phinsn98

iTrader: (2)

Howard I might come down just to root you on.

BDC

That means somebody needs to come down here when they're in Texas.

rxsexen

Howard thankyou for your interesting and very informative thread, i will be contacting rice racing because i am here in australia about a water injection set up, i have found that alot of tunners her will only tune upto 14psi because of fear that if you get a bad batch of fuel that it will run lean but with this set up it opens up alot of doors to how much hp you want to produce,reliability and internal condition of the motor once its pulled down...again thank you and keep the dream alive mate all the best..

MakoRacing

iTrader: (12)

Good to see more helpful information added, thanks Howard!

twinturborx7pete

iTrader: (3)

Very interesting thread... I plan on going with the Aspec 500r and running some sort of injection. The intercooler I have already is set up for Alternative Injection. I'm interested to see how your new setup works for you. I'm looking for 450 rwhp reliably.

I guess the only sad thing about these cars is that they don't make them anymore, so putting miles on the car is fun yet frustrating at the same time... but what is a car made for but driving?

_Bahrx7_

iTrader: (8)

Amazing Thread! The rotary community owes all you contributing members big time, especially Howard. Thank you.

I was just curious if anyone had any pics of the inside of their downpipe and if the cleaning effectiveness of AI continued from the inside of the engine through the exhaust too?

Howard Coleman

iTrader: (6)

Much of this post can be found scattered around this board but i thought it would be a good idea to put it all together and add in alternative fuels such as ethanol and methanol.

The rotary is, of course, unique and as such it would be a big mistake to use piston metrics when planning setup.

How unique?

Let's talk airflow:

A piston engine can generally make ten hp for every pound per minute of air, so a 70 pound per minute turbo can make 700 piston hp. As we navigate the web looking at turbos we often see a hp tag... for instance a 73 pound per minute TO4Z/GT500/PT67 is often rated at 730 hp. If you are looking for 730 you'd best look elsewhere because they are talking PISTON lingo.

Should you wish to translate to rotary you'd take the pounds per minute, or the estimated HP number, and divide by 1.3.

73 pounds per minute is 561 ROTARY rwhp.

BTW, that doesn't mean the rotary takes a back seat to the piston engine. While it does take a discount due to lower volumetric efficiency (VE), it makes up for lower VE by being able to flow more air V displacement.

O K, let's get into it starting with airflow and hp.

FDs are all about airfow from turbos.

Most turbos have a compressor map which sets forth maximum airflow in pounds per minute and other metrics such as efficiency and airflow at differing boost levels etc. (see Sean's How To Read a Compressor Map thread sticky in the Single Turbo Section).

This thread is about properly sizing the fuel system(s) so let's just focus on the maximum air as set forth on a commonly used GT3582R compressor map.

Airflow is represented in pounds per minute. The GT35 makes approx 62 pounds per minute max.
Rotaries require 1.92 CFM (cubic feet per minute) to make one rear wheel hp. Transposing pounds per minute to CFM, we multiply by 14.471.

14.471 times 62 = 897 cubic feet per minute.

Now that we have CFM we divide by 1.92 to get rear wheel rotary hp.
897/1.92 = 467 max rotary rwhp.

TO4Z, GT500, PT67 turbos make 73 pounds per minute.
73 X 14.471 = 1056 CFM/1.92 = 550 max rotary rwhp

The GT4294 puts out 85 pounds per minute.
85 X 14.471 = 1230 CFM/1.92 = 641 max rotary rwhp

Now that we have an understanding how to get CFM from pounds per minute and then rw rotary hp let's move on to solving for fuel requirements from air generated.

AFR

Air Fuel Ratio... 10 to 1, 11 to 1, 12 to 1. These ratios are for air and fuel measured in POUNDS.
Back to the GT35r and let’s calculate fuel injector sizing.

I suggest we use a couple of "givens."

"Given" we want to have enough fuel to run 10.0 to 1 AFR if necessary.
"Given" we want to run our fuel injectors at no more than 85% capacity (expressed as duty cycle).

Assuming 62 pounds per minute of air, at a 10 to 1 ratio we need 6.2 pounds per minute of gasoline.

62 pounds air
6.2 pounds gasoline

We wish to limit our fuel injectors to 85% duty so we divide 1 by .85
1/.85 = 1.1764

We now take our adjuster (1.1764) and multiply it times our 6.2 pounds per minute of gasoline.
1.1764 X 6.2 = 7.294 pounds per minute of fuel delivery capacity.

The next step is to convert the pounds of gasoline to gallons. Gasoline weighs 6.35 pounds per gallon.

7.294 pounds / 6.35 = 1.14868 gallons per minute

Off to my favorite "converter" website (http://online.unitconverterpro.com/u...ha/volume.html)...

Select “Gallon” converted to “Cubic Centimeter” (CC) and find that 1.14868 gallons is 4348 CC

So 4348 CC/Min at 85% delivery is 3695 CC/Min net of duty cycle.
That number will produce fuel necessary to service the max air GT35r at a 10 to 1 AFR.

Given the above calculations we can now answer some common FD injector questions…

“If I run my 550s as primaries what do I need as secondaries with my GT35?”
4348 - 1100 = 3248 CC/Min needed in addition to 550 primaries
Run a couple of 1600s and you are fine!

“How about 850 primaries and 1300 secondaries?”
4348 required…
(850 X2) = 1700
(1300 X2) = 2600
Total = 4300… fine.

Moving up to the larger 73 pound per minute turbo... Let’s do it simply by just multiplying by the increase in air delivery V the GT35r..
73/62 = 1.1774
4348 X 1.1774 = 5119 CC/Min

“Will 550s work as primaries?”
5119 - 1100 = 4019 required for secondaries so given our assumptions the 1600s won't work.

“What do I need w 850s as primaries?”
5119 - 1700 = 3419 CC/Min. 1600s will probably be O K, especially considering 1600s generally flow 1680 each.

“How about a GT4294 at 83 pounds per minute?”
83/62 = 1.3387
4348 X 1.3387 = 5820 CC/Min

“What do i need in addition to my 850 primaries?”
5820 - 1700 = 4121 CC/Min

As I understand, the Bosch 1600 injector is no longer being made. There are a few new injectors that have become recently available. I believe there is a Siemans injector that is around 2000+ CC/Min and there is at least one brand of aftermarket injectors that offer increased deliverability w good spray pattern.

Additional injector option info welcomed.

So far, we have been talking gasoline.

We also need to understand two other fuels since either they, or water, must be introduced into the combustion process or we will be destroying our turbo'd rotary in short order.

Fuel, whether gasoline or some derivative of alcohol (ethanol or methanol), is really about BTUs.

A combo of oxygen and BTUs creates energy as in Torque and HP.

BTUs per Gallon

Gasoline (any octane)..................................116,090
Ethanol (alcohol)......................................... .76,330
E85............................................... .................82,293
Methanol (alcohol)......................................... 57,250

Gasoline wins the energy per gallon contest, so why would we want to run methanol or ethanol?

Alcohol delivers immense cooling compared to gasoline. Cooling is expressed as “latent heat.” The bigger the number the higher the cooling capacity. (BTU/Gal)

Gasoline.......................952
Methanol.....................3136................. ..........3.29 times more cooling than gasoline
Ethanol........................2398............... ............2.52 times more cooling than gasoline
E85..............................2181............. ...............2.29 times more cooling than gasoline

The immense cooling provided by alcohol allows boost to be raised without encountering motor destroying knock. Note that methanol delivers 31% more cooling than ethanol which is why methanol is the non gasoline fuel of choice amongst many pro racers.

Real world proof is provided by Jose LeDuc's 13 B-REW (two rotor) 1000+ rear wheel horsepower drag racing RX3. Powered my methanol alone, the 1150+ flywheel horsepower two rotor doesn’t even use an intercooler! The upper intake manifold is freezing to the touch after a 180+ MPH quarter.

An excellent indicator of rotary health is absence of knock. Low knock equals low CCP Low knock equals less calls to your engine builder. Running about 20% methanol with 93 octane pump gas my 507 SAE hp FD shows less than 10 knock at 20 psi! My motor ran in this state of tune for four years and generated it’s highest compression just as I decided to pull and examine it. (Purely out of curiosity) All was well inside thanks to the methanol.

Rotaries generally fail due to warped apex seals (loss of compression), broken apex seals from knock or blown out coolant seals from too much CCP/heat. Alcohol ‘s ability to defeat heat solves the problems.

Another benefit of alcohol is that it’s autoignition point is much higher than gasoline.

gasoline...........................495 F
methanol..........................867 F
ethanol.............................793 F
E85...................................748 F

Methanol ignites at a 75% higher temperature than gasoline. This delivers important benefits should a piece of carbon decide to glow in the motor.

Our 159 cubic inch 2 rotor motors routinely put out 300, 400, 500 rwhp w the help of turbocharging. Corrected to flywheel hp this is 345, 460, 575 flywheel hp and is 2.16, 2.89, and 3.61 hp per cubic inch! These are all stratospheric compared to the $300,000 AMG hotrodded twin turbo SL65 Benz at 1.81 or the $106,000 Corvette ZR1 at 1.69.

That's why it is necessary to use either water or alcohol derivatives to cool our motors at higher output/boost levels. (please see my thread "the Fix" in the 3rd Gen section for the details.)

Let's get back to the details relative to ethanol and methanol so you can properly size your total fuel needs...

BTU content is the key.

We know what we need as far as gasoline to make "X" hp from above. Since gasoline contains 116,090 BTUs and meth is 57,250 BTUs per gallon, if we are to replace, say 20%, of our gasoline w meth we need to replace it on an equal BTU basis.

Back to the GT35r…

3695 (net of 85% duty cycle) CC/Min Max gasoline is .9761 gallons per minute. (thanks converter site).

.9761 gallons times 116,090 BTUs/Gal = 113,315 BTUs.

Let’s assume we want to take our gasoline injector duty cycle from 85% to 70% using methanol.
That’s a drop of 21.1%. We would be removing 21.1% of the BTUs. .

.211 X 113,315 = 23,996. BTUs removed by cutting base fuel (gasoline.)

To replace those BTUs…

One gallon of methanol has 57,250 BTUs.

23,996/57,250 = 42% of a gallon which is 1586 CC/Min. I run two FJO 700 CC/Min injectors to deliver my meth and am around 76% duty cycle on base fuel w 850/1600 injectors at 11.3 AFR.

As you can see it is a pretty simple procedure to dial in fuel combos. Since the alcohols are “fuel” you can run as much or as little as you wish. I suggest around 1000- 1400 CC/Min.

Finally, there’s water, which can also be an important solution to rotary longevity and increased power.

Water of course is not a fuel, and as such adds no energy.
Water’s big attribute is subtractive! It subtracts/removes heat in a big way.

Heat (BTUs) removed per gallon

Gasoline....................952
Ethanol....................2398
Methanol..................3136
Water.......................8087

Three things jump out.

Water, as far as cooling, is king.
Methanol is king of fuels as far as cooling

Gasoline is lame, very lame. This underlines the inefficiency of purposely tuning to a rich AFR with gasoline. A rich gasoline tune carbons up the motor and adds little cooling-wise compared to water or methanol.

In addition, both methanol and water clean carbon from the rotary interior.

The addition of water is not unlimited since it doesn’t burn. FD tuners generally use between 300 and 500 CC/Min to cool CCP. Should you be wishing to raise boost and make more hp, water in the amount of 700+ CC/Min, has been utilized and 700 rw rotary hp has been made using water and pump gas. An uprated ignition system is required as you start using more than 400 CC.


Howard Coleman

no_more_rice

So why can't you tune to, say, high 12s AFR with water injection?

thewird

iTrader: (8)

Howard, my motor had no problem firing 900cc's of water @ 20 PSi running 11.0 AFR with nothing but Twin Power and the R7420 plugs. However, I did notice it would start struggling if it went richer then 10.6 AFR.

thewird

neit_jnf

iTrader: (17)

injector options:

Injector Dynamics high impedance top feed injectors! 2x ID1000 pri and 2x ID2000 secondaries for a total 6000cc of fuel... or since they are linear all the way down to very low duty cycles you could go up to 4x ID2000...

Myself I'd like to try just 2x ID2000's in the primary locations with a simplified fuel system... (stock twins)

M104-AMG

iTrader: (8)

Can these injectors drop-in and replace the stock 850cc secondaries in the stock rails ?

TIA,
:-) neil

thewird

iTrader: (8)

No, their like any other low impedence top-feed injector. You need a rail and run resistors or a low-impedance injector driver.

thewird

neit_jnf

iTrader: (17)

they are top feed high impedance, they need top feed rails but don't need resistors or extra injector drivers which makes them more attractive to our applications. www.injectordynamics.com

Howard Coleman

iTrader: (6)

..................gasoline............Energy...... ...Cooling................Addit'l Cooling BTUs
rwRhp........CC/min...............BTUs.............BTUs........... ............from water AI

217 (stock)....2018...............61,899............50 8................................640........ 300 CC/Min

300...............2790...............85,578....... .....702................................854....... ..400 CC/Min

400...............3720..............114,105....... ....936................................854........ ..400 CC/Min

500...............4650..............142,018....... ...1165..............................1068......... .500 CC/Min

600...............5580..............171,158....... ...1404..............................1495......... 700 CC/Min

fuel requirements assume we can deliver at a 10.0 AFR at 85% max duty cycle.

column 2 is required injector capacity at the stated hp level.

column 3 is the total BTUs of energy required to make the stated rotary hp level.

column 4 is the inherent cooling ability in negative BTUs from the gasoline.

column 4 is the additional cooling from the introduction of water.

column 5 is the amount of water.

note that the water adds approximately 100% additional cooling. this is not small potatoes. remember, we are easily running 10% more gasoline in an effort to cool our motors courtesy of Mazda.

at the 400 hp level 10% of the gasoline cooling BTUs is 94.

the introduction of 400 CC/Min of water adds 854 cooling BTUs!

by running rich and screwing up our motors w carbon we gain 94 BTUs of cooling... by running some water, and removing the excess gas we gain 760 cooling BTUs, defeat engine blowing hi CCP and steamclean our motors.

win win win.

lose the gasoline and it's carbon

cool the CCP by an additional 9X

steam clean the carboned up motor.

hc

BDC

After reading about this, I'm half-tempted to construct and install a simple mechanical WI system that sprays pre-turbo (at a constant amount) and do a before/after on my hot-air setup. I'm curious to see what the EGT's will be different as well as power once I get it all back up and running.

B

no_more_rice

Brian, what are your thoughts on the AFR issue? Should I be able to run 12s AFR with water and 19 psi (pump gas)?

I may have to get you to stop by NC for another tuning session

Dudemaaanownsanrx7

iTrader: (23)

I'm curious how it would work in a hot air setup as well. In a normal setup, the air temps don't change much since the intercooler does most of the work. But with the higher air temps the water might be enough to bring them down to a reasonable level. If nothing else it would probably allow for lower methanol requirements, which would save money and reduce the amount of lbase fuel taken out.

BDC

Like I've read others say (such as rx72c), it seems to me that you need a strong ignition setup. I think it pretty much boils down to that depending upon the amount of water that's being thrown in.

B

BDC

Hey Brent, on my hot-air setup I was able to pull IAT's down to just below ambient at around 1bar of boost when I used 25-30% of fuel as methanol injected upstream in the pipe. On a ~70* day at 24psi, the IAT's never went above 102*F. I'm curious to see what the change would be with a little water (300-400cc/min maybe?) up-front of the turbo. The IAT's weren't a concern for me after getting it all sorted but the fact that the motor broke at some point is. I'm still not sure what broke it. Even though I argued against it, Enzo mentioned once that it could be because the setup is just being run too aggressively. While I'd rather not think that, it could be he is right and it strikes me that water would help if that were the case.

B

WaachBack

iTrader: (21)

That totally depends on how much water. How much ccs are you talking about?

Dudemaaanownsanrx7

iTrader: (23)

Yes you could run leaner with water. Personally I like to let the boost make the power while staying more on the conservative side tuning wise. You'll make more power just by increasing the boost 1 or 2 psi compared to leaning it out more. Cooling is one side of things, the mixture is another, the richer you go the harder it is to ignite, If it becomes harder for the plug to ignite the mixture, you can also be sure it's harder for a hot spot or bad fuel to pre-ignite. When you start leaning it out, you'll give up some of this safety margin. Another advantage to running more conservative, is if you stop spraying for any reason at all, you're engine has better odds of surviving. While a few people have dabbled in running leaner with water, its mainly uncharted waters. Most people don't have the spare cash or time to blow up engines experimenting with things like that. But I personally would like to see it done, and the outcome of it all.
Yes, the required strength of the ignition system is largely dependent on how much water is being run, and how rich the mixture is. As the mixture is leaned out it becomes easier to ignite excess water mixtures.

It is quite possible. It's so hard to look at an engine and know exactly what was going on inside to make it break. No CSI computer generated recaps of what went on. In any case water sure wouldn't hurt things. It does a very good job at killing knock even when injecting lower amounts. Water does most it's work inside the engine, whereas I think Alcohol shines at really lowering the air temps. As I recall you weren't monitoring knock, except by ear... might do well to get a knock sensor and see where you're at in different situations.

thewird

iTrader: (8)

Ah, I must be blind, you would still need a top-feed rail.

thewird

MStempted

Lots of good information. Thanks!

BDC

Yep, no knock sensor setup here. Haven't ever had one. But, since I'm doing so much experimentation, I'll probably change my mind on that and try and figure something out.

B

Dudemaaanownsanrx7

iTrader: (23)

Yeah my knock sensor is hit and miss on working. Fortunately it was working when i tuned for the big boost so when it stops working i dont worry about it.