Is it how much PSI or how much HP stock block can take.. different size turbos.!
 

Ok.. this is a question that always confuses me.

Say you get a small turbo like a t-25 and run it at 7psi and that gives you say 70whp gain... and say the turbo flows at cfm of 500 or so..

Now get a hugh striaght T4 truck turbo and run it at 7psi,... what hp gain will you get?? doesn't the T4 give more CFM thus more hp/PSI?

I'm asking this because I don't know what PSI is safe.. like if i have an ultra small turbo that gives me 20hp at 70psi, so does that mean i need to run at that high PSI?

Is our stock internals related to WHP or PSI or CFM? I'm putting a small RHB5 and i want to get 170whp on my d16, but it's small so i do'nt know about 9psi cuz i heard d16 can only hold 8psi.. but then again.. 8psi of what? it's so confusing.

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

Q.Now get a hugh striaght T4 truck turbo and run it at 7psi,... what hp gain will you get?? doesn't the T4 give more CFM thus more hp/PSI?
A.Yes. The T4 will flow more CFM leading to a bigger gain in hp.

Q. like if i have an ultra small turbo that gives me 20hp at 70psi, so does that mean i need to run at that high PSI?
A.You will never see 70psi. :P That turbo will crap out at high psi because it can't flow enough CFM. At say 15 psi the difference between 8 psi will be small since it cannot flow the CFM. The only real difference would be the extra unwanted heat in the intake air.

Q.Is our stock internals related to WHP or PSI or CFM?
A.Ummmm...this really depends on how well it is tuned, the condition of the motor, the psi you are running, the size of the turbo, and how efficient the IC is. Basicaly it will depend on horsepower. My tiny rods on my D15 are said to be safe up to ~210~hp. Extra psi will cause extra stress on the cylinder walls, extra horsepower will cause stress on the rods/pistons.

You could safley reach your goal of 170hp if the psi is within a safe range and it is tuned right.


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Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

so you are sayin my 170whp goal is ok as long as my psi isn't that high on my RHB5 (say 9-10psi MAX)??

so PSI adds more stress to the cyl walls and HP adds piston, rod stress...

so.. is this right.. the best ideal setup to get HP is low boost PSI with high HP gain right.. like 5psi for 170whp instead of 15psi 170whp.

ya so if my RHB5 needs 15psi to gain 170whp, it's bad compared to something with 8psi to get 170whp am i right?

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

Correct.

It would be great to get 170hp out of only 5 psi, but unlikely. The lower the psi the safer you will be.
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Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

ok.. hmm now the question of how much can a d series block take in psi safely on streets.... anyone know?

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

<<<currently running 12

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

hahha 12.. so my 8 is nothing then~!

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

DR boost your not entirely correct about the T4 question. A smaller turbo and a huge turbo running the same psi (amount of air flow restriced by the engine) will make about the same power. The only way to tell which one will make more is to see which one is more efficient at the airflow you have. Bigger does not always mean more hp at the same pressure level. The trick is to find the compressor size that best fits your engine. That will make the most power at the boost pressure you decide you want to run.

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

its never a question of how much psi can my engine handle. in stock trim its not like u can be running 7psi then spike to 7.5 and blow up. It's all about control and the more psi u get in there the more precise control u need. Things have to be put into perspective. There are limits. Like I would never run 20psi on a stock d16. wouldnt last long. 10-12 is probably the highest u could go w/o changin internals. 5-8 is usually what people run. more towards 8 because 5 doesnt increase hp much.

Re:Is it how much PSI or how much HP stock block can take.. different size turbo
 

the question about how much psi can my engine handle.. its not psi, its how much hp can it take. if you have it dyno tuned with good fuel management and a wideband a stock dseries can take 200-250 hp daily or 300 (jan style – reliable but wouldn’t be the best daily driver). its all about tuning.

you can relate hp to psi by figuring in what size turbo at what cfm.

example:
BoostedED9
d16a6 - t3t04e 50trim .60/.63 ar, stage 3 wheel
302hp 251tq @ 16.5 psi

now i cant find a dyno of a d16a6 with a smaller turbo like a tdo5h or rhb5 but at that psi they will make less horsepower. i would guess 240-250ish. they will also be less efficient at that psi. if you compared them both at 10psi you would see the difference.

also these turbos have different purposes.. i am talking about peak hp, ie drag racing. if you want a car for rally or road race you want to spool before 4500rpm. but for drag you will never be in that rpm range.