I
Iamdreaver
Guest
Some people have told me that if i get a hot air car that i shouldnt even worry about an intercooler. they say to go strait to alky, what do you guys think?
Welcome!
By registering with us, you'll be able to discuss, share and private message with other members of our community.
While the alky will lower charge air temps it's not a substitute for an intercooler. On my dad's car it typically lowered temps by about 50 degrees. With the addition of an intercooler charge air temps went from ~300 degrees to ~120 degrees on a cool day.
My calculations - this is all theoretical - say that with water/alky injection you should be able to get close to IC performance, but not quite. But darn good. You just have to inject a lot more than what the IC guys inject.
Here's the hypothesis:
1. You get a temperature drop all the way up to the point where the injected fluid stops evaporating. Once the air is saturated with the fluid, injecting more just leaves it as little droplets, it doesn't turn to vapor.
2. With a hot air car, the air into the intake is so much hotter than an IC car, you can inject a lot more.
3. Making some basic assumptions (ie 20 psi boost, 70% efficient compressor, etc...) you could inject 8 times more water than a comparable IC car. Whereas the IC car would see a 20 deg drop in intake temperature (from an assumed 125F to 105F), the hot air car would see a 170 deg drop, from 310F down to 140 F.
4. I don't know if the available alky systems have the volume range to 8 times more than what the IC cars normally take. Something to ask Chlupsa I guess. If not, then a homebuilt setup might be the ticket to get the flow.
5. I don't know what this volume would do to the combustion process. If you were to squirt that much alky, I think you'd really have to back off the fuel or you'd end up way rich. If you injected straight water, I have no idea what effect that would have.
6. This also assumes that the vaporization (which is what does the cooling) actually takes place. This sort of process should happen fast (and the finer the mist the faster it should happen), but then the air is moving to the cylinders pretty fast too. Which one is faster? Good question... If the vaporization only partly happens, then you wouldn't see as much of a temperature drop. It also means that the measured temperature would depend on the location of the thermocouple; a thermocouple 6 inches downstream of the injection point might read different than a thermocouple at the port.
Hope this stirred some brain cells... I think water or alky injection would be a great fit for a hot air car. But again, it might not get you all the way to intercooled performance. But might be close enough, esp considering the money and hassle factor of each.
John Estill
Here's the hypothesis:
1. You get a temperature drop all the way up to the point where the injected fluid stops evaporating. Once the air is saturated with the fluid, injecting more just leaves it as little droplets, it doesn't turn to vapor.
2. With a hot air car, the air into the intake is so much hotter than an IC car, you can inject a lot more.
3. Making some basic assumptions (ie 20 psi boost, 70% efficient compressor, etc...) you could inject 8 times more water than a comparable IC car. Whereas the IC car would see a 20 deg drop in intake temperature (from an assumed 125F to 105F), the hot air car would see a 170 deg drop, from 310F down to 140 F.
4. I don't know if the available alky systems have the volume range to 8 times more than what the IC cars normally take. Something to ask Chlupsa I guess. If not, then a homebuilt setup might be the ticket to get the flow.
5. I don't know what this volume would do to the combustion process. If you were to squirt that much alky, I think you'd really have to back off the fuel or you'd end up way rich. If you injected straight water, I have no idea what effect that would have.
6. This also assumes that the vaporization (which is what does the cooling) actually takes place. This sort of process should happen fast (and the finer the mist the faster it should happen), but then the air is moving to the cylinders pretty fast too. Which one is faster? Good question... If the vaporization only partly happens, then you wouldn't see as much of a temperature drop. It also means that the measured temperature would depend on the location of the thermocouple; a thermocouple 6 inches downstream of the injection point might read different than a thermocouple at the port.
Hope this stirred some brain cells... I think water or alky injection would be a great fit for a hot air car. But again, it might not get you all the way to intercooled performance. But might be close enough, esp considering the money and hassle factor of each.
John Estill
turbowrenchhead
Drive like you stole it!
- Joined
- May 25, 2001
- Messages
- 854
I put on the smc alky kit and I was able to run 5 more pds of boost on pump gas. I could turn it up more and turn up the boost more but I didn't see much of a differece. It would get bogged down after a certain point. I do like the system and would recommend it. I put in the ford i/c after the alky and the i/c made a much bigger difference then the alky. Just my experciences.
I've seen the effects of both on the charge air guage. The intercooler gave a solid 180 degree drop. This was with a bigger turbo but it was also at 5 extra pounds of boost (turbo and IC were installed at the same time).
The alcohol dropped it another 50 degrees, the air was nearly ambient at 24psi boost.
I'm sure the alcohol would have more of an effect on a non-intercooled car but I doubt it could drop temps 180 degrees.
The alcohol dropped it another 50 degrees, the air was nearly ambient at 24psi boost.
I'm sure the alcohol would have more of an effect on a non-intercooled car but I doubt it could drop temps 180 degrees.
turbowrenchhead
Drive like you stole it!
- Joined
- May 25, 2001
- Messages
- 854
Yes, that is still on a stock turbo. I still have not upgraded yet. The next mod will be a TA-54.
Well, if you ask me, I think that you will see a bigger improvement with an IC than with an alky system. But for the money and the hassle, it's not a clear cut call. Kinda up to the user to decide what he thinks is more cost effective.
I also don't think that you can really max out the existing alky systems. There is some ideal ratio of water/alky to fuel, I can't remember what it is. 1:3 maybe? The alky systems I know of inject a constant amount all the time. So if you have just the right amount at 3000 rpm, you have less than the right amount at 5000 rpm. Get it to where you have the right amount at 5000 rpm, and you have too much at 3000 rpm.
Ideally you'd have an ecm type of thing, controling the water/alky inejction rate vs. air flow, just like the fuel injectors are controlled.
But, to go cheaper, if someone could just figure up a way to scale the injection rate to rpm, I think they would have the better mousetrap, and you'd see a big improvement in alky system performance. The two ways I can think of would be to use either the tach lead under the hood, or to intercept the injector pw signal. Then have that automatically adjust the pump output in some fashion.
I do think that alky on a 20 psi hot air car could drop the temperature by 170F, given the caveats I listed in my post above. I think the limitations of the current systems out there would not let you actually do it though, you'd probably bog the heck out of the engine while trying to get there.
John Estill
I also don't think that you can really max out the existing alky systems. There is some ideal ratio of water/alky to fuel, I can't remember what it is. 1:3 maybe? The alky systems I know of inject a constant amount all the time. So if you have just the right amount at 3000 rpm, you have less than the right amount at 5000 rpm. Get it to where you have the right amount at 5000 rpm, and you have too much at 3000 rpm.
Ideally you'd have an ecm type of thing, controling the water/alky inejction rate vs. air flow, just like the fuel injectors are controlled.
But, to go cheaper, if someone could just figure up a way to scale the injection rate to rpm, I think they would have the better mousetrap, and you'd see a big improvement in alky system performance. The two ways I can think of would be to use either the tach lead under the hood, or to intercept the injector pw signal. Then have that automatically adjust the pump output in some fashion.
I do think that alky on a 20 psi hot air car could drop the temperature by 170F, given the caveats I listed in my post above. I think the limitations of the current systems out there would not let you actually do it though, you'd probably bog the heck out of the engine while trying to get there.
John Estill
The Max Effort will work with the SMC alky kit. It can be set up to back way off on the injector pulsewidth when the alky triggers so instead of using it as an anti-detonate it's being used as a fuel too. If I remember right the car's running somewhere near halfway on alcohol. That's the only way I could see temp drops you mention. Like I said, we had a charge air guage right in front of us and the alky dropped temps ~50 degrees. 170 is a big jump. Maybe nitrous but probably not alky.
We've tried straight alcohol, methanol, and straight water, and we could run the highest boost with a 70-30 mix of alky and water. Water is needed.
We've tried straight alcohol, methanol, and straight water, and we could run the highest boost with a 70-30 mix of alky and water. Water is needed.
If everything goes as planned I'll let you know how alky works on a hot air 4-7. Opening day at the track and I hope to be there with the car ready.............'course the plate reads CNSPRCY.
That's what it's like to try and get this damn hot air to run correctly!
Changes since best time.....V3
SMC, PTE's 2nd try rebuilding my 33 (which had 9 k since new on it the 1st time it had to be rebuilt), and well I guess that's it.
Anyway if you're in MI already swing by Mid MI Motorplex in Stanton...(20 miles North of Ionia) and bring your Turbo Buick good luck charm, rabbits foot, and anything else you can think of to take the vodo off this heap.
Later,
CHRISTIAN
That's what it's like to try and get this damn hot air to run correctly!
Changes since best time.....V3
SMC, PTE's 2nd try rebuilding my 33 (which had 9 k since new on it the 1st time it had to be rebuilt), and well I guess that's it.Anyway if you're in MI already swing by Mid MI Motorplex in Stanton...(20 miles North of Ionia) and bring your Turbo Buick good luck charm, rabbits foot, and anything else you can think of to take the vodo off this heap.
Later,
CHRISTIAN
hey john,i have thought about this a little bit too,i was thinking that a guy could use one of red's volt boosters(they run off a hobbs switch right?)to "boost" the alky pump at a predetermined boost level.so you could set your alky controller to turn on at a lower point at a lower speed,then the booster would kick in farther up the rpm range to compensate for the increased demand.
think it'd work
?later,sean
turbowrenchhead
Drive like you stole it!
- Joined
- May 25, 2001
- Messages
- 854
Aquamist uses an injector pulse to inject alky, I think that is the best way to do it. You need some kind of module to control the amount of alky injector so it corisponds with the fuel. I have to set the turn on point about 9 pds of boost. Because the I have the r's up enough it won't bog the engine. But then sometimes you don't get enough when the when you reach 5000 rpm.
Hmmm, I was just pondering, there is an ideal ratio of water to fuel, something like 1:3, although I forget the exact number. But it does imply that for max performance you would want just as good control over the water injection as you do over the fuel injection.
Anyway, I think there are 2 benefits, one is charge air cooling, the other is whatever effect it has in the combustion process (and I'm not sure exactly what all that is). But what I was wondering, when you get to the desired ratio, is the air saturated with the injection fluid? If not you could still inject more and get more charge cooling, but being over rich in injection fluid I guess you would be losing power. On the other hand, if the air is already saturated at that point, then you are putting enough fluid in to get liquid droplets into the combustion chamber rather than having it all vaporized. When I get some time I think I'll run some numbers and see where it is, I'm curious. Unless someone already knows? Probably a topic for the alky area...
John
Anyway, I think there are 2 benefits, one is charge air cooling, the other is whatever effect it has in the combustion process (and I'm not sure exactly what all that is). But what I was wondering, when you get to the desired ratio, is the air saturated with the injection fluid? If not you could still inject more and get more charge cooling, but being over rich in injection fluid I guess you would be losing power. On the other hand, if the air is already saturated at that point, then you are putting enough fluid in to get liquid droplets into the combustion chamber rather than having it all vaporized. When I get some time I think I'll run some numbers and see where it is, I'm curious. Unless someone already knows? Probably a topic for the alky area...
John
Here's what I've learned. The alky evaporates as soon as it's injected thus cooling the air and it also adds a little octane. The water works it's magic in the combustion chamber. Like I've said a 70-30 mix is what allowed us to run the most boost. Straight alky and straight water will work but not as good as when they're combined in the right mixture.
Another thing to look at is when set on kill at the track on C-16 people don't use the alky because it will slow them down. It's great stuff but still isn't quite as good as pure racegas.
It would be interesting to see what would happen with C-16 and pure alky (since I think the water is what kills a little power over pure racegas at the same boost levels) being used just for cooling.
Another thing to look at is when set on kill at the track on C-16 people don't use the alky because it will slow them down. It's great stuff but still isn't quite as good as pure racegas.
It would be interesting to see what would happen with C-16 and pure alky (since I think the water is what kills a little power over pure racegas at the same boost levels) being used just for cooling.
turbowrenchhead
Drive like you stole it!
- Joined
- May 25, 2001
- Messages
- 854
I ran 110 octane at the track and tried pure denatured alky and I tried a meth and water mix, it doesn't help. It will slow you down if anything when you run racegas.
turbowrenchhead
Drive like you stole it!
- Joined
- May 25, 2001
- Messages
- 854
Sorry about that. It was noon when I called 
Actually, a couple of my friends think it's funny to wake me up early on the weekends. This was the first morning in a long time I didn't get a wakeup call at 6am. In fact I thought you were one of them at first but then I saw sunlight through the window.
