okay, i have a boost question, what is the difference between running 15psi on a t3/t4 and running 10psi on a t4???

why would you upgrade to a bigger turbo when people dont efficiently use up all of thier turbos power.

doesnt that just equate to more lag???

becausei am running my t3t4 at 10psi and everyone sayd i should upgrade to a 60-1, when im not using all of my turbos potential.

if im wrong hellp me out

 

larger turbos have the same flow rate at a lower boost.

a supra with stock turbo can flow lets say 500cfm at 20 psi. but its very hot air.
but upgrade the turbo and you may get 800cfm at only 10 psi.

this would make more power. at a lower boost.

the draw back is more lag.


numbers are just examples, so all nitpickers go screw off.

 

thanks but if i am only using say 9-10 psi on my t3t4 why would i upgrade to a straight T4???

 

Like he said, you'd prob make more power at the same or lower boost. but your trade-off is more lag

 

forget it then, i like my turbo

 

I'm a person who strongly believes in maximizing in what you have. That is why I still have a 14b on my car. No need to throw on a bigger turbo to make up for my lack of supporting modifications. Granted, after next week I will have a perfect set up for a 20g, I will still keep the 14b until I can get some solid 12s passes.

It depends on what t3/t4 you are running. And also what T4 you are talking about. Like compressor wheel, exhausts wheel, exhaust housing, and compressor housing. This information will help in answering your question.

 

You are correct. i was not looking at the whole picture.

were you expecting a whole picuture from a 6 line reply. ?


the case is very diffrent for every motor / turbo combo. but the general rule of thumb is larger means more air with less boost. at the expence of lag.

i also didnt cover all the neato tuning tricks to help eleminate lag. but thats not the topic here.

 

im not too bothered by the "lag" of mt t3t4, its not that bad at all. i have the basic turbo that came with my drag gen III kit, i think it has a .48exhaust, and a .53 compressor, in my eyes it is a great street/track turbo. for an everyday driven car. right now i have gotten brave enough to run 12psi, and it is enough power for me.

i have a firend with an integra, "the one from north carolina that raced at gandy a month ago" he has a T04e or B, im not too sure, but he doesnt even make boost till 5500 on an integra. i only have a b16a2 and slightly less compression, and he has to spray it to compensate for the boost lag.

i dont want that

 

well...

a T3/T4 is mainly geared towards engines under 2.5 Liters... they mate the big compressor wheel (and housnig) to a small exhaust side. The T3 is the only way to get an exhaust housing small enough to efficiently spool a turbine yet make decent power on a 2.5 liter engine. Plus its convenient for import and even domestic tuners who are lookin to increase the efficiency of their small-displacment engines. Mainly because its a relativly universal turbo and has many different combinations to suit many needs and also is available w/ an internal waste gate... an option that can save hundreds of dollars, packaging issues and space under the hood as well as limit the complexity of the system.

Straight T4's (T04B/E/S/R, etc) are for larger engines, that are over 2.5 Liters in displacment... or where >2.5liters feed one turbo,, like on a V8. a 5.0 Liter V8 will do WELL with T3's or T3/T4's... simply strapping on a pair of T3's from the Turbo coupe's will make that thing fly, mainly cuz its got ~2.5liters feeding each turbo. Now, if i had say... a 350, i could get away w/ a pair of 50trim T4's...

BUT....

the problem w/ STraight T4's and T-series turbos, is they dont have internal gates... which means you have to make a provision to mount an External gate... and spend ~$250 or more for a middle-of-the-road wastegate, and also rig up a way to mount it. Ive seen some exhaust housings that have a flange to bolt it right onto the side, but most of the time, i see WG coming off the manifold/header collector. This complicates construction and is not conducive to producing a mass-marketable turbo... but then again, people who are willing to run a turbo like this already know its a given that its gonna require a new/custom manifold and external WG and all the good stuff... so we already know its a larger commitment to run a really big, externally gated T04E-60trim than it is to run a moderate, internally gated T3/T04E-50trim.

But, you can get the same turbo in either series:

T3/T4-60trim
T4-60trim

they will both produce the same amount of boost, but one is cheaper and will be easier to find the right size exhaust housing and turbine wheel to install on a B16B or SR20DE or Ecotec :o
but asking "which is better, a T3/T4 or a straight T4?" may be like asking "which is better, a Ford V8 or a Chevy V8?" they both have specific applications that they would be ideal for, but neither one would substantially outshine the other... you know? kind of a loaded question i guess.