flamethrower13b

Which turbo spools faster and hits 20lbs of boost faster? 60-1 AR.70 compressor and p trim exhaust wheel in a on center .69 AR hot side. Or 67-1 compressor wheel and p trim exhaust wheel in a on center .69 AR hot side. Both have 3inch inlets and 3inch 4 bolt dump tubes. Anyone?

Aaron Cake

iTrader: (1)

On center turbine housings suck.

And .69 is way, way, way too small for any rotary.

But clearly, all things being equal the larger compressor will spool slower.

flamethrower13b

Why do on center turbo housings suck? Whats the advantage to a tangetial housing and how hard would it be to convert mine over?

flamethrower13b

I realize you would gain more top end going to a 1.0 or 1.16 AR hot side or exhaust housing but what about lag? I doesn't matter if my motor has a 30 or even 70 more horsepower and 8000 RPM if my turbo wont hit boost till 5000 rpm. Any LSI equipped sand rail will blow my doors off for sure! Right now my four seater is keeping up with NA 400 to 500hp LSI and even beating ones that are heavy with all the bells and whistles on them. Mostly due to the fact that my car weighs 1600lbs and the turbo spools really fast and hits 20lbs of boost by 3500 RPM and rockets to 8000 RPM. These cars I am racing have about the same horsepower with lots more torque down low but weigh 2500 to 3000 lbs. The awesome turbo response is the main reason the car is so quick out of the whole in first and second gear and makes it much more fun to drive in the dunes.

flamethrower13b

My Dads car had a smaller turbo with same mods to the motor execpt for smaller injectors and it had much more Lag. It is a mid engine two seater about the same weight 1600 lbs same size tires and similar gear ratios but a taller ring and pinion. Anyways his car had the same awesome power from 5000 RPM to 8000 RPM but had much more LAG! IT was a garret T04 E with a smaller compressor and what looked to be smaller exhaust housing but after close inspection its a P trim wheel and .69 AR on center housing. It looks smaller though the 60-1. We just went to a COMP TURBO 67mm compressor and P trim exhaust with a .69 AR on center housing to match my car that has great response. The both have 3inch inlets and outlets. So far its much closer but still not a responsive as my 60-1. I have remapped his Electromotive 17 times and am almost there but need a little more adjustment in the 2000 to 4000 RPM range. I think it still wants to be leaner so I will lower the injector duty cycle a but more in GPO screen.

Do you think a larger hot side would really help?

How much and were in the power band?

Should I drop back down to a 60mm wheel on the compressor?

flamethrower13b

We are running both cars on race gas all the time. Mostly VP 110 purple stuff and sometimes C12 green stuff. We mix it with 6oz of premix 2 stroke oil. I like to run full synthetic Maxima stuff mostly because I have run 2 stroke dirt bike motors through High compression and high RPM torture and have had good luck with it keep the crank and rod bearings lubed and lasting longer. My Dad is old school and loves to use Maxima Castor oil in his mostly I think he likes the smell. We both are tired of paying over 8 dollars a gallon in so cal and are soon going to switch to 91 octane pump gas and go water methanol injection.

Aaron Cake

iTrader: (1)

On center housings hit the wheel at a very shallow angle. You're throwing out a lot of energy.

Anything smaller then .96 is generally too small for a 13B. There are cases where you may want to run something smaller but in most cases, .96 is as small as you want to go. The 13B pushes far more air then a piston engine of equivalent size. Small hotsides make massive pre-turbine EGTs and backpressure so a load of power is wasted pushing exhaust gasses through a pinhole. A larger hotside will give you better response in this case.

20 PSI by 3500RPM is impressive, but that's an ungodly amount of boost. Uncork the exhaust and you'll probably make a lot more power on a lot less boost.