AI: Pay NOW or PAY 3X+ LATER
03-24-09, 09:43 PM
#1
Racing Rotary Since 1983
Thread Starter
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AI: Pay NOW or PAY 3X+ LATER
i just answered a PM from someone wanting my advice as to whether he should spend $300 on a basic AI system or alot more ($700-1000)
the answer, of course, depends on usage. if your FD sees light duty and is making 300 rwhp the chances are an inexpensive water, pumpspeed/nozzle system will work fine. it will steam clean the carbon off your rotors, free your apex and side seal grooves while cooling your motor. case closed.
"basic" systems in the $300 range:
AEM (new to the space)
Coolingmist (has been a good friend to the FD)
Devil's Own (funny name, interesting new prods)
SnowPerformance (heavyweight in the space)
as we get into 350-400 rwhp, which is easier to do these days, things get a bit more complex and expensive.
with good reason.
a 400 rwhp FD is considered by many to be conservatively tuned! after all we hear lots of 500 and 600 numbers these days so 400 must be cool right?
wrong.
let's do a quick review from a previous thread of mine... the numbers are important enough to reconsider.
400 rwhp is 460 flywheel hp.
460/159 cubic inches is 2.89 hp per cubic inch!!!
the state of the art supercharged intercooled dry sumped titanium rodded $110,000 ZR1 Corvette makes 638 from 378 cubic inches or 1.68 hp per cubic inch. most of the $40,000 dollar margin over the ZO6 is in the engine BTW.
how about the AMG Twin-Turbo'd Mercedes Black Series SL65? $304,000. titanium everything that isn't carbon fiber. 661 flywheel hp from 365 cubic inches... just about as much as you can get from a high tech street racer... 1.81 hp per cubic inch. (the output per cubic inch diff is primarily the diff between a two valve and four valve engine)
so to review:
our conservative 400 rwhp FD makes 2.89 hp/cu inch
the ZR1 makes 1.68 hp/cu inch
the Twin Turbo AMG Merc makes 1.81
still think your measly 400 rwhp FD is conservatively tuned?
Combustion Chamber Pressure (CCP) and Heat rise with hp per cubic inch.
what do you think the CCP is like at 2.89 hp/cu inch?
add in the fact that the rotary has a less durable combustion seal architecture than a piston engine and then consider what you are going to do to protect your motor.
and you can protect the turbo'd 400+ hp rotary.
you do it w the proper application of Auxiliary Injection.
the key word is "proper."
all of the above basic systems employ a pump and nozzle system. a controller varies voltage to the pump to effect changes in delivery rate. perhaps the pump starts out at 100 psi and tops out at 150 to 250 psi.
that sounds good on paper...
looked at more closely we find something a bit different.
first off let's take a look at how your engine uses fuel.
in this modern era where fuel injectors have replaced carbs we talk in Milliseconds (thousandths of a second) of ontime. ontime is the amount of time the fuel injector is open.
the FD factory fuel map varies from about 7 Ms at zero boost zero vacuum to around 24 Ms at 6000 RPM near peak boost.
since fuel pressure net of boost is constant it is apparent that fuel delivery increases by a factor of more than 3 from boost onset.
but it isn't that simple. peak fuel delivery decreases 28% from 6000 to 8000 (from 24 Ms to 17 Ms) due to recession from peak torque. this happens while boost remains constant!
back to the basic AI system...
delivery changes are governed by pumpspeed. let's make an incorrect assumption that the pump can keep up with the engine. let's assume our pump can make between 100 and 200 psi. that seems pretty good... we can double our injectant output.
nope.
the rate of flow varies w the square root of the pressure change.
100 to 200... a 100% change in pressure. square root of 100 is.... 10.
double the pressure. get 10% more flow. hmmmm.
that is of course if the pump can keep up. probably in 4th gear. probably not in 2nd gear.
o k, so it may not be a perfect world... but Rich and many others are doing just fine w their basic AI systems.
the reason they work o k is that they are using water. water isn't a fuel. water COOLS BIGTIME. it also CLEANS BIGTIME. so get the right nozzle size w the basic kit, something around 300-400 CC/Minute, realise you are really spraying a constant delivery no matter how you adjust your controller, and you will get cool and clean.
Cool and Clean on the street and for drag racing.
The basic kit may work well for most of us.
OTOH, if you place your FD onto the kind of track for which it was designed (a road racing circuit) you will want to look elsewhere than the basic architecture.
Unlike drag racing where generally the pedal is on the metal, road racing requires a lot of throttle modulation under boost.
Modulate the throttle and the boost immediately varies. The basic system’s drawbacks become immediately apparent:
Reliance on pump speed to accurately vary output doesn’t work because:
Pump mass creates slow reaction time
Since it is the square root of pressure change there is little variability
Pump not controlled with RPM, only boost. (i e, same delivery at ALL RPMs if boost constant while gasoline map varies 28%)
As long as you are happy using water it is possible to get along on a road course at modest power levels.
Some want more than to just get along. The FD, properly fixtured and tuned is a true SUPERCAR performance wise.
Currently most Fds on track are garnering more than their share of hardware running below the 400 rwhp level.
Imagine the FD on a road course with 550 rwhp. Truly, the only people capable of appreciating how fast the car would be would be those already on track w 400.
A majority of those in the know would wager the engine would come back in pieces.
Not me.
Enter alcohol and the 21st century AI system.
Alcohol is Magic when combined w the turbo’d rotary.
My friend Jose LeDuc has been making 1000 rwhp w his 13B-REW for a couple of years. He thinks there is a significant amount of additional hp in the motor. You would be shocked at how reliable his motors are.
Jose runs 100% alcohol (methanol) with no intercooler and the engine is 100% happy.
I have run between 1200 and 1400 CC/Min of methanol on my FD for 2 seasons. Knock between 6000 and 8200 in 4th gear on the dyno averages 9! Preturbo EGTs top out at 1577 F.
498 rhwp SAE at 20 psi with stock port timing.
I will be back on the dyno in a couple of weeks w an engine with my own port design featuring another 20 degrees of duration and a few other tricks as well as some uprated actuators that will allow me to tune to my 27 psi target. I expect 630 rwhp with the same under the carpet knock metrics. i expect to run my car ontrack at the 550 power level.
All on 93 octane pump gas and methanol. no racegas.
If you plan to use alcohol you really need one of the 21st century AI HD systems.
Offerors are:
Aquamist
Coolingmist
FJO
Each system is a little different but all HD systems make use of the fuel injector rather than a nozzle and pump speed. (the pump just supplies a constant pressure)
Aquamist has designed a module that “sums” the output of our primary and secondary injectors to reach an overall injector duty cycle. It then directs the AI injectors to deliver a parallel amount of AI injectant to the motor. very slick.
BTW, all HD systems work wonderfully with water as well…
Coolingmist employs an injector as well and it can be directed off an X Y grid similar to the OEM base fuel grid.
FJO also employs fuel injectors with a 16 by 16 156 cell grid which allows tuning in each cell.
So the executive summary here is that you have many AI options. The basic kit works very well. The future is evolving towards HD. If you are into making monster power alcohol is the ticket.
The single takeaway is that our motors are in a higher state of stress than we generally understand. That’s why the we see lots of rebuild and transplant threads.
There is a solution… spending $300 to $1000 on the right AI system beats building a succession of motors.
howard coleman
the answer, of course, depends on usage. if your FD sees light duty and is making 300 rwhp the chances are an inexpensive water, pumpspeed/nozzle system will work fine. it will steam clean the carbon off your rotors, free your apex and side seal grooves while cooling your motor. case closed.
"basic" systems in the $300 range:
AEM (new to the space)
Coolingmist (has been a good friend to the FD)
Devil's Own (funny name, interesting new prods)
SnowPerformance (heavyweight in the space)
as we get into 350-400 rwhp, which is easier to do these days, things get a bit more complex and expensive.
with good reason.
a 400 rwhp FD is considered by many to be conservatively tuned! after all we hear lots of 500 and 600 numbers these days so 400 must be cool right?
wrong.
let's do a quick review from a previous thread of mine... the numbers are important enough to reconsider.
400 rwhp is 460 flywheel hp.
460/159 cubic inches is 2.89 hp per cubic inch!!!
the state of the art supercharged intercooled dry sumped titanium rodded $110,000 ZR1 Corvette makes 638 from 378 cubic inches or 1.68 hp per cubic inch. most of the $40,000 dollar margin over the ZO6 is in the engine BTW.
how about the AMG Twin-Turbo'd Mercedes Black Series SL65? $304,000. titanium everything that isn't carbon fiber. 661 flywheel hp from 365 cubic inches... just about as much as you can get from a high tech street racer... 1.81 hp per cubic inch. (the output per cubic inch diff is primarily the diff between a two valve and four valve engine)
so to review:
our conservative 400 rwhp FD makes 2.89 hp/cu inch
the ZR1 makes 1.68 hp/cu inch
the Twin Turbo AMG Merc makes 1.81
still think your measly 400 rwhp FD is conservatively tuned?
Combustion Chamber Pressure (CCP) and Heat rise with hp per cubic inch.
what do you think the CCP is like at 2.89 hp/cu inch?
add in the fact that the rotary has a less durable combustion seal architecture than a piston engine and then consider what you are going to do to protect your motor.
and you can protect the turbo'd 400+ hp rotary.
you do it w the proper application of Auxiliary Injection.
the key word is "proper."
all of the above basic systems employ a pump and nozzle system. a controller varies voltage to the pump to effect changes in delivery rate. perhaps the pump starts out at 100 psi and tops out at 150 to 250 psi.
that sounds good on paper...
looked at more closely we find something a bit different.
first off let's take a look at how your engine uses fuel.
in this modern era where fuel injectors have replaced carbs we talk in Milliseconds (thousandths of a second) of ontime. ontime is the amount of time the fuel injector is open.
the FD factory fuel map varies from about 7 Ms at zero boost zero vacuum to around 24 Ms at 6000 RPM near peak boost.
since fuel pressure net of boost is constant it is apparent that fuel delivery increases by a factor of more than 3 from boost onset.
but it isn't that simple. peak fuel delivery decreases 28% from 6000 to 8000 (from 24 Ms to 17 Ms) due to recession from peak torque. this happens while boost remains constant!
back to the basic AI system...
delivery changes are governed by pumpspeed. let's make an incorrect assumption that the pump can keep up with the engine. let's assume our pump can make between 100 and 200 psi. that seems pretty good... we can double our injectant output.
nope.
the rate of flow varies w the square root of the pressure change.
100 to 200... a 100% change in pressure. square root of 100 is.... 10.
double the pressure. get 10% more flow. hmmmm.
that is of course if the pump can keep up. probably in 4th gear. probably not in 2nd gear.
o k, so it may not be a perfect world... but Rich and many others are doing just fine w their basic AI systems.
the reason they work o k is that they are using water. water isn't a fuel. water COOLS BIGTIME. it also CLEANS BIGTIME. so get the right nozzle size w the basic kit, something around 300-400 CC/Minute, realise you are really spraying a constant delivery no matter how you adjust your controller, and you will get cool and clean.
Cool and Clean on the street and for drag racing.
The basic kit may work well for most of us.
OTOH, if you place your FD onto the kind of track for which it was designed (a road racing circuit) you will want to look elsewhere than the basic architecture.
Unlike drag racing where generally the pedal is on the metal, road racing requires a lot of throttle modulation under boost.
Modulate the throttle and the boost immediately varies. The basic system’s drawbacks become immediately apparent:
Reliance on pump speed to accurately vary output doesn’t work because:
Pump mass creates slow reaction time
Since it is the square root of pressure change there is little variability
Pump not controlled with RPM, only boost. (i e, same delivery at ALL RPMs if boost constant while gasoline map varies 28%)
As long as you are happy using water it is possible to get along on a road course at modest power levels.
Some want more than to just get along. The FD, properly fixtured and tuned is a true SUPERCAR performance wise.
Currently most Fds on track are garnering more than their share of hardware running below the 400 rwhp level.
Imagine the FD on a road course with 550 rwhp. Truly, the only people capable of appreciating how fast the car would be would be those already on track w 400.
A majority of those in the know would wager the engine would come back in pieces.
Not me.
Enter alcohol and the 21st century AI system.
Alcohol is Magic when combined w the turbo’d rotary.
My friend Jose LeDuc has been making 1000 rwhp w his 13B-REW for a couple of years. He thinks there is a significant amount of additional hp in the motor. You would be shocked at how reliable his motors are.
Jose runs 100% alcohol (methanol) with no intercooler and the engine is 100% happy.
I have run between 1200 and 1400 CC/Min of methanol on my FD for 2 seasons. Knock between 6000 and 8200 in 4th gear on the dyno averages 9! Preturbo EGTs top out at 1577 F.
498 rhwp SAE at 20 psi with stock port timing.
I will be back on the dyno in a couple of weeks w an engine with my own port design featuring another 20 degrees of duration and a few other tricks as well as some uprated actuators that will allow me to tune to my 27 psi target. I expect 630 rwhp with the same under the carpet knock metrics. i expect to run my car ontrack at the 550 power level.
All on 93 octane pump gas and methanol. no racegas.
If you plan to use alcohol you really need one of the 21st century AI HD systems.
Offerors are:
Aquamist
Coolingmist
FJO
Each system is a little different but all HD systems make use of the fuel injector rather than a nozzle and pump speed. (the pump just supplies a constant pressure)
Aquamist has designed a module that “sums” the output of our primary and secondary injectors to reach an overall injector duty cycle. It then directs the AI injectors to deliver a parallel amount of AI injectant to the motor. very slick.
BTW, all HD systems work wonderfully with water as well…
Coolingmist employs an injector as well and it can be directed off an X Y grid similar to the OEM base fuel grid.
FJO also employs fuel injectors with a 16 by 16 156 cell grid which allows tuning in each cell.
So the executive summary here is that you have many AI options. The basic kit works very well. The future is evolving towards HD. If you are into making monster power alcohol is the ticket.
The single takeaway is that our motors are in a higher state of stress than we generally understand. That’s why the we see lots of rebuild and transplant threads.
There is a solution… spending $300 to $1000 on the right AI system beats building a succession of motors.
howard coleman
Last edited by Howard Coleman; 03-25-09 at 07:43 PM.
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03-24-09, 11:15 PM
#8
F'n Newbie...
iTrader: (6)
Yup, I'm using the same kit. I'm running my BNRs at 18-19psi all day, every day, and I've had no (engine) problem as of yet.
Even if you happen to run out of your water/meth mix while you're driving (2 liter waterbottle full in the passenger bin FTW!) the motor won't burn out for anything less than 2 min of constant (non-stop) boost while running on empty iirc.
Even if you happen to run out of your water/meth mix while you're driving (2 liter waterbottle full in the passenger bin FTW!) the motor won't burn out for anything less than 2 min of constant (non-stop) boost while running on empty iirc.
03-25-09, 01:18 PM
#12
Bosozoomku
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Great info, Howard! Hopefully the notion that an inexpensive upgrade can have a profound effect on the function of the rotary is hitting home.
This is exactly how I plan on introducing myself and my FD to WI... And it's going to be cheap protection! Will post details when the parts arrive: Pump, nozzle, on at +/- max boost... detonation be gone!
Originally Posted by howard coleman
water COOLS BIGTIME. it also CLEANS BIGTIME. so get the right nozzle size w the basic kit, something around 300-400 CC/Minute, realise you are really spraying a constant delivery no matter how you adjust your controller, and you will get cool and clean.
03-25-09, 01:37 PM
#14
Rotary Enthusiast
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First off i don't have AI, its in the future for me i think once i go single. But for me some questions arise:
IT seems Very very difficult to get the Water/Alcohol Injection to work like it should.
Sounds to me, It's not just down to buying one and putting it in. You need a tuner, and some one with allot of knowledge of these systems to rig it up and properly tune it within your Engine to get the best possible results. It may even be a hindrance or be useless, if not done correctly.
Howard, what steps are involved to tune the HD AI or just the normal AI? Can any tuner do it? You make it sound easy:
1)Buy AI or HD AI
2)Install it
3)Reap the benefits
But allot of people i think would be lost once buying a system, as to how to tune it and where. Any insight into this?
-mark
IT seems Very very difficult to get the Water/Alcohol Injection to work like it should.
Sounds to me, It's not just down to buying one and putting it in. You need a tuner, and some one with allot of knowledge of these systems to rig it up and properly tune it within your Engine to get the best possible results. It may even be a hindrance or be useless, if not done correctly.
Howard, what steps are involved to tune the HD AI or just the normal AI? Can any tuner do it? You make it sound easy:
1)Buy AI or HD AI
2)Install it
3)Reap the benefits
But allot of people i think would be lost once buying a system, as to how to tune it and where. Any insight into this?
-mark
03-25-09, 05:30 PM
#15
First off i don't have AI, its in the future for me i think once i go single. But for me some questions arise:
IT seems Very very difficult to get the Water/Alcohol Injection to work like it should.
Sounds to me, It's not just down to buying one and putting it in. You need a tuner, and some one with allot of knowledge of these systems to rig it up and properly tune it within your Engine to get the best possible results. It may even be a hindrance or be useless, if not done correctly.
Howard, what steps are involved to tune the HD AI or just the normal AI? Can any tuner do it? You make it sound easy:
1)Buy AI or HD AI
2)Install it
3)Reap the benefits
But allot of people i think would be lost once buying a system, as to how to tune it and where. Any insight into this?
-mark
IT seems Very very difficult to get the Water/Alcohol Injection to work like it should.
Sounds to me, It's not just down to buying one and putting it in. You need a tuner, and some one with allot of knowledge of these systems to rig it up and properly tune it within your Engine to get the best possible results. It may even be a hindrance or be useless, if not done correctly.
Howard, what steps are involved to tune the HD AI or just the normal AI? Can any tuner do it? You make it sound easy:
1)Buy AI or HD AI
2)Install it
3)Reap the benefits
But allot of people i think would be lost once buying a system, as to how to tune it and where. Any insight into this?
-mark
The tuning of "HD" AI is what I am most concerned with. For some reason it is just not "clicking" in my head. Where to take fuel (gasoline) out while adding water/meth...etc....etc... Obviously while in boost but other than that useless generality. I am basically
03-25-09, 06:44 PM
#16
rx7 addict
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How often does one need to refill their water/methanol tank? Do you need to use distilled water? I'm thinking this may be a neat alternative to an upgraded IC at least for owners with fairly stock FDs like myself.
03-25-09, 07:11 PM
#17
Racing Rotary Since 1983
Thread Starter
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gordon is exactly correct as to the Aquamist forum. it is one of the two best sites available for info, the other being the alcohol tuning site at Turbobuick.com. the tuning procedures on the buick site are exactly the same as for the rotary... around 200 pages of high value threads.
here's my current FJO tune expressed as a % of injector delivery:
hc
here's my current FJO tune expressed as a % of injector delivery:
hc
Last edited by Howard Coleman; 03-25-09 at 07:13 PM.
03-25-09, 07:28 PM
#18
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Ok call me ignorant if you want. but I have the money and I need some sort of shopping list. I have the Mircotech Lt10s system, single turbo 400hp+, and all the supporting cooling mods except AI. I'm asking if it is possible to help compile a list of exactly what to buy from FJO. I want to get the HD AI system.
03-25-09, 08:02 PM
#19
Gordon, thank you for the great link. I just registered.
Howard, Thank you so much for being so forthcoming with a map. So many are so private with such things. I know you posted it in another AI thread but thought it deserved a second large thank you. I applaud your commitments to providing good, accurate, and knowledgeable information. Most importantly though, the knowledge you provide is REAL and from experience and that speaks VOLUMES..
OK, now it is starting to make a little more sense the more I look at that and study all systems involved. I have so much reading/research to do....
Howard, Thank you so much for being so forthcoming with a map. So many are so private with such things. I know you posted it in another AI thread but thought it deserved a second large thank you. I applaud your commitments to providing good, accurate, and knowledgeable information. Most importantly though, the knowledge you provide is REAL and from experience and that speaks VOLUMES..
OK, now it is starting to make a little more sense the more I look at that and study all systems involved. I have so much reading/research to do....
03-25-09, 08:30 PM
#20
Finally Knows
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To the people wondering about tuning with A/I - You do not need to tune for water. However, you do need to tune for meth. Usually, you will end up taking out *about* 25% fuel in upper RPM ranges in a 450Rwhpish car running 50/50 using a 550cc nozzle.
03-25-09, 08:40 PM
#21
Diamond Cut Seven
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Agree'd. when the single goes in, you can count on an aquamist going in. My question is can you run just water or does it have to be a meth/water mix? The reason I ask is doesn't meth corrode the engine over time?
03-25-09, 09:30 PM
#23
Original Gangster/Rotary!
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I've been injecting windshield wiper fluid into my motor from the stock wiper tank for just about three years now 
https://www.rx7club.com/showthread.p...=aquamist+pics
https://www.rx7club.com/showthread.p...=aquamist+pics
03-25-09, 10:24 PM
#24
I'm doing a "diy budget" HD water injection system, haven't installed it yet as the car needs a clutch but it has Coolingmist's 250psi pump, trunkmount tank, High Speed Valve, dual M2 nozzles and all controlled by a simple boost switch as trigger and Aquamist's RX-7 IDC Summer driving the HSV that will be setup for 15% (per mass) water/fuel ratio.
Both David from Coolingmist and Richard L from Aquamist have provided me with oustanding support and technical advise for this "diy" kit.
Both David from Coolingmist and Richard L from Aquamist have provided me with oustanding support and technical advise for this "diy" kit.
