There are members and sponsors out there who have a significant amount of experience with turbos. I have a few questions and would like to turn this into a general discussion tech thread about turbos.

First; front mount vs. rear mount. Those who have switched how would you describe the difference in power delivery, transient response and boost potential? Under a consistant load can you reach full boost at the same RPM with a front mount and rear mount? Does the front mount reach full boost under the same load quicker?

Second; if you have a T4 turbine, does the exhaust housing remain the same size for all T4 applications? I know the AR varies with application, but if you have a .96 with a 60mm compressor is it the same size for a .96 with a 76mm compressor?

Third; pressure ratio across the engine. Has anyone measured their pressure ratio and if so can you give the info (displacement, cam, boost level, front or rear mount)? Is the pressure ratio different between front mount and rear mount at the same boost level on the same enigne?

Lastly; twin vs. single. If you need X amount of airflow and can choose twins or single to get you there, what will the characteristics of each be? Will the single come on slower but hit harder?

Thanks for any input. If anyone wants to add items to discuss feel free.

 

I know of a donor truck if your interested in finding out #1 and #3.

 

Let me know when. I guess no one else wants to talk about turbos?

 

Like telling a bunch of dudes there is an all girl party down the street, your going to get everyone in here for this thread.

There is too much info to list, might want to focus on one subject at a time.

R

 

So far no one has commented on anything, lol.

Rick, have you done any front singles? Would a single feel the same as twins at the same power level?

 

I have and yes and no is your answer.

A big single will flow and support the air needed for power and cubes, but with the downside of not much down low. The twins are where you can divide up work to have the same power but better responce through the power band. But the twins come with a big penalty, package sizing. More room needed, more cost, ect. The single is easy to work with, but can still hold issues when trying to build as a responsive street car. The issue I see in a single, or the ones that are being sold on this forum, is only one side is changing the manifold. You are asking for internal hot spots and pressure problems because there is no piping that has directed the flow of exhaust pulses to the turbo, instead its a mumbo jumbo gather of pressure and it then has to find its path of least resistance.

R

 

Any1 know of any great places to learn of general turbo concepts. Im lookin to reduce my spool times after reading so many people talk about having full boost at 2200 rpm and such.

 

Full boost in 1st gear at 2200 or 4th with the Converter locked?
First gear it takes till 3300 till i get full 5psi.
So my truck is a turd off the line.

I Finally figured out how Wastegates and Turbos work together.. I never could understand it, just riding down the road one day it literally hit me.. So basically im just now learning the basics.

 

On your
FIRST: KB switch but keep the same a/r he had, so boost spool was stupid fast. The thing I see its not just pressure spooling the turbo. Heat and pulses. The closer the turbo the better the quality of the energy your tring to harness.

2nd.
Not all T4 housing are the same. That is just showing the mounting area you are dealing with. I noticed the precision 88 T4 we did had a larger inlet then the 62-1 we get from turbonetics.

3rd. No one that know of has measured that I know of. yet.

4th. Whats in your bank account. The benifit of the twins over a single in large HP applications is you have a large section of turbos to choose from. You can match the system to HUGE hp goals better, but at an expense..
The twins I seen on the forum used cast manifolds and really just did not look the part. chewed up a huge amounts of room rerouting wires etc.
Also there is always a chance for one turbo to be working harder then the other. A twin also has to deal with 2 heat source in the engine compartment.

In a HUGE hp applications a single may spool slow then twins it really depends on how the parts are matched up.

A single shines in packaging and over all ease. Easier to install, you have fewer parts so you have fewer chances to have an issue.
Singles work just fine for 95% of the customer base out there. The air flow going throu the tubing makes it all work just snazy. No problems with pulses not getting to the turbos etc.

So it really comes down to pocket book on the bling factor in my opinion..

We can swap a/r for the 4.8 you have and pick up spool time easy.

 

Hm Rick staying up late 2 nite. Haha i may give ya a call 2 mmrw.


At 70 mph i have full boost as soon as i touch the throttle. Off the line you can tell when the boost kicks in. I wouldnt call it laggy by any mean. Im looking for reading over turbo air mass type of concepts. Like my 4.8 doesnt move enough air at lower rpm to get the turbo to spin fast enough or what, Im missing some things in these concepts.