https://www.rx7club.com/showthread.p...hreadid=245290

Hybrid Turbo questions;

Thanks much,

-Robert

 

I would think that the higher degree will allow the turbo to spool to a higher psi but the lag is going to be more evident because there is less force on the outer blades of the turbo. If the degree was not so steep it would probally spool faster but max out when the pressure of the exhaust gas is maxed. By putting it in further it can spool faster but takes longer getting here. Then again I could be wrong, just my take on the way it works.

 

well my local builder said that the main reason to clip a turbo is weight reduction, for inertia but he said there is alot better ways to acomplish that same objective.

we shall see,

P.S. still looking for turbine wheel advice

 

I always thought you clipped the turbine to make the wheel smaller. Having a smaller wheel in the same size housing wont choke the motor as much at high rpm's.

 

Not real sure, the whole thing is quite confusing to me.

 

nope if you clip the wheel you actually loose some of it's original desing of the turbine, which is in essence take away from it's performance. In some instances some can be taken off without detrimental consequences however, in this case it seems to have huge consequences...
RPECK have you talked to the *BUILDER* of the turbo in person he migh warantee it, tell him you have a second opinion and they think that the turbo was clipped too much!

 

Sorry must have read what you were asking wrong, hehe

 

No I have not talked to the builder, nor do i really have a intrest in doing so. It's frustrating that I have turned every single nut and bolt on this car myslef.. From the rebuild and street port to every other mod I have done. Yet the one thing that does not work right is the one part I did not do myself, the turbo. I have no intrest in arguing over money/warranty or anything else, I just want it RIGHT. I am paying this local shop whatever they charge to make it perform like it should, and with a local shop doign the work I have alot more recourse in the event of any problems, and I can have them make more changes until it is right.


-Robert

 

Okay the more I read the more confused I get. I have questions.

Okay, my understanding is that the compressor end of this turbo is a 60-1. I assume that is the size? Of the wheel? Now does that have anything to do with the amount of blades, shape or style of the wheel, or is that just the size?

Being that it is a hybrid my understanding it that the exhaust side is a stock Hitachi HT-18? Is that close? What blades can/will go into that? What do the different Stages mean? What blades am I looking at getting .. should I look for T3 turbines? Or HT18? Or T04?

This just all seems a lot more confusing to me then it should be ..

Thanks.

-Robert

 

I have a lot to say, but no time right now since I"m at work. I think I can explain it all....I'll reply when I get home this evening

-Chris

 

Pffft. RX7's > Work

J/K Please explain some it when you can, thank you.

 

the exhaust wheel can be a T04 turbine however it will have to be clipped to fit into the exhaust housing! You will loose some of the wheels capability, But you do have to realize one thing is the stock exhaust turbine housing is "Impact" type, thus the stock exhuast housing will allow a clipped T04 wheel however you will have trouble venting this, Ie waste gate should be severely ported and preferably have a custom WG flapper door installed.
Mine has a T04 wheel machined and the stock housing was machined also to lessen the "impact" properties of the stock Manifold!
I hope that helps you in your quest for knowlege to make an educated decision.

 

Maybe, but the main reason for clipping the turbine wheel of a hybrid turbo is to reduce the efficiency of the wheel, which will reduce spool, increase flow capability and ultimately help to control boost creep. There will be a slight decrease in spool but it shouldn't really be that noticeable. A 15 degree clip is fairly normal FWIW. With the upgraded compressor on a stock wheel you will boost creep and the wheel will become a restriction in the system.

This goes along with my above statement.

Yes a 60-1 refers to the compressor wheel. Basically the "60" refers to the diameter of the inducer (smallest diameter) on the compressor wheel in mm. There can be other 60mm wheels that may have a different number of blades, shape etc, but when you say 60-1 that is generally accepted as a 60mm wheel with a set number of fins, set shape etc. IE all 60-1 wheels will be the same. (FWIW a 62-1 is a 62mm wheel, a T66 has a 66mm compressor wheel etc. The Garrett T78, T88 etc do not follow this size nomenclature so don't be confused and think a T78 has a 78mm wheel)

Yes, you have the stock exhaust side with a clipped exhaust wheel. Usually the options for a hybrid turbo are:
Leave the wheel alone
Clip the wheel 5, 10, or 15 degrees
Machine the housing to fit an "O" trim
Machine the housing to fit a "P" trim

Each step up the ladder will result in more flow, more top end, less spool and better boost control. I wouldn't recomend a P trim b/c enough material will need to be machined from the housing that it will tend to fail. An O trim seems to be a fairly good option. I'm not sure why you would clip a T4 type wheel (O trim for example) to fit in the stock housing. Usually you'd just modify the housing.

Either way you will certainly need to increase the W/G flow capability with heavy porting, different flapper door or an adapted external W/G. My problem with all this machining, custom work etc, is that by the time you do all that, you are well on your way to buying small T04B manifold etc.

So, if you are going to stick with the hybrid theory, you might consider an "O" trim turbine wheel with a machined housing..... but be sure to watch out for boost creep, it'll kill a motor if you're not watching.

Does all this help any?

-Chris

 

Shoot, I alway forget that my wife signs in on the home computer. The above reply is from me

 

Yeah, right.
Seeing what your wife just posted, I'm betting $10 that she has all the RX-knowledge and does all of the wrenching, and your job is to sit pretty in the passenger seat.

 

Thanks Carx. The married wastegate is ported as large as it will really go, infact it has a bigger cover on it also. I hope thats good enough .. if it is not I will do a divorced wastegate setup of some kind. I am thinking I will see about going P trim with 0, or very little clip. I am sure i will not have a problem producing the ~12-13 PSI or so i want to max out at ... so of all those choices what one would your recomend for responce, but still reach 12-14?

Thanks,

Robert

 

Well my responce was soooo bad, that it was like 5k+ till i made decent boost, and I spent months trying to figure out where my leak was. Turns out there was no leak, I pressure tested the whole system a piece at a time, then all together. That was with a 15 deg. clip .. so I am not sure why it was so bad.

Click here to see the dyno sheet if you wnt to now how bad it really was;

Dyno sheet of boost

Unreal huh? for a hybrid? they are getting less lag out of T78+'s

One more question, Garret makes staged wheels .. Stage 1, 2, and 3. Are those compressor end, or Turbine? and what is the diference with those? are they usable on my setup?

Thanks again

-Robert

 

I'm caught Please don't tell anyone

On the turbo:

I would say an O trim. I was told by a turbo builder, and based on my knowledge I believe him, that you will need to cut so much material from the turbine housing to run a P trim that you run the risk of the housing cracking and failing.

I should state that I have never used a hybrid turbo, HOWEVER I did research them THOROUGHLY before I purchased the monster that I am running now. Having said that, if I were building a hybrid for myself, I would have chosen the O trim with the 60-1 compressor.

As for stage 1, 2 and 3... that's the turbine wheel, but I don't know really what it means. If I were guessing, I'd say that was just another way of saying that it was clipped 5, 10, or 15 degrees....

 

hehe, wow, I just looked at that graph... that does suck. Ouch. Hope the new one works out better

 

Hm. Makes me wonder what exactly is done to my hybrid. Here is what I know:

T04B compressor housing/wheel
Stage 3(whatever that means) turbine wheel and turbine housing machined to fit
360 degree thrust bearing
wastegate ported all to hell with a larger flapper door welded on

Boost is strong as hell, but it falls off towards redline.

 

sounds very similar to mine. Did you have a clip on the turbine?

 

Nope, no clip. And I have the stock catback so it could have something to do with the boost falling off.

 

Ya, Like I have said in some of my other threads concering this. My local turbo guy thinks my severe lag is from huge overkill on the clip... So thats prolly why you seem to boost fine with a similar setup, my boost was still going up at 7.8k though .. so, need a happy medium. I am going to have the **** modded out of this turbo .. then if I am still not happy full T04 is next.

 

rpeck,
I know thy hyrbid sounds like a good fix, and you have already invested huge amounts of money into it, but have you sourced out good T04 turbos as it may be just as economical and you would have way more tunability with a to4 then with the hybrid! It may be just a thaught but it may be better for you in the long run!

 

Ya, i keep thinking that man, trust me. But .. manifold, External wastegate, new DP, alot more tuning, and a stand alone EMS .. are all pretty much a must. thats big $$. I am just afraid if something was to happen to the car i would be out so much dough.. . I live in an area where dipshit drivers grow on trees!! I alredy had some bitch ren a red light at 50 MPH and total my 00 Dodge Truck .. I just want power, not 450+ RWHP and alot of dinking around all the time, and unrelability. Plus I HAVE to pass smog every 2 years .. it's hard enough now, but with a snail the size of china sitting on the side of my engine I am sure to fail.