zyounker

Ok, i have gone off the deep end. I am having my motor with 0 miles rebuilt with a full bridge port.. What i need help doing is finding a good turbo and manifold to match it.

This will be on a S5 13BT block.


I am thinking T66 or maybe a T51-R SPL.

Anyone know what type of specs i should be looking at with these turbos? What manifold would be good for the turbos? I know with the T66 i can use the HKS cast manifold with a spacer, but i rather go divided and SS tube.

Anyone know if that OBX muffler will work with a T66 on a 13BT? i guess i could get that and make a spacer.


Any other turbo suggestions are welcome.


Thanks,
-Zach

Mercury

I really like this bad boy...

https://www.rx7club.com/forum/showth...highlight=gt42

zyounker

That might be a little larger then i am looking for.

Although maybe the GT35/42 would be a good option.


Thanks,
-Zach

zyounker

scratch that, the GT35/42 would have way to restrictive turbine.. (Thought about it for a second)


-Zach

zyounker

hmm, the T51R SPL only goes up to a 1.0 A/R it looks like.. I would think that is a little small..

TYSON

UUhm, If sokudo makes 650 RWHP and Scoot makes 710 PS with this turbo, what exactly are YOUR goals?

zyounker

Not worried about HP acutally. I am just trying to find a turbo that best suits the powerband.. 1.0 i would think a little small for a bridge. But I guess the trim would really be what mattered.


-Zach

zyounker

Ok, looking at the T66 compressor map, i think i want to go that way.

So it will either be a plain T66 or maybe a GT66bb from innovative, assuming i can afford it


What A/R would you guys recommend for a T66 on a mild bridge 13BT? what if i go GT66bb? Any good manifolds out there that are affordable?



Thanks,
-Zach

Bridgeported

Anyone of the popular large singles (T78, T51, T66, GT40, T04S, T72, etc) should work well for you as long as you get it in the proper size. If I had to choose though I would probably go with one of the bigger ones like a T72.
A 1.15 a/r would be best for a birdgeported 13B - 1.00 is getting too small in my opinion but could still be made to work well. With a 1.00 a/r the turbo MAY begin dying down when you get up into the high revs (since your redline should be at 9,000pm - or more depending on tuning)

With one of the above turbochargers boost in the 20-25 psi range you should be able to make 580-680 rwhp!

zyounker

Ok, you are right.. I just did a crap load of multiplying


Looks like T76 would be pretty AWSOME on a bridge.


I will post up some of my flow # later.. make sure i am right


Thanks,
-Zach

sokudo

i am running 51 BB kai on full bridge. the a/r is not that small. with the exaust flow of a bridge you get very good response for it being such a large turbo. the kai and spl both have same a/r but spl has bigger compressor good for 800 + hp

680RWHP12A

i have a bridge, with a t72, work great,,,, also it has a q trim, with a .81housing on a 12a... ive been told the .81 is too small but it made good power!!!

check out the dyno sheet@www.rotaryshack.com/dyno

crispeed

Most of the highest horsepower rotaries that I know of run a .81 to 1.0 turbine housing. My buddy is running a .96 and making over 800 RWHP without nitrous.
In my opinion the turbine wheel trim has more of an effect on power than the turbine housing. The turbine housing trim should be selected to suit the rpm and power band needed.

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

HWO

Yeah there was a good thread about exhuast housing size/ wheel trim for a bridgey about 2 months ago i suppose it would have been, guys found that ever a 1.5A/R P trim was creating too much back pressure, so a Q trim was the only way to go to get the exhaust flowing sufficiently to make the power the motor should have been.

Cheers
Shane

zyounker

Ok, the compressor map on the T76 looks almost ideal for a bridge port. But i am worried i will have trouble spooling the turbo. No i don't want to use nitrous to spool it.

And since you guys seem to think a Q trim 1.0 turbine would be good, I will take your word for it.

So the T51 KIA is in.. I think the SPL is a little larger then i am looking for.



So anyone have a compressor map for the T51 KIA or is that one they wont release?




Thanks for the input so far,
-Zach

crispeed

The size of the compressor you're going to be using is dependant on intended use. How much boost you planned on running?

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

680RWHP12A

what kind of porting do you have??? what gear ratio do you have??? goal hp????13B i assume

zyounker

Yes, i know this.. But for a pressure ratio of 2.0-2.4 & for rpms of 7000-9000 it is within 70-76% efficiancy. Which is about as good as you can get. I am just worried i will have trouble spooling a T76 with a 13B bridge port.


-Zach

crispeed

At that low boost pressure you should not be running a T-76 in my opinion. A T-66 or T-70 is better suited at that pressure ratio. You're not going to make any more power with the larger turbo than you will with the smaller ones at that boost.

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

zyounker

Well, i would like to stick to around ~20psi just cause of the gas i will run. I will be running 118 octane gas on the street daily. but it will be ethonal. So i will be running very large injectors.

My company makes E85 so i can pick up barrels very cheap. and this car does not need to run, i have a reliable daily driver.

Ok, now on to the problem.. the way i figured the math it will flow ~70-74lbs at 2.4 pressure ratio & 9K rpms.

on a T70 compressor, that is almost off the map.



So is something wrong with my math or what. The only thing that might have been a problem with it is i doubled the displacement, cause it was a rotary.


Maybe that is what is wrong. Anyone?



Thanks,
- Zach

crispeed

If you can flow 74lbs at 2.4 pressure ratio on a 13B then you'll should be making 740 to 750hp at 20 psi!
A more realistic goal on a BP 13 turbo motor at 20spi should be 550 to 575hp which would be around 55 to 60lbs.

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

crispeed

Depending on HP goals even the Q-trim is too small!

crispeed

zyounker

ok, so what is wrong with my math?

D=Displacement
R=RPM
VE=Volumetric Efficiancy
PR=Pressure Ratio
E = elevation (1728)

(D*R*0.5*VE*PR/E)*0.069

Would the displacement in this equation be 79.788 or 159.576? I know the actual displacement is 79.788 but since it is a rotary don't you double it?

Ok, RPM we will solve for 9K.

VE we will say 100% because a BP should be over 100%.


PR, we will solve for is 2.4 which is about 20.3 PSI.

79.788 * 9000 = 718092
718092 * 0.5 = 359046
359046 * 1 = 359046
359046 * 2.4 = 861710.4
861710.4 / 1728 = 498.675

So the engine flows 498.675CFM

498.675 * 0.069 = 34.408/lbs a minute.


and if i solve the same for the displacement of 159.576 it would flow 997.35CFM or 68.817



So what am i screwing up? cause you are thinking it should flow ~50-60lbs/min


Thanks,
-Zach

FatalFD

Has anyone ever heard of anyone running a turbonetics y2k on a bridgeported 13b. What results did they get