I still have only heard little bits and pieces of that argument; it doesn't matter anyway because GearDownSon and I went to the dyno and got you guys some stock + RRM turbo numbers from a mustang dyno. If you add 10-20% on to those you will get ~dynojet numbers. those are real numbers, because we aren't selling any turbo kit and have nothing to gain or lose by showing one number or another in particular. we even have some NA numbers in the same thread to compare to, although I wouldn't say they are good numbers (yeah, they're my numbers )

 

All you need to know is that forged pistons will handle the psi and forged rods will handle the tq.

As for the psi = psi, the only change is the volume of air and temps made creating it. Obviously a larger turbo (50trim) will move more air and cooler at 8psi than a smaller turbo (t25).

 

^^ but obviously at 8psi a larger turbo is gonna have too much lag to be efficient.

 

no, the much larger turbo has more lag because the turbine wheel is far bigger. Add in a larger housing and there is more lag but more flowing capabilities.

Btw, you can have a very large turbo and rather poor efficiency, just look up the gt2876r aka gt25/40r and the t3t4 57trim.

 

^^ thats exactly what I said. The larger turbine wheel is a larger rotating mass and therefore takes longer to speed up. I used the wrong term when I said efficient, feasible would have been more appropriate. A large turbo is almost useless when your dealing with such a small amount of boost.

 

the rpm is the more limiting factor. If you can rev the motor out to 7.5-8k, you can take advantage of a much larger turbo. Even at 14psi, a 50trim or a gt3076r will make far more power than a t25 at much higher boost.

Just look at the Honda guys, they make the same hp as use vw/audi guys on the same turbo at just over half the boost, both using a 1.8L. There head flow makes a huge difference.

 

so what you are saying is if you want more power buy a bigger turbo

all well, I'm not going turbo anyway so I won't worry about this issue any more. you must be right because of the vague references to other people using X turbo instead of y turbo and making different amounts of power on different cars. real scientific information you're presenting there, way to make a point

 

I would speak more technical but i didnt want to talk over your little head.

Its always nice when you provide people with the info they want, there is always some smart mouth that makes it not worth helping others.

 

I've posted concrete arguments for my point many times in this thread already. your claim is unsupported with fact and is a vague comparison at best, yet you expect me to continue to speak my viewpoint if I disagree? to what end? I think I'm good now

or maybe you failed to read the rest of the thread? sorry you don't like my tone but I am sure you will understand it's frustrating to argue the same point over and over.

 

I read the entire thread and I saw you arguing a point that had nothing to do with the topic and are still continuing it to just argue with people. I answered the original ? in my first post. Recap, pistons = psi, rods = tq

Here you go, ill make it in the simplest terms as possible. I never made any real comparison because it wasn’t important to the conversation I had with Cow Town. But if you want more info, I will take 2mins out of my day to spoon feed you. Bigger turbos with bigger compressor wheels move more air at a given psi and create the same power output with far less heat. The increase in compressor wheel plays a small role in when a turbo spools. Within a given family (say gt28, they all use the same turbine wheels and housings) the lag increase is minimum, usually 200rpms. This holds true from a gt2860r (gt28rs) to a gt2871r and gt3071r to a gt3076r. The last 2 numbers are the size of the exducer, the bottom part or the compressor wheel. So with the increase from 60mm to 71mm, the gt2871r can move ~50hp more than a gt2860r at its peak.

The turbine wheel needs to match the size of the engine, psi going to be used, and flow of the compressor. It will surge or choke if the wheels or housing is to small for the any of the above listed. Obviously if the wheels are bigger, they will increase lag but will be able to flow more air.

As for my comments about a vw/audi and a Honda, the Honda head flows far more CFM than a vw/audi head allowing it to make the huge increase in power. They need turbos that flow huge amounts of air with low pressure and we vw/audi guys need turbos that love to make boost. With headwork like porting and cams, we can come close to matching a basically stock B series head allowing us to make more hp at lower boost. Basically we run most of our turbos at 20-25psi on pump where they only run 10-15psi.

 

If this is the statement you are talking about.... well


He meant power output will be the same, not the pressure. And if you really think you are going to make the same power at the same psi... wow, you are diluted Go look in the evo turbo section and see what people are making with 30psi on a stock turbo and then what they put down on a gt35r. I think that 250awhp+ would be a easy way to tell that same psi does NOT = same hp. If this is what you truely believe, wow

 

you made my point for me: the only difference between turbos on identical setups is the turbo size itself. that means the only thing that can vary the output (laws of physics) would be the temperature of the charge. I was never trying to compare moving from an overtaxed stock setup to a setup matched to the engines potential. I don't want to argue with you, you are not arguing the same point I am trying to make. he's not staging up, he's comparing two very similar turbos matched fairly well to the engine at low boost levels. I believe at one point he claimed 50+HP, which almost all can be attributed to the better design and tuning capability of the kit he was referring too.

and you read the whole thread? your point is about the efficiency the efficiency of the two turbos is too close, and the point was covered. I have not been arguing to argue with people, we've been having a grownup conversation. what thread did you say you read again?

 

What? You are now making stuff up. I never once said anything about a turbo’s efficiency. For the last time, bigger compressor wheels = more air at Xpsi than a smaller compressor wheel, not just lower temps. Until you grasp that concept, you are a lost cause and shouldn’t enter a thread about turbos. The point he made in his first post was a safe assessment, the 50trim is rated 75hp more than a 16g which is about another 75hp more than a t28. With all things equal, a 50trim at 8psi will be about the same power as a 16g at 9-10psi and the same power as a t28 at 11-12psi. The differences would be greater as the boost increases. Im not continuing his argument, just clarifying his original post where this all started.

You really should go to turbobygarrett.com and read turbo tech 101-103. Im sure 103 is way over your head

PS, you really need to reread my previous post since you still think same psi = same power

 

I have already read the information on garretts website, thanks for the link. It was a good refresher.

I'm growing weary. compressor maps are just that, maps. they are nonlinear for a reason: many variables make up the potential for the turbo. If you want to believe you can just put a bigger turbo on to make more power at 8psi then feel free to start throwing them on man I'd be concentrating on the more important parts of the kit though, because the turbo should be matched to the output and then left alone.

maybe I have misunderstood, I'd be willing to admit that, but only if you promise to stop calling me stoopid get a grip man, and act like your old enough to have an adult conversation

 

Let's not start insulting guys. Basically, that was what I was saying, as much as was worded wrong maybe. It's the power output I was thinking of. You will need 10 psi on a 16G to make power what T3T4 is making at 8psi. From my experience, I've noticed that pattern with different cars.