Just finished reading up the third and final rotary tech article in Turbo magazine.The third one deals with porting.What was specifically stated was that any kind of porting helped top end but decrassed low end power.
As we all know rotaries lack low end torque.So to me it would seem rather counterproductive to port a rotary unless you race the car proffesionally and at very high speeds.If I am wrong then someone show me the light.
My car has 106,000 on the odometer and im sure sooner or later I will have to get a rebuild.I was thinking of getting a mild streetport but now I think I may stick with the stock porting.For obvious reasons.
What Im looking for is good low to mid range responsiveness and not so much emphasis on the top end.It will be a street car.Heres what im considering.
3mm apex iannati ceramics so I can run say 19 to 20 psi if desired.
Dowel pins in the engine block to counteract the negative effects of heat warpage.
Water jacket modification to increase the cooling of the engine.
And maybe if I have the money some racing beat aluminum housings which are about a third of the weight.Once again for obvious reasons.
Am I forgetting anything else that would make for a really potent engine?
As far as Horsepower figures.Id say I would be more than happy with say 400 to 500 ponies on high boost and maybe low to mid 300s on conservative boost for some good ol crusing.

 

Ok first off, if you "would be more than happy with say 400 to 500" I hope you have real deep pockets, because your going to have to spend alot of money, If you want 500 you def will have to go with single turbo.. most likely somthing around a t78, gt35/40, or somthing in the larger single range. Then you need full fuel upgrades, a helluva fuel pump, some 1600cc injectors, move your 850s up to your primaries, new fuel lines and fittings, nice fuel pressure regulator, block off plates, Real big intercooler, full exhaust so I hope you dont have emmissions where you live, new radiator and maybe new oilcoolers to accomidate that large turbo, you are going to need to rebuild your motor, if you plan on 400hp on stock ports your going to be really having to push some major boost to get the power out of it you would get if it was a nice street port. If you want 500hp, your going to definatly get some nice porting, dont forget a power fc, haltech or some sort of engine managment, clutch, flywheel, pulleys, and some kick *** tuning.. basically plan to spend about 20k+ to get to your mark..

 

Why do you need 400-500hp for a street car?

 

that does prove to be a bit too much.I was going to go with these mods.
A blitz fmic
Apex power fc
An upgraded single turbo or some upgraded twins
A downpipe,high flow cat and blitz cat back.
Already have the blitz intake.
The 3mm ceramics
The dowell pin treatment
The water jacket treatment
Upgrade to an aluminum radiator
Underdrive pulleys
Lightened flywheel.
Im looking to make the car faster in the low end to mid range department.Also im looking to make the engine tougher than its is.Less prone to blowing up.Hence the upgraded seals,dowel pins and water jacket treatment.
I want it to be able to handle more boost,and i want it to run cooler.
I think the limiting factor may be the intercooler since ive heard that the blitz and greddy 2 row can handle up to 15 psi.
I wonder what kind of power a rotary makes on 15 psi.
Also I dont think the stock turbos can handle 15 psi.So my next question would be this.Is there a single tubo out there that can handle 15 psi and spools just as fast or faster than the stock twins?

 

I dont know 400 to 500 horsepower sounds nice.Although it may be a bit much.Who knows how much power I can handle.Maybe 350 will be more than enough for me.But as most drivers know.You always hunger for more power.I would hope that all the mods im going to do will yield at least 300 horses.

 

Why don't you just go with a 5 rotor motor and 1500 hp. You can handle it.

 

no such thing jackass.

 

Ok, you are mixing apples and oranges here....


You can get an Apexi single kit:

http://66.216.67.51/product.asp?0=220&1=311&3=467

That would give you basically the same power as upgraded twins with probably less heat. IMO, if you are going to get upgraded twins and run them non-seq, you may as well get the Apexi single instead. If you want upgraded twins but keep them sequential, the BNR Stage 2's have put down around 380rwhp at 15PSI.

As for the porting, IMO, it's a waste to get a "mild" port. I would recommend either getting a large port or no porting at all. The amount of low end you lose from porting will not be signifigant once you open up the airflow and the turbos start spooling a lot faster.

As for the seals, if your rotors need milling, then get 3mm seals. If they don't, just use 2mm.

 

ok let me revise my plan.
I want to run 15 psi so what upgrades will I need.
Most likely a ems.
Not sure if I would need bigger injectors or a more powerfull fuel pump.
An upgraded intercooler.Blitz.
Most likely a rebuild with upgraded apex seals.
I plan on running a downpipe high flow cat and catbakc exhaust system.
Im also thinking that ill have to upgrade to a single turbo.Im looking for a single turbo that spools up as fast or faster than the twins and will handle 15 psi.
Hows that.Nice and simple.

 

Holy crap.I didnt know the bnr's made that much power.
380 horses sounds like more than enough.Hmm I guess it will be a matter of preference.So youre saying that the apex single spools up as fast as the bnrs or as fast as the stock twins?

 

By the way.Thanx for the advice mahjik.

 

I think what Mahjik is saying is that the Apex spool time will be similar to or slightly faster than stock non-sequential twins, which would be slower than the stock twins or the BNR's. I think if you are worried about the small amount of torque you lose from a port job, you will definitaly want to stay sequential. Upgrading to a single or non-sequential setup will probably cost you more low end torque than a streetport.

 

 

Ok heres something that I dont exactly understand about the twin system.The first turbo spools on start up and then at 5500rpms it transitions to the second turbo.
So what happens to the first turbo? does it stop spinning? Since the boost pattern is 10 8 10 I would assume that both turbos do not spool since that would make the patterns more like 10 8 20.Am I right?
So then here lies my great confusion with the system.If the first turbo and the second turbo are exactly the same theres no difference in power out put.So why even have a second turbo unless the second turbo is in fact bigger.That would then make sense since you can use a smaller turbo to build up boost faster and then the boost transfers to the larger turbo resulting in even more power and less lag for the second larger turbo.

 

You can get the stock twin turbos to make that much power. However, it's how efficiently that power comes is where the upgraded turbos play a bigger role.

The Apexi single would probably be closer to the BNR upgraded twins than the stock twins. Probably the quickest spooling turbos you'll find would be the M2 upgraded twins. If you have the money, those would be the set to get. They are expensive but well worth it if you want good but quick power. If I had the money, I would definitely go for the M2 turbos before any other upgraded turbo option (single or twin).

You'll also need some type of fuel upgrade to go along with your system if you want to run 15 PSI (or higher). The easiest fuel modification would be to use 1300cc secondary injectors. They will fit in the stock rail without any modifications.

 

You won't be able to make much over 350 rwhp with a hi-flow cat in there....

There is NO single turbo that hits as low in the rpm band as the stock twins. The Apexi RX6 is the closest and it starts making good power at least 500 rpm later than the twins.

Running 15 psi on stock/upgraded twins, with all the supporting computer and fuel mods and a mild streetport, should get you in the 350+ rwhp range. Some of the guys have made 400 rwhp, but that takes a strong motor, good tuning, and a midpipe for sure -- and 17+ psi.

 

On the stock sequential system; after the 4500rpm transition, both turbos are active.

 

Not quite true. Kwik's FD was running a hi-flo cat with the BNR Stage 2's.

 

good info to know guys.I appreciatte all the help.

 

Damn, he made the 380 w/ the hi-flow? Impressive. Still, typically it will take a midpipe to get close to 400 rwhp.

 

hmm.ok so after 4500rpms does each turbo push 10 psi a piece? or does each turbo push 5 psi a piece?

 

You are mistaking PRESSURE with FLOW. They are not the same thing. As the rpms increase, the engine sucks more and more air. It becomes more difficult for a small compressor wheel to flow enough air to increase the pressure to 10 psi (or whatever). Therefore, both turbos work together to achieve enough flow to pressurize the intake air to 10 psi.

 

aha.ok I think im starting to understand it a little better now.Basically a twin turbo system acts like a small turbo and a large turbo at the same time.Quicker spooling because of the smaller turbine and when required the second turbo basically doubles the flow.Which is why huge turbos generate big power in the top end.So the twins act like a big turbo in the top end.Correct?

 

i just finished checking up on the m2 ball bearing twins.
I take it that the stock twins dont use ball bearing cartriges.Does anyone know whether m2 uses new turbos and then puts the bb cartriges in or if they use your old twins.They also dont specify how much boost those puppies can handle.

 

The M2 set uses new Garrett GT30 turbos on a stock manifold. You send in your entire stock setup as a core.