftermarket heads using the same setup, turbo, supercharger it doesnt matter, and at the same rpms the boost pressure indicated actually drops, but hp goes up. the reason is that the engine is breathing better, thus more airflow gets through with less pressure.

so before you boost an engine, optimize the intake and exhaust tracts as best you can, then boost the engine.

yes detonation and timing kill motors, but there are limits to things as you already know, i can have a standalone and have a perfect tune,but cetain parts can only take so much.

now for the stock vs. aftermarket head,ect,ect, at the same psi,,,,,,,,,,,,
in my tests(on a awd dyno with a 4 banger dohc turbo car), opening up stuff for better flow head,ect, you get the same power at a lower rpm range than before and more at a higher rpm with the same psi as before, i did not lose any psi, what ever your wategate is set up to run you will run.

 

[JGTurbo]

yes there are other things that do factor in,, but no matter how you cut it a
ihi vj-11 (small tubro came on mazda 2.2 sohc) at 10 psi will never make as much power as a holset hx-35 (bigger turbo came on mostly dodge desiels) at 10 psi, no matter what motor it is on, so 10 psi is not same, so you can not go around saying my straight 6 can take 20psi,, cause 20psi on this turbo is not 20 psi on that turbo.

Now I'll say you're wrong. 10psi in the manifold is 10 psi in the manifold regardless of what puts it there (all other things being equal). The only reason a vj-11 might not make the same power as a hx-35 is because it cannot make 10psi at the mass flow rate required to match the hx-35. An overly small turbo will over-speed and self destruct before it makes 10 psi on a straight 6. An overly large turbo might never spin fast enough to make 10 psi on a straight six. But all turbos that can make 10 psi manifold pressure over a similar rpm range with similar efficiencies will make the same power. I'm only arguing this because saying that the same manifold pressure from a different turbo will make different power (all else being equal) is absurd. Just don't want ideas like that to spread very far.

 

[ryan11]

yes there are other things that do factor in,, but no matter how you cut it a
ihi vj-11 (small tubro came on mazda 2.2 sohc) at 10 psi will never make as much power as a holset hx-35 (bigger turbo came on mostly dodge desiels) at 10 psi, no matter what motor it is on, so 10 psi is not same, so you can not go around saying my straight 6 can take 20psi,, cause 20psi on this turbo is not 20 psi on that turbo.

Now I'll say you're wrong. 10psi in the manifold is 10 psi in the manifold regardless of what puts it there (all other things being equal). The only reason a vj-11 might not make the same power as a hx-35 is because it cannot make 10psi at the mass flow rate required to match the hx-35. An overly small turbo will over-speed and self destruct before it makes 10 psi on a straight 6. An overly large turbo might never spin fast enough to make 10 psi on a straight six. But all turbos that can make 10 psi manifold pressure over a similar rpm range with similar efficiencies will make the same power. I'm only arguing this because saying that the same manifold pressure from a different turbo will make different power (all else being equal) is absurd. Just don't want ideas like that to spread very far.

o.k. fair enough, im not trying to misinform anyone or try to start and war with you or anyone..
but let say you have a .42/.48 t3 and you do a small hybrid(very miniamal at that in hybrid turbo speaking) with a .60 comp housing and wheel and leave the exhaust housing and wheel still at the .48 stuff.
a .42/.48 t3 at 10psi will make less power that a .60/.48 t3 at 10psi.

 

[RacinNdrummin]

That would depend on efficiency...

If the .42 compressor has a better effieciency at 10psi pn that particular engine, it will make more power than the hybrid.

Just like a .60/.63 will make more power on a 200 at 10 psi than a holset will, because a .60/.63 T3 is more efficient a 10 psi than a holset is with the amount of air a 200 can flow. Put the CI aluminum head on there and I bet the holset would make more power at 10 psi.

Depends on the flow characteristics of the engine and where the turbo is most efficient.