T04E A/R ratio

[sidewaymambo]

Have 2 set of T04E turbo sit on top of my desk, however slightly difference, one has 60(compressor)/70(turbine), and one has 50(compressor)/63(turbine).

Question:

What will be the difference when install on on RB20/25DET, say rpm to spool or hiot the boost..etc? thanks.

[meggala]

more lag

the 50 will spool earlier but might be to small for an rb20 but would probably be ok on an rb20.

but ask a turbo place.

meggala

[sidewaymambo]

thanks mag,

Did we call the hot side (echaust side) turbine or compressor? get confused......

[meggala]

turbine I think I call it the exhaust housing

[sidewaymambo]

Thanks.

If the exhaust side A/R is smaller then compressor side A/R will it lag? or opposit?

[whistla]

turbine: exhaust side, hot side

impeller: compressor, cold side, intake

[Joe]

The smaller then exhaust housing the faster it will spool.

Find out the diameter & i might be able to tell u.

[sidewaymambo]

looks like most people prefer the T3/T4 setup, and the advice from most people recommanded it that 220kw will able to reach.

However T04E might lag, but it will be fun to drive around town at low boost, and when you want it, nail it and the power come..may be I'm wrong..

will open for suggestion..

[Joe]

I myself would prefer a t3/t4 setup but when u weigh the value of a t3/t4 from cgc $2000 & at the same time a HKS GT2530 brand new would cost just the same so ppl look at other alt.

You can sometime see on for sale for $1000+

The reason why its so popular, its just so simple, take it out for them 2 trim all the bits they need, add larger compressor wheels etc & pop it stright back in.

Dont think of lag as drivable but think of your power band. Mainly Fast street cars aim towards Mid-Range torque over Top end.

eg.

You have till 7000RPM till REDLINE & if a turbo start spooling at 5000rpm, you have 2000rpm left for power then change of gear. How fast do you think it will reach to 5000rpm on lag?....quite long i imagine.

You have 5000cc more then i do (i own a r32) hence you would have less lag time compaired to a RB20

All depends on what you aiming for 180rwkw....you dont even need 2 think of a turbo since the r33 turbo can do 180rwkw before running out of puff

Joe.

[sidewaymambo]

Don't laugh at me guys, initially I was planning a three stage upgrade towards to 300rwkw..I mean it..

stage one: upgrade the exhaust system, FMIC (P-FC already in place)

Stage two: upgrade the stock turbo with T04E, HKS ex manifold, wastegate, dump pipe run at 14 psi (if fuel lean out, the stage three comes in)

Stage three: upgrade stock injectors with 550cc item, fuel pump, forgie pistons, gasket..

The most concern for me is bring the lag down to minimun, and I will see if a switchable "side exhaust" helps..

I don't know how relistic can go, but open for suggestion..

[Joe]

It is possible to change the exhaust housing on the turbo & getting a smaller one for less lag.

300rwkw....that would be great, just make sure you take it one step at a time & also include injectors & fuel pump on stage two of your work, this will keep your engine from leaning out & destroying the engine.

but just 2 let u know, you might need alot more work then that to reach 300rwkw.

esp. internal work to the engine to cope with it, you got to remember nissan never designed the rb20/25 to make 300kw but its do-able.

[macka]

Hey that housing isnt big at all!

a .63 housing is great infact it doesnt even sound like a T4 turbine housing.

Use the .70 comp and .63 ex and i dont think there will be much lag at all........taken those figures..

Should spool up good

Im happy with my t3/4 I get full boost 3000rpm in 2nd gear :uh-huh:

[adam 32]

ive got a t04e on my RB20. lag is pretty bad! full boost by 4-4500rpm but it goes fairly hard when on boost. am currently making 201rwkw @ 14psi

[macka]

Originally posted by adam 32

ive got a t04e on my RB20. lag is pretty bad! full boost by 4-4500rpm but it goes fairly hard when on boost. am currently making 201rwkw @ 14psi

Adam you gobbler you have an exhaust A/R of 1.06 my whole turbo could fit in your ex housing thats why you should bring it down to a .86

Sidewaymambo ex housing is only a baby .63 which is whay i mentioned it could spool not so late as yours

[sidewaymambo]

mine has 60(compressor)/70(exhaust), what you recon?

I hope the sppol can come in before 4000, but might need to find it out ....

[adam 32]

i didnt actually read the whole thread. besides mack we dont know how big my exhaust wheel/housing is cos we havent looked!

[Joe]

No1 can really tell you when its gonna spool up.

I dont think it would be that big of a problem.

50(compressor)/63(turbine) is one of the smallest t04e ive ever come accross & it would give or take spool on my RB20 ill say around 3500 or 3000 give or take.

60(compressor)/70(turbine), would be just a size down (few mm difference) from the above & you have RB25 so you got more cubic (5000cc) then i do so im giving an est guess of 3500rpm but pretty sure it will be under 4000 rpm but we will find out in the end

we can always port the head & get bigger cams 2 bring down alittle bit of lag

Hopefully my figures are right if so it would be sweet.

Almost forgot, your HKS manifold has a Split-Pulse Flange so it will help the turbo spool alot quicker also.

Joe.

[adam 32]

just went outside and looked at turbo

compressor AR is .50

cant see shit on the exhaust side.

[sidewaymambo]

Almost forgot, your HKS manifold has a Split-Pulse Flange so it will help the turbo spool alot quicker also.  

Split-Pulse?

[Joe]

Compressor A/R means SHIT regarding lag. the bigger the more power it can produce (i beleive as im still learning how 2 read compression maps on turbos abit better)

What determins lag is the exhaust housing. The bigger the exhaust housing the more lag you gonna have.

as macka stated:

Adam you gobbler you have an exhaust A/R of 1.06 my whole turbo could fit in your ex housing thats why you should bring it down to a .86

sidewaymambo: yours is .70 which should be good for your application.

anything around or above .90 should be fitted on a rotor, is what i beleive.

Joe.

Correct me if im wrong.