I have stock block, stock head, stock cams. Please tell me how tapering the boost down at redline is going to help me make power.

You said it yourself in your post. There are 2 reasons boost tapers: a turbo that can't flow enough (mine obviously can), and a wastegate that can't support it (obviously the EF3 turbosmart wastegate can as well) so what are you not understanding about the fact that my car needs to hold 30psi to redline to make power? If I had a ported/built motor your statement would be true, but on my stock head/cams car I need every bit of 30psi to make power. Purposely tapering off the boost to say 25psi would NOT make more power. If it did, I think Tom (tscompusa) would have done that...

When I said "my car breathes up top" I did not mean the head, I was referring to the tubular manifold, the o2 dump, non-restricting exhaust and also the utilization of a 3-port controller to prevent boost taper. On the other side of the turbo there is the ported intake manifold, TB, efficient ETS intercooler and short route piping to deliver the boost to the motor. My car is set up for the turbo to breath. My motor is stock.

I chose to go the route of a car that pulls and pulls to redline. I hated the stock turbo TQ spike and then just boring nothing after that. I wanted a car that keeps you pinned to your seat until you shift (not that my 450whp car pins me to my seat, but you know what I mean)

 

You are looking at the wrong parts of what I am saying.

My initial response was aimed at the comment, I have a really well flowing setup and that is why I can hold 30psi out to redline. (not exact words)

What I am trying to say, is the better flowing your setup is the less PSI you will be able to hold, not more given two identical cars and turbos (minus "high flowing items").

I am not saying running more boost doesn't make more power on your car at all.

 

IE: 2.3 stroker on evo 8/9 eats the **** out of a stock 9 turbo hence the need for a bigger FP Black, EF4, 6266, 6466 etc to really maximize the motors capabilities

 

everything can be a restriction if you think about it. but in general boost is a power adder more so than a restriction. as long as the turbos efficient doing it, boost = more lb/min (cfm/airflow) once you go outside of the efficiency level of the turbo's compressor map then it will become a restriction to the power you can safely produce given the temps of the air & speed of the shaft.

a fmic is a power adder also, but since air has to pass through it from the turbo you could also call it a restriction as well to the turbos airflow. too big of a FMIC creates to much pressure drop, which hurts the car also. requires working the turbo harder.

better flowing engine that moves air faster and quicker & has more displacement to fill, of course its going to need a larger turbo then say something that is restrictive with airflow to hold boost at high RPM with less displacement.

just think of fluids when thinking about airflow and restrictions and stuff, its the easiest way to put a perspective on it. the more volume something is the more fluid its going to require to get through it and hold that same pressure at the end.

Garden hose maybe? big hose vs small, but on the same fauset. the smaller hose is going to hold better pressure at the end of the hose, vs the larger hose will not have the same pressure at the end because it has more volume to fill and the faucet is not flowing enough to fill the big hose fast enough to hold the pressure at the end like the smaller hose. so you turn the faucet up more (boost), making the system less efficient since you have to work it harder to fill that area and end with the same pressure at the end of the hose. and sometimes not even possible to see the same pressure at all at the end until you upgrade the faucet aka turbo.

Fauset being the turbo, hose being the engine. small engines don't require huge turbos to hold boost. take our engines for example with a 6266 almost no pressure drop on a well prepared setup. put that same turbo on a 8 cyl or something larger and see what happens with just running wastegate pressure. more volume to fill, not enough turbo = turbo is now a restriction to potential power output of that vehicle. upgrade the turbo to match the displacement of the engine and the boost starts to stay better on its own without tapering off.

the above is an example of fluid dynamics.

in short you have more volume to fill in a larger displacement engine, so it will require a bigger turbo than say a 2.0L to hold boost at high rpm.

boost taper is a sign of a turbo not being big enough for the engines displacement, although of course there are many other variables as well that effect it. but i'm just being simple minded posting this so others can understand it easier.

 

^nothing that really contradicts what I am saying but still kind of off point on what I was trying to say.

All I am trying to say in regards to this is boost is a sign of how restrictive your setup is in a sense.

If you have a stock head and are running say 350whp at 27psi for example:

Then you put on a ported head you maybe make 360whp at 26psi. You increased flow with less psi as you got rid of a restriction. Then you put cams in and make 375whp at the same boost level (26psi). And I could go on.

Typically when you free up your setup your boost will drop as you are hitting the same load cells with less boost as you are more efficient now.

So again...where this all started was someone was saying how they were having trouble holding 30psi and then someone said I am holding 30 psi "because my setup is free flowing" isn't really true...its holding 30psi because you have a better wastegate setup or proper one. And again I was implying a truly free flowing setup vs a non free flowing setup should have a lot harder time holding boost but it won't matter as you are making more power with less.

I feel like I am rambling now...hopefully someone gets this lol.

 

maybe you didn't read what i said, or maybe you don't understand simple physics of water flowing through a hose? <-- i'm kidding. you basically just said the same thing i did, but don't realize it i guess.

also i was not contradicting you or trying to in any way. clog the hose with mud and slow down the flow, then remove the mud and its the same thing you're trying to say with a ported head vs unported lol.

I'm just trying to keep what i say very simple so others can grasp it.

 

When in rome...

 

you don't realize it yourself, but were saying the same thing.

you port the head, it moves more air. so before the car may have been at 28psi, and after the port job since its got more room to fill its at 27psi, but now its making the same power it did at 28 with less boost.

so as long as the turbos good for it, if you up it to 28 with the ported head you got a nice gain in power and at the same time the setups more efficiently now at making power at the higher boost level as well.

so in reality you can't base a cars efficiency off the boost its running unless you know what's being done with the tune and the whole story behind the mods.

and as i mentioned his cars able to hold 28psi+ like that because of the ecu boost control.

of course the wga plays a roll in keeping the gate shut as well. if it had a too weak of spring pressure then exhaust gases would blow the flapper open.

but yes you are correct, what he said was not accurate.

and yes i agree with you, that boost can tell you how restrictive a particular setup is. the more you do to increase airflow the more your boost is going to drop as long as you don't touch the boost controller. so in that sense yes i agree. its creating more volume for the air to fill, so the more volume to fill will require more pressure to get back to where it was before opening that volume. my hose example explained that if you read it all.

 

his main point was that my boost should taper off at high rpm, not hold to 28psi... is that true or not

 

LOL, that was not my point.

I was trying to tell you your comments of being able to hold boost to redline is not because of anything that is "high flowing".

Tom, I know we are saying the main thing basically. I was a bit off topic on what I was trying to convey is all I was saying.

I was trying to Ron Burgandy the situation with the when in rome, failed.

 

this was never said, I simply said my car holds boost to redline. You went off on a tangent saying my boost should taper to make power and all these assumptions that I had something other than a stock cam/stock head car. I understand what you're saying (it's true) about a car with head work and cams, but none of this pertains to my car and that's what I was defending, my car. We all know the stock head is restrictive so that's what you were trying to prove?

 

never mind dude, point missed completely and thread derailed far enough. Tom knows what I meant, maybe another time lol.

More dyno charts of EF turbos needed.

 

its all good no worries!

 

those are actually pretty good numbers on pump gas. I will say this...I am still skeptical that the EF3 will actually outflow the FP Red on E85 regardless of what anyone says. With that being said, I am not trying to bash on the EF3. If I had the choice I would choose the EF3 over the red for the simple fact that the EF3 seems to make much better numbers on pump gas, and it's much cheaper. The red is a pig on pump with low timing.

 

Yea I agree with you 100% it's a great turbo for the money and like I said I'm not sure if its just out of breath or what on e85 since at 29lbs I made 499.8 and when we turned the boost up to 31 ( keep in mind it's only a small peak up top controlled by the 3port) it only picked up 7hp. All I'm all I'm happy with It and very pleased with the power band and everything it pulls very hard on both pump and e85.

I actually might be selling my set up soon too though I'm going t4 twin scroll 3586 or 6266 in the near future