ok just out of curiousity reguardin the turbo greddy uses.........does it have an external wastegate????or is it internal??? now is the reason why people cant go over 9 - 11 psi in it, is becuz it takes it out of its efficiency range........or is it too much pressure for the waste gate n it sticks open...........could someone pm n explain it to me...........i know how a turbo system works im just curious as to that problem with the turbo

 

for the wastegate issue.. has anyone replaced the stock WG with a aftermarkey one?

(stock as in greddy turbo kit stock)

 

RX8PR did it when he first had a Greddy kit on his car. He made 290+whp, if I recall correctly.

 

maddog what kind of bov are u using? have you upgraded any other greddy turbo parts?

 

Read your note on how you solved problem 3. I would like to do the same to my RX8 here in Chile but want to make sure I do it right. Could you help me with instructions to try to do it right? Any watch outs to avoid problems?

thanks in advance.

 

Please forgive me in advance in case this has already been asked (i am not very good in searching....) as well as for being kind of off-topic.
After reading the first pages of this thread and in case i have understood at least some portion of the fixes mentioned, i assume that the extra injectors of the 231 BHP version are not needed for the Greedy Turbo Kit.
So here is the question.....
I have a 192 HP RX8 (sold as "CHALLENGE" here in Greece) and i am interested on putting a Turbo Kit on.
Do you think (or know) whether i could do so safely, bearing in mind that the low-power version is missing the extra injectors? (Maybe by exchanging my stock injectors with bigger ones?)
I use it mostly as a daily car and i am more interested in torque upgrade than HP gain. What would be a reasonable, yet safe boost on such a setup?

Thank you again for any reply,

Regards,
George

 

what does that mean exactly? sorry for the noob question. new to turbo as well.

 

What does what mean?
I don't understand the question based on the parts you quoted.

You don't understand the net effect on boost pressure after the installation of that fix?

 

like, what does it mean that the net boost is 2psi lower. example, suppose i were boosting 10 i'd be boosting 8 after the fix? btw love your avatar. also the last 20.

 

It means that after the fix, you will be about 2 PSI lower because the wastegate will judge its opening point based on a different reference.

 

would the boost gauge be affected in anyway? or will it still read exactly what the turbo boosts? also should i do the fix before or after my tune?

man.... turbos so confusing for first timers like me. i've read so many threads and taken many tylenol pills to kill the headache.

edit: im going to order the interX from mazsport and scott will load a map for me but he said i would still have to take it to a tuner.

 

You need to study. These are fundamental concepts.
Get these books:

Maximum Boost by Corky Bell
Street Turbocharging by Mark Warner

 

Buying now...

 

Both of those books should be required reading for anyone who is getting into the aftermarket turbo game.
Moreover, if one can't understand what the books are conveying, one shouldn't be messing with FI.

The Bell book is pretty deep, but he does a good job (I think) of bringing the science down to earth at the end of each chapter.
The Warner book is a bit looser and more general, but he is a turbo guru (he is the owner of Simple Digital Systems) and he gives a good genral overview from a practical stand point.

Bear in mind - neither of these books have any rotary content.

 

You are the man MM, I got the Street Turbocharging One and How to Tune and Modify Engine Management Systems by Jeff Hartman, I have 9 months to research before I get home, so time is not a problem. Thanks again.

 

uhm..... im going to purchase these for my own reference for learning, thanks btw MM. My problem is.... i already got the turbo and going to get it installed at a shop. i think i know how to do the fix #2. i just wanted to understand what that 2psi boost thing had to do. ill figure it out sooner or later. =) thanks MM!

 

Look up general gas law on the internet, that will help.

I will paraphrase " The functions of volume, temperatur and pressure are related. A change in any one will affect a corresponding change in the others"

Temp and Volume / Pressure are directly proportional

Volume and Pressure are inversly proportional

Help any?

 

^^ Probably not.

More simply - if you tell the turbo to open the wastegate, it will.
In the original configuration, you tell it to open when the manifold reaches 6 PSI.
After the fix, you are telling it to open when the turbo hits 6 PSI.
Because of losses in the system (flow reduction in the piping and intercooler), the net pressure in the manifold will be lower.

 

Now that I am doubting my sanity...

MM, when you say flow reduction etc, you are reffering to the cooling effect of the intercooler (temp down - PSI down) and the volume differences in the system as the air travels (volume up - PSI down) Right?

 

Well, flow is also reduced by restriction and obstruction.
Since the turbo is a centrifugal compressor, much of its energy is the velocity at which the air exits the scroll.
Throw a bunch of extra turns and passages in its way and the air looses pressure as it looses speed.
There is always a drop across an intercooler, but not all of it is because of the increased charge density.

The pressure at the outlet of the turbo is always higher than the pressure in the manifold.

 

ok i think i understand now. thanks alot mm! and kane for trying to help. even though you confused me and threw me off. haha.

 

Well I tried....

I guess it helps to be a diver, air pressure, volume, heat etc are the name of tha game.

To illustrate a lot of times we will fill a ballon, slowly heat it up / cool it down (volume change) and take it a few feet underwater (volume change)..... same principles, different industry.

Edit: I am really not trying to be an ***, but I thought I had this knocked and now am not so sure. How does airspeed increase PSI? Technically, only an increase in pressure (in a rigid contained such as an intake pipe, scuba jug, etc.) IE forcing more air in a rigid space - which creates pressure and heat. The speed that this occurs only matters because faster compressing creates MORE heat, so when the charge cools, you lose more of your pressure. If volume of rigid space goes up, pressure goes down and charge also cools as a byproduct. I can't see how flow creates a pressure increase other than as heat / volume changes.

 

Yeah, the gas laws apply as do all the thermodynamics.
But, sometimes the practical "impracticalities" are more important.

 

MM, too fast for me, I was trying to edit my post.

 

It's the decrease that is relevant in this case...caused by friction so too speak.