BLUE TII

iTrader: (9)

See pronounced "knee" in the HA shock dyno when set to stiff? That is digressive damping that is used to control body roll, have more response on turn in or make the car drift easier (depending on application).

You don't want too much of that on the rear of a high power car as it will interfere with your ability to transfer weight to the rear tires on acceleration for traction.

renkenkyo

iTrader: (6)

I think the car is currently set with 10 kg front / 8 kg rear for springs. I'm using the hard setting on the front and soft on the rear. This probably isn't optimal though as I haven't really played with the settings all that much. Part of the reason that I'm looking at the RE-A spec quantums is that it's what they run on their track cars and it seems that having been fully adjusted for our cars it takes alot of the guess work out. The biggest problem is that they are set up at 18 kg front / 20 kg rear which seems like to would not do well on tracks with a really rough surface not to mention any street driving.

As far as the EFR's go, does anyone have a compressor map comparision to a GTX35R?

ScorpionT

iTrader: (3)

GTX35R



8374 - comparable compressor to GTX35R



7064 - EFR I recommend

renkenkyo

iTrader: (6)

Seems like the peak efficiency numbers for the EFR are worse but they have a much broader compression map. Not sure if I'm reading those graphs correctly. The 7064 EFR seems to be sized closer to what I'm looking for. Anyone on the boards try one of these out yet?

ScorpionT

iTrader: (3)

Exactly. You read them correctly.

I recommended the 7064 for just that reason, it seems to be a great fit for your goals. Its efficient, quick spooling, and has two divided housings to choose from.

Jobro

iTrader: (2)

Both of the EFR compressor maps are a **** poor match to the flow vs. pressure that the 12A or 13B will actually achieve.

Look at what flow and efficiency you get at say 2.0PR and say 45lb/min?

These turbos are not Rotary Engine application specific. They are designed for engines with **** all airflow at low pressure ratios and **** all exhaust energy to drive the turbine with.

What you want is to support 60lb/min airflow with the best efficiency available at a maximum Boost pressure of about 17psi. Its ok if increasing the pressure higher makes efficiency or flow better but you really need to support 60lb/min @ about 1.2BAR / 2.2PR.

Spend all the money in the world but these turbos seem to be optimised for using 40psi and a puny engine.

Look at the 100000RPM compressor wheel speed line of the GTX-3582R compressor map. It intersects the 70% compressor efficiency island at ~2.25PR and ~65lb/min.

At lower RPM you will be at a higher efficiency point. Based off the dynos I've seen you are pretty close to the peak efficiency of the map during the whole 2000-5000rpm band.

Now squander over ate the EFR 83mm exducer compressor map.

If we fix the comparision at 70% efficiency and ~2.25PR. Look at the airflow you can achieve for the same operating conditions. 57lb/min.

Also look at the trend of what will happen as you rev past that point where you would hypothetically get 65lb/min @ 2.25PR. The EFR compressor map efficiency is falling at a much more rapid rate than the GTX compressor map.

I don't want to know what has to be wrong inside your brain to think the EFR 83mm compressor wheel will work better on a rotary engine.

Further to this point if you look at the trend of what happens as you go smaller in the EFR lineup that is the turbos below the 83mm exducer such as the 76mm and the 70mm the picture is even worse. There is no capability to support rotary engine airflow at typical rotary engine operation conditions...

End of story.

Sesshoumaru

iTrader: (1)

He makes a good point and you have to consider it based off what you really are going to run.

Most people do not run that high pr unless running AI/Race gas etc....

Most people, and I believe in yours case, will not benefit from this and cannot capitalize on these new turbos to the maxinum extent (the billet on the 35 will give you a bit better vs standard)

To give a contrast -

This is an old Turbonetics 62-1 and is what i would call a "low pressure" turbo.

Notice at what PR it give max flow - 2 pr .... 60lbs
even the standard GT3585 needs 2.5 pr to achieve it's max of around 60lbs

I have ran this turbo for years and really have hard time for my power goals and PR, finding a good replacement (very similar to the GT35 but with a p trim wheel).

I've spent alot of time oogle'n over the new turbos and fancy tech but in all honestly it's mild improvements vs money because i really dont' want to run over 16-19psi.

If i had alot of money to throw for min gain I would get one of these new turbos (for a BW i would give up the drop in compressor performance for that fancy turbine wheel and the new garretts just flow more than the old turbos).

The garrett maps are not as bad as the BW's for lower PR applications.

There are alot of factors when condsidering what works best - the BW have larger turbines and SS housings with integrated BOV so that might offset some factors when you choose what to run.

no silver bullet.

renkenkyo

iTrader: (6)

That's alot of good info . Based on using that turbo calculator, I know I want to get the initial line going up the high efficiency portion of the graph and then tapering over to the right edge. Using the calculator a GT2871 is the best mate for my car. Any suggestions from you? I'm looking at about 360 bhp or 300 rwhp

How about something like a Sean (A-spec) was suggesting, 58/65 using a .82 turbine housing?

Jobro

iTrader: (2)

This car apparently had a GT2871R on it at one stage

http://www.youtube.com/watch?v=jUyCLVVF-bo

I believe the mentality with the small turbo there was the 34mm restrictor plate required to race in the class with a turbo motor.


You really need a 55mm turbine exducer + 1.0 A/R housing, or a 62mm turbine exducer with an AR between 0.80A/R and 1.0 A/R to make your goal.

If you were going to go for a turbo with a 65mm turbine exducer (p-trim) and a 0.7 or 0.84 then you are probably better off with a 62mm turbine exducer and a 1.0 housing.

And if you were to get a 0.8 housing on a 62mm turbine, you are possibly better off with a 1.0 housing on a 55mm turbine wheel.

If you compare all the Garrett turbine maps available for similar size wheels and turbos you will see there is a line where a logical step does not translate to more flow.

A-Spec Tuning

This is what you would think in most cases, having a larger A/r with a smaller exducer will not help for better response or power in all cases. Actually when running a non BB CHRA P-trim wheel here on a divided .84 it outperformed the BB CHRA 62mm GTwheel on a 1.06 T4. From a standstill it had better response, between shifts it didn't fall out nearly as much, and it lost nothing up top as far as power. It didn't have the crispness of the BB unit ie BB GT CHRA's tend to explode into boost rather than just come on smoothly but that was simply a matter of BB versus non BB. We also did this same test on a older 62mm based 500R and got the same exact results. We also did this on diesel testing in a bit larger frames as well. What is more volume going to get you if you can't get it out of the exit any faster? I'm not saying your wrong, just saying it depends.

I wouldn't run smaller than a 62mm turbine wheel on a car that will see RPM's, and the abuse of track temps. Your asking for high exhaust temperatures and thermal wear issues.

Sesshoumaru

iTrader: (1)

That sounds similar to what I would love to run with a GTX3076 on a p-trim wheel (57/65 with a .84 divided)

I have a .84 housing and the GTX turbos don't come with one anyway so it would be a wheel swap.

It'll move 50lbs at 15psi (~380 rwhp)

I've toiled over this long and hard

I personally think it would be a killer setup - Sean obviously knows his ****.

I run a non-street port so i think it would be a good fit.

My 62-1 is essentially a 62/65 with a .84 divided (P trim).

Sesshoumaru

iTrader: (1)

Summed up -

The PTE 5865 with .84 divided is a very good choice

Jobro

iTrader: (2)

Yeah sure. I've used a 0.84 split oldschool journal p-trim on a piston motor and noticed that the onset of boost was much nicer than the T04Z.

T04Z would basically explode at 4000rpm in the car I was in. T04S /.84 would nicely com onto boost woo I'm accelerating hard with no uncontrollable wheel-spin.

You can't get it out the exit any faster but it has more of a chance to cool and damp the impulse of the exhaust gas entering the turbine housing when the housing is bigger.

My feeling is that the 0.84 journal p-trim will outperform a 62mm GT wheel in a 1.06A/R housing primarily because all the journal p-trim wheels I've had in my hands have a heavy backcut on them that started at the production line.

If you take particular note of the p-trim turbine flow map that is available it is for a T04Z turbine wheel that has full blades like on the stock S5 hitachi.

Now take a look at the p-trim in a T04S, half the blade is missing. Of course its slower onto boost and flows better at 7000rpm. What you can't see is how much you loose in efficiency. You might be trading away 5% turbine wheel efficiency that could have been harvested to get the car onto boost.

A-Spec Tuning

These were unclipped wheels. We also tried clipping wheels in three different ways. One is the standard way you would see on say a HKS TO4R "Back cut" wheel, clipped the full length. The others were done a bit differently not fully going from the shaft to tips of the exducer. But clipped roughly half way down the fin to the tips of the exducer at different degree's, I can't remember what they where as it was years ago but I want to say 10 degree and 15 degrees. The fins almost looked like diamond shapes. You'll see clips done like this from some manufacturers, IHI comes to mind. We did this to compare how much we lost and gained. I can tell you the response lost was nothing and power gain was marginal at boost considered by most to be what they would run on pump gas 15-20psi.

renkenkyo

iTrader: (6)

That's a great information guys. Have any of you heard of Comp Turbo? They are located in southern california and the turner I'm currently using (FSR motorsports) recommends them because they have the fastest spooling turbo due to their ceramic triple ball bearing and oiless designs.

Thoughts?