How much boost can a B18A handle? I have stock internals running 450DSM injectors and 255 walboro pump. I’m running turboedit, I was thinking of boosting 10psi is this manageable for a stock internals? or would I end up blowing something?
any amount of boost will blow anything. TUNING is the key!!! :rockon: this TOPIC has been covered before search please next time!!! :search:
the amount of boost dosn’t blow engines, BAD tunning or lack of tunning and horsepower blows engines. 10psi on a t25 is different than 10psi on a gt35r.
How is 10psi of Manifold pressure different? I thought 10psi was 10psi, just like a pound of lead = pound of feathers. :think:
actually it is “different” but I’m not one to really say how.
But different turbos, at the same “boost” will make different power.
yes 10 psi on a t25 isnt the same as a sc61 on 10 psi
Are you all saying the Power is different or are you saying the impact on the engine is different?
To be honest bro, I’ll admit that I really don’t know. I know that it has to do with the efficiency of a turbo, and the compressor size.
It’s one of the reasons why every turbo’d car should receive an individual tuning, and not a generic program.
CHUNK :“How is 10psi of Manifold pressure different? I thought 10psi was 10psi, just like a pound of lead = pound of feathers.”
the difference is the amount of cfm “volume of air”. you will have much more cfm at 10 psi on T66 than you would at 10 psi using a T25. that is why spool times are different you are moving much more air using the bigger turbo, but you could still be at the same psi. Turbo Maps Rule!!!
the difference is the amount of cfm “volume of air”. you will have much more cfm at 10 psi on T66 than you would at 10 psi using a T25. that is why spool times are different you are moving much more air using the bigger turbo, but you could still be at the same psi. Turbo Maps Rule!!!
I agree with what your saying but that still doesnt address how 10psi (once achieved) is any different. When you speak of volume of air you are speaking of how quickly you can achive a specific psi or how long you can maintain a specific psi. A higher cfm turbocharger will “fill” an intake quicker, assuming of couse an engine can efficiently spin it.
A bicycle tire doesnt work “better” if you fill it to 25psi with an air compressor(T66) vs a manual tire pump(T25). You simply can fill it much faster (and achive much higher pressures).
I still think 10psi is 10psi once achived.
There are two variables any time forced induction is used. CFM and PSI compare it to electricity current is different from voltage you can die from very low voltage (PSI) and extreme current (CFM) and vice versa, thats why if you get shocked by your distributor 40,000 volts you can still survive because there is very little current, the same goes for forced induction im not saying if you use a giant turbo and spool 6 pounds you will automatically blow your motor, it is just a different kind of boost. YOU GOTTA LOOK AT TURBO MAPS!!!
Yea, you keep saying look at compressor maps, but they don’t tell me how 10psi is any different. Looking at a compressor map I see that pressure (read as absolute) is actually an axis on the map which would indicate to me its a constant.
By choosing the pressure you want to achieve and figuring out air flow of your engine, crossing these 2 points on a graph and overlaying compressor maps is how you choose which turbo will operate at optimum efficiency, with your engine at a specific absolute pressure (calculated out to relative manifold pressure - psi).
I agree that one turbo can produce 10 psi more or less efficiently which can effect other perfomance factors. 10psi is still 10psi to me.
:bump:
you said it yourself, to have a turbo work at optimum efficiency air flow must be considered, you wouldnt get much power using a T25 on a Chevy 350, sure you can get 10psi out of it but air flow would suffer because the little T25 cant produce enough CFM to cover all the displacement. But a T4 would be able to because it can flow more CFM, and the efficiency is in a better range.
will lets just say a t25 produces 200cfm at 10 psi and a t88 producess 500 cfm at 10 psi thats the different just like what TurboG2teg311 is saying
exactly, thats what he keeps saying about looking at the compressor maps as well, i think he is talking about comparing how much you need to flow in lbs/min (15-20 on a stock b18) and then compare it to how much boost you want to run, by looking at a compressor map you can tell if that turbo will be good to run all 4 cylinders at a certain cfm, a t25 will make enough to run 10psi on the engine but it would have to run at 100 percent efficientcy. on the other hand 10psi is 10psi, but a t25 will not be able to maintain that 10psi the same way a t3 or t4 would. a t3 would get to that 10psi and hold it all the way where a t25 would not. not to mention that some turbos just make more power at a give psi and hp can kill a motor if not maintained properly, and its safe to assume that a t3 will put out more power at 10psi then a t25, thats no assumption its proven just look what people are running and you can see that
NOW TO ANSWER THE QUESTION AT HAND- as previously stated tuning is the key, some guys on homemadeturbo blew up a b16 on 3lbs of boost, which goes to show you 1 do it right and 2 tuning is everything, as far as being reliable and safe, you could run a t3 .48/.60 a/r turbo at 8psi tuned properly and you should be pretty good, but again tuning and maintaining is key
I hope that helps
Dont forget that everything has its limits as well…
You can tune the crap out of a stock engine, but how it was treated before it was turbo’d will determine how long it will last as well as the limitations of the parts inside.
Also, if you are boosting 18psi on stock internals…good luck…it may last, it may not. Tuning will allow you boost that high as safely as possible, but the strenght of the rods, pistons, ring lands, sleeves will all determine as well if the engine will fail…
Tuning can only do so much…
yeah i dont want you to get the wrong idea, xenocron is right, boost at your own risk however boosting at 10psi untuned and 10psi tuned will make all the difference in the world
Thanks guys this is very informative specially the links
http://www.gnttype.org/techarea/turbo/turboflow.html
http://www.automotivearticles.com/Turbo_Selection.shtml