Turbo

[R33]

Originally Posted by R34 GTR

R33

I am going to use the GT-RS's this time round in my new engine as got used to the power of the 2530s . They are suppose to be suited to a 2.8L stroker kit. Anyway, they are going to be matched with high lift 272 cams. From my guess after seeing them, it looks like they are a hydbrid of 2835 & 2530 turbos:

2835 compressor wheel
2530 turbine wheel

]

That would completely rock the place! I have spoken to a mechanic over here about the GT-SS and GT-RS. It appears that the GT-RS is even bigger than the 2450 and is capable of churning out more power than the 2540. But as it is the newest of the GT series, it spools up as fast as, if not faster, than the 2540. I am getting a photocopy of the specs from him soon. Will post them once I get them.

[R34 GTR]

From the HKS Goods Master:

GT2540 - 350ps
GT2540R - 370ps
GT-RS - 400ps

So it looks like these RS's will make more power and spin up quicker have a smaller turbine side!

[SkylineUSA]

Vincent,

It sounds like you are well on your way of having a very powerful beast.

I was at Option the other week, and they were building a GT-RS engine in a Silver R33 GTR. All I can say is you might want to invest in a parachute

The top end power is going to be awesome, but I am not sure about the lower rpm power? When you get her done, please post what you think of the whole marriage of the parts and its ability to produce a broad power band.

[R33]

Ok. Here's the deal:

Model Inlet wheel size Wheel trim size AR (comp) AR (ex) Power
GTSS 46.6mm 60.1mm 0.60 0.64 280ps
2510 47.7 60.1 0.60 0.64 300
2530 47.7 60.1 0.60 0.64 320
2540 51.7 76.2 0.60 0.64 350
GTRS 51.2 76.2 0.50 0.64 400

That's it.

[R34 GTR]

Originally Posted by SkylineUSA

Vincent,

It sounds like you are well on your way of having a very powerful beast.

I was at Option the other week, and they were building a GT-RS engine in a Silver R33 GTR. All I can say is you might want to invest in a parachute

The top end power is going to be awesome, but I am not sure about the lower rpm power? When you get her done, please post what you think of the whole marriage of the parts and its ability to produce a broad power band.

Tony

No problem, will report once the car is finished and 'run in'.
Its just a matter of time when its put back together. The only weakness now is the gearbox. The synchros are a bit crunchy specially going into 3rd.

btw - My tuner says because its a JUN engine and they supplied the new block, they have done some sort of treatment to the bores of the cylinder and using JUN pistons, there's really no need for running the engine in!! I'm not too sure about this so I'll take it easy for the first 1K miles or so to be on the safe side!

[SkylineUSA]

Originally Posted by R34 GTR

Tony

No problem, will report once the car is finished and 'run in'.
Its just a matter of time when its put back together. The only weakness now is the gearbox. The synchros are a bit crunchy specially going into 3rd.

btw - My tuner says because its a JUN engine and they supplied the new block, they have done some sort of treatment to the bores of the cylinder and using JUN pistons, there's really no need for running the engine in!! I'm not too sure about this so I'll take it easy for the first 1K miles or so to be on the safe side!

Vincent,

Yep, I would do the same thing.

R33,

Good info, thanks.

[Derby]

Can some one explain to me how the AR relates to power/spooling/efficiency?

Does HKS use the Garrett GT series as basis to tune.
The GT series preforms well enough as far as i've seen

Derby

[SkylineUSA]

I pulled this off of www.turbomustangs.com this is the best turbo site on the net, point blank. A bunch of very smart guys willing to type, and help.

Go there, you will not be dissapointed.

A/R is mearly a mathematical calculation!! It has more to do with RPM relationships for a given application than anything else.

The larger the A/R the more time it will take a given compressor wheel to create pressure.(in the case of the compressor) Or how long it will take a given volume of exhaust gasses to generate a certain amount of pressure or kenetic energy on the turbine wheel to achieve a certain RPM. (in otherwords spool-up time when putting both together)

The smaller the A/R the faster the compressor wheel can generate pressure in the compressor housing and the faster a given amount of exhaust gasses can generate a certain pressure to drive the turbine wheel to begine spinning the compressor to make possitive manifold pressure.

Now, Yes A/R ratios have an impact on HP potential. Simply by deciding where in an RPM range the engine will generate boost and reach optimal airflow.

For example, you have a given compressor wheel and A/R Compressor housing, lets use and example of a T64E. This turbo has a compressor wheel that roughly measures 2.5" Inducer, 3.28" Exducer and has a E housing with a .60 A/R. We then have a turbine side consisting of a P-trim wheel and a .69 A/R turbine housing. This turbo on a given 302 will generate say 9psi by 3,000RPM. It will them make say 450RWHP at about 4,800-5,200RPM.

We then replace the turbine side housing with a .81 A/R. It would then reach full boost at about 3,200-3,300RPM and make a HP peak in the 5,300-5,500RPm range at about 475HP.

Ok, so now lets take the same turbo, add a Q-trim wheel in the .81A/R housing. It will spool up at about 3,400-3,600RPM and generate about an additional 10-20HP at about the same RPM, maybe a tad higher.

So you can see A/R has an impact on power production but more importantly it mearly determines the RPM range in which a given set of wheels will operate on a particular application.

More important to flow is Compressor and Turbine wheel SIZE. The physical size of the wheel has a huge impact on flow capability. The larger the wheel, the more flow.

For example, we will use a T04 with a E .60A/R compressor housing. Both with a .69A/R turbine and P-trim wheel. One will have a 57trim wheel the other the aforementioned T64E which uses a T66 wheel. What would be the difference in these turbos? How would they perform comparitively on a 302?

I think pretty much everyone will agree the 57trim will have a tad better esponse (less inertia in the smaller wheel) and offer much less flow potential.

My point is, before buying a turbo of A/R this, A/R that, have who ever it is that is selling it measure the wheels. That is just about the most critical aspects of turbo sizing.

[SkylineUSA]

Derby,
I know you know this, but for some of the other guys.

http://www.turbomustangs.com/forums/...p?postid=85581

[SkylineUSA]

So basically it has to do with volume, velocity, and wheels size. Bigger the A, less volume/velocity more time it takes to spool. Changes the power band. It all depends on the engine, and where you want the power?

Its a marriage of a bunch of equations, to get it right!

[Derby]

my appreciation is huge.

there are so many things in engine technology that keep me thinking.

Like the backpressure. Everyone knows something but put it all together and you know nothing more then when you started.

But skyline usa...big respect. how is your stang doing?

Derby

BTW http://www.turbomustangs.com/forums/ rules big time.

*why didn't i find that sooner...

[R33]

Sky, excellent info. Actually it all make sense. In short, it's about rpm. If I want peak power at low rpm, go for smaller AR. And vice versa. Of course there are other consideartions, like cam degree n lift etc. But the single most important factor is, IMHO, rpm. I now hv a new equation, which is:

big ASS turbo + short ratio 6 speed seq = really good lap time!

[SkylineUSA]

Derby,

You can spend days there, reading up on some very good info. I am getting ready to sale the Stang. I need money for my project car. Right now I am sorting out the wires. Splicing the two harness together. It takes a while, but it should a one of kind when I get done.

R33,

Yes, RPMs play a huge factor, but like you said there are other considerations.

Are you still running 2540s?

[R33]

Sky, I am still running the 2540s. But I suspect they are damaged in some ways now as I could hear them whistling. On the dyno, the peak power keeps on spiking up and down as the boost spikes as well. And there's always a sec or two before they spool at full steam at some rpms (some hesitation). I have checked the boost controller/actuator etc and they are okay. I think it's the shaft hitting the housing. But the power is still there when it comes.
Anyway, I have purchased a set of 2530s. I will start rebuilding the whole thing sometime this year, probably after the endurance race in August. I want better response around the corners/turns and about the same top end this time. That's why I hv opted for 2530s after some research and your advice as well. I will prolly ditch the 264in 272ex cams as well. I will prolly use a set of low lift 264s this time around. We will see how it goes.

[SkylineUSA]

With my limited knowledge on the subject, it sounds like you are going in the right direction. That would be the way I would go.

PM me, if there are any parts that you are going to sell