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.


__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

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.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

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
 

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
 

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
 

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.

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

I don't know about that. A T4 at 10 psi will outflow a T25 at 10 psi. It's all about the CFM, not the psi. The T4 at 10 psi is just getting started in it's flow, but a T25 is done and past it's power output, but yeah it would depend on your motor also. Obviously a gigantic turbo won't work as well on a tiny motor, while a palm sized turbo will spool up quick and build boost for most of the rpm band.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

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

don't know about that. A T4 at 10 psi will outflow a T25 at 10 psi. It's all about the CFM, not the psi


What you said right there is what I am talking about. A certain amount of cfm of flow on a set engine is what will give you 10psi if restriction. So say on this engine that number is 500cfm. If both turbos are capable of blowing that much air then they can both make 10psi. The question is which one does it more efficiently. Which ever one that is will make the most power at that cfm of flow.

For example.. You have a .60 trim t3 and your d seires engine is right in the middle of the 75% efficiency island. Then you jump up to a 60-1 turbo and its in the 60% island. I believe the properly sized turbo will make the most power.. In this case the t3.

Do you agree?

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

Haha, agreed. :) My head hurts now. ;D
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

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

One more thing to really mess things up.....It also depends on things like how much CFM your engine can flow. You can't get air in without first getting it out.

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

jeff ran 15 on a dx with out an intercooler and with out fuel management.

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

2000psi- huh? Are you refering to our big turbo is better debate?

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

yep. I would rather have a more efficient setup (running a larger turbo slower) and have to wait for the boost than overspeeding a smaller turbo. I think alot of people miss the boat on how important the exhaust flow is out of the engine. Turbine wheel and housing size is VERY important in the efiicieny of your engine....You think about how much more exhaust volume there is in an engine running 10psi @ 7K RPM than a NA engine @7K RPM. Those small turbos like the RHB5 cause exhaust gasses to back up in your exhaust manifold at higher RPMs. And where does this gas go during valve overlap? back in the combustion chamber, keeping an amount of fresh charge out of the cylinder and heating things up in general. I like the idea of having boost only past 3500RPMs or so. That usually means exhaust flow is set up well for that particular engine....through the use of a large A/R turbine housing, open exhaust and a proper exhaust manifold. People see the importance of exhaust flow when their cars are NA, why do they forget when their car becomes turbocharged? sorry for the Novel.

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

Damn some of you guys make things so complicated. Basically you just want a turbo that will kick in at about 3k and pull to redline. If your turbo dies out before redline it doesnt mean the turbo isnt working it just means it is just pushing too much hot air through the engine because it is working too hard. Case and point is my turbo project. My accord (2.2 f22a) had a tdo4 mitsu turbo on it which was way too small. I hit full boost at like 2200 and it died off like crazy around redline where I would also get some detonation because the air was so hot because of the turbo being overworked. Then I put a mitsu tdo4 on and I hit full boost (9psi) at around 3500 and it pulled all the way to redline with no pinging at all. Reason being because it was bigger and could handle the size of my engine better and more efficiently. Understand now? My car couldnt really handle the 9psi with the smaller turbo because it was too small and wasnt efficient at high rpms but it handles 9psi fine now because the turbo is more suited to the size of the engine.

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

i learned a lot from this. it should be added to new user faq.

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

****************

first of all, you don't make sense in saying you have the same td04 turbo TWICE....

now, if you set the wastegate at 7psi, when it's fully spooled at 2200 rpm, it's GONNA STAY AT 7PSI weather you are at 3000rpm or 9500000rpm, the wastegate will limit the spinning of the turbine to 7psi...

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

true, but to produce 7psi at redline, the turbo must work much harder than at lower rpms since the engine is taking in much more air

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

******************************************

ok.. you don't understand what i'm saying...

say your boost guage will tell you at 3000rpm, it's saying 7psi.. and you keep flooring it, it still says 7psi.. so whatever "work" the turbo does, does it before 3000rpm, after that it doesn't need to do more work as long as you want 7psi MAX... i'm not talking about you crazy people running 50psi on a stock block, just 7psi.

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

ok, you dont understand what I'M saying....to produce 7 psi all the way from when you first get max boost to redline, the work the turbo does increases. As the engine spins faster, it needs more air, hence the turbo works harder to produce the same 7 psi. Case in point: my twin-turbo vr-4 that runs 9 psi stock. It will hold 9 psi to redline all day long, but turn the boost up to say 15 where i have it, and the turbos can only flow enough air to hold about 11 to redline. I can set the boost as high as i want, and i may see that boost down low in the rpm range, but at redline the turbos just cant keep up with the motor....get it?

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

so so if i got a t25, 5psi is cookies for that turbo, it will have NO PROBLEM for 5psi!

that's what you guys don't get it.. i'm not shooting for 10000hp at 750 psi... i just want 60whp at 7psi and that's it.. i'm not going for the competition crap.. i just want a more peppy car for fun. hell i won't even go to the track...

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

lol damn I did say i put another tdo4 on didnt I. Sorry I meant to say tdo5. Stupid typing. I think we are all saying basically the same thing here just in different ways.

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

i ran d16z6 not a6 :)

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

get a garrett T3 and think of the exhuast A/R as the cam, and the compressor A/R as "how much boost you wanna run".

don't mind lag ? get a .60+ A/R exhuast housing
want no lag ? get a .40ish turbine housing

Want low boost ? .48-.55ish compressor housing
want insane boost ? .55ish+ or .55++ or .55+++

I'm hoping for 250whp @ 17ish PSI ( with water/alcoy injection )on a D16Z6 with an D16A6 head, 8.4/1 compressoin ratio, and a garrett T3 .48/.63 turbo ported.

little more lag ( for hooking up ), decent compressor ( prob. a little too small ) and low compression = good mid-high rpm power.

WRX turbo @ 8 psi would rock as a daily beater. ( first I'm going to use the WRX turbo to make sure the car is going to hold-up to any kinda boost, then I'm swapping the T3 on. I already have both. )